Chapter 24 Flashcards
this is the origin of new species and is the focal point of Darwin’s evolutionary theory
speciation
this consists of adaptations that evolve within a population, confined to one gene pool
microevolution
this refers to evolutionary change above the species level
macroevolution
describe the biological species concept
a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations
this is the existence of biological factors that impede two different species from producing viable, fertile offspring
reproductive isolation
these are offspring of crosses between different species
hybrids
what are some ways that prezygotic barriers black fertilization from occurring
impeding different species from attempting to mate, preventing the successful completion of mating, hindering fertilization if mating is successful
examples of prezygotic barriers include…(5)
temporal, habitat, behavioral, mechanical, and gamete isolation
what is habitat isolation
when two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers
what is temporal isolation
species that breed at different times of the day, different seasons, or different years cannot mix their gametes
what is behavioral isolation
courtship rituals and other behaviors unique to a species are effective barriers
what is gametic isolation
sperm of one species may not be able to fertilize eggs of another species
what are postzygotic barriers
those that prevent the hybrid zygote from developing into a viable, fertile adult
what are the three types of postzygotic barriers
reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown (1st gen is fertile, 2nd is not)
this is a weakness in the biological species concept
cannot be applied to fossils or asexual organisms
this defines a species by structural features
the morphological species concept
weakness of the morphological concept
it relies on subjective criteria
this views a species in terms of its ecological niche
ecological species concept
this defines a species as the smallest group of individuals on a phylogenetic tree
phylogenetic species concept
weakness of the phylogenetic species concept
can be difficult to determine the degree of difference required for separate species
what are the two types of speciation
allopatric (geographic barrier), and sympatric (no geographic barrier)
this is the presence of extra sets of chromosomes due to accidents during cell division
polyploidy
this is an individual with more than two chromosome sets, derived from one species
autopolyploid
this is a species with multiple sets of chromosomes derived from different species
allopolyploid
