Real species - two mechanisms?

[JOCQUE Rudy]

It would seem that what some of us consider to be species is  the result of  two clearly different mechanisms. Speciation in allopatry results in clines of forms that are gradually drifting apart. Vast distributions may have the same effect  and may give rise to a circle of subspecies. There is no doubt there that telling these forms apart is very subjective.

In the other case ( speciation in sympatry), we deal with discrete steps (punctuated equilibrium). So we are facing strongly different forms without intermediates. But in the course of speciation these apparently occur within the same species! Such polymorphism is well documented in certain spiders and insects. In my opinion these are indeed steps in the  speciation process and only when the intraspecific recognition system changes, the way conspecifics recognize each other,  speciation is complete. In that scheme  it is arguable that we deal with “real species” whereas in the former we have clines that are often cut up artificially and for which  the different subgroups can thus not be regarded as real species.

--

Rudy JOCQUÉ
Royal Museum for Central Africa 
B-3080 Tervuren
Belgium
TEL  32 2 7695410
FAX  32 2 7695695
e-mail: jocque at africamuseum.be



###########################################

This message has been scanned by ICT - Africa Museum