Ecology and Behavioral Biology: Key Concepts and Study Guide

Behavioral Ecology

Fixed Action Pattern (FAP)

A Fixed Action Pattern is an innate, preprogrammed response to a specific stimulus, often seen in animal behavior.

• Sign stimulus: The specific trigger that initiates the FAP.

• Example: A goose rolling an egg back to its nest, even if the egg is replaced with another object.

Innate Behavior

Innate behaviors are genetically programmed and do not require learning.

• Kinesis: Non-directional movement in response to a stimulus.

• Taxis: Directional movement toward or away from a stimulus.

• Migration: Seasonal movement patterns, often for breeding or resource availability.

Signals and Communication

Animals use various signals to communicate, including chemical, auditory, and visual cues.

• Auditory communication: Use of sound to convey information.

• Pheromones: Chemical signals that affect the behavior of other animals.

Imprinting

Imprinting is a rapid form of learning occurring during a sensitive period, often early in life.

• Example: Ducklings following the first moving object they see after hatching.

Learning

Learning involves modification of behavior based on experience.

• Habituation: Decreased response to a repeated stimulus.

• Spatial learning: Use of environmental cues to navigate.

• Associative learning: Linking two stimuli or events together.

  • Classical conditioning: Associating a neutral stimulus with a significant one.

  • Operant conditioning: Learning through rewards and punishments.

Cognition

Cognition refers to mental processes such as problem-solving and decision-making.

• Example: Tool use in primates.

Special Learning in Evolution

• Optimal foraging theory: Animals maximize energy gain while minimizing effort.

• Polygamy and mate choice: Various mating systems such as monogamy, polygyny, polyandry, and parental care.

Game Theory and Altruism

Game theory models strategic interactions; altruism involves behaviors that benefit others at a cost to oneself.

• Genetic basis for altruism: Kin selection and inclusive fitness.

Sociobiology

Sociobiology studies the evolutionary basis of social behavior.

Intro to Ecology

Ecology: Subfields

Ecology is the study of interactions between organisms and their environment.

• Biotic factors: Living components (e.g., plants, animals).

• Abiotic factors: Non-living components (e.g., temperature, water).

Factors Influencing Distribution

• Dispersal: Movement of individuals from one area to another.

• Biotic and abiotic factors: Influence where organisms can live.

Climate

Climate describes long-term patterns of temperature and precipitation.

• Types: Global, regional, local, micro-climate.

• Influences: Sunlight, wind patterns, ocean currents, mountains, human activity.

Aquatic Ecosystems

Productivity

Productivity in aquatic ecosystems is limited by light and nutrients.

• Zones: Photic (light), aphotic (no light), benthic (bottom).

• Nutrient distribution: Affects organism abundance.

Aquatic and Terrestrial Biomes

Biomes are large ecological areas with distinct climate and organisms.

• Examples: Rivers, lakes, wetlands, estuaries, marine zones, tropical rain forest, savanna, temperate grassland, tundra, etc.

Population Ecology

Population Concepts

Population ecology studies groups of individuals of the same species in a given area.

• Population: Group of individuals of one species.

• Density: Number of individuals per unit area.

• Dispersion: Pattern of spacing (uniform, random, clumped).

• Demography: Study of vital statistics (birth, death, immigration, emigration).

Survivorship Curves

Survivorship curves show patterns of survival over time.

• Type I: High survival early, drops later (e.g., humans).

• Type II: Constant death rate (e.g., birds).

• Type III: High death rate early, survivors live long (e.g., oysters).

Population Growth Models

• Exponential growth: Population increases rapidly under ideal conditions.

• Logistic growth: Population growth slows as it approaches carrying capacity.

Equations:

• Exponential growth: $\frac{dN}{dt} = rN$

• Logistic growth: $\frac{dN}{dt} = rN\left(\frac{K-N}{K}\right)$

Community Ecology & Ecosystems

Niche and Competition

A niche is the role an organism plays in its environment. Competitive exclusion can prevent extinction by resource partitioning.

Predation and Mimicry

• Predation: One organism eats another.

• Crypsis: Camouflage to avoid detection.

• Batesian mimicry: Harmless species mimics harmful one.

• Müllerian mimicry: Two harmful species mimic each other.

Herbivory, Parasitism, Disease

• Herbivory: Animals eat plants.

• Parasitism: Parasite benefits, host is harmed.

• Disease: Pathogens cause harm to hosts.

Symbiosis

• Mutualism: Both species benefit.

• Commensalism: One benefits, other unaffected.

Community Structure

• Species diversity: Variety of species in a community.

• Relative abundance: Proportion of each species.

• Trophic structure: Feeding relationships (producers, consumers).

Limits to Food Chain Length

• Energy loss at each trophic level limits chain length.

• Dominant and keystone species have large effects on community structure.

Disturbance

Disturbance is a vital part of community dynamics, influencing succession and diversity.

Productivity and Biogeochemical Cycles

Primary and Secondary Productivity

• Primary productivity: Rate at which producers convert energy.

• Secondary productivity: Rate at which consumers convert energy from food.

• Limiting factors: Light, nutrients.

Biogeochemical Cycles

• Water cycle

• Nitrogen cycle

• Carbon cycle

Effects of Human Activity

• Nutrient enrichment and nitrogen cycle disruption

• Atmospheric CO2 increase

• Acid precipitation

• Ozone depletion

Conservation Biology

Genetic, Species, and Ecosystem Diversity

Conservation biology focuses on preserving genetic, species, and ecosystem diversity.

• Threats: Habitat destruction, fragmentation, overexploitation, invasive species.

• Small populations: Vulnerable to extinction due to genetic drift and inbreeding.

• Edge effects: Changes in population or community structures at habitat boundaries.

Protected Areas and Restoration

• Protected areas: Nature reserves, biosphere reserves.

• Restoration: Bioremediation (using organisms to clean up pollution), biological augmentation (adding essential materials to degraded ecosystems).

• Sustainable development: Balancing human needs with conservation.

Summary Table: Types of Species Interactions

Interaction Type	Effect on Species 1	Effect on Species 2	Example
Mutualism	+	+	Bees and flowers
Commensalism	+	0	Barnacles on whales
Parasitism	+	-	Ticks on mammals
Predation	+	-	Lions hunting zebras
Competition	-	-	Plants competing for sunlight