Cool thread about the splitting of our beloved WESTERN SCRUB-JAY into two
different species.
I am fascinated by the discussions that relate to splitting or lumping
species of plants or animals. Or about hybrids that occur between
"different" recognized species I read a lot of the manuscript that Bob
Archer provided earlier .... here it is again.
http://www.aoucospubs.org/doi/pdf/10.1642/AUK-16-77.1
Several times the evidence for making the species split is given as ....
"Differences in morphology, ecology, vocalizations", etc .... But there
appears to be little/no evidence or mention of the inability to
hybridize/mate and generate normal and fertile offspring/progeny that can
successfully mate again.
Even though there is some debate about what constitutes speciation, "the
biological species concept" would state simply that .... If two organisms
(plant/animal/fungi) can mate and produce fertile offspring, then they are
the same species. Granted this can be harder to "check" in animals vs
plants. Physical isolation for centuries can cause changes in morphology,
but it doesn't necessarily change speciation. With genomic technology
available today, it is quite simple to show clear significant differences
in DNA sequences between very different individuals of the same species.
The use of sub-species classification is commonly used, and provides a good
option for where there are differences in morphology, vocalizations
or ecology, but mating status is unknown. Domestic dog used to
be considered a different species than wolves, but that has recently been
revised so that domestic dog is now a sub-species of wolf due to the fact
that they can successfully interbreed and dogs are selected descendants
from wolves.
Lumping or splitting is an ongoing debate in the taxonomic world.
Good birding!
Roger Freeman
