BIO 1070 Exam 4 Study Guide: Evolution, Speciation, Ecology, Communities, and Ecosystems

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Evolution: Descent with Modification (Chapters 22 & 23)

Darwin’s Voyage and the Development of Evolutionary Theory

Charles Darwin’s observations during his voyage on the Beagle were foundational in shaping his ideas about evolution by natural selection. His studies of diverse species and their adaptations to different environments led to the formulation of key evolutionary concepts.

Natural Selection: The process by which individuals with advantageous traits survive and reproduce more successfully, leading to the accumulation of those traits in the population.
Darwin’s Observations:
- Observation 1: Members of a population often vary in their inherited traits.
- Observation 2: All species can produce more offspring than the environment can support, and many offspring fail to survive and reproduce.
Darwin’s Inferences:
- Inference 1: Individuals whose inherited traits give them a higher probability of surviving and reproducing tend to leave more offspring.
- Inference 2: This unequal ability to survive and reproduce leads to the accumulation of favorable traits over generations.
Acceptance of Natural Selection: The accumulation of evidence from comparative anatomy, fossil records, and biogeography led to the acceptance of Darwin’s ideas.
Diversity and Unity: Evolution explains both the diversity of life (adaptations to different environments) and the unity of life (shared ancestry).

Evidence for Evolution

Fossil Record: Shows changes in organisms over time.
Homology: Similar structures in different species due to common ancestry.
Biogeography: Geographic distribution of species supports evolutionary relationships.
Direct Observation: Examples include antibiotic resistance in bacteria.

Genetic Variation and Evolutionary Mechanisms

Basic Unit of Evolution: The population.
Sources of Genetic Variation:
- Mutation
- Gene duplication
- Sexual reproduction (recombination)
Mechanisms Altering Allele Frequencies:
- Natural selection
- Genetic drift (random changes in allele frequencies)
- Gene flow (movement of alleles between populations)

Hardy-Weinberg Equilibrium

Definition: A principle stating that allele and genotype frequencies in a population remain constant from generation to generation in the absence of evolutionary influences.
Theorem: For two alleles, and , the genotype frequencies are:
Use: To determine if a population is evolving.

Key Vocabulary

Adaptation: Inherited trait that increases survival and reproduction.
Artificial Selection: Human-driven selection of desirable traits.
Population: Group of individuals of the same species in an area.
Gene Pool: All alleles in a population.
Microevolution: Change in allele frequencies over time.
Macroevolution: Broad patterns of evolutionary change above the species level.
Homology: Similarity due to shared ancestry.
Biogeography: Study of species distribution.

Speciation and the Origin of Species (Chapter 24)

Species Concepts and Reproductive Isolation

Speciation is the process by which one species splits into two or more species. The definition of a species can vary depending on the concept used.

Biological Species Concept: Species are groups of interbreeding populations that are reproductively isolated from others.
Ecological Species Concept: Species are defined by their ecological niche.
Morphological Species Concept: Species are defined by structural features.

Reproductive Barriers

Reproductive Isolation: The existence of biological factors that impede members of two species from interbreeding.
Prezygotic Barriers (before fertilization):
- Habitat isolation
- Temporal isolation
- Behavioral isolation
- Mechanical isolation
- Gametic isolation
Postzygotic Barriers (after fertilization):
- 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 via polyploidy, sexual selection, or habitat differentiation.

Microevolution and Macroevolution

Microevolutionary changes can accumulate, leading to macroevolutionary events such as speciation.

Key Vocabulary

Speciation: Formation of new species.
Hybrid: Offspring of crosses between different species.
Polyploidy: Extra sets of chromosomes, common in plant speciation.
Sexual Selection: Selection for traits that improve mating success.
Habitat Differentiation: Subpopulations exploit different habitats or resources.

Ecology: The Biosphere and Biomes (Chapter 52)

Levels of Ecological Study

Organismal ecology
Population ecology
Community ecology
Ecosystem ecology
Landscape ecology
Global ecology

Global Climate Patterns

Determinants: Solar energy, Earth's movement in space, atmospheric and oceanic circulation.
Solar Radiation: Drives global air circulation and precipitation patterns.
Latitude: Sun intensity is highest at the equator, decreasing toward the poles.
Wind Patterns: Influence ocean currents, which in turn affect climate on land masses.
Local Factors: Seasonality, bodies of water, and mountains modify local climates.

Biomes and Abiotic/Biotic Factors

Abiotic Factors: Non-living components (temperature, light, water, nutrients).
Biotic Factors: Living components (plants, animals, microbes).
Key Climate Factors: Temperature and precipitation most strongly influence terrestrial biomes.
Disturbance: Events like fire or storms that alter communities and ecosystems.

Aquatic Biomes and Zonation

Zonation: Distribution of organisms into zones based on abiotic factors.
Aquatic Zones:
- Photic: Light-penetrated, supports photosynthesis
- Aphotic: Little or no light
- Neritic: Coastal waters
- Oceanic: Open ocean
- Pelagic: Open water
- Abyssal: Deep ocean
- Benthic: Bottom substrate
- Littoral: Near shore (lake)
- Limnetic: Open water (lake)
Thermocline: Layer of rapid temperature change in a body of water.
Turnover and Upwelling: Both bring nutrients to surface waters; turnover occurs in lakes, upwelling in oceans.

Primary Producers

Terrestrial Biomes: Main producers are plants.
Aquatic Biomes: Main producers are phytoplankton.

Key Vocabulary

Ecology: Study of interactions between organisms and their environment.
Biome: Major life zone characterized by vegetation type or physical environment.
Ecosystem: Community of organisms and their abiotic environment.
Community: All populations in an area.
Climate: Long-term weather patterns.
Abiotic/Biotic: Non-living/living factors.
Microclimate: Localized climate conditions.
Climograph: Plot of temperature and precipitation.
Vertical Layering: Stratification of vegetation.
Phytoplankton: Microscopic photosynthetic organisms in water.
Zooplankton: Small heterotrophic organisms in water.

Community Ecology (Chapter 54)

Interspecific Interactions

Competition: (-/-) Both species are harmed by shared resource use.
Predation: (+/-) Predator benefits, prey is harmed.
Herbivory: (+/-) Herbivore eats plants/algae.
Symbiosis: Close interaction between species.
- Parasitism (+/-)
- Mutualism (+/+)
- Commensalism (+/0)
Facilitation: One species benefits another without direct contact.

Competition and Niche Concepts

Competitive Exclusion: Two species competing for the same resource cannot coexist.
Resource Partitioning: Differentiation of niches to allow coexistence.

Adaptations and Community Structure

Predator Adaptations: Claws, fangs, speed, camouflage.
Prey Adaptations: Camouflage, mimicry, chemical defenses.
Species Diversity: Variety of organisms in a community.
Species Richness: Number of species present.
Relative Abundance: Proportion of each species.

Key Species in Communities

Type	Definition	Example
Dominant Species	Most abundant or highest biomass	Oak trees in a forest
Keystone Species	Exert strong control despite low abundance	Sea otters
Ecosystem Engineer (Foundation Species)	Alter environment physically	Beavers

Invasive Species: Non-native species that disrupt ecosystems.

Key Vocabulary

Obligate/Facultative Mutualism: Required/optional mutualistic relationship.
Niche: Role of a species in its environment.
Succession: Sequence of community changes (primary: new area; secondary: after disturbance).

Ecosystems and Restoration Ecology (Chapter 55)

Ecosystem Structure and Energy Flow

Ecosystem: All organisms and abiotic factors in an area.
Main Processes: Energy flow and chemical cycling.
Energy Flow: Energy enters as sunlight, flows through trophic levels, and exits as heat.

Trophic Structure

Definition: Feeding relationships among organisms.
Levels:
- Primary Producer: Autotrophs (plants, algae)
- Primary Consumer: Herbivores
- Secondary Consumer: Carnivores eating herbivores
- Tertiary Consumer: Carnivores eating other carnivores
- Detritivore/Decomposer: Consume dead organic matter (e.g., fungi, bacteria)

Primary Production

Gross Primary Production (GPP): Total energy from photosynthesis.
Net Primary Production (NPP): GPP minus energy used by producers for respiration.
Limiting Factors:
- Aquatic: Light and nutrients
- Terrestrial: Temperature, moisture, nutrients

Secondary Production and Energy Transfer

Secondary Production: Amount of chemical energy in food converted to new biomass by consumers.
Production Efficiency: Fraction of energy stored in food not used for respiration.
Trophic Efficiency: Percentage of production transferred from one trophic level to the next (average ~10%).

Chemical Cycling and Decomposition

Chemical Cycling: Movement of elements through biotic and abiotic components.
Decomposers: Break down organic matter, releasing nutrients.
Biogeochemical Cycles:
- Water Cycle: Evaporation, condensation, precipitation, transpiration
- Carbon Cycle: Photosynthesis, respiration, decomposition
- Phosphorus Cycle: Weathering of rocks, uptake by organisms
- Nitrogen Cycle: Nitrogen fixation, nitrification, denitrification
Factors Affecting Decomposition: Temperature, moisture, nutrient availability

Restoration Ecology

Restoration Ecology: Seeks to return degraded ecosystems to a more natural state.
Bioremediation: Use of organisms to detoxify polluted ecosystems.
Biological Augmentation: Adding essential materials to degraded ecosystems.

Key Vocabulary

Solar Energy: Energy from the sun.
Chemical Energy: Energy stored in chemical bonds.
Autotroph: Organism that produces its own food.
Heterotroph: Organism that consumes others for food.
Food Chain/Web: Pathways of energy flow.
Biomass: Total mass of living matter.
Inorganic/Organic Molecules: Non-carbon/carbon-based molecules.
Evaporation, Condensation, Transpiration: Water cycle processes.