Evolution

• Fitness


  ability of organism to survive and reproduce fertile offspring
• Species


  group of organisms that can breed and produce fertile offspring together
• Population


  individuals of the same species that live in the same area and can breed together
• Gene Pool

  all of the alleles in a population at any one time
• Allele Frequency


  how often a gene appears in a gene pool relative to the other alleles for that gene
• What does selective pressure lead to?

  changes in phenotypes of a population
• Directional selection


  shift of a population toward an extreme version of a beneficial trait
• Disruptive selection

  favors individuals at both extremes but not the median.
• Stabilizing selection

  favors median and reduces variation
• Sexual Selection

  organisms with particular traits are more likely to find mates
• Sexual Dimorphism


  distinction in appearance of sexes
• Bottleneck effect

  A change in allele frequency following a dramatic reduction in the size of a population
• Founder effect


  change in allele frequencies as a result of the migration of a small subgroup of a population
• Genetic Drift

  random changes in allele frequencies that happen by chance and occur in small populations
• Gene Flow


  immigration and emigration causes population to gain or lose alleles
• Microevolution


  occurs over short period of time within a population/species
• Macroevolution

  occurs over geologic time above the level of the species
• What are the 5 evidences of evolution?

  Biogeography, fossil records, embryology, anatomy, genetics
• Biogeography


  study of distribution patterns between living species and fossils of extinct/extant species
• Convergent Evolution


  unrelated species with similar ecological conditions/similar pressures can look alike
• What does embryology tell us?

  evidence that organisms have descended from a common ancestor
• How is embryology evidence of evolution?

  embryos develop in similar patterns across varied species but features present in embryo are not present at birth
• Homologous Structures

  Structures in different species that are similar because of common ancestry.
• Analogous Structures


  Body parts that share a common function, but not structure
• Vestigial Structures


  remnant of structure an ancestor had, but has lost its function in modern species
• How do genetics prove evolution?

  common proteins across different species
• What are the 4 factors of evolution?

  mutations, gene flow, genetic drift, natural selection
• Natural Selection


  Individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
• Artificial Selection

  the selective breeding of organisms by humans for specific characteristics
• Speciation

  process by which a new species evolves
• Allopatric Speciation


  some members of a species become geographically separated and overtime evolve genetic differences that prevent them from breeding with orignal species
• Sympatric Speciation


  a new species forms without geographic seperation
• Coevolution

  Process by which two species in symbiotic relationships evolve in response to changes in each other
• Gradualism


  when geologic and climatic conditions are stable, evolution may occur slowly
• Punctuated Equilibrium


  when geologic and climatic conditions are changing, evolution may occur quickly
• Adaptive Radiation

  An evolutionary pattern in which many species evolve from a single ancestral species