Ecology

Stimulus — A change in an organism’s internal or external environment that triggers a response.

Communication (Signaling Behavior) — The transfer of information between organisms; important for survival and reproduction.

Types of Communication — Chemical (pheromones), visual (body language), auditory (sounds), tactile (touch).

Innate Behavior — Inherited behavior that an organism is born with (e.g., reflexes, instincts).

Learned Behavior — Behavior developed through experience or observation.

Cooperative Behavior — When organisms work together for mutual benefit (e.g., hunting in packs, caring for young).

Endotherms — Organisms that regulate body temperature internally (e.g., mammals, birds).

Ectotherms — Organisms that rely on external sources for body temperature (e.g., reptiles).

Reproductive Strategies & Energy — Organisms adjust reproduction (more or fewer offspring) based on energy availability.

Producers (Autotrophs) — Organisms that make their own food (plants, algae).

Types of Autotrophs — Photoautotrophs (use sunlight), chemoautotrophs (use chemicals).

Consumers (Heterotrophs) — Organisms that obtain energy by eating others.

Herbivores — Eat plants.

Carnivores — Eat animals.

Omnivores — Eat both plants and animals.

Decomposers — Break down dead organisms and recycle nutrients.

Trophic Levels — Steps in a food chain that show energy transfer.

Energy Pyramid — Shows decreasing energy at higher trophic levels.

Biomass Pyramid — Shows total mass of organisms at each level.

Pyramid of Numbers — Shows number of organisms at each level.

Energy & Population Size — Less energy = smaller populations; more energy = larger populations.

Energy vs Matter — Energy flows one way through ecosystems; matter cycles and is reused.

Water Cycle — Movement of water through evaporation, condensation, precipitation.

Carbon Cycle — Movement of carbon through photosynthesis, respiration, combustion.

Nitrogen Cycle — Movement of nitrogen through fixation, nitrification, assimilation, decomposition.

Phosphorus Cycle — Movement of phosphorus through rocks, soil, water, and organisms.

Population — A group of individuals of the same species in a given area.

Energy & Population Growth — More energy allows populations to grow larger.

Adaptations — Traits that help organisms survive changes in energy availability.

Population Growth Factors — Birth rate, death rate, immigration, emigration.

Exponential Growth — Rapid population growth with no limiting factors (J-shaped curve).

Growth Rate (r) — Rate at which a population increases.

Population Density — Number of individuals per unit area.

Density-Dependent Factors — Factors that depend on population size (competition, disease).

Density-Independent Factors — Factors unrelated to population size (weather, natural disasters).

Logistic Growth — Population growth that slows as it reaches carrying capacity (S-shaped curve).

Carrying Capacity — Maximum population an environment can support.

Community — All the different populations living together in an area.

Species Diversity — Variety and abundance of species in a community.

Simpson’s Diversity Index — A measure of biodiversity.

Interspecific Competition — Competition between different species.

Intraspecific Competition — Competition within the same species.

Mutualism — Both species benefit.

Commensalism — One benefits, the other is unaffected.

Parasitism — One benefits, the other is harmed.

Predator-Prey Relationship — Interaction where one organism hunts another.

Trophic Cascade — Changes in one species affect multiple trophic levels.

Niche Partitioning — Species divide resources to reduce competition.

Ecosystem — A community and its physical environment.

Abiotic Factors — Nonliving components (temperature, water, soil).

Biotic Factors — Living components (plants, animals).

Keystone Species — A species with a large impact on its ecosystem.

Biodiversity & Resilience — Higher biodiversity makes ecosystems more stable.

HIPOC — Human impacts: Habitat loss, Invasive species, Pollution, Overexploitation, Climate change.

Biomagnification — Increase in toxin concentration at higher trophic levels.

Eutrophication — Excess nutrients cause algal blooms, leading to oxygen depletion.

Algal Bloom Effects — Blocks sunlight, reduces oxygen, kills aquatic life.

Geological/Meteorological Events — Natural events (volcanoes, storms) that disrupt ecosystems.