Untitled Flashcards Set

Chapter 22

Vocabulary:

• Evolution: Change in populations over generations due to genetic variation and natural selection.

• Adaptation: A heritable trait that improves an organism's ability to survive and reproduce.

• Natural Selection: Process where individuals with beneficial traits survive and reproduce more.

• Artificial Selection: Human-driven breeding to enhance specific traits in organisms.

• Homologous Structures: Body parts with a common ancestor but different functions (e.g., human arm & whale fin).

• Vestigial Structures: Reduced or non-functional remnants of ancestral traits (e.g., human appendix).

1. Hutton & Lyell’s Influence on Darwin: Proposed Earth was old and shaped by gradual processes, supporting slow evolutionary changes.

2. Lamarck’s Theories:

   • Use & Disuse: Traits used more become stronger, unused ones fade.

   • Inheritance of Acquired Traits: Traits gained in life passed to offspring.

   • Innate Drive to Complexity: Organisms evolve towards complexity.

3. Pre-Darwin Beliefs: Earth was young; populations were unchanging.

4. Darwin’s Observations & Inferences: (See page 475)

5. Key Features of Natural Selection: (See page 476)

6. Sequence of Evolutionary Events:

   • (b) Change in environment → (d) Poorly adapted die → (a) Well-adapted reproduce → (c) Genetic shift.

7. Evolutionary Tree: (See Fig. 22.17, page 480)

Chapter 23

Vocabulary:

• Gene Pool: All the genetic material in a population.

• Allele Frequency: Proportion of a specific allele in a population.

• Genetic Drift: Random changes in allele frequencies due to chance events.

• Founder Effect: Genetic drift when a new population starts with few individuals.

• Bottleneck Effect: Genetic drift from a drastic population size reduction.

• Gene Flow: Movement of alleles between populations through migration.

• Relative Fitness: An organism’s reproductive success compared to others.

1. Sources of Genetic Variation: Mutations & sexual reproduction (independent assortment, crossing over, random fertilization).

2. Hardy-Weinberg Equilibrium: Describes non-evolving populations.

3. Five Conditions for Hardy-Weinberg: No mutations, random mating, no natural selection, large population, no gene flow.

4. Hardy-Weinberg Equations:

   • Allele frequency: p + q = 1

   • Genotype frequency: p² + 2pq + q² = 1

   • Solve for q² first.

5. Selection Types:

   • Directional: Favors one extreme.

   • Disruptive: Favors both extremes.

   • Stabilizing: Favors intermediate traits.

6. Resistance Mechanisms:

   • Bacteria: Mutations → Antibiotic resistance.

   • Pests: Mutations → Pesticide resistance.

   • Weeds: Mutations → Herbicide resistance.

Chapter 24

Vocabulary:

• Species: A group of interbreeding organisms that produce viable offspring.

• Speciation: Formation of new species.

• Reproductive Isolation: Barriers preventing different species from interbreeding.

• Punctuated Equilibrium: Evolution occurring in rapid bursts, followed by stability.

1. Biological Species Concept & Limitations: Defines species by interbreeding; issues with asexual/fossil species.

2. Phylogenetic Species Concept: Based on shared evolutionary history.

3. Reproductive Barriers:

   • Prezygotic: Prevents fertilization.

   • Postzygotic: Hybrid issues (e.g., sterility).

4. Allopatric vs. Sympatric Speciation:

   • Allopatric: Geographic separation.

   • Sympatric: No physical barrier.

5. Sympatric Speciation Factors:

   • Polyploidy: Chromosome changes.

   • Sexual Selection: Mate choice.

   • Habitat Differentiation: Niche adaptation.

6. Hybrid Zone Outcomes:

   • Reinforcement: Strengthened barriers.

   • Fusion: Merging species.

   • Stability: Ongoing hybrids.

Chapter 25

Vocabulary:

• Radioactive Dating: Determining fossil age using radioactive isotopes.

• Half-Life: Time for half of a radioactive sample to decay.

1. Early Earth Atmosphere: Low oxygen, rich in methane, ammonia.

2. Miller & Urey’s Experiment: Simulated early Earth, produced organic molecules.

3. Significance of Cyanobacteria: First oxygen producers.

4. Origin of Life Sequence:

   • (b) Organic monomers → (c) Organic polymers → (a) Protocells → (d) DNA genetic systems.

5. First Genetic Material: RNA; self-replicating.

6. RNA to DNA Transition: DNA more stable, less mutation-prone.

7. Evolutionary Order:

   • (c) Photosynthetic prokaryotes → (d) Mitochondria → (b) Chloroplasts → (a) Multicellular eukaryotes.

8. Endosymbiosis Evidence: Mitochondria/plastids have DNA, ribosomes, double membranes.

9. Half-Life Calculation: 6.25% = 4 half-lives.

10. Fossil Formation Factors: Hard body parts, rapid burial, low oxygen.

11. Earth’s Age: ~4.6 billion years.

12. Oldest Fossil: ~3.5 billion years, prokaryote.

13. Key Events:

• 2.7 bya: Oxygen revolution.

• 1.8 bya: First eukaryotes.

• 1.2 bya: Multicellular life.

Reminder: Individuals do not evolve; populations do!