Studying Adaptation

Define” adaptationist program”

Research leading to an understanding of the adaptive significance of traits

Know that an adaptationist hypothsis is simply a hypothesis

just because you can make a plausible adaptationist hypothesis about a trait does NOT mean that that trait is an adaptation or that your hypothesis about its functionality and fitness value is true. (examples: polar bear fur, giraffe’s neck)

Describe why a trait might exist in a population even if it is not an adaptation

Evolution can also occur by genetic drift, some uses of organs are “incidental” and not selected for, there are trade-offs and constraints that limit “effectiveness” of selection

After reading about and discussing several examples of tests of adaptationist hypotheses, be able to propose strategies for testing a novel hypothesis.

Several examples in chapter 9, and in Evolution video series.

Describe how phenotypic plasticity can complicate the study of adaptations and know that phenotypic plasticity itself can be an adaptation.

many traits are influenced by both genes and environment – trait has one appearance in one environment and another in different environment

Define “evolutionary tradeoff” and describe how it limits adaptation.

jack of all trades is a master of none

Flower size in begonia

Know that natural selection can only act on the phenotypic variance that is “available”

Sometimes adaptations appear that don’t seem optimal, but are “the best that can be done” given the constraints of physiology or development.

Flower color in Fuschia

some adaptations do not exist because genes that code for that adaptation do not exist in the population.

Host shifts in herbivorous beetles

Know that natural selection is situational