Test Review chapter 19 & 21

Quizlet-Style Flashcards

Chapter 19: Descent with Modification

Classification & Taxonomy

• Carolus Linnaeus – Founder of taxonomy

• Taxonomy – Science of classifying/naming organisms

• Binomial nomenclature – Two-part scientific naming system (genus + species)

• Classification hierarchy – Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species
  (Mnemonic: Dear King Philip Came Over For Good Spaghetti)

Fossils & Geology

• Strata – Layers of rock containing fossil records

• Charles Lyell – Earth’s geological processes are slow and constant → Earth is very old

• Paleontology – Study of fossils and ancient life

Evolutionary Theories

• Jean-Baptiste de Lamarck – Species evolve by use/disuse & passing on acquired traits (flawed idea)

• Use and Disuse – Parts used grow stronger; unused deteriorate

• Inheritance of Acquired Characteristics – Organisms pass on traits gained in lifetime

Natural vs Artificial Selection

• Charles Darwin – Developed theory of natural selection; studied Galápagos species

• Natural selection – Nature selects traits that enhance survival/reproduction

• Adaptations – Traits that increase fitness in an environment

• Artificial selection – Humans select desirable traits (e.g., dog breeding)

Evidence for Evolution

• Homologous structures – Similar structures from a common ancestor (e.g., forelimbs)

• Embryonic homologies – Similar embryos across species = shared ancestry

• Vestigial organs – Leftover structures (e.g., human appendix)

• Molecular homologies – Shared DNA/protein sequences among species

Evolutionary Patterns

• Convergent evolution – Unrelated species evolve similar traits (e.g., wings)

• Analogous structures – Similar function, different origin (e.g., bat vs insect wings)

Biogeography

• Fossil record – Shows extinction, transitional forms, evolutionary change

• Biogeography – Study of where organisms live & why

• Continental drift – Movement of Earth’s plates explains species distribution

• Endemic species – Found only in one place (e.g., Galápagos finches)

Chapter 21: Evolution of Populations

Genetic Variation

• Microevolution – Change in allele frequencies over time

• Mutation – Source of new genes/alleles

  • Point mutation – Change in one DNA base

  • Chromosomal mutation – Changes to whole chromosomes

• Crossing over – Exchange of DNA during meiosis

• Independent assortment – Random distribution of chromosomes during meiosis

• Fertilization – Combines genes from two parents

Population Genetics

• Population – Group of same species in same area, interbreeding

• Gene pool – All alleles in a population

• Fixed allele – One allele for a gene = no variation

• Population genetics – Study of allele changes in populations

Hardy-Weinberg Equilibrium

• Equation:

  • Alleles: p + q = 1

  • Genotypes: p² + 2pq + q² = 1

• Conditions (no evolution if all met):

  1. No mutations

  2. Random mating

  3. No natural selection

  4. Large population

  5. No gene flow

Evolutionary Mechanisms

• Genetic drift – Random change in allele frequency (especially in small populations)

  • Founder effect – Few individuals start a new population

  • Bottleneck effect – Disaster reduces population size

• Gene flow – Movement of alleles in/out of populations

• Sexual selection – Certain traits improve chances of mating

• Relative fitness – Contribution to next generation’s gene pool

Types of Natural Selection

• Directional selection – Favors one extreme (e.g., larger beak)

• Disruptive selection – Favors both extremes (e.g., large and small beaks)

• Stabilizing selection – Favors average (e.g., human birth weight)

🚀 Adaptive Evolution & Advantages

• Adaptive evolution – Increase in traits that improve survival

• Heterozygote advantage – Heterozygotes have greater fitness (e.g., sickle cell = malaria resistance)

Cheat Sheet Summary

Chapter 19 (Evolution Basics)

• Linnaeus = classification

• Fossils + strata = evidence

• Lamarck = flawed but important

• Darwin = natural selection

• Evidence = homologous, vestigial, embryonic, molecular

• Biogeography & fossil record support evolution

Chapter 21 (Population Evolution)

• Mutation = new alleles

• Genetic variation maintained by meiosis & fertilization

• Hardy-Weinberg = no evolution IF 5 conditions met

• Evolution happens by:

  • Natural selection

  • Genetic drift

  • Gene flow

  • Sexual selection

• Selection types: directional, disruptive, stabilizing

• Heterozygote advantage = extra fitness