If someone speaks contumely of other beliefs or convictions, this
proves his absolutely deadened position. Darwinian Evolution is the
merely remaining sanctuary for Atheists to justify and explain their
nesciently state of enormously spurned incredulity. I didn't demand
Roger to speak contumeliously of other beliefs. I just asked him to
cite the proof of humans allegedly evolving from Chimpanzee. I just
couldn't believe that our common ancestor as a species was a gorilla
or chimpanzee. This is tremendously preposterous. Nonetheless, this
mythical notion is conveniently ratified by Evolutionists and their
blind embracers like Roger the wangled. They couldn't exhibit decisive
evidence of evolution. They thence draw portraits of it in their
politically motivated textbooks. Who sanctions and funds these theses?
Are they politically motivated? Despite the fact that evolution is
scientifically fallacious, they obstinately cleave into its absurd
tenets. There is no other way to totally deny creation but this.
Therefore, they fend for it with all their fortes. Carl doesn't seem
to care that much about seeking the truth. He has reposed his ethical
disposal. Roger is utterly conscienceless. He is afraid of admitting
creation. If he does, this shall then lead to admitting faith which he
hatefully despises. He will progressively continue to accuse me of
harassing him. This reaction is naturally expected. He is mentally
perturbed with faith because it indubitably taunts his miserably
unconscionable temperament. Roger often speaks libellously of
religion. He does so because it profoundly nettles his cognitive
dissonance. He and his apprentices tell us, that knowledge is solely
derived from empirical experience. Be that as it may, evolution is
forcefully imposed upon us as an alleged scientific fact. It isn't a
phenomenon. It's rather a conjectured notion strongly held and fended
for by majorly Atheists. Thence, it has never been brought to be
examined empirically. It is irrelevant to be quizzed at the science
laboratory. . The one singular motive for them to wholeheartedly
attempt to bear out Evolution is the crucial conception, that it's the
only manner by which the divine could be perfectly abnegated. Atheism
bases its principles on evolution. The latter is essentially based on
Stalinism and intellectual terrorism. Just as religious
fundamentalists promote their ideology through intimidation and
coercion, Atheists throttle the panel of cerebral development by
somewhat coercing evolution on the scientific empyrean. I urge Roger
to cite a decisively evidenced scientific corporeal that affirms the
actual occurrent of evolution. He surely won't be able to do that.
Therefore, he will, as many times previously, seek refuge with
unsuccessfully attempting to marginalise, denounce, defame and
denigrate my theological stance. I never considered this life to be
paradisal. It contains both, joy and sorrow. Roger doesn't have hope.
Thence, his state of bliss couldn't be deferred to hereafter. He
therefore couldn't cope with cataclysms of this life. Hence, he
unconsciously locomoted to interpret everything materialistically.
Roger doesn't like to hear the subsequent sentiment. Science doesn't
replace faith. Instead, it integrates with it. What does he hate this
statement for? Well, he basically needs to scold something for
desolating faith. What should that be then? Well, science. Religion is
its major adversary. Does religion negate the scientific fact that
says, water freezes at zero ° and boils at 100 °? Well, I knew it
doesn't. This scientific fact is bore witness by dozens and has been
tried million times. But, could the lab then, the scientific lab,
prove to us, that human being has evolved from some other creature? I
think what I am talking about is pretty obvious. Oh well, perhaps it
isn't, for those whom their intelligence quotient is below average.
When we say science, we mean what has been recognised by empirical
research. Is this condition applicable to evolution? I hope and urge
Roger to find the correct answer. Although I knew he will diss and
assault, I am not prepared to relinquish my disposition. I am quite
used to his typically imperious notion. Despite the fact that he is
definitely unjustified for this, I will attempt to put up with his
unbearable tendency. The question in basic terms, is there any
authenticated scientific research that explicitly affirms the
phenomenon of evolution as a genuine proposition? Simulating any pro
evolution reference or resource will ultimately be dismissed and
disposed with. I destined to be thorough this time. I urge Roger not
to unwisely hasten with getting an answer. I talk simply and hope I am
fathomed properly. Ah, if someone has got any trouble discerning my
vocabulary usage, please, keep me notified, so I'll narrow it down for
him or her. I learned English at the British Council. Consequently, my
use of expressions may slightly differ from what is commonly practiced
in American colloquial rhetoric.
On 6/9/19, Roger Loran Bailey <rogerbailey81@xxxxxxx> wrote:
Carl, I hope you didn't mean it, but you seem to be saying that
evolution is an unproven theory equivalent to religion. In fact,
evolution is as much of a scientific fact as any scientific fact can be.
But another thing I wonder about is whether there is really any such
thing as an evolutionist. The term is used only by creationist
ignoramuses and it implies that evolution is some kind of ideology. I
think the words scientist or biologist work better. If you are going to
call them evolutionists you may as well call people who believe in
bananas bananaists.
---
Carl Sagan
“ Extraordinary claims require extraordinary evidence. ”
― Carl Sagan
On 6/8/2019 11:28 AM, Carl Jarvis wrote:
Just for the record Mostafa, I am not an Evolutionist any more than I
am a Creationist. What I am is an Observer of Life, an Agnostic...one
who is tied to no particular belief.
My reasons are simple, we, like all Life on Earth, exist for such a
brief time, and are so interwoven in this existence that we have
neither the wisdom nor the broad overview needed to begin to make
sence out of it all.
Religion is as good a theory as Evolution, but nonetheless, it is just
another unprovable theory.
Perhaps the Big Bang Theory has some value since it does not deny the
possibility of any other theory. But so what. What if all Matter
began with a huge explosion and we are merely part of the aftermath?
What if a small creature set off some sort of fire cracker, and the
explosion sent sparks in all directions. And we are living our
existence out as near invisible shadows on little specks of fire,
which will end when the last spark of fire burns out and we return to
nothing?
What if every Fourth of July's fireworks created millions of fires
from hundreds of explosions? We could be part of vast universes, but
all be gone by the morning in some super existence.
What if we are nothing more that a bad dream by some madman chained in
his prison cell?
And what if a White Rabbit dressed in a top hat and a suit jacket,
passes us and we follow him down a rabbit hole into Wonderland?
All God is, is one more theory, passed down over thousands of years
and through the process of evolution, has taken on a detailed form
that makes God far more compelling that that White Rabbit.
Life is such an interesting experience that I will never tire of it,
if I live to be 120.
Carl Jarvis(with 36 years to go)
On 6/7/19, Mostafa <ebob824@xxxxxxxxx> wrote:
Why couldn't we empirically examine the Evolution process? Has it been
halted in human species? Could Evolutionists possibly exhibit before
us a fully functional experience of physically growing taxonomies?
Evolution is not physically examined in empirical science. It is a
theory held by majorly phenomenalists to relentlessly decline the
concept of intelligent design which necessarily leads to the belief in
a unique Creator Who providentially sustains and maintains this vast
and complicated universe. Nonetheless, this conclusion is already
refused by Atheists, synonymously, Evolutionists. Evolution is their
sacred conception. It is the only way by which they could absorb their
incredulity with somewhat scientific rendition. Up until this moment,
they couldn't showcase a creature as it evolves from one assortment to
another. They tell us, that humans have evolved from monkeys. However,
the monkey still exist today and we haven't detected any mutual
behaviour or intelligence rate. Furthermore, we haven't yet examined
the actual process of monkeys gradually evolving into humans within
experimental procedures. They attempt to evade discussing these
details. At its inception, if evolution were genuine, they should have
been capable of plainly demonstrating it. But since it isn't, they
couldn't. Moreover, each physical law has primal rulings. So for
instance, Gravity has rulings. So, what are the primal rulings of
evolution? Zippo. Thence, it is essentially based on random mutation
and ungrasped natural selection. Evolution is a doctrinal theory that
dresses in fallaciously scientific garment. It has therefore been
exposed and robustly refuted by plenty of scientists. Their identity
and expertise are cited here.
https://christiananswers.net/creation/people/home.html
I urge people to spend time learning about those scientists who're
declining the mythical theory of Evolution. I wish we see decisive
evidence for the proposition of Darwinian Evolution. Despite your
philosophical orientation, you shouldn't be convinced of Evolution if
you develop the leastwise amount of rational adequacy. Could chaos
bring organisation? Where is that seen before?
On 6/7/19, Carl Jarvis <carjar82@xxxxxxxxx> wrote:
Spell Check. Never leave home without it!
Carl Jarvis
On 6/7/19, Roger Loran Bailey <dmarc-noreply@xxxxxxxxxxxxx> wrote:
Mostafa wrote: "What is the initial motive that brought the tineist
particle into actual existence?"
What in tarnation is a tineist
particle?
---
Carl Sagan
??? Extraordinary claims require extraordinary evidence. ???
??? Carl Sagan
On 6/7/2019 11:54 AM, Mostafa wrote:
Carl, the subject is thoroughly prevalent. Roger, where are the
evidence of evolution's authenticity? Various archeologies are
allegedly the proof of evolution theory. Nonetheless, none of them
presents decisively empirical evidence for the evolutionary
proposition. All of these are mere speculations based on dithery
presumptions. What is the initial motive that brought the tineist
particle into actual existence? Evolution is the Darwinian myth by
which modern Atheists seek refuge with to marginalise faith. I want
your own knowledge on the subject. Replicating a pro evolution
website
won't do you any good. I want to particularly discern the structural
fundament of Evolution. It is mostly philosophical rather than
controversially scientific. I wish you good luck with providing
sufficiently testable evidence. I fathom though why religion
generically might be of primally inveterate molestation for you. It
persistently hassles your profoundly encompassed conscience. This is
why you are mentally perturbed. Carl, if you truly understand the
natural fate of this world, you will recognise, that our life has
never meant to be free out of tribulations. This life is essentially
of trial. With multiple and interminably versatile calamities, Allah
glory be to Him tries our forbearance and grateful disposal. We
couldn't alter this world into heaven. Nevertheless. we are given the
moral sense by which we are independently competent of distinguishing
and thence, determining right and wrong. This is how I envision life.
I genuinely appreciate the discussion with Carl. As I stated earlier,
despite our major dissensions, Carl and I are still able to
beautifully converse. Ah by the way, as you may have noticed, I
initially learned English at the British Council. That's why, my use
of vocabulary might be a bit different from what is commonly expended
in American English. I am sure your language is better than mine as
a
native speaker. I would be commendable if you correct some of my many
mistakes. I'd just appreciate it if you specify a sentence or set of
sentences and follow that by the relevant correction. I enjoy writing
English as my style keeps improving. Practice makes anything better.
Betterment is attained by devoted praxis. Thank you for reading.
On 6/7/19, Roger Loran Bailey <rogerbailey81@xxxxxxx> wrote:
By the way, I would like to recommend a book. I have already
recommended
this book on this list before, but this time I want to recommend it
specifically to Mostafa because he just keeps repeating that
watchmaker
fallacy that I clearly showed to be circular logic. It has been
years
since I read this book, but I remember clearly that it does address
Mostafa's fallacy. It is The Blind Watchmaker by Richard Dawkins.
The
watchmaker in the title does refer to William Paley's watchmaker and
Dawkins does an excellent job of refuting that fallacy. However, the
subject of the book is not in its entirety a book about the
watchmaker
fallacy. After all, I refuted it pretty well in a single email. So
it
would be kind of silly to devote an entire book to just that point.
What
the book is all about is, for one thing, showing how highly complex
systems can arise out of very simple beginnings without any
conscious
intervention. But Dawkins is a professional evolutionary biologist.
Back
when I was reading those journals in the basement of my college's
library I think I remember reading some of his peer reviewed papers
on
the subject. So the highly complex system he concentrates on in The
Blind Watchmaker is biological evolution. In fact, the real subject
of
the book is how evolution works. If Mostafa is serious about his
questions about how something as complex as the biological world
could
arise from the so-called primordial soup then the answer is right
there
in that book. I should point out that even though Dawkins is a
professional evolutionary biologist this book is not very technical.
It
was written especially for a lay audience.
---
Carl Sagan
??? Extraordinary claims require extraordinary evidence. ???
??? Carl Sagan
On 6/6/2019 8:48 PM, Roger Loran Bailey (Redacted sender
rogerbailey81
for DMARC) wrote:
Okay, I just posted a few articles about the actual observation of
evolution in progress. I found them with a simple Google search. I
got
tens of thousands of results and I don't have the time to post all
of
them and I am sure that the rest of you do not have the patience to
read all of them. What I have already posted is plenty sufficient
to
show that Mostafa does not know what he is talking about. If any of
you are interested in the subject I would urge you to visit
TalkOrigins.org or just do some Googling around yourselves. To be
honest, though, I sometimes feel a bit embarrassed for Mostafa.
---
Carl Sagan
??? Extraordinary claims require extraordinary evidence. ???
????? Carl Sagan
On 6/6/2019 8:39 PM, Roger Loran Bailey (Redacted sender
rogerbailey81
for DMARC) wrote:
http://www.bio.miami.edu/dana/160/160S13_4.html
The Fact of Evolution: Observable Evidence
??Despite what some might believe, the physical evidence that
evolution has happened is overwhelming. This might not have been
the
case in Darwin's time. But since the publication of On the Origin
of
Species, a great deal more has come to light.
There are at least four major lines of physical evidence telling
us
that evolution has occurred, and is still occurring.
??? observable examples of the evolutionary process
??? fossils
??? distribution in space and time
??? homologies
Species and Speciation
??Recall the definition of a species (a topic of some debate).
Macroevolution = Speciation
Speciation is the generation of two (or possibly more)
reproductively
isolated new species from an ancestral species.
Speciation implies that the two new species are no longer able to
produce fertile, viable offspring with each other: they are
reproductively isolated.
Speciation is synonymous with macroevolution.
Speciation can be relatively quick or gradual, depending on the
species and circumstances.
Microevolution
??A population can undergo genetic change with respect to other
populations of the same species, but not become reproductively
isolated from them. Such genetic change is known as
microevolution.
There is copious documented evidence for observed instances of
both
macroevolution and microevolution.
Observable Examples of Evolutionary Processes
??Let us examine the various lines of evidence.
Evidence: Microevolution Observed
??There are thousands of scientifically documented cases of
microevoltion. Here are a few of the more famous ones.
??1. MRSA
??? Staphylococcus aureus (S. aureus) is ubiquitous and usually
harmless
??? Opportunistic infections of S. aureus can usually be treated
with
a penicillins, a ??-lactam antibiotic.
??? These antibiotics interfere with the activity of an enzyme
used
by the bacteria to construct their cell walls during cell division
??? In the early 1960s, strains of S. aureus began to show up that
were not killed by methicillin (a ??-lactam relative of
penicillin)
??? The ??-lactam antibiotics are so called because they all
contain
a ??-lactam ring (the square portion of the molecule's structure
in
the diagram).
??? The new S. aureus were found to be making a new enzyme, ??
lactamase, that disrupts the ?? lactam ring, rendering the
antibiotic
inactive.
??? These new bacteria were dubbed Methicillin-resistant Staph
aureus
(MRSA)
??? These are some of the nasty "flesh eating" bacteria that are
becoming more and more common as overuse of antibiotics
(especially
in hospital settings) selects for resistance not only in S.
aureus,
but many other bacterial species.
??? ?? lactamases (there are many!) are believed to be derived
from
bacterial enzymes that originally functioned in cell wall
construction.
??? Mutations of the genes encoding these original enzymes changed
them into the various ?? lactamases.
??? As antibiotics evolve by human manipulation, bacterial enzymes
mutate, and the beneficial mutations (such as those inactivating
antibiotics) are selected.
??? An so goes the Evolutionary Arms Race.
2. Antibiotic-resistant Mycobacterium tuberculosis
??? Mycobacterium tuberculosis causes tuberculosis (TB) in humans
and
other primates.
??? In the middle of the 20th century, new antibiotics nearly
eradicated TB
??? Late 1980's: new resurgence of TB in developing nations
??? Some strains were resistant to antibiotics to which they had
been
sensitive before.
??? How did this happen? "Felt need?" "Natural Selection?"
??? The answer came from an AIDS patient...??? HIV+ individual
diagnosed with TB
??? treated with rifampin and isoniazid (normally effective
against
M. tuberculosis)
??? Infection cleared; chest radiographs normal
??? Two months later, patient readmitted with TB symptoms
??? Treated with same antibiotics, but died 10 days later
??? Culture and sensitivity test on lung discharge revealed M.
tuberculosis, but these were resistant to rifampin.
Was this an example of natural selection? Let's put Darwin to the
(post hoc) test.
??1. Did variation exist in the bacterial population?
YES - both sensitive and resistant strains were present in the
patient)
2. Was the variation heritable?
YES- Rifampin's mode of action is to bind specifically to RNA
polymerase, interfering with transcription of all genes.
Resistant M. tuberculosis had a point mutation in the RNA
polymerase
gene (rpoB): leucine (TCG) --> serine (TTG). This was enough to
render the RNA polymerase unrecognizable to rifampin.
The mutation was heritable; all progeny of the mutant, resistant
strain had the same point mutation.
3. Did differential reproduction among variable bacteria occur?
YES - M. tuberculosis with the point mutation left more offspring
than those that lacked the mutation.
4. Did a non-random subset of the original population remain after
selection?YES - The populations before and after rifampin
administration were significantly different, with resistant
bacteria
replacing rifampin-sensitive individuals.
3. North American House Sparrow body mass and wing surface area
???
A
tale of The American Acclimatization Society and Shakespeare...
??? Bergmann's Rule: Animals in higher latitudes/colder climates
tend
to have larger bodies (with a lower surface area to volume ratio)
than those in lower latitudes/warmer climates. (Why should this be
so?)
??? This can be true not only across species, but within a species
with a wide geographic range.
??? What would you predict with respect to body size (northern
hemisphere) in northern and southern populations?
??? Now consider color. Darker colors (pigments) absorbs
light/heat.
Lighter colors reflect light/heat.
??? What would you predict with respect to pigmentation (northern
hemisphere) in northern and southern populations?
??? This was studied in House Sparrows by Johnston and Selander,
who
published their work in the early 1970s.
??? All House Sparrows in the U.S. are descended from a few pairs
imported from central England.
??? Yet the North American populations at higher latitudes are
darker
and larger than those in southern populations.
4. Evolution of flower size
??? How does pollinator preference and the influence of
nectar-thieving ants result in a change in the flower population
(in
terms of size, morphology, and fragrance)?
??? Read about this HERE!
Evidence: Macroevolution Observed
??One battle cry of those who do not wish to accept the reality of
evolution is "Well, yes, we can see microevolution. But we've
never
observed speciation."
This is simply INCORRECT.
Evidence: What the Rocks and Fossils Tell Us
??While fossils are not the most powerful line of evidence for how
life changed over time, they are vital to our understanding of how
long life has been here, having the opportunity to evolve.
Paleontology and Geology were perhaps the first scientific
disciplines to yield information suggesting the earth wasn't a few
thousand years old. Countless mountain ranges filled with marine
fossils tell us that the earth we see today was quite different
long
ago.
??The mountains surrounding Convict Lake in the Sierra Nevada
??contain 400-million year old marine fossils in their oldest
sedimentary layers.
Still, fossils are rare. Most dead things are consumed and
destroyed
relatively soon after they die. Only rarely do properties of the
organism and environmental conditions promote fossilization. If
you're going to become a fossil, it helps to have...
??? hard body parts
??? a rapid burial
??? protection from scavengers/bacteria
??? protection from oxygen
What are Fossils?
??Fossils can be parts of an organism's body, or they can be trace
fossils, left by living things long gone. The latter include???
burrows
??? tracks
??? castings
??? gastroliths (stones from inside the stomach)
??? coproliths (fossilized excrement)
??? molds (the impression left by the outside of an organism,
pressed
into substrate)
??? casts (the entire body of the organism, replaced by minerals)
Fossils can be unaltered (composed of actual matter from the
organism):
??? encased in preserving material, such as amber
??? mummified (arid conditions)
??? frozen (for example, mammoth carcasses)
??...or they can be altered ??? permineralized - spaces in the
tissue
are filled by minerals over time
??? mineralized - tissues are fully replaced by minerals, but keep
their shape
??All of these can be studied to track changes not only in
biodiversity, but in lineages of organisms still alive today.
Relative Dating
??Early paleontologists and geologists did not have the technology
to
determine the absolute age of a fossil they were studying. But
they
were still able to determine the relative sequence of the past.
The
process of determining the chronological order of fossil
deposition
is known as relative dating.
Some common forms of sedimentary rock:
??? sandstone - compressed layers of silica-based minerals such as
quartz and feldspar
??? limestone - composed of the crushed calcium carbonate shells
and
other parts of marine invertebrates (that's Florida!)
??? shale - compressed layers of clay
??? gypsum - composed of sulfur-containing minerals, gypsum is
laid
down in marine environments, and solidifies when the ocean water
evaporates.
??? conglomerate
How does sedimentary rock form?
??Erosion by wind and water over millions of years will gradually
wear away particles of earth and wash them into bodies of water
(streams, rivers, oceans). As these particles settle to the
bottom,
they solidify. As more layers are laid on top of older ones, the
lower layers are compressed, and eventually turn into rock.
Geologists represent such formations as a stratigraphic column,
which
describes the vertical placement of rock layers/units in a
particular
location.
In Geology...
??? Older layers of sediment are covered by younger layers; the
most
recent layers are at the top. (Principle of Superposition)
??? If organisms evolve and change over time, then specific
species
found in a particular layer can be used as age markers, linking
even
geographically distant sediments. (Principle of Fossil Succession)
Any pebbles, fossils, or other fragments embedded in sedimentary
rock
must be older than the rock matrix itself.
??? Intrusions that cut through sediments are younger than the
sedimentary layers they cross (Principle of Cross-cutting
Relationships)
??? Sedimentary rocks that have been deformed by folding, lifting
or
other malformation must be older than the event that changed them.
(Principle of Deformation)
Using these principles, geologists can determine the relative age
of
fossils embedded in sedimentary rock.
To give an absolute age to a fossil, one must use radiometric
techniques that we'll discuss later.
Instances of Observed Speciation
Catherine A. Callaghan
The American Biology Teacher,?? Vol. 49?? No. 1,?? Jan., 1987;??
(pp.
34-36)?? DOI: 10.2307/4448413
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Observed Instances of Speciation
by Joseph Boxhorn
Copyright ?? 1993-2004
??[Last Update: September 1, 1995]
1.0 Introduction and Acknowledgements
T his FAQ discusses several instances where speciation has been
observed. It also discusses several issues related to speciation.
Other Links:
Some More Observed Speciation EventsA group of articles originally
posted to the talk.origins newsgroup that provides some instances
of
speciation not covered by this document.
I have divided this FAQ into several sections. Part 2 discusses
several definitions of what a species is. Part 3 explains the
context
in which observations of speciation are made. Part 4 looks at the
question, "How can we tell when a speciation event has occurred?"
Part 5 describes a number of observed speciation events and
several
experiments which (in my opinion) failed to produce speciation.
Part
6 is a list of references.
The descriptions of each observation come from the primary
literature. I went back to this literature for two reasons. First,
many of these observations are not discussed (or not discussed in
much detail) in secondary sources such as reviews, texts and
popular
articles. Second, it is difficult, if not impossible, to evaluate
what a piece of research actually established without looking at
the
methods and data. Secondary sources rarely give this information
in
any detail. Anyway, I have included only those observations that I
have been able to find the original sources for.
I consider this FAQ incomplete. One reason for this is that I am
still chasing references (I still have a list of over 115 to
find).
More important is the fact that observations of speciation are
buried
in papers on a number of topics. If you know of observations that
I
should include, let me know and I will chase down the reference,
read
it and modify the file (assuming that the data are the least bit
convincing). I ask that you try to give me as complete a reference
as
possible to aid me in finding the original source.
1.1 Acknowledgements
Back in April of 1993, Rich Fox asked a series of questions
related
to species and speciation events. These questions got me
interested
in the topic. I hope that I have, at least, provided grist for the
mill that will grind out an answer to Rich's questions. In any
case,
Rich deserves the credit (or blame :-)) for inspiring me to write
this. My starting point was the references contained in the old
speciation FAQ. I wish to thank the authors of this, Chris
Stassen,
James Meritt, Anneliese Lilje and L. Drew Davis. Tom Scharle and
Simon Clippingdale sent a couple of references my way. Finally,
John
Edstrom sent me considerable information on symbiosis in Amoeba.
While I have not had a chance to get all the references that he
has
sent me, he has given me a great deal to think about over the role
of
symbiosis in speciation. Many thanks to all.
2.0 Species Definitions
A discussion of speciation requires a definition of what
constitutes
a species. This is a topic of considerable debate within the
biological community. Three recent reviews in the Journal of
Phycology give some idea of the scope of the debate (Castenholz
1992,
Manhart and McCourt 1992, Wood and Leatham 1992). There are a
variety
of different species concept currently in use by biologists. These
include folk, biological, morphological, genetic, paleontological,
evolutionary, phylogenetic and biosystematic definitions. In the
interest of brevity, I'll only discuss four of these -- folk,
biological, morphological and phylogenetic. A good review of
species
definitions is given in Stuessy 1990.
2.1 The Folk Concept of Species
Naturalists around the world have found that the individual plants
and animals they see can be mentally grouped into a number of
taxa,
in which the individuals are basically alike. In societies that
are
close to nature, each taxon is given a name. These sorts of folk
taxonomies have two features in common. One aspect is the idea of
reproductive compatability and continuity within a species. Dogs
beget dogs, they never beget cats! This has a firm grounding in
folk
knowledge. The second notion is that there is a discontinuity of
variation between species. In other words, you can tell species
apart
by looking at them (Cronquist 1988).
2.2 The Biological Species Concept
Over the last few decades the theoretically preeminent species
definition has been the biological species concept (BSC). This
concept defines a species as a reproductive community.
2.2.1 History of the Biological Species Concept
The BSC has undergone a number of changes over the years. The
earliest precursor that I could find was in Du Rietz 1930. Du
Rietz
defined a species as
"... the smallest natural populations permanently separated from
each
other by a distinct discontinuity in the series of biotypes."
Barriers to interbreeding are implicit in this definition and
explicit in Du Rietz's dicussion of it.
A few years later, Dobzhansky defined a species as
"... that stage of evolutionary progress at which the once
actually
or potentially interbreeding array of forms becomes segregated
into
two or more separate arrays which are physiologically incapable of
interbreeding." (Dobzhansky 1937)
It is important to note that this is a highly restrictive
definition
of species. It emphasizes experimental approaches and ignores what
goes on in nature. By the publication of the third edition of the
book this appeared in, Dobzhansky (1951) had relaxed this
definition
to the point that is substantially agreed with Mayr's.
The definition of a species that is accepted as the BSC was
promulgated by Mayr (1942). He defined species as
"... groups of actually or potentially interbreeding natural
populations which are reproductively isolated from other such
groups."
Note that the emphasis in this definition is on what happens in
nature. Mayr later amended this definition to include an
ecological
component. In this form of the definition a species is
"... a reproductive community of populations (reproductively
isolated
from others) that occupies a specific niche in nature."
The BSC is most strongly accepted among vertebrate zoologists and
entomologists. Two facts account for this. First, these are the
groups that the authors of the BSC worked with :-). (Note: Mayr is
an
ornithologist and Dobzhansky worked extensively with Drosophila).
More importantly, obligate sexuality is the predominant form of
reproduction in these groups. It is not coincidental that the BSC
is
less widely accepted among botanists. Terrestrial plants exhibit
much
greater diversity in their "mode of reproduction" than do
vertebrates
and insects.
2.2.2 Criticisms of the Biological Species Concept
There has been considerable criticism of the theoretical validity
and
practical utility of the BSC. (Cracraft 1989, Donoghue 1985, Levin
1979, Mishler and Donoghue 1985, Sokal and Crovello 1970).
The application of the BSC to a number of groups, including land
plants, is problematical because of interspecific hybridization
between clearly delimited species (McCourt and Hoshaw 1990,
Mishler
1985).
There is an abundance of asexual populations that this definition
just doesn't apply to (Budd and Mishler 1990). Examples of taxa
which
are obligately asexual include bdelloid rotifers, euglenoid
flagellates, some members of the Oocystaceae (coccoid green
algae),
chloromonad flagellates and some araphid pennate diatoms. Asexual
forms of normally sexual organisms are known. Obligately asexual
populations of Daphnia are found in some arctic lakes. The BSD can
be
of no help in delimiting species in these groups. A similar
situation
is found in the prokaryotes. Though genes can be exchanged among
bacteria by a number of mechanisms, sexuality, as defined in
eukaryotes, in unknown in the prokaryotes. One popular
microbiology
text doesn't even mention the BSC (Brock and Madigan 1988).
The applicability of the BSC is also questionable in those land
plants that primarily self-pollinate (Cronquist 1988).
A more serious criticism is that the BSC is inapplicable in
practice.
This charge asserts that, in most cases, the BSC cannot be
practically applied to delimit species. The BSC suggests breeding
experiments as the test of species membership. But this is a test
that is rarely made. The number of crosses needed to delimit
membership in a species can be astronomical. The following example
will illustrate the problem.
Here in Wisconsin we have about 16,000 lakes and ponds. A common
(and
tasty ;-)) inhabitant of many of these bodies of water is the
bluegill sunfish. Let's ask a question -- do all these bluegill
populations constitute one species or several morphologically
similar
species? Assume that only 1,000 of these lakes and ponds contain
bluegills. Assuming that each lake constitutes a population, an
investigator would have to perform 499,500 separate crosses to
determine whether the populations could interbreed. But to do this
right we should really do reciprocal crosses (i.e. cross a male
from
population A with a female from population B and a male from
population B with a female from population A). This brings the
total
crosses we need to make up to 999,000. But don't we also need to
make
replicates? Having three replicates brings the total to 2,997,000
crosses. In addition, you just can't put a pair of bluegills into
a
bucket and expect them to mate. In nature, male bluegills excavate
and defend nests in large mating colonies. After the nests are
excavated the females come in to the colony to spawn. Here the
females choose among potential mates. This means that we would
need
to simulate a colony in our test. Assume that 20 fish would be
sufficient for a single test. We find that we would need about
60,000,000 fish to test whether all these populations are members
of
the same species! (We would also need a large number of large
aquaria
to run these crosses in). But bluegills are not restricted to
Wisconsin...
I could go on, but I think the point is now obvious. The fact of
the
matter is that the time, effort and money needed to delimit
species
using the BSC is, to say the least, prohibitive.
Another reason why using the BSC to delimit species is impractical
is
that breeding experiments can often be inconclusive. Interbreeding
in
nature can be heavily influenced by variable and unstable
environmental factors. (Any angler who has waited for the
bluegills
to get on to the beds can confirm this one). If we can't duplicate
natural conditions of breeding, a failure to breed doesn't mean
that
the critters can't (or don't) interbreed in the wild. The
difficulties that were encountered in breeding pandas in captivity
illustrate this. In addition, experimentally showing that A
doesn't
interbreed with B doesn't preclude both interbreeding with C. This
gets even more complicated in groups that don't have nice,
straightforward sexes. An example of this occurs in a number of
protozoan species. These critters have numerous mating types.
There
can be very complicated compatability of mating types. Finally,
breeding experiments can be inconclusive because actual
interbreeding
and gene flow among phenetically similar, genetically compatible
local populations is often more restricted than the BSC would
suggest
(Cronquist 1988).
In practice, even strong adherents of the BSC use phenetic
similarities and discontinuities for delimiting species. If the
organisms are phenotypically similar, they are considered
conspecific
until a reproductive barrier is demonstrated.
Another criticism of the BSC comes from the cladistic school of
taxonomy (e.g. Donoghue 1985). The cladists argue that sexual
compatibility is a primitive trait. Organisms that are no longer
closely related may have retained the ability for genetic
recombination with each other through sex. This is not a derived
characteristic. Because of this it is invalid for defining
monophyletic taxa.
A final problem with the BSC is that groups that do not occur
together in time cannot be evaluated. We simply cannot know
whether
two such groups would interbreed freely if they came together
under
natural conditions. This makes it impossible to delimit the
boundaries of extinct groups using the BSC. One question will
illustrate the problem. Do Homo erectus and Homo sapiens represent
the same or different species? This question is unresolvable using
the biological definition.
Several alternatives to the biological species concept have been
suggested. I will discuss two.
2.3 The Phenetic (or Morphological) Species Concept
Cronquist (1988) proposed an alternative to the BSC that he called
a
"renewed practical species definition". He defines species as
"... the smallest groups that are consistently and persistently
distinct and distinguishable by ordinary means."
Three comments must be made about this definition. First,
"ordinary
means" includes any techniques that are widely available, cheap
and
relatively easy to apply. These means will differ among different
groups of organisms. For example, to a botanist working with
angiosperms ordinary means might mean a hand lens; to an
entomologist
working with beetles it might mean a dissecting microscope; to a
phycologist working with diatoms it might mean a scanning electron
microscope. What means are ordinary are determined by what is
needed
to examine the organisms in question.
Second, the requirement that species be persistently distinct
implies
a certain degree of reproductive continuity. This is because
phenetic
discontinuity between groups cannot persist in the absence of a
barrier to interbreeding.
Third, this definition places a heavy, though not exclusive,
emphasis
on morphological characters. It also recognizes phenetic
characters
such as chromosome number, chromosome morphology, cell
ultrastructure, secondary metabolites, habitats and other
features.
2.4 Phylogenetic Species Concepts
There are several phylogenetic species definitions. All of them
assert that classifications should reflect the best supported
hypotheses of the phylogeny of the organisms. Baum (1992)
describes
two types of phylogenetic species concepts.
1.A species is the smallest cluster of organisms that possesses at
least one diagnostic character. This character may be
morphological,
biochemical or molecular and must be fixed in reproductively
cohesive
units. It is important to realize that this reproductive
continuity
is not used in the same way as in the BSC. Phylogenetic species
may
be reproductive communities. Reproductively compatible individuals
need not have the diagnostic character of a species. In this case,
the individuals need not be conspecific.
2.A species must be monophyletic and share one or more derived
character. There are two meanings to monophyletic (de Queiroz and
Donoghue 1988, Nelson 1989). The first defines a monophyletic
group
as all the descendants of a common ancestor and the ancestor. The
second defines a monophyletic group as a group of organisms that
are
more closely related to each other than to any other organisms.
These
distinctions are discussed in Baum 1992 and de Queiroz and
Donoghue
1990.
A recently offered hypothesis suggests that phylogenetic species
concepts and the biological species concept may be highly, if not
completely, incompatible. "Parallel speciation " has been defined
as
the repeated independent evolution of the same reproductive
isolating
mechanism (Schluter and Nagel 1995). An example of this may occur
when a species colonizes several new areas which are isolated
from,
but environmentally similar to, each other. Similar selective
pressures in these environments result in parallel evolution among
the traits that confer reproductive isolation. There is some
experimental evidence that this might occur (Kilias, et al. 1980;
Dodd 1989). The implication of this is that biological species (as
defined by the BSC) may often be polyphyletic. If this occurs in
nature, it could undermine the usefulness of phylogenetic species
concepts.
2.5 Why This is Included
What is all of this doing in a discussion of observed instances of
speciation? What a biologist will consider as a speciation event
is,
in part, dependent on which species definition that biologist
accepts. The biological species concept has been very successful
as
a
theoretical model for explaining species differences among
vertebrates and some groups of arthropods. This can lead us to
glibly
assert its universal applicability, despite its irrelevance to
many
groups. When we examine putative speciation events, we need to ask
the question, which species definition is the most reasonable for
this group of organisms? In many cases it will be the biological
definition. In many other cases some other definition will be more
appropriate.
3.0 The Context of Reports of Observed Speciations
The literature on observed speciations events is not well
organized.
I found only a few papers that had an observation of a speciation
event as the author's main point (e.g. Weinberg, et al. 1992). In
addition, I found only one review that was specifically on this
topic
(Callaghan 1987). This review cited only four examples of
speciation
events. Why is there such a seeming lack of interest in reporting
observations of speciation events?
In my humble opinion, four things account for this lack of
interest.
First, it appears that the biological community considers this a
settled question. Many researchers feel that there are already
ample
reports in the literature. Few of these folks have actually looked
closely. To test this idea, I asked about two dozen graduate
students
and faculty members in the department where I'm a student whether
there were examples where speciation had been observed in the
literature. Everyone said that they were sure that there were.
Next
I
asked them for citings or descriptions. Only eight of the people I
talked to could give an example, only three could give more than
one.
But everyone was sure that there were papers in the literature.
Second, most biologists accept the idea that speciation takes a
long
time (relative to human life spans). Because of this we would not
expect to see many speciation events actually occur. The
literature
has many more examples where a speciation event has been inferred
from evidence than it has examples where the event is seen. This
is
what we would expect if speciation takes a long time.
Third, the literature contains many instances where a speciation
event has been inferred. The number and quality of these cases may
be
evidence enough to convince most workers that speciation does
occur.
Finally, most of the current interest in speciation concerns
theoretical issues. Most biologists are convinced that speciation
occurs. What they want to know is how it occurs. One recent book
on
speciation (Otte and Endler 1989) has few example of observed
speciation, but a lot of discussion of theory and mechanisms.
Most of the reports, especially the recent reports, can be found
in
papers that describe experimental tests of hypotheses related to
speciation. Usually these experiments focus on questions related
to
mechanisms of speciation. Examples of these questions include:
???Does speciation precede or follow adaptation to local
ecological
conditions?
???Is speciation a by-product of genetic divergence among
populations
or does it occur directly by natural selection through lower
fitness
of hybrids?
???How quickly does speciation occur?
???What roles do bottlenecks and genetic drift play in speciation?
???Can speciation occur sympatrically (i.e. can two or more
lineages
diverge while they are intermingled in the same place) or must the
populations be separated in space or time?
???What roles do pleiotropy and genetic hitchhiking play in
speciation?
It is important to note that a common theme running through these
questions is that they all attempt to address the issue of how
speciation occurs.
4.0 Telling Whether a Speciation Event Has Occurred
What evidence is necessary to show that a change produced in a
population of organisms constitutes a speciation event? The answer
to
this question will depend on which species definition applies to
the
organisms involved.
4.1 Cases Where the Biological Species Concept Applies
One advantage of the BSC is that it provides a reasonably
unambiguous
test that can be applied to possible speciation events. Recall
that
under the BSC species are defined as being reproductively isolated
from other species. Demonstrating that a population is
reproductively
isolated (in a nontrivial way) from populations that it was
formerly
able to interbreed with shows that speciation has occurred. In
practice, it is also necessary to show that at least one isolating
mechanism with a hereditary basis is present. After all, just
because
a pair of critters don't breed during an experiment doesn't mean
they
can't breed or even that they won't breed. Debates about whether a
speciation event has occurred often turn on whether isolating
mechanisms have been produced.
4.1.1 Isolating Mechanisms
Mechanisms which produce reproductive isolation fall into two
broad
categories -- premating mechanisms and postmating mechanisms.
Premating isolating mechanisms operate to keep species separate
before mating occurs. Often they act to prevent mating altogether.
Examples of premating mechanisms include ecological, temporal,
behavioral and mechanical mechanisms.
Ecological isolation occurs when species occupy or breed in
different
habitats. It is important to be careful when claiming ecological
isolation. For example, I have a population of Dinobryon
cylindricum
(a colonial algal flagellate) growing in a culture tube in an
environmental chamber. It's been there for three years (which is a
lot of time in flagellate years! :-)). Even though there is no
possibility that they will mate with the D. cylindricum in Lake
Michigan, it would be silly to assert that they therefore
constitute
a separate species. Physical isolation alone does not constitute
an
isolating mechanism with an hereditary basis.
Temporal isolation occurs when species breed at different times.
This
may be different times of the year or different times of day.
Behavioral isolating mechanisms rely on organisms making a choice
of
whether to mate and a choice of who to mate with. Differences in
courtship behavior, for instance, may be sufficient to prevent
mating
from occurring. A behavioral isolating mechanism should result in
some sort of positive assortative mating. Simply put, positive
assortative mating occurs when organisms that differ in some way
tend
to mate with organism that are like themselves. For example, if
blonds mate exclusively with blonds, brunettes mate exclusively
with
brunettes, redheads mate exclusively with redheads (and those of
us
without much hair don't get to mate :-() the human population
would
exhibit a high degree of positive assortative mating. In most
examples in the literature when positive assortative mating is
seen
it is not this strong. Positive assortative mating is especially
important in discussions of sympatric speciation.
Mechanical isolating mechanisms occur when morphological or
physiological differences prevent normal mating.
Postmating isolating mechanisms prevent hybrid offspring from
developing or breeding when mating does occur. There are also
several
examples of postmating mechanisms.
Mechanical postmating isolating mechanisms occur in those cases
where
mating is possible, but the gametes are unable to reach each other
or
to fuse. Mortality acts as an isolating mechanism when the hybrid
dies prior to maturity. Sterility of hybrids can act as an
isolating
mechanism. Finally a reduction in the fitness of the hybrid
offspring
can isolate two populations. This happens when the F1 hybrid is
fertile but the F2 hybrid has lower fitness than either of the
parental species.
4.2 Cases Where the Biological Species Concept Does Not Apply
There is no unambiguous criterion for determining that a
speciation
event has occurred in those cases where the BSC does not apply.
This
is especially true for obligately asexual organisms. Usually
phenetic
(e.g. phenotypic and genetic) differences between populations are
used to justify a claim of speciation. A few caveats are germane
to
this. It is not obvious how much change is necessary to claim that
a
population has speciated. In my humble opinion, the difference
between the "new species" and its "ancestor" should be at least as
great as the differences among recognized species in the group
(i.e.
genus, family) involved. The investigator should show that the
change
is persistent. Finally, many organisms have life cycles/life
histories that involve alternative morphologies and/or an ability
to
adjust their phenotypes in response to short term changes in
ecological conditions. The investigator should be sure to rule
these
things out before claiming that a phenetic change constitutes a
speciation event.
5.0 Observed Instances of Speciation
The following are several examples of observations of speciation.
5.1 Speciations Involving Polyploidy, Hybridization or
Hybridization
Followed by Polyploidization.
5.1.1 Plants
(See also the discussion in de Wet 1971).
5.1.1.1 Evening Primrose (Oenothera gigas)
While studying the genetics of the evening primrose, Oenothera
lamarckiana, de Vries (1905) found an unusual variant among his
plants. O. lamarckiana has a chromosome number of 2N = 14. The
variant had a chromosome number of 2N = 28. He found that he was
unable to breed this variant with O. lamarckiana. He named this
new
species O. gigas.
5.1.1.2 Kew Primrose (Primula kewensis)
Digby (1912) crossed the primrose species Primula verticillata and
P.
floribunda to produce a sterile hybrid. Polyploidization occurred
in
a few of these plants to produce fertile offspring. The new
species
was named P. kewensis. Newton and Pellew (1929) note that
spontaneous
hybrids of P. verticillata and P. floribunda set tetraploid seed
on
at least three occasions. These happened in 1905, 1923 and 1926.
5.1.1.3 Tragopogon
Owenby (1950) demonstrated that two species in this genus were
produced by polyploidization from hybrids. He showed that
Tragopogon
miscellus found in a colony in Moscow, Idaho was produced by
hybridization of T. dubius and T. pratensis. He also showed that
T.
mirus found in a colony near Pullman, Washington was produced by
hybridization of T. dubius and T. porrifolius. Evidence from
chloroplast DNA suggests that T. mirus has originated
independently
by hybridization in eastern Washington and western Idaho at least
three times (Soltis and Soltis 1989). The same study also shows
multiple origins for T. micellus.
5.1.1.4 Raphanobrassica
The Russian cytologist Karpchenko (1927, 1928) crossed the radish,
Raphanus sativus, with the cabbage, Brassica oleracea. Despite the
fact that the plants were in different genera, he got a sterile
hybrid. Some unreduced gametes were formed in the hybrids. This
allowed for the production of seed. Plants grown from the seeds
were
interfertile with each other. They were not interfertile with
either
parental species. Unfortunately the new plant (genus
Raphanobrassica)
had the foliage of a radish and the root of a cabbage.
5.1.1.5 Hemp Nettle (Galeopsis tetrahit)
A species of hemp nettle, Galeopsis tetrahit, was hypothesized to
be
the result of a natural hybridization of two other species, G.
pubescens and G. speciosa (Muntzing 1932). The two species were
crossed. The hybrids matched G. tetrahit in both visible features
and
chromosome morphology.
5.1.1.6 Madia citrigracilis
Along similar lines, Clausen et al. (1945) hypothesized that Madia
citrigracilis was a hexaploid hybrid of M. gracilis and M.
citriodora
As evidence they noted that the species have gametic chromosome
numbers of n = 24, 16 and 8 respectively. Crossing M. gracilis and
M.
citriodora resulted in a highly sterile triploid with n = 24. The
chromosomes formed almost no bivalents during meiosis.
Artificially
doubling the chromosome number using colchecine produced a
hexaploid
hybrid which closely resembled M. citrigracilis and was fertile.
5.1.1.7 Brassica
Frandsen (1943, 1947) was able to do this same sort of recreation
of
species in the genus Brassica (cabbage, etc.). His experiments
showed
that B. carinata (n = 17) may be recreated by hybridizing B. nigra
(n
= 8) and B. oleracea, B. juncea (n = 18) may be recreated by
hybridizing B. nigra and B. campestris (n = 10), and B. napus (n =
19) may be recreated by hybridizing B. oleracea and B. campestris.
5.1.1.8 Maidenhair Fern (Adiantum pedatum)
Rabe and Haufler (1992) found a naturally occurring diploid
sporophyte of maidenhair fern which produced unreduced (2N)
spores.
These spores resulted from a failure of the paired chromosomes to
dissociate during the first division of meiosis. The spores
germinated normally and grew into diploid gametophytes. These did
not
appear to produce antheridia. Nonetheless, a subsequent generation
of
tetraploid sporophytes was produced. When grown in the lab, the
tetraploid sporophytes appear to be less vigorous than the normal
diploid sporophytes. The 4N individuals were found near Baldwin
City,
Kansas.
5.1.1.9 Woodsia Fern (Woodsia abbeae)
Woodsia abbeae was described as a hybrid of W. cathcariana and W.
ilvensis (Butters 1941). Plants of this hybrid normally produce
abortive sporangia containing inviable spores. In 1944 Butters
found
a W. abbeae plant near Grand Portage, Minn. that had one fertile
frond (Butters and Tryon 1948). The apical portion of this frond
had
fertile sporangia. Spores from this frond germinated and grew into
prothallia. About six months after germination sporophytes were
produced. They survived for about one year. Based on cytological
evidence, Butters and Tryon concluded that the frond that produced
the viable spores had gone tetraploid. They made no statement as
to
whether the sporophytes grown produced viable spores.
5.1.2 Animals
Speciation through hybridization and/or polyploidy has long been
considered much less important in animals than in plants
[[[refs.]]].
A number of reviews suggest that this view may be mistaken. (Lokki
and Saura 1980; Bullini and Nascetti 1990; Vrijenhoek 1994).
Bullini
and Nasceti (1990) review chromosomal and genetic evidence that
suggest that speciation through hybridization may occur in a
number
of insect species, including walking sticks, grasshoppers,
blackflies
and cucurlionid beetles. Lokki and Saura (1980) discuss the role
of
polyploidy in insect evolution. Vrijenhoek (1994) reviews the
literature on parthenogenesis and hybridogenesis in fish. I will
tackle this topic in greater depth in the next version of this
document.
5.2 Speciations in Plant Species not Involving Hybridization or
Polyploidy
5.2.1 Stephanomeira malheurensis
Gottlieb (1973) documented the speciation of Stephanomeira
malheurensis. He found a single small population (< 250 plants)
among
a much larger population (> 25,000 plants) of S. exigua in Harney
Co., Oregon. Both species are diploid and have the same number of
chromosomes (N = 8). S. exigua is an obligate outcrosser
exhibiting
sporophytic self-incompatibility. S. malheurensis exhibits no
self-incompatibility and self-pollinates. Though the two species
look
very similar, Gottlieb was able to document morphological
differences
in five characters plus chromosomal differences. F1 hybrids
between
the species produces only 50% of the seeds and 24% of the pollen
that
conspecific crosses produced. F2 hybrids showed various
developmental
abnormalities.
5.2.2 Maize (Zea mays)
Pasterniani (1969) produced almost complete reproductive isolation
between two varieties of maize. The varieties were distinguishable
by
seed color, white versus yellow. Other genetic markers allowed him
to
identify hybrids. The two varieties were planted in a common
field.
Any plant's nearest neighbors were always plants of the other
strain.
Selection was applied against hybridization by using only those
ears
of corn that showed a low degree of hybridization as the source of
the next years seed. Only parental type kernels from these ears
were
planted. The strength of selection was increased each year. In the
first year, only ears with less than 30% intercrossed seed were
used.
In the fifth year, only ears with less than 1% intercrossed seed
were
used. After five years the average percentage of intercrossed
matings
dropped from 35.8% to 4.9% in the white strain and from 46.7% to
3.4%
in the yellow strain.
5.2.3 Speciation as a Result of Selection for Tolerance to a
Toxin:
Yellow Monkey Flower (Mimulus guttatus)
At reasonably low concentrations, copper is toxic to many plant
species. Several plants have been seen to develop a tolerance to
this
metal (Macnair 1981). Macnair and Christie (1983) used this to
examine the genetic basis of a postmating isolating mechanism in
yellow monkey flower. When they crossed plants from the copper
tolerant "Copperopolis" population with plants from the
nontolerant
"Cerig" population, they found that many of the hybrids were
inviable. During early growth, just after the four leaf stage, the
leaves of many of the hybrids turned yellow and became necrotic.
Death followed this. This was seen only in hybrids between the two
populations. Through mapping studies, the authors were able to
show
that the copper tolerance gene and the gene responsible for hybrid
inviability were either the same gene or were very tightly linked.
These results suggest that reproductive isolation may require
changes
in only a small number of genes.
5.3 The Fruit Fly Literature
5.3.1 Drosophila paulistorum
Dobzhansky and Pavlovsky (1971) reported a speciation event that
occurred in a laboratory culture of Drosophila paulistorum
sometime
between 1958 and 1963. The culture was descended from a single
inseminated female that was captured in the Llanos of Colombia. In
1958 this strain produced fertile hybrids when crossed with
conspecifics of different strains from Orinocan. From 1963 onward
crosses with Orinocan strains produced only sterile males.
Initially
no assortative mating or behavioral isolation was seen between the
Llanos strain and the Orinocan strains. Later on Dobzhansky
produced
assortative mating (Dobzhansky 1972).
5.3.2 Disruptive Selection on Drosophila melanogaster
Thoday and Gibson (1962) established a population of Drosophila
melanogaster from four gravid females. They applied selection on
this
population for flies with the highest and lowest numbers of
sternoplural chaetae (hairs). In each generation, eight flies with
high numbers of chaetae were allowed to interbreed and eight flies
with low numbers of chaetae were allowed to interbreed.
Periodically
they performed mate choice experiments on the two lines. They
found
that they had produced a high degree of positive assortative
mating
between the two groups. In the decade or so following this,
eighteen
labs attempted unsuccessfully to reproduce these results.
References
are given in Thoday and Gibson 1970.
5.3.3 Selection on Courtship Behavior in Drosophila melanogaster
Crossley (1974) was able to produce changes in mating behavior in
two
mutant strains of D. melanogaster. Four treatments were used. In
each
treatment, 55 virgin males and 55 virgin females of both ebony
body
mutant flies and vestigial wing mutant flies (220 flies total)
were
put into a jar and allowed to mate for 20 hours. The females were
collected and each was put into a separate vial. The phenotypes of
the offspring were recorded. Wild type offspring were hybrids
between
the mutants. In two of the four treatments, mating was carried out
in
the light. In one of these treatments all hybrid offspring were
destroyed. This was repeated for 40 generations. Mating was
carried
out in the dark in the other two treatments. Again, in one of
these
all hybrids were destroyed. This was repeated for 49 generations.
Crossley ran mate choice tests and observed mating behavior.
Positive
assortative mating was found in the treatment which had mated in
the
light and had been subject to strong selection against
hybridization.
The basis of this was changes in the courtship behaviors of both
sexes. Similar experiments, without observation of mating
behavior,
were performed by Knight, et al. (1956).
5.3.4 Sexual Isolation as a Byproduct of Adaptation to
Environmental
Conditions in Drosophila melanogaster
Kilias, et al. (1980) exposed D. melanogaster populations to
different temperature and humidity regimes for several years. They
performed mating tests to check for reproductive isolation. They
found some sterility in crosses among populations raised under
different conditions. They also showed some positive assortative
mating. These things were not observed in populations which were
separated but raised under the same conditions. They concluded
that
sexual isolation was produced as a byproduct of selection.
5.3.5 Sympatric Speciation in Drosophila melanogaster
In a series of papers (Rice 1985, Rice and Salt 1988 and Rice and
Salt 1990) Rice and Salt presented experimental evidence for the
possibility of sympatric speciation. They started from the premise
that whenever organisms sort themselves into the environment first
and then mate locally, individuals with the same habitat
preferences
will necessarily mate assortatively. They established a stock
population of D. melanogaster with flies collected in an orchard
near
Davis, California. Pupae from the culture were placed into a
habitat
maze. Newly emerged flies had to negotiate the maze to find food.
The
maze simulated several environmental gradients simultaneously. The
flies had to make three choices of which way to go. The first was
between light and dark (phototaxis). The second was between up and
down (geotaxis). The last was between the scent of acetaldehyde
and
the scent of ethanol (chemotaxis). This divided the flies among
eight
habitats. The flies were further divided by the time of day of
emergence. In total the flies were divided among 24
spatio-temporal
habitats.
They next cultured two strains of flies that had chosen opposite
habitats. One strain emerged early, flew upward and was attracted
to
dark and acetaldehyde. The other emerged late, flew downward and
was
attracted to light and ethanol. Pupae from these two strains were
placed together in the maze. They were allowed to mate at the food
site and were collected. Eye color differences between the strains
allowed Rice and Salt to distinguish between the two strains. A
selective penalty was imposed on flies that switched habitats.
Females that switched habitats were destroyed. None of their
gametes
passed into the next generation. Males that switched habitats
received no penalty. After 25 generations of this mating tests
showed
reproductive isolation between the two strains. Habitat
specialization was also produced.
They next repeated the experiment without the penalty against
habitat
switching. The result was the same -- reproductive isolation was
produced. They argued that a switching penalty is not necessary to
produce reproductive isolation. Their results, they stated, show
the
possibility of sympatric speciation.
5.3.6 Isolation Produced as an Incidental Effect of Selection on
several Drosophila species
In a series of experiments, del Solar (1966) derived positively
and
negatively geotactic and phototactic strains of D. pseudoobscura
from
the same population by running the flies through mazes. Flies from
different strains were then introduced into mating chambers (10
males
and 10 females from each strain). Matings were recorded.
Statistically significant positive assortative mating was found.
In a separate series of experiments Dodd (1989) raised eight
populations derived from a single population of D. Pseudoobscura
on
stressful media. Four populations were raised on a starch based
medium, the other four were raised on a maltose based medium. The
fly
populations in both treatments took several months to get
established, implying that they were under strong selection. Dodd
found some evidence of genetic divergence between flies in the two
treatments. He performed mate choice tests among experimental
populations. He found statistically significant assortative mating
between populations raised on different media, but no assortative
mating among populations raised within the same medium regime. He
argued that since there was no direct selection for reproductive
isolation, the behavioral isolation results from a pleiotropic
by-product to adaptation to the two media. Schluter and Nagel
(1995)
have argued that these results provide experimental support for
the
hypothesis of parallel speciation.
Less dramatic results were obtained by growing D. willistoni on
media
of different pH levels (de Oliveira and Cordeiro 1980). Mate
choice
tests after 26, 32, 52 and 69 generations of growth showed
statistically significant assortative mating between some
populations
grown in different pH treatments. This ethological isolation did
not
always persist over time. They also found that some crosses made
after 106 and 122 generations showed significant hybrid
inferiority,
but only when grown in acid medium.
5.3.7 Selection for Reinforcement in Drosophila melanogaster
Some proposed models of speciation rely on a process called
reinforcement to complete the speciation process. Reinforcement
occurs when to partially isolated allopatric populations come into
contact. Lower relative fitness of hybrids between the two
populations results in increased selection for isolating
mechanisms.
I should note that a recent review (Rice and Hostert 1993) argues
that there is little experimental evidence to support
reinforcement
models. Two experiments in which the authors argue that their
results
provide support are discussed below.
Ehrman (1971) established strains of wild-type and mutant (black
body) D. melanogaster. These flies were derived from compound
autosome strains such that heterotypic matings would produce no
progeny. The two strains were reared together in common fly cages.
After two years, the isolation index generated from mate choice
experiments had increased from 0.04 to 0.43, indicating the
appearance of considerable assortative mating. After four years
this
index had risen to 0.64 (Ehrman 1973).
Along the same lines, Koopman (1950) was able to increase the
degree
of reproductive isolation between two partially isolated species,
D.
pseudoobscura and D. persimilis.
5.3.8 Tests of the Founder-flush Speciation Hypothesis Using
Drosophila
The founder-flush (a.k.a. flush-crash) hypothesis posits that
genetic
drift and founder effects play a major role in speciation (Powell
1978). During a founder-flush cycle a new habitat is colonized by
a
small number of individuals (e.g. one inseminated female). The
population rapidly expands (the flush phase). This is followed by
the
population crashing. During this crash period the population
experiences strong genetic drift. The population undergoes another
rapid expansion followed by another crash. This cycle repeats
several
times. Reproductive isolation is produced as a byproduct of
genetic
drift.
Dodd and Powell (1985) tested this hypothesis using D.
pseudoobscura.
A large, heterogeneous population was allowed to grow rapidly in a
very large population cage. Twelve experimental populations were
derived from this population from single pair matings. These
populations were allowed to flush. Fourteen months later, mating
tests were performed among the twelve populations. No postmating
isolation was seen. One cross showed strong behavioral isolation.
The
populations underwent three more flush-crash cycles. Forty-four
months after the start of the experiment (and fifteen months after
the last flush) the populations were again tested. Once again, no
postmating isolation was seen. Three populations showed behavioral
isolation in the form of positive assortative mating. Later tests
between 1980 and 1984 showed that the isolation persisted, though
it
was weaker in some cases.
Galina, et al. (1993) performed similar experiments with D.
pseudoobscura. Mating tests between populations that underwent
flush-crash cycles and their ancestral populations showed 8 cases
of
positive assortative mating out of 118 crosses. They also showed 5
cases of negative assortative mating (i.e. the flies preferred to
mate with flies of the other strain). Tests among the
founder-flush
populations showed 36 cases of positive assortative mating out of
370
crosses. These tests also found 4 cases of negative assortative
mating. Most of these mating preferences did not persist over
time.
Galina, et al. concluded that the founder-flush protocol yields
reproductive isolation only as a rare and erratic event.
Ahearn (1980) applied the founder-flush protocol to D. silvestris.
Flies from a line of this species underwent several flush-crash
cycles. They were tested in mate choice experiments against flies
from a continuously large population. Female flies from both
strains
preferred to mate with males from the large population. Females
from
the large population would not mate with males from the founder
flush
population. An asymmetric reproductive isolation was produced.
In a three year experiment, Ringo, et al. (1985) compared the
effects
of a founder-flush protocol to the effects of selection on various
traits. A large population of D. simulans was created from flies
from
69 wild caught stocks from several locations. Founder-flush lines
and
selection lines were derived from this population. The
founder-flush
lines went through six flush-crash cycles. The selection lines
experienced equal intensities of selection for various traits.
Mating
test were performed between strains within a treatment and between
treatment strains and the source population. Crosses were also
checked for postmating isolation. In the selection lines, 10 out
of
216 crosses showed positive assortative mating (2 crosses showed
negative assortative mating). They also found that 25 out of 216
crosses showed postmating isolation. Of these, 9 cases involved
crosses with the source population. In the founder-flush lines 12
out
of 216 crosses showed positive assortative mating (3 crosses
showed
negative assortative mating). Postmating isolation was found in 15
out of 216 crosses, 11 involving the source population. They
concluded that only weak isolation was found and that there was
little difference between the effects of natural selection and the
effects of genetic drift.
A final test of the founder-flush hypothesis will be described
with
the housefly cases below.
5.4 Housefly Speciation Experiments
5.4.1 A Test of the Founder-flush Hypothesis Using Houseflies
Meffert and Bryant (1991) used houseflies to test whether
bottlenecks
in populations can cause permanent alterations in courtship
behavior
that lead to premating isolation. They collected over 100 flies of
each sex from a landfill near Alvin, Texas. These were used to
initiate an ancestral population. From this ancestral population
they
established six lines. Two of these lines were started with one
pair
of flies, two lines were started with four pairs of flies and two
lines were started with sixteen pairs of flies. These populations
were flushed to about 2,000 flies each. They then went through
five
bottlenecks followed by flushes. This took 35 generations. Mate
choice tests were performed. One case of positive assortative
mating
was found. One case of negative assortative mating was also found.
5.4.2 Selection for Geotaxis with and without Gene Flow
Soans, et al. (1974) used houseflies to test Pimentel's model of
speciation. This model posits that speciation requires two steps.
The
first is the formation of races in subpopulations. This is
followed
by the establishment of reproductive isolation. Houseflies were
subjected to intense divergent selection on the basis of positive
and
negative geotaxis. In some treatments no gene flow was allowed,
while
in others there was 30% gene flow. Selection was imposed by
placing
1000 flies into the center of a 108 cm vertical tube. The first 50
flies that reached the top and the first 50 flies that reached the
bottom were used to found positively and negatively geotactic
populations. Four populations were established:
Population A + geotaxis, no gene flow
Population B - geotaxis, no gene flow
Population C + geotaxis, 30% gene flow
Population D - geotaxis, 30% gene flow
Selection was repeated within these populations each generations.
After 38 generations the time to collect 50 flies had dropped from
6
hours to 2 hours in Pop A, from 4 hours to 4 minutes in Pop B,
from
6
hours to 2 hours in Pop C and from 4 hours to 45 minutes in Pop D.
Mate choice tests were performed. Positive assortative mating was
found in all crosses. They concluded that reproductive isolation
occurred under both allopatric and sympatric conditions when very
strong selection was present.
Hurd and Eisenberg (1975) performed a similar experiment on
houseflies using 50% gene flow and got the same results.
5.5 Speciation Through Host Race Differentiation
Recently there has been a lot of interest in whether the
differentiation of an herbivorous or parasitic species into races
living on different hosts can lead to sympatric speciation. It has
been argued that in animals that mate on (or in) their preferred
hosts, positive assortative mating is an inevitable byproduct of
habitat selection (Rice 1985; Barton, et al. 1988). This would
suggest that differentiated host races may represent incipient
species.
5.5.1 Apple Maggot Fly (Rhagoletis pomonella)
Rhagoletis pomonella is a fly that is native to North America. Its
normal host is the hawthorn tree. Sometime during the nineteenth
century it began to infest apple trees. Since then it has begun to
infest cherries, roses, pears and possibly other members of the
rosaceae. Quite a bit of work has been done on the differences
between flies infesting hawthorn and flies infesting apple. There
appear to be differences in host preferences among populations.
Offspring of females collected from on of these two hosts are more
likely to select that host for oviposition (Prokopy et al. 1988).
Genetic differences between flies on these two hosts have been
found
at 6 out of 13 allozyme loci (Feder et al. 1988, see also McPheron
et
al. 1988). Laboratory studies have shown an asynchrony in
emergence
time of adults between these two host races (Smith 1988). Flies
from
apple trees take about 40 days to mature, whereas flies from
hawthorn
trees take 54-60 days to mature. This makes sense when we consider
that hawthorn fruit tends to mature later in the season that
apples.
Hybridization studies show that host preferences are inherited,
but
give no evidence of barriers to mating. This is a very exciting
case.
It may represent the early stages of a sympatric speciation event
(considering the dispersal of R. pomonella to other plants it may
even represent the beginning of an adaptive radiation). It is
important to note that some of the leading researchers on this
question are urging caution in interpreting it. Feder and Bush
(1989)
stated:
"Hawthorn and apple "host races" of R. pomonella may therefore
represent incipient species. However, it remains to be seen
whether
host-associated traits can evolve into effective enough barriers
to
gene flow to result eventually in the complete reproductive
isolation
of R. pomonella populations."
5.5.2 Gall Former Fly (Eurosta solidaginis)
Eurosta solidaginis is a gall forming fly that is associated with
goldenrod plants. It has two hosts: over most of its range it lays
its eggs in Solidago altissima, but in some areas it uses S.
gigantea
as its host. Recent electrophoretic work has shown that the
genetic
distances among flies from different sympatric hosts species are
greater than the distances among flies on the same host in
different
geographic areas (Waring et al. 1990). This same study also found
reduced variability in flies on S. gigantea. This suggests that
some
E. solidaginis have recently shifted hosts to this species. A
recent
study has compared reproductive behavior of the flies associated
with
the two hosts (Craig et al. 1993). They found that flies
associated
with S. gigantea emerge earlier in the season than flies
associated
with S. altissima. In host choice experiments, each fly strain
ovipunctured its own host much more frequently than the other
host.
Craig et al. (1993) also performed several mating experiments.
When
no host was present and females mated with males from either
strain,
if males from only one strain were present. When males of both
strains were present, statistically significant positive
assortative
mating was seen. In the presence of a host, assortative mating was
also seen. When both hosts and flies from both populations were
present, females waited on the buds of the host that they are
normally associated with. The males fly to the host to mate. Like
the
Rhagoletis case above, this may represent the beginning of a
sympatric speciation.
5.6 Flour Beetles (Tribolium castaneum)
Halliburton and Gall (1981) established a population of flour
beetles
collected in Davis, California. In each generation they selected
the
8 lightest and the 8 heaviest pupae of each sex. When these 32
beetles had emerged, they were placed together and allowed to mate
for 24 hours. Eggs were collected for 48 hours. The pupae that
developed from these eggs were weighed at 19 days. This was
repeated
for 15 generations. The results of mate choice tests between heavy
and light beetles was compared to tests among control lines
derived
from randomly chosen pupae. Positive assortative mating on the
basis
of size was found in 2 out of 4 experimental lines.
5.7 Speciation in a Lab Rat Worm, Nereis acuminata
In 1964 five or six individuals of the polychaete worm, Nereis
acuminata, were collected in Long Beach Harbor, California. These
were allowed to grow into a population of thousands of
individuals.
Four pairs from this population were transferred to the Woods Hole
Oceanographic Institute. For over 20 years these worms were used
as
test organisms in environmental toxicology. From 1986 to 1991 the
Long Beach area was searched for populations of the worm. Two
populations, P1 and P2, were found. Weinberg, et al. (1992)
performed
tests on these two populations and the Woods Hole population (WH)
for
both postmating and premating isolation. To test for postmating
isolation, they looked at whether broods from crosses were
successfully reared. The results below give the percentage of
successful rearings for each group of crosses.
WH ?? WH - 75%
P1 ?? P1 - 95%
P2 ?? P2 - 80%
P1 ?? P2 - 77%
WH ?? P1 -?? 0%
WH ?? P2 -?? 0%
They also found statistically significant premating isolation
between
the WH population and the field populations. Finally, the Woods
Hole
population showed slightly different karyotypes from the field
populations.
5.8 Speciation Through Cytoplasmic Incompatability Resulting from
the
Presence of a Parasite or Symbiont
In some species the presence of intracellular bacterial parasites
(or
symbionts) is associated with postmating isolation. This results
from
a cytoplasmic incompatability between gametes from strains that
have
the parasite (or symbiont) and stains that don't. An example of
this
is seen in the mosquito Culex pipiens (Yen and Barr 1971).
Compared
to within strain matings, matings between strains from different
geographic regions may may have any of three results: These
matings
may produce a normal number of offspring, they may produce a
reduced
number of offspring or they may produce no offspring. Reciprocal
crosses may give the same or different results. In an incompatible
cross, the egg and sperm nuclei fail to unite during
fertilization.
The egg dies during embryogenesis. In some of these strains, Yen
and
Barr (1971) found substantial numbers of Rickettsia-like microbes
in
adults, eggs and embryos. Compatibility of mosquito strains seems
to
be correlated with the strain of the microbe present. Mosquitoes
that
carry different strains of the microbe exhibit cytoplasmic
incompatibility; those that carry the same strain of microbe are
interfertile.
Similar phenomena have been seen in a number of other insects.
Microoganisms are seen in the eggs of both Nasonia vitripennis and
N.
giraulti. These two species do not normally hybridize. Following
treatment with antibiotics, hybrids occur between them (Breeuwer
and
Werren 1990). In this case, the symbiont is associated with
improper
condensation of host chromosomes.
For more examples and a critical review of this topic, see
Thompson
1987.
5.9 A Couple of Ambiguous Cases
So far the BSC has applied to all of the experiments discussed.
The
following are a couple of major morphological changes produced in
asexual species. Do these represent speciation events? The answer
depends on how species is defined.
5.9.1 Coloniality in Chlorella vulgaris
Boraas (1983) reported the induction of multicellularity in a
strain
of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by
predation. He was growing the unicellular green alga in the first
stage of a two stage continuous culture system as for food for a
flagellate predator, Ochromonas sp., that was growing in the
second
stage. Due to the failure of a pump, flagellates washed back into
the
first stage. Within five days a colonial form of the Chlorella
appeared. It rapidly came to dominate the culture. The colony size
ranged from 4 cells to 32 cells. Eventually it stabilized at 8
cells.
This colonial form has persisted in culture for about a decade.
The
new form has been keyed out using a number of algal taxonomic
keys.
They key out now as being in the genus Coelosphaerium, which is in
a
different family from Chlorella.
5.9.2 Morphological Changes in Bacteria
Shikano, et al. (1990) reported that an unidentified bacterium
underwent a major morphological change when grown in the presence
of
a ciliate predator. This bacterium's normal morphology is a short
(1.5 um) rod. After 8 - 10 weeks of growing with the predator it
assumed the form of long (20 um) cells. These cells have no cross
walls. Filaments of this type have also been produced under
circumstances similar to Boraas' induction of multicellularity in
Chlorella. Microscopic examination of these filaments is described
in
Gillott et al. (1993). Multicellularity has also been produced in
unicellular bacterial by predation (Nakajima and Kurihara 1994).
In
this study, growth in the presence of protozoal grazers resulted
in
the production of chains of bacterial cells.
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The FAQ | Must-Read Files | Index | Creationism | Evolution | Age
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the Earth | Flood Geology | Catastrophism | Debate
??Return to Papers & Articles
Evidence of Evolution
Speciation: the formation of new species:
??Speciation is essentially the process of "microevolution"
(mainly
through natural selection), typically over many generations,
during
which a new population of organisms accumulates sufficient
genetic,
physical, and/or behavioral changes that they can no longer mate
and
produce fertile offspring with members of the parent population.
This
new population is therefore considered as a new species. As this
process continues over time, more and more new species may
accumulate, and at some point they can all be considered
collectively
as a genus (category with two or more different species that are
very
similar, with evidence of relatively recent divergence into
species).
And so on, for the ever larger groupings in the hierarchy for
classifying organisms. [See Microevolution to Microevolution
presentation with diagram.]
Molecular Clues to Evolution
Macroevolution: Evolution on a Big Scale
Evidence for speciation
Observed Instances of Speciation
by Joseph BoxhornCopyright????1993-2004. [Last Update: September
1,
1995]
Evolution: Watching Speciation Occur | Observations (in Scientific
American online - Science Sushi)
Evidence for Evolution
The Evolution List: Macroevolution: Examples and Evidence
8 Examples of Evolution in Action
Mistakes That Argue for Evolution
Why Evolution is True
15 Evolutionary Gems (pdf)
Examples of Evolution(Understanding Evolution)
Transitional Fossils
Speciation in the Tragopogons (in the sunflower family):
??Polyploidy in Tragopogon spp. by hybridization in the wild (in
eastern Washington state):
??Cross pollinatios between T. porrifolius (2n=12) and T. dubius
(2n=12) produced the hybrid T. mirus (2n=24).
??Cross pollination between T. dubius (2n=12) and T. pratensis
(2n=12) produced the hybrid T. miscellus (2n=24).
??Each hybrid is now self-propagating (as two new species), and
neither can cross with its parent plants.
??Polyploidy (doubling the chromosome numbers) happened in a
single
generation.Tragopogon.spp.
---
Carl Sagan
??? Extraordinary claims require extraordinary evidence. ???
????? Carl Sagan
On 6/6/2019 3:18 PM, Mostafa wrote:
Well Carl, I certainly understand each and every term I use. What
you
said about that is not acceptable. You are exercising prejudice
once
again. I won't defer to these attempts to evade answering the
question. What has incredulity brought to you so far? I am quite
confident, not arrogant. People like Roger who hate religion have
reasons for that. These reasons are divided into two major
categories.
Actual motives and fraudulent causes. They fallaciously claim
that
science intercepts with fundamental religious propositions. They
thence submit to the doctrine of Darwinism. Well, it's just?? a
theory
of organic??evolution. It allegedly claims that new species arise
and
are perpetuated by natural??selection.?? . Nonetheless, this
averred
hypothesis hasn't yet been examined. Each and every supposed
proof
has
been countered. People in the scientific community who are dare
to
oppugn or oppose the Darwinian myth, are critically subjected to
redundancy and deprivation. Evolutionists act so strenuously to
keep
their sacred surmisal inviolate. So, as proven numerously,
science
is
not the real reason for them to decline and despise faith. If
anyone
acted presumptuously toward holy evolution, he is threatened with
being deposed. The theory of intelligent design is not even an
option
for those people. Why? Well, because the Darwinian excogitation
has
somewhat been coerced to be ecumenical. Its guardians have
incessantly
inhibited anyone who just attempts to doubt or interrogate its
factuality. Each and every physical substance is made of
Elements,
Atoms and Molecules. How has this rarified complexity been
brought
into its current state of perfection within the theory of
evolution?
A
molecule is the smallest particle of a substance that exists
independently. Curiously, how has this developed arbitrarily? I
never
measured scientific concepts to be of any opposition to Islam.
The
Koran talks about and occasionally, refers to scientific facts
such
as
the consecutive phases of an embryo, as it gradually maturates
inside
the womb. The Koran talks about that in details. This of course
would
offend someone like Roger, the never proved Biologist, because he
hates associating faith with human science. Is there anything in
classical Chemistry, Physics or Biology that refutes the
existence
of
God? Theology is in fact a psychical discipline. To those who
complain
about my use of vocabulary, this means settled outside the sphere
of
physical??science, mainly attained with human intellectual effort
and
development. I hope someone has the courage to confront what I
posed.
If someone has chosen to cowardly delude himself of eh, defeating
his
rival, this just counts as another form of evasion. It
furthermore
proves his utterly untutored disposal. He is impious,
impercipient
and
hence, empiricist. Have evolutionists purposely orientated
scientific
facts to make them fit their interest of maintaining mass
disbelief?
What scientists say about life after death? On what basis they
negate
its probability?
On 6/6/19, Carl Jarvis <carjar82@xxxxxxxxx> wrote:
Hi Roger,
What I try to point out to Mostafa is that his use of words
which
he
obviously does not understand, detract from whatever point he is
trying to make.
While I will never agree with Mostafa on his fundamental
religious
beliefs, I would like to be able to follow his rationale...or
what
passes for rationale.
I understand the difficulty of debating in a language that is
not
your
native tongue.
The cultural differences alone, make it very difficult to handle
the
subtle nuances.?? But Mostafa projects himself to me with a
"wiser
than
Thou" attitude.?? I find myself wanting to give him "tit for
tat",
but
in sober reflection, that would not be..."the Christian thing to
do".
What I envision is a cocky, brash young blind Egyptian man
trying
to
find his way through a difficult world.?? Maybe I'm imposing my
own
early years as a newly blind man.?? I keep thinking that given
time
and
understanding, he will modify his rather radical religious
posturing.
But, as my Grandma Ludwig used to say, "A closed mind gathers no
wisdom".
Carl Jarvis
On 6/5/19, Roger Loran Bailey <rogerbailey81@xxxxxxx> wrote:
That was a bit stilted, Carl, but I am inclined to look over
his
word
choice until it becomes incomprehensible. I think your
objection
is to
what are commonly called big words. For the most part they are
not
really big words. I have even heard the word id called a big
word.
What
they are is rare words. They are rare because they have subtle
meanings
and very specific meanings and connotations that are rarely
called
for.
Not too long ago I was accused of using the big word peruse. I
think the
person who did that did not even know the word at all and if I
had
known
that I would have avoided it. I explained that it meant to read
and
I
was asked why I didn't just say read. The reason I didn't say
read
was
because the specific context in which I was using it called for
the word
peruse to precisely convey my meaning. The trouble was that I
still did
not precisely convey my meaning if the person I was talking to
did
not
understand the word. But all these subtleties of word meaning
are
especially prone to get lost when someone is in incomplete
understanding
of the language. Have you ever learned a foreign language??? I
have.
Through all four years of high school I took Spanish classes.
When
I
graduated I felt like I was speaking Spanish fairly fluently.
But
don't
expect me to translate anything for you now. I have forgotten
so
much of
it through disuse that now if I listen to a Spanish language
broadcast
the best I can do is pick out an occasional word. I think I
might
be
able to pick out a few more words if they would only slow down.
But as
fluently as I thought I was speaking on my high school
graduation
I
might not have come off that way to a native speaker. I had no
native
speakers to test it on, though, so I can't be really sure. But
as
much
of the language as I have forgotten I seem to remember the
learning
process better than what I actually learned. Part of the
learning
process was memorizing vocabulary lists. Each word came with
the
English
equivalent. There was no attempt to define the words and
certainly
no
attempt to explain the specific contexts in which one word
meaning
essentially the same thing should be used instead of another
word.
Spanish-English dictionaries were the same except that they
usually
contained more Spanish equivalents for an English word than the
class
vocabulary lists did. I expect that some of these words were
more
rare
than others and there was no way for me to know the specific
contexts in
which a more rare word should be used rather than a more common
word.
You have to learn a language really well before you can start
picking up
on subtleties that fine. I imagine that is what Mostafa is
dealing
with
when he uses a so-called big word. It can be really hard to
tell
which
words are the rare ones and which contexts call for the rare
usage.
I
will admit, though, that sometimes I do find his misuse of some
words
irritating. I try to look over it, but when he uses the word
destine
where he should be using either the word mean or the word
intend
I
find
myself irritated by it. Still, though, I have to remind myself
that he
probably does not have a way to determine just in what contexts
the word
destine should be used. It is a little hard for me to explain
it
myself.
There is something that irritates me far more though. That is
why
he
seems to have bothered to learn English in the first place. It
appears
that he learned the language specifically to use it to beat
English
speakers over the head with his religion. Like I have said,
there
are
any number of religious people whom I have known with whom I
have
gotten
along with perfectly well. I don't bother them about their
religion and
they don't bother me with it. One thing I have a really hard
time
abiding, though, is a person who goes around harassing others
with
his
or her religion. That is what Mostafa does.
---
Carl Sagan
??? Extraordinary claims require extraordinary evidence. ???
????? Carl Sagan
On 6/5/2019 10:40 AM, Carl Jarvis wrote:
Mostafa,
Part of the problem here, although certainly not the central
problem,
but part of it is your use of the English language.?? You have
improved
greatly over the time you have been posting on Blind
Democracy,
but
you are still tossing out Word Salad that has little
meaning.??
If you
were to use more basic language, and check with the dictionary
the
meanings of the central words, you might be better
understood.??
This
is not to say that your positions are acceptable to me, but
they
would
be clearer and allow us to discuss them more comfortably.
Below?? is a sample.?? If you can, would you tell me in
American
English
just what your point is?
Carl Jarvis
"why are you so baited with the subject of faith? Is it
because
it urges fatuity and retardation? Or, it actually punches out
something into your perceptive conscience? You're attempting
quite
strenuously to evade confronting your own scruples.
Nonetheless,
these
attempts are unfortunately futile. Thence, you are so
rebellious,
malcontented and psychologically straitened with religion in
general.
What has incredulity brought to you so far?"
On 6/4/19, Mostafa Almahdy <mostafa.almahdy@xxxxxxxxx> wrote:
Roger, why are you so baited with the subject of faith? Is it
because
it urges fatuity and retardation? Or, it actually punches out
something into your perceptive conscience? You're attempting
quite
strenuously to evade confronting your own scruples.
Nonetheless,
these
attempts are unfortunately futile. Thence, you are so
rebellious,
malcontented and psychologically straitened with religion in
general.
What has incredulity brought to you so far? What am I going
to
attain
if I'd to embrace this enormously despondent notion? I stated
earlier,
despite what Carl has stereotypically prejudiced, I am
flawlessly
felicitous with being religious. My faith gives me hope and
aids
me to
cope. Haven't any of you examined the awkward phenomenon,??
that
disbelievers are more potential to be critically suicidal
than
others?
What am I suppose to strive for in the rough state of
disbelief?
I
wish to be presented with plain answers.
On 6/4/19, Roger Loran Bailey <rogerbailey81@xxxxxxx> wrote:
You aren't being of any help right now, Mostafa. Now let me--
try
again
with something that I have tried over and over to help you
with
before.
Without dying just how do you know that Allah exists and how
do
you
know
that hell exists? Try answering with the kind of answer that
you have
not tried yet. Give me an answer that has something to do
with
it
being
true. If you cannot do that - and I think you cannot because
you have
never been able to yet and no religious person in the
history
of
humanity has yet - then that would be a strong indication
that
there
is
no reason to believe it at all. But please be my guest.
Become
the
greatest prophet that ever lived. Be the first person who
can
actually
mount an argument for that absurd proposition that actually
addresses
its truth. If you cannot do that it doesn't help your
position
one bit
to start hurling insults and to start calling names. That is
exactly
what you have done before when you found one of my points
unanswerable.
This time if you cannot come up with an answer then let me
help
you.
If
you become ready to pay attention I will be glad to help you
understand
how to arrive at the truth.
---
Carl Sagan
??? Extraordinary claims require extraordinary evidence. ???
????? Carl Sagan
On 6/3/2019 3:59 AM, Mostafa Almahdy wrote:
Carl, when you die and go to hell, you will realise that
Allah
exists.
That's the time when I won't be able to help you.
On 6/3/19, Carl Jarvis <carjar82@xxxxxxxxx> wrote:
My Dear Mostafa,
I know, without your needing to tell me, that in your eyes
I
am
"worthless".?? You have made that clear all along. Not
just
for me,
or
Roger, but for everyone who dares disagree with your
"Truth".
I can only hope for a day when you awaken and realize that
your
Allah
is nothing but a paper tiger, the Wizard in the Wizard of
Oz.?? And
when the curtain is rolled away, you and all people of
Planet
Earth
will learn to trust themselves.
Cordially,
Carl Jarvis
On 6/2/19, Mostafa <ebob824@xxxxxxxxx> wrote:
Carl, you are worthless to me. That's it, adieu.
On 6/2/19, Carl Jarvis <carjar82@xxxxxxxxx> wrote:
Mostafa,
You wrote, "Religion has given my life a meaning. Yours
is
absolutely
meaningless."
And therein lies the problem.?? I, as an Agnostic, do
not
have the
power to enter your head and tell what you think, and
feel
what
you
feel.?? You, as a devout Man of Allah, feel that your
Absolute
Wisdom
enables you to enter my head and understand all about
me,
my
feelings,
my dreams and my culture.
To which I say, "Hog Wash!!!"
And by the way, my comment about my belief that you live
in
a more
precarious situation comes only via the news that is
aired
here in
the
USA.?? But if you say you live a safe life, I can accept
that.
However, I am not so self satisfied as to believe that
some
Great
Power is protecting me.?? Even if I believed that such a
Being
existed,
I am not such an important being that He would keep me
safe.?? You
seem
to feel that you are such a person.?? I recall a mine
accident back
around 1971, in Idaho.?? 92 miners were killed.?? Only 2
survived.
And
what did the one man say?
"God was watching over me!"?? So, God looked down and
saw
94 miners
about to be killed due to the lack of safety measures by
the mine
owners.?? God then said, "I can only save one or two of
these
fellows."
?????? And he allowed the others to "enter the gates of
Heaven".?? But
here's
a funny thing.?? The mine owners, the ones that had
allowed
their
equipment and tunnels to fall into disrepair, they went
on
living
the
Good Life.?? Mostafa, in my mind the Trinity consists of
God the
Father, the Power Hungry, and Greed.?? Every religion,
including
yours,
works to expand and to dominate all other
religions...and
all
people.
Believe what you will, but that is the sad and real
truth.
This is a true fact.?? I am not dumping on religions.??
It
is in the
nature of all religions.
Just the thought of looking down my nose at several
billions of
people
just because they refused to believe what I believe.??
How
selfish
and
arrogant!?? But it is what it is.
Cordially,
Carl Jarvis
On 6/2/19, Roger Loran Bailey
<dmarc-noreply@xxxxxxxxxxxxx>
wrote:
Mostafa, if you are so satisfied with your life then
why
do you
try
to
force your religion on others and why do you throw
tantrums when
you
have no refutation to a logical argument? Throwing
tantrums does
not
sound like the behavior of a complacent and satisfied
person.
---
David Hume
??? In our reasonings concerning matter of fact, there
are
all
imaginable
degrees of assurance, from the highest certainty to the
lowest
species
of
moral evidence. A wise man, therefore, proportions his
belief to
the
evidence. ???
????? David Hume,?? An Enquiry Concerning Human
Understanding
On 5/31/2019 4:17 PM, Mostafa wrote:
Carl, I do not live a far more precarious life than
you
in the
United
States. Your manner of referring to my life here
indicates
prejudice.
It also proves that you incorrectly assume I am
affected
with
any
of
the civil wars or the brutal famishments out there.
Fortuitously,
I
am
mentally confident and contented. My life is quite
stable
and it
hasn't been impacted with major dominance of
philistinism. Roger
seems
to be somewhat your mentor. Well, good for you. He
isn't
more
than
just a blind embracer of empiricism. Over the course
of
my
constant
debates with him, I proved to?? this unworthy
character
his
enormous
incompetency and unprecedented nescience of basic
rational
premisses.
He overused circular reasoning while fallaciously
presuming it's
counterfeit to do so. Back to Carl, has incredulity
solved world
junctures? As someone who doesn't believe in any form
of
deity
and
thence, has no purpose in life. What are you here for?
I
urge
you
to
search, as to why many people who do not believe, are
generically
more
potential to consider channeling suicidal thoughts and
acts. Why
many
people in your glorious nation periodically jump off
the
Golden
Gate
Bridge? Religion has given my life a meaning. Yours is
absolutely
meaningless. The state of unjustified disbelief is a
major
threat
to
natural human development. The gap broadens, as
disbelievers
lose
the
discernment of the supreme aim of this life.
Gradually,
they
become
numb to canonical perceptions and life thereupon
becomes
quite
terrifying and insignificant. So, if you are struck
with
a
toughly
catastrophic incident, who would you turn to for aid?
A
friend
of
mine
lives in Britain. He tells me, that a typical worker
there would
depart to the pub after his business day is over to
drink. This
happens on almost a routinely fashion. They do so to
distract
themselves from the arduous pressure they incessantly
are
besieged
with. I as a believer never had the pressure or the
stress that
demands such model of insalubrious beguilement. I am
pretty
satisfied
with my life. At least, I am not threatened with
someone
entering
a
public complex with a loaded rifle and insanely,
shoots
arbitrarily.
I
am safe here with the grace of Allah and His
providential
conservation.
On 5/31/19, Roger Loran Bailey <rogerbailey81@xxxxxxx>
wrote:
But you do seem to have a lot of time to waste with
silly
theology.
And
it is silly. It is silly because as long as you are
contemplating
and
working out the implications of premises that have
not
been
proven
to
exist every bit of that work is meaningless. As I
have
pointed
out
before, when a fantasy writer does the same thing it
is
called
world
building and the more time he or she invests in the
world
building
the
better the fantasy novel is. But when you just keep
up
the
world
building and you never write the fantasy novel you
are
doing
nothing
but
wasting your time. Again, Mostafa, you don't have to
do
this.
You
can
still give up the theology and have plenty of time
left
to make
something useful of yourself. You do not have to
antagonize
people
all
over the Internet. You are so determined to make
yourself
unpopular,
but
you really do not have to.
---
David Hume
??? In our reasonings concerning matter of fact,
there
are all
imaginable
degrees of assurance, from the highest certainty to
the
lowest
species
of
moral evidence. A wise man, therefore, proportions
his
belief
to
the
evidence. ???
????? David Hume,?? An Enquiry Concerning Human
Understanding
On 5/31/2019 9:16 AM, Mostafa wrote:
I don't have time to waste with some bunch of
rapscallions.
On 5/29/19, Carl Jarvis <carjar82@xxxxxxxxx> wrote:
In all my years as an interested onlooker, and as a
reformed
Christian, I have never known God to disagree with
those who
are
"Called" by Him.
The closest to that are those folks who tell me, "I
didn't
want
to
do
what God told me to do, but I had no choice".
Carl Jarvis
On 5/28/19, Roger Loran Bailey
<rogerbailey81@xxxxxxx>
wrote:
It was Robert Ingersoll who pointed out that
whenever
someone
asserts
that god wants something it always agrees with
what
the
person
making
the claim wants. Have you ever heard anyone say,
"I
don't
like
this,
but
god wants it."
---
David Hume
??? In our reasonings concerning matter of fact,
there are
all
imaginable
degrees of assurance, from the highest certainty
to
the
lowest
species
of
moral evidence. A wise man, therefore, proportions
his
belief
to
the
evidence. ???
????? David Hume,?? An Enquiry Concerning Human
Understanding
On 5/28/2019 8:48 PM, Carl Jarvis wrote:
Jews and Christians are one and the same
religion.??
Men
wrote
down
God's Word and followed that Word for
centuries.??
Then a
young
prophet
named Jesus came along, teaching as a Jewish
Teacher, and
when
he
was
murdered for his crimes against the Roman Empire,
his name
became
a
rallying point.?? New men wrote new rules as the
Word of
God,
changed
the Sabbath from Saturday to Sunday and claimed
to
have a
New
Testament.?? Most of the governing Word of this
new
fringe
group
was
written by Saul/Paul.
If we think that government can glut the world
with
piles
of
rules,
laws, regulations and interpretations of all that
stuff, we
should
understand that men...human people like you and
me,
can
write
mountains of words claimed to have fallen from
the
lips of
God.
But
it's all bogus.?? Just like government leveling
laws
to
protect
those
in power, *ALL religions set down volumes of Laws
aimed at
protecting
whatever God they are backing at the time.
Life would be so much easier if we would only
learn
to rely
on
our
inner selves, rather than feeling the need to
make
up
a
Superman
in
whom we are told we can place our total trust.??
And
the
very
first
teaching of each of our Gods is to smite our
opponents,
those
who
worship false gods.
Carl Jarvis
On 5/28/19, Mostafa Almahdy
<mostafa.almahdy@xxxxxxxxx>
wrote:
Antisemitism is a major crime everywhere in the
west. If
you
say
something that seems to be unfavourable to
Israel
and its
practices,
you will be instantly labeled as antisemite,
Jew-baiter,
hater
of
Jews. Are Jews uniquely the Semite people in the
Middle
East?
Not
too
many think so. They actually are claiming the
smallest
proportion
of
Semite subspecieses. So, Ethiopians and Arabs,
both
belong
to
Semitic
descent. Nonetheless, neither of them incites
western
people
if
they
were harassed or pestered. In fact, they
themselves
are
hassled
by
white westerns. I exposed how white western
Christians are
wholly
possessed by Jews. The latter fully controls
what
Christians
embrace.
Paul wrote for them a tremendous amount of their
scripture.
What
first
came in religion proceeded into politics and
beyond. How
many
Christian today opposes the move of US embassy
to
Jerusalem
proposed
by Trump the scoundrel? Not much of them.
Christians are
ridden
by
Jews. They are not ashamed of admitting that.
Jews
are the
ones
who
say we crucified Christ and Christians agree
with
them.
So,
we
could
conveniently assert, that Christians are
inspired
by Jews
to
formulate
their faith for them. Therefore, if someone
criticises
their
masters,
they'd call him antisemitic. Jews declined to
follow
prophet
Muhammad
because he came from Ishmael lineage. They
consider
the
great
grandfather of prophet Muhammad a pariah. They
wished the
last
messenger would have came from the posterity of
Isaac.
Thence,
they
justify their hostility to all Arabs.
Unfortunately,
Christians
are
codded by Jews to despise Arabs. Yes, because
most
of them
follow
the
prophet whom they previously rejected. Allah
confirms in
the
Koran
what I stated above. Jews lead, Christians
follow.
This is
why,
Christians generically are somewhat constrained
to
comply
to
what
Jews
desire. Each and every missile?? discharged into
the hearts
of
Palestinian children is paid up by US tax
revenue.
Taxpayers
in
the
US
are implicitly murdering innocent civilians on
virtually a
daily
basis. No one could deny this unless he has the
proof for
that.
What
do Christians think of Israel? Many of them say,
it
has
the
right
to
exist. Despite the fact that Jews have invaded
Palestine
and
displaced
its people into refugee camps, allegedly
peaceful
Christians
endorse
them. I therefore urge westerns to redress their
definition
of
antisemitism. It's crucial to do so.
--
(Seeking knowledge is compulsory from cratle to
grave
because
it
is
a
shoreless ocean.)
(Seeking knowledge is compulsory from cratle to grave because
it
is a
shoreless ocean.)
