Unit 8 - Ecology

Taxis

A directional movement in response to a stimulus (e.g., toward light or away from chemicals).

Kinesis

A random movement that increases or decreases in intensity depending on stimulus strength, not direction.

Diurnal animals

Animals that are active during the day and rest at night.

Nocturnal animals

Animals that are active at night and rest during the day.

Migration

Seasonal movement of animals from one region to another for better living or breeding conditions.

Hibernation

A state of inactivity and metabolic depression in animals during cold seasons.

Estivation

A state of dormancy in animals during hot or dry periods to avoid extreme heat.

Phototropism

A plant’s growth response toward or away from light.

Photoperiodism

A plant or animal’s response to the length of day or night, often affecting flowering or behavior.

Endotherms

Organisms that regulate body temperature internally through metabolism (e.g., mammals, birds).

Ectotherms

Organisms that rely on external sources to regulate body temperature (e.g., reptiles, fish).

Vasodilation

Widening of blood vessels to release heat and cool the body.

Vasoconstriction

Narrowing of blood vessels to conserve heat and maintain body temperature.

Ecological Pyramid

A diagram showing the energy, biomass, or numbers of organisms at each trophic level.

A food chain

A linear sequence of organisms where each is eaten by the next in line.

A food web

A network of interconnected food chains showing energy flow in an ecosystem.

Autotrophs

Organisms that make their own food using sunlight or chemicals (e.g., plants, algae).

Heterotrophs

Organisms that consume other organisms for energy (e.g., animals, fungi).

Herbivores

Organisms that eat only plants.

Carnivores

Organisms that eat only other animals.

Omnivores

Organisms that eat both plants and animals.

Detritivores

Organisms that feed on dead matter or waste (e.g., earthworms, millipedes).

Decomposers

Microorganisms that break down dead organic matter and recycle nutrients (e.g., bacteria, fungi).

Scavengers

Animals that consume dead animals they did not kill (e.g., vultures, hyenas).

Biotic

Living factors in an ecosystem (e.g., animals, plants, bacteria).

Abiotic

Nonliving physical or chemical components in an environment (e.g., sunlight, temperature, water).

A biological community

A group of interacting populations of different species living in the same area.

A niche

The role or function of an organism in its ecosystem, including its habitat and interactions.

Mutualism

A symbiotic relationship where both species benefit.

Commensalism

A symbiotic relationship where one species benefits and the other is not affected.

Parasitism

A symbiotic relationship where one species benefits and the other is harmed.

Symbiosis

Any close and long-term biological interaction between two different species.

Species richness

The number of different species in a given area.

Relative abundance

The proportion of each species in an ecosystem relative to the total number of organisms.

Primary Succession

The development of ecosystems in areas with no previous life (e.g., after volcanic eruptions).

Secondary Succession

The recovery of an ecosystem after a disturbance that didn’t eliminate all life (e.g., fire).

Genetic Diversity

The variety of genes within a population or species.

Species Diversity

The variety and abundance of different species in an ecosystem.

Ecosystem Diversity

The variety of ecosystems in a region or across the planet.

Urbanization

The growth of cities and human development, often reducing natural habitats.

Deforestation

The large-scale removal of forests, which affects biodiversity and climate.

Eutrophication

Excess nutrients in water bodies, often from fertilizers, causing algae blooms and low oxygen.

Greenhouse effect

The trapping of heat by gases in Earth’s atmosphere, warming the planet.

Biological Modification

Changes made to living organisms by humans, such as genetic engineering or selective breeding.

El Niño Events

Climate patterns where ocean temperatures rise in the Pacific, disrupting weather globally.

Continental Drift

The slow movement of Earth’s continents over geological time.