Final Exam

Evolution Definition & Forces of Evolutionary Change:

• Evolution: A change in allele frequencies within a population over time.

• Forces of Evolution:

  • Natural selection

  • Mutation

  • Gene flow (migration)

  • Genetic drift (bottleneck and founder effects)

  • Non-random mating

2. Bottleneck Event & Founder Effect:

• Bottleneck Event: A sharp reduction in the size of a population due to environmental events (e.g., natural disaster), leading to loss of genetic diversity.

• Founder Effect: When a small group of individuals establishes a new population, the genetic diversity of the new population is limited to the genes of the founders.

3. Hardy-Weinberg Principle (Equilibrium):

• The population’s allele frequencies remain constant unless acted on by evolutionary forces.

• Conditions: no mutation, random mating, no natural selection, large population, and no gene flow.

4. Convergent vs Divergent Evolution:

• Convergent Evolution: Unrelated species evolve similar traits due to similar environmental pressures (analogous structures).

• Divergent Evolution: Related species evolve different traits due to different environmental pressures (homologous structures).

5. Types of Speciation:

• Allopatric: Geographic separation leads to speciation.

• Peripatric: A small group is isolated at the edge of a larger population, leading to speciation.

• Parapatric: Populations are adjacent but have no geographic barriers.

• Sympatric: Speciation occurs without geographic isolation, often due to ecological niches or behavioral differences.

6. Prezygotic vs Postzygotic Barriers:

• Prezygotic: Barriers before fertilization (e.g., behavioral isolation, temporal isolation).

• Postzygotic: Barriers after fertilization (e.g., hybrid infertility, hybrid breakdown).

7. Natural Selection Types:

• Directional Selection: Favors one extreme phenotype.

• Stabilizing Selection: Favors average phenotypes.

• Diversifying (Disruptive) Selection: Favors extreme phenotypes at both ends.

8. Hybrid Zone Changes (Reinforcement, Fusion, Stability):

• Reinforcement: Strengthening of reproductive barriers.

• Fusion: Two species merge into one.

• Stability: Continued hybridization but no significant speciation.

9. Cline:

• A gradual change in a trait or genetic variation across a geographic area.

10. Evolutionary Fitness:

• The ability of an organism to survive and reproduce in its environment, passing on its genes.

11. Sexual Selection:

• Intrasexual Selection: Competition among same-sex individuals.

• Intersexual Selection: Mate choice based on traits.

Viruses, Prokaryotes, Protists, Fungi

12. Viruses, Viroids, Prions:

• Viruses: Infectious particles made of nucleic acid and protein.

• Viroids: Small circular RNA that infect plants.

• Prions: Infectious proteins that cause diseases (e.g., mad cow disease).

13. Prokaryotes vs Eukaryotes:

• Prokaryotes: No nucleus, smaller, single-celled (e.g., bacteria).

• Eukaryotes: Nucleus, larger, single or multicellular (e.g., plants, animals, fungi).

14. Prokaryotic Reproduction & Horizontal Gene Transfer:

• Asexual reproduction: Binary fission.

• Horizontal Gene Transfer: Transfer of genes between organisms (e.g., conjugation, transformation).

15. Role of Bacteria in Ecosystems:

• Decomposers, nitrogen fixers, symbionts, pathogens.

16. Endosymbiotic Theory:

• Mitochondria and chloroplasts originated from free-living bacteria that formed symbiotic relationships with early eukaryotes.

17. Protists Evolutionary Relationships:

• Protists are a diverse group, some are more closely related to plants, animals, or fungi.

18. Fungi Evolutionary Relationships:

• Fungi are more closely related to animals than plants.

19. Characteristics of Fungi:

• Cell walls made of chitin, heterotrophic, reproduction via spores.

Plants

22. Challenges to Plants on Land & Adaptations:

• Challenges: Desiccation, gravity, reproduction, nutrient acquisition.

• Adaptations: Cuticle, vascular tissue, roots, seeds, flowers.

23. Types of Plants:

• Nonvascular plants (Bryophytes): No vascular tissue, rely on diffusion (e.g., moss).

• Seedless Vascular Plants: Have vascular tissue, but no seeds (e.g., ferns).

• Seed Plants: Vascular tissue and seeds (e.g., gymnosperms, angiosperms).

24. Progymnosperms, Gymnosperms, & Angiosperms:

• Progymnosperms: Early seedless vascular plants.

• Gymnosperms: Seed plants without flowers (e.g., conifers).

• Angiosperms: Flowering plants with seeds enclosed in fruit.

26. Water Transport in Plants:

• Water potential: Determines the direction of water movement.

• Transpiration: Evaporation of water from leaves, driving water uptake from roots.

• Stomatal Regulation: Controls water loss and gas exchange.

Animals

29. Animal Kingdom Features:

• Multicellular, heterotrophic, lack cell walls, capable of movement.

30. Hox Genes:

• Regulate body plan development and differentiation in animals.

34. Evolution of Jaws, Gills, Lungs, & Limbs:

• Jaws evolved from gill arches, allowing vertebrates to exploit new food sources.

Animal Systems

38. Bioenergetics & Body Size:

• Larger animals require more energy but are more efficient in energy use per unit body mass.

40. Thermoregulation:

• Endotherms: Generate their own heat (e.g., mammals).

• Ectotherms: Rely on external heat sources (e.g., reptiles).

Ecology

45. Survivorship Curves:

• Type I: Low mortality in early life, high mortality in later life (e.g., humans).

• Type II: Constant mortality rate throughout life (e.g., birds).

• Type III: High mortality in early life, lower mortality in later life (e.g., fish).

49. Species Types:

• Endemic: Species found only in one location.

• Keystone Species: Species that have a disproportionate effect on their ecosystem.

• Invasive Species: Non-native species that disrupt ecosystems.

General/Comparison Questions

52. Evolutionary Relationships Between Domains:

• Archaea & Eukarya are more closely related to each other than to bacteria.

54. Life Cycles:

• Haplontic: Haploid stage dominates.

• Diplontic: Diploid stage dominates.

• Haplodiplontic: Alternation of generations between haploid and diploid stages (common in plants).