Evolution
Change in allele frequencies of a population over generations
Natural Selection
Individuals with specific traits survive or reproduce viable offspring more, so these traits become more common
Adaptation
A heritable trait that increases an organisms fitness
Extant
A species that is currently living
Extinct
A species that no longer exists
Fossil
Any preserved remains, impressions, or traces of past organisms
Fossil record
Collection of all fossils that documents the history of life and evolutionary change
Transitional feature
A reduced structure with little or no current function, inherited from an ancestor where it was functional
Phylogeny
Hypothetical branching diagram that represents evolutionary relationships and common ancestries
Homology
Similarity due to shared ancestry
Homologous structures
Have same common ancestor but structures have different functions now
Analogy
Similarity due to similar function (not shared ancestry)
Analogous structures
Structures that perform similar functions but evolved independently
Divergent evolution
Evolution of differences among related species as they adapt to different environments
Convergent evolution
Independent evolution of similar traits in distantly related species due to similar environments/selective pressures
Darwin’s four postulates (evolution b/c natural selection)
- Individuals vary in traits
- Some variation is heritable
- More offspring are produced than can survive
- Individuals with advantageous traits have higher success
Artificial selection
Human-directed breeding that increases the frequency of desired traits
Maladaptation
A trait that reduces an organism’s fitness in its environment
Fitness
An individuals survival and reproductive success relative to others in the population
Biogeography
Geographic distribution of species and how it relates to evolution
Acclimation
short-term, reversible adjustment to environmental change
Trade-off
When an adaptation improves one trait but compromises another
