Final Exam Notes

🌎 Lec 1: Climate and Biomes (Chapter 47)

• Climate:

  • Long-term average of weather patterns in an area.

  • Determined by solar radiation, wind and ocean circulation, and topography (rain shadow effect).

• Biomes:

  • Origin: Driven by temperature and precipitation patterns.

  • Differentiation: By climatic conditions and dominant vegetation.

• Biomes and Adaptations:

  • Tropical Rainforest: High rainfall, constant warm temps. Dense vegetation, epiphytes.

  • Desert: Low rainfall, extreme temps. Organisms have water conservation adaptations (cacti, nocturnal animals).

  • Temperate Forests: Moderate rainfall, cold winters and warm summers. Trees with broad leaves, hibernating animals.

  • Tundra: Very low temps, low precipitation. Plants are low-growing, animals have insulation (fur/fat).

♻ Lec 2: Carbon, Nitrogen, and Phosphorus Cycles (Chapter 46)

• Key Organisms:

  • Carbon: Plants fix CO₂ via photosynthesis.

  • Nitrogen: Bacteria fix atmospheric N₂ into usable forms.

  • Phosphorus: Weathering of rocks releases phosphorus.

• Food Webs:

  • Energy and nutrients flow through trophic levels: producers → consumers → decomposers.

🧬 Lec 3: Mechanisms of Evolution – Natural Selection (Chapter 20)

• Evolution:

  • Change in genetic structure (allele frequencies) over time within a population.

• Mechanisms:

  • Adaptive: Natural selection.

  • Non-adaptive: Mutation, gene flow, genetic drift.

• Key Scholars:

  • Darwin, Wallace (natural selection); Malthus (population limits); Lyell (gradual geological changes).

• 3 Conditions for Natural Selection:

  1. Variation in traits.

  2. Heritability.

  3. Differential reproductive success.

🔄 Lec 4: Non-Adaptive Evolutionary Mechanisms (Chapter 20)

• Three Mechanisms:

  • Mutation: Random changes in DNA.

  • Gene Flow: Movement of alleles between populations.

  • Genetic Drift: Random changes in allele frequencies (small populations).

• Genetic Drift Types:

  • Random mortality/reproduction.

  • Founder Effect: Small group starts a new population.

  • Bottleneck: Sudden population reduction.

• Outcomes:

  • Mutations: Deleterious, neutral, or advantageous.

  • Gene flow: Genetic homogenization.

  • Drift: Random loss of genetic diversity.

📈 Lec 5: Hardy-Weinberg Equilibrium (Chapter 20)

• Genotype vs. Phenotype:

  • Genotype = genetic makeup.

  • Phenotype = observable traits.

• Hardy-Weinberg Equations:

  • Allele Frequencies: p + q = 1

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

  • Use Chi-square tests to test for equilibrium.

• Violations Indicate Evolution:

  • Natural selection, gene flow, mutation, genetic drift.

🧬 Lec 6: Macroevolution and Species Concepts (Chapter 21)

• Micro vs. Macro Evolution:

  • Micro: Small changes (allele frequencies).

  • Macro: Large-scale events (speciation).

• Species Concepts:

  • Biological: Reproductive isolation.

  • Morphospecies: Physical characteristics.

  • Ecological: Niche.

  • Phylogenetic: Ancestor-descendant relationships.

• Speciation:

  • Populations become reproductively isolated and genetically distinct.

🧪 Lec 7: Speciation and Reproductive Isolation (Chapter 21)

• Speciation Process:

  • Gradual development of reproductive isolation.

• Barriers:

  • Prezygotic: Geographic, behavioral, temporal, mechanical, gametic.

  • Postzygotic: Hybrid sterility, hybrid inviability.

• Allopatric vs. Sympatric:

  • Allopatric = physical separation.

  • Sympatric = same location.

🌳 Lec 8: Phylogenetic Trees and Fossils (Chapter 22)

• Phylogeny Basics:

  • Nodes = common ancestors.

  • Branches = lineages.

• Relationships:

  • Monophyletic (one ancestor and all descendants).

  • Paraphyletic (ancestor and some descendants).

  • Polyphyletic (groups without common ancestor).

• Fossil Evidence:

  • Transitional forms, age, extinction patterns, environmental changes.

• Important Terms:

  • Synapomorphy, homologous traits (common ancestry), analogous traits (convergent evolution).

🐾 Lec 10-11: Animal Behavior (Chapter 43)

• Behavior Causes:

  • Proximate: Mechanistic (how).

  • Ultimate: Evolutionary (why).

• Innate vs. Learned:

  • Innate = genetic.

  • Learned = experience-based.

• Terms:

  • Biological Clocks: Circadian, lunar, annual cycles.

  • Communication: Visual, auditory, chemical, electrical, mechanical.

  • Fixed Action Pattern: Instinctual, completed once triggered.

• Learning Types:

  • Non-associative (habituation, sensitization).

  • Associative (classical and operant conditioning).

• Cooperative Behavior:

  • Altruism: Helping others at a cost.

  • Reciprocal Altruism: Help expecting return.

  • Kin Selection: Helping relatives.

👥 Lec 12-13: Population Ecology (Chapter 44)

• Ecology Levels:

  • Population, community, global.

• Population Characteristics:

  • Size, density, distribution (random, clumped, uniform), growth rate.

• Growth Types:

  • Exponential vs. Logistic (carrying capacity K).

• Factors:

  • Biotic (living) vs. Abiotic (non-living).

  • Density-dependent vs. Density-independent effects.

• Survivorship Curves:

  • Type I (late death - elephants).

  • Type II (constant - songbirds).

  • Type III (early death - turtles).

• Reproductive Strategies:

  • r-strategists: Many, little care.

  • K-strategists: Few, high care.

• Metapopulation Dynamics:

  • Connected patches, migration between.

🌱 Lec 14-16: Community Ecology (Chapter 45)

• Niche:

  • Fundamental (potential) vs. Realized (actual).

• Interactions:

  • Competition, predation, mutualism, commensalism.

• Competitive Exclusion vs. Resource Partitioning:

  • One species excluded vs. niche differentiation.

• Food Webs:

  • Producers → Consumers (primary, secondary, tertiary).

  • Arrows show energy flow and effect.

• Species Loss or Addition:

  • Ecosystem disruption (e.g., Yellowstone wolves).

• Succession:

  • Primary (no soil).

  • Secondary (soil present).

🌍 Lec 17-18: The Anthropocene (Chapter 48)

• Anthropocene Evidence:

  • Mass extinctions, human-driven changes.

• Human Impacts:

  • Habitat destruction, invasive species, climate change.

• Ecosystem Services:

  • Carbon cycling, erosion control, food, medicine.

• Conservation Priorities:

  • Protect biodiversity hotspots, endangered species.

• Additional Impacts:

  • Fertilizer runoff, evolutionary changes.

• CO₂ and Global Warming:

  • Positive correlation between CO₂ levels and temperature rise.

• Effects of Warming:

  • Range shifts, habitat loss, exotic invasions, disease spread.

• Human Actions:

  • Can worsen or mitigate global warming (e.g., emissions control).