Species & Speciation Chapter 22 Flashcards
species are ____ from other species
reproductively isolated
species are a ___ gene pool
closed
what does the biological species concept say?
species are groups of interbreeding organisms that are reproductively separated from one another
why does reproductive compatibility mean more than just making babies?
because it also has to do with making babies who can also have babies
____ still counts as reproductive isolation
geographical separation
which is the better concept to use and why?
morphospecies because it holds that members of the same species look alike-also extended to similar DNA sequences
___ discredit the morphospecies concept
polymorphisms
some species meet ___ criteria and not ___
biological species concept; morphospecies concept
what are cryptic species?
organisms that people thought were 1 species but in reality are 2
what are some problems with the BSC?
- doesn’t apply to asexual or extinct species
- ring species & hybridization complicate it
ring species
populations that are reproductively but not genetically isolated
how does ring species occur?
gene flow through intermediate populations
hybridization
interbreeding
why does hybridization complicate the BSC?
because these different forms should be considered one large species bc they are able to reproduce and produce fertile offspring but bc they maintain their distinct appearances, natural selection works against the hybrid offspring
what is the evolutionary species concept?
different species means having different nutritional needs
what is the phylogenetic species concept?
requires that all members of a species are descended from a single common ancestor. but it’s limited
why are the ESC and PSC used?
to broaden the BSC concept
what are pre-zygotic isolating factors?
prevent fertilization from taking place
what are post-zygotic isolating factors?
when fertilized egg develops into fertile organism
behavioral isolation is a type of
pre-zygotic factor
involves specific courtship rituals, songs, etc.
gametic isolation is a type of
pre-zygotic factor
2 different species can’t mate/cross because they’re incompatible