Evolution Flashcards
Define ‘phylogeny’
the diversification of lineages through evolutionary descent with modification
State the simplest type of phylogeny
3 groups (species)
What are the uses of phylogeny? (3)
”- Track patterns of evolution of traits
- Test for convergent evolution (= independent evolution of similar traits)
- Examine correlation of ““trait”” evolution
- e.g species & continents (= biogeography), hosts & parasites, adaptation & diversification
Define ‘anagenesis’
gradual transformation (along branches) of one species into another (i.e rapid extinction of the ancestor); one ancestor is tranformed into the descendant
Define ‘cladogenesis’
rapid splitting of a species into two or more parts (at nodes) instead of just transforming it into one species (creates biodiversity)
State the sources of variation (4)
”- Mutation
- Recombination, independent assortment, segregation, etc.
- Phenotypic plasticity
- Constraints”
State the modifiers of variation (3)
”- Natural selection
- Sexual selection
- Genetic drift”
Define ‘adaptation’
a trait that enhances fitness and that arose historically as a result of natural selection for its current biological role
State what adaptation requires (4)
”- feature
- more offspring reproducing
- favoured by natural selection
- appear in conjunction w/ its current function in its environment (was not previously used for another function)”
Define ‘key innovation’
a novel trait that originated in a particular lineage, providing evolutionary “advantages”
State alternative explanations for adaptation (8)
”- Phylogenetic constraint
- Design constraints prevent the optimal
- Sexual selection
- Neutral features
- Co-variation w/ other traits
- Exaptation
- Random genetic drift
- etc.”
How do species undergo adaptive radiation?
Diversification of ecologies and phenotypes can cause key innovation
