General Biology Study Guide: Evolution, Ecology, Communities, and Conservation

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Chapter 13: How Populations Evolve

Key Concepts in Evolution

This chapter explores the mechanisms by which populations change over time, focusing on evolutionary theory and its supporting evidence.

Evolution: The process by which species change over generations through genetic variation and natural selection.
Population: A group of individuals of the same species living in a specific area.
Variation: Differences in traits among individuals within a population.
Adaptation: Traits that enhance survival and reproduction in a particular environment.
Natural Selection: The process by which individuals with advantageous traits are more likely to survive and reproduce.

Evidence for Evolution

Fossils: Remains or traces of ancient organisms that provide evidence of evolutionary change.
Homology: Similarity in structure due to shared ancestry (e.g., comparative anatomy).
Analogous Structures: Structures with similar function but different evolutionary origins.
Vestigial Structures: Remnants of features that served important functions in ancestors.

Mechanisms of Evolution

Mutation: Changes in DNA that introduce genetic variation.
Gene Flow: Movement of genes between populations.
Genetic Drift: Random changes in allele frequencies, especially in small populations.
Sexual Selection: Selection for traits that improve mating success.

Population Genetics

Gene Pool: The total collection of genes in a population.
Hardy-Weinberg Equilibrium: Describes a non-evolving population. The equation is: where p and q are allele frequencies.
Calculating Allele Frequencies: Use Hardy-Weinberg equations to determine genotype and allele frequencies.

Types of Selection

Directional Selection: Favors one extreme phenotype.
Disruptive Selection: Favors both extreme phenotypes.
Stabilizing Selection: Favors intermediate phenotypes.

Speciation and Diversity

Speciation: The formation of new species through evolutionary processes.
Microevolution vs. Macroevolution: Microevolution refers to changes within populations; macroevolution refers to large-scale changes that result in new species.

Chapter 14: The Origin of Species

Defining Species and Speciation

This chapter examines how new species arise and the mechanisms that maintain species boundaries.

Species: A group of organisms capable of interbreeding and producing fertile offspring.
Reproductive Barriers: Mechanisms that prevent species from interbreeding.

Types of Reproductive Barriers

Prezygotic Barriers: Prevent mating or fertilization.
- Habitat isolation
- Temporal isolation
- Behavioral isolation
- Mechanical isolation
- Gametic isolation
Postzygotic Barriers: Prevent hybrid offspring from developing into viable, fertile adults.
- Reduced hybrid viability
- Reduced hybrid fertility
- Hybrid breakdown

Modes of Speciation

Allopatric Speciation: Occurs when populations are geographically separated.
Sympatric Speciation: Occurs without geographic separation, often through genetic changes.

Chapter 34: The Biosphere

Ecology and the Biosphere

This chapter introduces the study of ecology and the relationships among organisms and their environments.

Ecology: The study of interactions between organisms and their environment.
Ecosystem: A community of organisms and their physical environment.
Biome: Large ecological areas with characteristic climate and vegetation.
Community: All populations of different species living in an area.
Population: Individuals of the same species in a given area.

Abiotic and Biotic Factors

Abiotic Factors: Non-living components (e.g., temperature, water, sunlight).
Biotic Factors: Living components (e.g., plants, animals, microbes).

Major Biomes

Biome	Characteristics
Tundra	Cold, low precipitation, permafrost
Desert	Low precipitation, extreme temperatures
Temperate Forest	Moderate climate, deciduous trees
Tropical Rain Forest	High rainfall, high biodiversity
Grassland	Moderate rainfall, grasses dominate
Coniferous Forest	Evergreen trees, cold climate
Freshwater (lakes, ponds)	Standing water, aquatic plants
Marine (oceans)	Saltwater, diverse marine life

Chapter 36: Population Ecology

Population Dynamics

This chapter focuses on the study of populations, their growth, and factors affecting their size and distribution.

Population Density: Number of individuals per unit area.
Dispersion Patterns: How individuals are spaced (clumped, uniform, random).
Population Growth: Change in population size over time.

Growth Models

Exponential Growth: Population increases rapidly under ideal conditions.
Logistic Growth: Population growth slows as it approaches carrying capacity.
Carrying Capacity (K): Maximum population size an environment can support.

Survivorship Curves

Type I: High survival in early/middle life, increased mortality in old age (e.g., humans).
Type II: Constant mortality rate throughout life (e.g., birds).
Type III: High mortality early in life, low survival for those who reach adulthood (e.g., oysters).

Limiting Factors

Density-Dependent Factors: Effects increase with population density (e.g., competition, disease).
Density-Independent Factors: Effects are unrelated to population density (e.g., weather, natural disasters).

Human Impacts

Resource Management: Sustainable use of resources to prevent depletion.
Ecological Footprint: Measure of human demand on Earth's ecosystems.

Chapter 37: Communities and Ecosystems

Community Interactions

This chapter examines the relationships among species within communities and the flow of energy through ecosystems.

Niche: The role and position of a species in its environment.
Habitat: The physical environment where a species lives.
Types of Interactions:
- Competition
- Predation
- Parasitism
- Mutualism
- Herbivory

Trophic Structure

Trophic Levels: Hierarchical levels in an ecosystem based on energy flow.
- Primary Producer
- Primary Consumer
- Secondary Consumer
- Tertiary Consumer
- Quaternary Consumer
- Decomposer

Succession

Primary Succession: Occurs in lifeless areas (e.g., after volcanic eruption).
Secondary Succession: Occurs in areas where a community has been disturbed but soil remains.

Biogeochemical Cycles

Energy Flow: Movement of energy through trophic levels.
Nutrient Cycling: Movement of elements (carbon, nitrogen, phosphorus) through ecosystems.

Human Impacts

Effects of Human Activity: Pollution, habitat destruction, and climate change alter biogeochemical cycles and ecosystem health.
Reproduction in Aquatic Ecosystems: Human activities can disrupt reproductive cycles and ecosystem stability.

Chapter 38: Conservation Biology

Conservation and Biodiversity

This chapter addresses the importance of conserving biological diversity and the strategies used to protect species and ecosystems.

Biodiversity: The variety of life in all its forms, including species, genetic, and ecosystem diversity.
Species Diversity: Number of different species in an area.
Genetic Diversity: Variation in genetic makeup among individuals within a species.

Threats to Biodiversity

Habitat Loss: Destruction or fragmentation of habitats.
Invasive Species: Non-native species that disrupt local ecosystems.
Pollution: Contamination of air, water, and soil (including biological magnification).
Overexploitation: Excessive harvesting of species.
Global Warming: Climate change affecting species distribution and survival.

Conservation Strategies

Protecting Endangered Populations: Legal protection, captive breeding, and habitat restoration.
Landscape Ecology: Managing ecosystems and movement corridors to maintain biodiversity.
Protected Areas: Establishing reserves and parks to safeguard habitats and species.
Restoration Ecology: Restoring degraded ecosystems and reintroducing species (e.g., Gray Wolves in Yellowstone).
Sustainable Development: Balancing human needs with conservation to ensure long-term ecosystem health.

Example:

Yellowstone Wolf Reintroduction: Restoration efforts have improved ecosystem balance and biodiversity.