4.1 Macroevolution

what can lead to speciation?

natural selection over long periods of time (due to environmental change)

what is speciation?

the creation of new species through incremental natural selection within breeding populations

what can result in rapid changes (i.e. hox genes)

natural selection of pleiotropic developmental gene mutations

what is the most important microevolutionary force for introducing new variation?

mutation

what can evolution not occur without?

variation

what is gene flow?

the reshuffling of genetic information between two breeding populations of the same species

what is the most important microevolutionary force for directing genetic variation?

natural selection

what is an adaptation?

a gene/trait that is the result of natural selection

what is allopatric speciation?

geographic separation/division

what is sympatric speciation?

local behavioral / niche separation

what is an example of allopatric speciation?

Darwin’s finches

what is an example of sympatric speciation?

squirrels and chipmunks exploiting different aspects of the same environment and inhavit different

evaluation of macroevolution

different adaptations with similar underlying structure and related evolutionary history

what is an example of vestigal structures?

hip sometimes found in some baylean whales

what are some examples of human vestigal genes?

male nipples

what are analogous structures?

structures with similar adaptation and appearance but different underlying structure and evolutionary history

what is an example of analogous structure?

an insect’s wing (soft tissue) vs. bird’s (muscles & feathers) vs. bat’s (fingers; tissue between)

what are properties of linear evolution?

incremental changes (theoretically, present couldn’t go back in time and breed because enough genetic changes have accumulated over time so that they are no longer compatible)

what are properties of divergent evolution?

two subpopulations that separate for some reason (behavioral/geographic)

what are properties of adaptive radiation?

rapid divergence of a species that occurs when new environments open up to that species (something that results in divergent evolution)

what are properties of convergent evolution?

very distinct, unrelated forms that undergo similar selective pressures to similar habitats