sarima@gryphon.CTS.COM (Stan Friesen) (05/15/88)
In article <819@ucsd.EDU> akkana@brain.UCSD.EDU (Akkana) writes: >In article <564@pedsga.UUCP> lae@pedsga.UUCP (Leslie Ann Ellis) writes: >>I seem to recall from my Physical Anthropology course that speciation >>is defined as occuring when the parts of a population that become >>physically isolated from each other either: >>1) Can no longer breed successfully, >>or >>2) Produce sterile offspring. > >I've heard that, but it doesn't seem consistent with current taxonomy. >What about dogs (Canis familiaris) and wolves (C. lupus) and >coyotes (C. latrans or something like that)? ... >Are dogs and wolves now considered to be the same species? No, they are not. The actual definition of species as it is now used is quite subtle. It is based on failure to interbreed when the opportunity arises *under *natural* conditions*. The dog-coyote and dog-wolf hybrids are due to the disturbance caused by human habitation and the ecological chaos it produces. There are quite a number of other examples where reporductive isolation breaks down between two otherwise well seperated species in areas of significant man-made disturbance. It seems that cleared and altered landscapes so change the interactions of organisms that normal isolating mechanisms fail to work. (Actually a case could be made for including dogs in Canis lupus, since they are apparently derived from a dwarf variety Asian Wolf) -- Sarima Cardolandion sarima@gryphon.CTS.COM aka Stanley Friesen rutgers!marque!gryphon!sarima Sherman Oaks, CA