Basics of Evolution
A variation that increases fitness
Adaptation
If females or males choose their mates based on a physical characteristic
non-random mating
When two species share a lot of DNA they are said to be
More related; descended from a common ancestor
A trait that has a common origin in a clade
Derived characteristic
A dramatic event that causes a large number of species to become extinct around the same time
Mass extinction
Homologous structures
Evolution that occurs by chance
Genetic Drift
When two groups cannot reproduce together
Reproductive isolation
Unicellular, prokaryotic organisms whose cell walls contain peptidoglycan
Bacteria
Gradualism
A structure that was inherited from ancestors, but has lost its size and function
Vestigial structure
When some individuals have higher fitness than others, this process will drive evolution
Natural selection
When individuals at both ends of the phenotype curve have a higher fitness than individuals in the center of the curve
Disruptive selection
Autotrophs whose cell walls contain cellulose; part of domain eukarya
Plantae
When two or more organisms evolve together
Coevolution
All of the genes and alleles in a population
Gene pool
When allele frequencies are not changing and the population is not evolving
Genetic equilibrium
When two groups evolve differences in mating rituals
Distinctive fossils that are found in only a few layers, all over the world that help scientists with relative dating
Index fossils
Theory that suggests eukaryotes arose from the fusion of two prokaryotic cells
Endosymbiont theory
One type of genetic recombination: the transfer of genes between two individuals, primarily in bacteria and archaea
Lateral gene transfer
Movement of genes into or out of the population
Gene flow
When two groups reproduce at different times of the year
Amount of time required for half of the radioactive atoms in a sample to decay
Half-life
Process where a single species evolves into several distinct species
Adaptive radiation