Adaptation Flashcards
(10 cards)
What is an adaptation?
A feature produced by natural selection that allows an organism to survive and reproduce better than if it lacked it.
What is the function of an adaptation?
The survival benefit of having that adaptation.
What are the principles of adaptation through natural selection?
- adaptation is ‘undirected’
- it results from different survival value of alternative alleles
- alternatives arise from random mutations which are not necessarily advantageous
What is a co-adaptation?
A complex adaptation involving multiple compatible changes at the same time.
e.g. eyes
What is a preadaptation?
A previous adaptation that had a different function to what its it used for today.
e.g. feathers in dinosaurs were adaptations because they wouldn’t have been used for flight (like birds) but temperature control or signalling.
What is an exadaptation.
A characteristic that performs a different function to the reason it evolved. (preadaptations become exadaptations)
What is a spandrel?
A side effect of an adaptation.
e.g. the large brain size in humans is an adaptation for foraging in a complex environment.
The spandrels of that is our advanced cognitive skills: produce art, science etc
Why are some fruits in South America too large to be eaten by anything?
Time lag.
10,000 years ago they were adapted to be eaten by large mammals like the giant sloth, but since they became extinct the fruit hasn’t adapted to its new environment.
How do genetic factors constrain adaptation?
If a heterozygote has higher fitness than either homozygote the population evolves to an equilibrium.
The heterozygote will still produce offspring that are homozygote, so some individuals in the population will have lower fitness.
How are historical factors sometimes a constraint?
The physiology of our ancestors can limit the adaptations in modern organisms.
e.g. the vagus nerve takes a complex route that doesnt make sense without looking at the physiology of fish (that we evolved from)
