Unit 2 Evolution Test

• Population


  A group of organisms of the same species living in the same area
• Macroevolution


  Evolution on a grand scale, change over a long period of time, e.g. evolution of a new species
• Microevolution


  Small scale evolution, changes in gene frequencies within a population over time, may lead to new species
• Genetic equilibrium


  A population where allele frequency remains the same over generations
• Allele frequency


  The percentage of a specific allele in a gene pool
• Factors that change allele frequencies

  • Mutation
  • Gene flow
  • Non-random mating
  • Genetic drift
  • Natural selection
• Types of genetic drift

  • Founder effect - Change in gene pool when a few individuals start a new isolated population
  • Bottleneck effect - Changes in gene distribution due to rapid population decrease
• Types of natural selection

  • Stabilizing selection - Favors intermediate phenotype
  • Directional selection - Favors one extreme
  • Disruptive selection - Favors extremes
• Sexual selection


  Natural selection based on competition between males and choices made by females
• Species


  A group of organisms that can interbreed and produce fertile offspring
• Speciation


  The formation of new species, a continuous process
• Pre-zygotic isolating mechanisms


  • Habitat isolation
  • Temporal isolation
  • Behavioral isolation
  • Mechanical isolation
  • Gametic isolation
• Post-zygotic isolating mechanisms


  • Zygote mortality
  • Hybrid inviability
  • Hybrid infertility
• Allopatric speciation


  Speciation that occurs when populations are geographically isolated
• Sympatric speciation


  Speciation that occurs without geographic isolation
• Adaptive radiation


  The rapid evolution of diverse species from a single ancestral species
• Types of evolution


  • Convergent evolution - Unrelated species evolve similar traits
  • Divergent evolution - Related species evolve different traits
  • Adaptive radiation - Rapid evolution of diverse species from a single ancestral species
• Co-evolution


  The evolution of two or more species that are interdependent, e.g. flowering plants and pollinating insects
• Gradualism


  The hypothesis that evolution occurs through small, gradual changes over long periods of time
• Punctuated equilibrium


  The hypothesis that evolution occurs through long periods of little change punctuated by rapid bursts of change
• Humans reduce habitats through activities like urbanization, agriculture, and resource extraction
• It is important to review and study all notes as well as complete practice questions