Light and dark color morphotypes, perhaps incipient species
, live off Argentina (Venurus et al.
Another reason is that, to Darwin, he is not an "incipient species
" (53), one whose variation of the reproductive drive, a variation in structure brought about by the environment, a structure transferable to the next generation and inheritable from an earlier one is qualified to be so classed.
may be incipient species
may be strengthened by our own recent molecular data that indicate that chromosomally identified larvae of S.
Variations on that skeletal theme at the African site and elsewhere arose from "short evolutionary experiments in small and fairly isolated populations that may have gone extinct as incipient species
," he argues.
These varieties may be incipient species
; more collection in the remote areas where they live is essential to unders tand better how isolated they are and whether they are genetically differentiated from the wide-ranging type variety.
Courtship rituals and reproductive isolation between the races or incipient species
of Drosophila paulistorum.
Further work on other floral characters as well as the soil ecology and population genetics is needed to understand how these incipient species
were established and to predict their likely long-term fate.
When discussing the significance of differences resulting from single or successive fusions or fissions it is common to ascribe their importance solely to postmating barriers to gene exchange and the progressive isolation of populations and incipient species
that result (cf.
But the effect on congruence of gene trees and species trees would depend on how speciation occurs; that is, whether the incipient species
arises in a geographically localized area or from the whole of the ancestral species population.
, presumably, later became isolated because mate choice was connected either ecologically or genetically to gall location (as with host races; Craig et al., 1993).