Evolution Flashcards
What are the three things required for evolution by natural selection?
Heritability of trait, variety of trait, differential selection
Define natural selection
The nonrandom mechanism by which the frequency of a trait in a population changes over time due to the beneficial or detrimental effect that it has on an organism’s ability to survive and pass on the trait.
Define evolution
The change in the frequency of a trait over time in a population
What are the four mechanisms of evolution?
Natural selection, genetic drift, mutation, and migration
What is fixation?
When the variety of a certain trait drops to zero (i.e. all the members of the population possess the same variation of that trait)
Define genetic drift
The change in the frequency of a certain trait in a population over time due to random chance alone
What does population size have to do with genetic drift?
Smaller populations are affected more strongly by genetic drift because it is easier to skew the frequency of a trait in a smaller population
How can natural selection or genetic drift cause biodiversity?
If these forces are applied differently to populations of the same species in different geographic regions, the populations can become different from each other and diverge
What facilitates the diversity of life via natural selection or genetic drift?
The presence of a physical barrier to separate a population into groups where the mechanisms of evolution can manifest themselves differently (e.g. island, mountain range, river, etc.)
