Evolution
Change in allele frequency in a population over time.
Population
The same species living in the same area and reproduce with each other.
Allele frequency
How often an allele occurs in a population. Can be showed as ratio or percentage.
Genetic variation
Presence of different genes for a trait in a population.
Gene pool
All the genes in a population.
Mutations
Random changes in DNA sequence. Increases genetic variation by adding new alleles to a gene pool.
Gene Flow
Individuals entering and leaving a population taking their genes with them.
Genetic Recombination
Recombining genes during crossing over in meiosis.
Genetic Drift
Random acts that affect a population's genetic variation.
Founder effect
Loss of genetic variation from a small population forming from leaving a larger population.
Natural Selection
Organisms with adaptations survive and reproduce passing on those traits to the next generation causing change in gene pool in the population over time. Drives evolution.
Adaptations
Traits that are beneficial to an organism to help them survive and reproduce. Can be physical, chemical, or behavioral.
Comparative Anatomy
Comparing the physical structures of different species to determine evolutionary relationship.
Homologous structures
Structures that are similar in different species suggesting they came from a common ancestor.
Comparative Embryology
Comparing the embryo development in different species. Similar development suggests a shared common ancestor.
Vestigial structures
Structures that do not have a function in today's organism, but did in the ancestor.
Fossils
Shows organisms that lived in the past and transitional species.
Comparative Molecular studies
Comparison of amino acid sequences from different species to show evolutionary relationships. Organism with more similarities are more closely related.
Universal Genetic Code
All organism have the same codons code for the same amino acids giving evidence that all life formed from a common ancestor.
Species
Group of organisms that look alike, can reproduce with one another, and produce viable offspring (offspring that can reproduce).
Speciation
Formation of a new species
Geographic Isolation
A population separated by geographic barrier resulting in isolation of gene pool and eventual speciation.
Genetic Isolation/Reproductive Isolation
When populations are separated and can no longer interbreed.
Phylogenetic tree
Diagram that shows evolutionary relationships among different species.