Behavioral Ecology

Fixed Action Pattern (FAP)

A Fixed Action Pattern is an innate, highly stereotyped behavior that is triggered by a specific stimulus, known as a sign stimulus.

• Definition: A sequence of unlearned acts directly linked to a simple stimulus.

• Example: The egg-rolling behavior of a goose, triggered by the sight of an egg outside its nest.

Innate Behavior

• Kinesis: A change in activity or turning rate in response to a stimulus (e.g., pill bugs move more in dry areas).

• Taxis: Oriented movement toward or away from a stimulus (e.g., moths flying toward light).

• Migration: Regular, long-distance change in location, often seasonal.

Signals and Communication

• Signal: A behavior that causes a change in another animal's behavior.

• Auditory Communication: Use of sound to convey information (e.g., bird songs).

• Pheromones: Chemical signals used in communication, especially among insects.

Imprinting

• Definition: A type of learning that occurs during a sensitive period and is generally irreversible.

• Example: Young geese following the first moving object they see, usually their mother.

Learning

• Habituation: Loss of responsiveness to stimuli that convey little or no information.

• Spatial Learning: Establishment of a memory that reflects the environment's spatial structure.

• Associative Learning: Ability to associate one environmental feature with another (e.g., classical and operant conditioning).

Cognition and Social Learning

• Cognition: The process of knowing that involves awareness, reasoning, recollection, and judgment.

• Social Learning: Learning through observing others.

Evolution of Behavior

• Experimental studies: Use model organisms like Drosophila (fruit fly) and honey bees to study behavioral evolution.

Mating Behavior and Mate Choice

• Monogamy: One male mates with one female.

• Polygamy: An individual of one sex mates with several of the other.

• Polygyny: One male, many females.

• Polyandry: One female, many males.

• Parental Care: Investment in offspring varies with mating system.

Game Theory and Altruism

• Game Theory: Evaluates alternative strategies in situations where the outcome depends on the strategies of all individuals involved.

• Altruism: Behavior that reduces an individual's fitness while increasing the fitness of another.

Sociobiology

• Study of the evolutionary basis for social behavior in animals, including humans.

Intro to Ecology

Ecology: Subfields

Ecology is the study of interactions between organisms and their environment. It is divided into several subfields:

• Population Ecology: Study of populations in relation to environment.

• Community Ecology: Study of interactions among species in a community.

• Ecosystem Ecology: Study of energy flow and chemical cycling among biotic and abiotic components.

• Landscape Ecology: Study of exchanges of energy, materials, and organisms across multiple ecosystems.

• Global Ecology: Study of the biosphere and global processes.

Factors Influencing Distribution

• Dispersal: Movement of individuals or gametes away from their area of origin.

• Biotic Factors: Living components (e.g., predation, competition).

• Abiotic Factors: Non-living components (e.g., temperature, water, sunlight, wind, rocks, soil).

Climate

• Definition: Long-term prevailing weather conditions in a given area.

• Types:

  • Global

  • Regional

  • Local

  • Microclimate

• Influences: Sunlight, wind patterns, bodies of water, mountains, elevation, and human activities.

Aquatic Ecosystems

Productivity and Zonation

• Productivity limited by:

  • Sunlight

  • Nutrients

• Zonation: Photic, aphotic, and benthic zones.

• Distribution: Nutrient distribution affects productivity.

Aquatic and Terrestrial Biomes

Biomes are major life zones characterized by vegetation type (terrestrial) or physical environment (aquatic).

• Examples: Wetlands, rivers, lakes, estuaries, intertidal zones, coral reefs, oceanic pelagic zone, marine benthic zone, tropical rain forest, desert, savanna, temperate grassland, temperate deciduous forest, coniferous forest, tundra.

Population Ecology

Population Concepts

• Population: Group of individuals of same species living in same area.

• Density: Number of individuals per unit area or volume.

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

• Demography: Study of vital statistics of populations and how they change over time.

Survivorship Curves

• Type I: Low death rates during early and middle life, increase in older age groups (e.g., humans).

• Type II: Constant death rate over the organism's life span (e.g., squirrels).

• Type III: High death rates for young, lower for survivors (e.g., oysters).

Population Growth Models

• Exponential Growth: Population increase under ideal conditions. $\frac{dN}{dt} = r_{max}N$

• Logistic Growth: Population growth slows as it approaches carrying capacity. $\frac{dN}{dt} = r_{max}N\left(\frac{K-N}{K}\right)$

Community Ecology & Ecosystems

Niche and Competition

• Niche: The role and position a species has in its environment.

• Competitive Exclusion Principle: Two species competing for the same limiting resource cannot coexist at constant population values.

Predation and Mimicry

• Predation: One organism kills and eats another.

• Crypsis: Camouflage to avoid detection.

• Batesian Mimicry: Harmless species mimics a harmful one.

• Müllerian Mimicry: Two or more unpalatable species resemble each other.

Herbivory, Parasitism, and Disease

• Herbivory: Organism eats parts of a plant or alga.

• Parasitism: Parasite derives nourishment from host, harming it.

• Disease: Pathogens harm host organisms.

Symbiosis

• Mutualism: Both species benefit.

• Commensalism: One benefits, other unaffected.

Community Structure

• Species Diversity: Variety of organisms in a community.

• Relative Abundance: Proportion each species represents of all individuals.

• Trophic Structure: Feeding relationships among organisms.

  • Producers

  • Primary consumers

  • Secondary consumers

  • Etc.

Limits to Food Chain Length

• Energy transfer inefficiency limits food chain length.

• Dynamic stability hypothesis: Long food chains are less stable.

Keystone Species and Disturbance

• Keystone Species: Species that have a disproportionately large effect on community structure.

• Disturbance: Events that change communities by removing organisms or altering resource availability.

Productivity and Biogeochemical Cycles

Primary and Secondary Productivity

• Gross Primary Productivity (GPP): Total primary production in an ecosystem.

• Net Primary Productivity (NPP): GPP minus energy used by producers for respiration. $\text{NPP} = \text{GPP} - R$

• Secondary Production: Amount of chemical energy in consumers' food converted to their own new biomass.

Ecological Efficiency

• Trophic Efficiency: Percentage of production transferred from one trophic level to the next.

• Ecological Pyramids: Show relative amounts of energy or matter at each trophic level.

Biogeochemical Cycles

• Water Cycle

• Nitrogen Cycle

• Carbon Cycle

• Effects of Human Activity: Nutrient enrichment, increased atmospheric CO2, acid precipitation, ozone depletion.

Conservation Biology

Genetic, Species, and Ecosystem Diversity

• Genetic Diversity: Variation within and between populations.

• Species Diversity: Number and relative abundance of species.

• Ecosystem Diversity: Variety of ecosystems in the biosphere.

Threats to Biodiversity

• Habitat destruction

• Introduced species

• Overexploitation

• Disruption of interactions within the community

Small Populations and Fragmentation

• Small populations are vulnerable to extinction due to inbreeding and genetic drift.

• Habitat fragmentation reduces population sizes and increases edge effects.

Protected Areas and Restoration

• Protected Areas: Nature reserves, biosphere reserves, zones of restricted human activity.

• Restoration: Bioremediation (using organisms to detoxify polluted ecosystems), biological augmentation (adding essential materials to degraded ecosystems).

• Sustainable Development: Using resources in ways that do not deplete them for future generations.