unit 9 notes 4 and 5 Flashcards
What are the 3 types of natural selection?
Stabilizing, Directional, Disrupitive
Define stabilizing selection
Favors the average indiviual
- reduces variation in a population
Define Directional selection
Favors one of the extrem variations
Define Disruptive selection
Favor both extremes of a variation
- 2 new species evolve
Define speciation
the evolution of a new species
When does speciation happen?
when 2 similar populations can no longer interbreed
Define geographic isolation
When 2 popluations are seperated by geographic barriers, like rivers or mountains
Define adaptive radiation
when 1 species evolves into many different species because of different environments
Define Divergent evolution
A pattern of evolution where 1 species evolves into different species with different traits
what structures show divergent evolution?
Homologous structures (are similar internally)
Defene convergent evolution
where unrelated organisms evolve into forms that resemble each other
What structures show convergent evolution?
Analogous structures (are similar externally)
Define gradualism
Species evolve through a slow, steady change in adaptations
Define punctuated equilibrium
Species evolve quickly, in rapid bursts, and than there are long periods with no change
