ECOLOGY UNIT TEST REVIEW 2025 • All information from Powerpoints and key homework questions.

Ecosystem

A complex, self-regulating system formed by the interactions of biotic factors with abiotic factors in a particular area.

Biotic Factors

Living things within an ecosystem such as plants, animals, and their remains.

Abiotic Factors

Non-living physical and chemical components of an ecosystem, including temperature, wind, and water.

Habitat

The place where an organism lives.

Terrestrial Habitats

Land habitats such as deserts, tropical rainforests, and frozen Arctic regions.

Aquatic Habitats

Water habitats including coral reefs, oceans, lakes, and ponds.

Biosphere

The part of Earth where life exists, including water, land, and air.

Atmosphere

The layer of gases surrounding Earth, composed mainly of nitrogen and oxygen.

Lithosphere

Earth’s solid outer layer including the crust and uppermost mantle.

Hydrosphere

All of Earth’s water, existing in solid, liquid, and gas forms.

Sustainability

The ability to maintain natural ecological conditions without interruption or loss of value.

Gaia Hypothesis

The idea that Earth behaves like a living organism through interactions among its spheres.

Human Activities Impacting Ecosystems

Activities like over-hunting, pollution, and habitat destruction that disrupt natural ecosystems.

Nitrogen Cycle

The process by which nitrogen is converted between its various chemical forms, essential for life.

Carbon Cycle

The series of processes by which carbon compounds are interconverted in the environment.

Water Cycle

The continuous movement of water on, above, and below the surface of the Earth.

Eutrophication

A process where water bodies become enriched with nutrients, leading to excessive growth of algae.

Food Chain

A linear sequence showing how energy and nutrients flow from one organism to another.

Food Web

A complex network of feeding relationships among various organisms in an ecosystem.

Trophic Levels

Feeding levels that describe the position of an organism in a food chain

Energy Pyramid

A graphical representation showing the flow of energy at different trophic levels in an ecosystem.

Biomass Pyramid

A pyramid that tells us the total mass of all organisms combined in a trophic level within an ecosystem. Biomass is the amount of matter in a particle or object

Invasive Species

Non-native species that cause harm to the ecosystem they invade, often outcompeting native species.

Ecological Pyramid

Diagrams that show relationships between trophic levels in ecosystems

Biotic Interactions

Interactions between living organisms, such as competition, predation, and symbiosis.

Mutualism

A type of symbiotic relationship where both species benefit.

Commensalism

A type of symbiotic relationship where one species benefits while the other is neither helped nor harmed.

Parasitism

A type of symbiotic relationship where one species benefits at the expense of another.

Carrying Capacity

The maximum number of individuals of a species that an environment can sustain without being degraded.

Pollution

Any physical change in water that can cause harm to living things.

Point Source Pollution

Pollution that enters a water body from a specific identifiable source.

Non-Point Source Pollution

Pollution that enters a water body indirectly from multiple diffuse sources.

Organic Pollution

Pollution primarily from organic solid waste, such as sewage and animal waste.

Pesticides

Substances used to kill pests, potentially causing harm to non-target species and ecosystems.

Bioaccumulation

The concentration of substances, like pesticides, in the tissues of living organisms over time.

Bioamplification

The increasing concentration of substances as they move up the food chain.

Agroecosystem

An ecosystem that is managed and altered by humans for the purpose of agriculture.

Biodiversity

The variety of species and ecosystems in a particular area.

Ecosystem Services

The benefits provided by ecosystems to humans, including clean air, water, and pollination.

Climate Change

Long-term shift in climate patterns, often due to human activities.

Water Quality Indicators

Measures of the conditions of water, including bacteria count and dissolved oxygen concentration.

Limiting Factors

Biotic and abiotic factors that restrict population growth.

Competition

The interaction between organisms competing for the same resources.

Predation

An interaction where one organism eats another for food.

Symbiosis

A close ecological relationship between two different species.

Tolerance Range

The range of environmental conditions in which a species can survive.

Optimal Range

The conditions under which a species thrives best.

Sustainable Use

Using resources in a way that meets current needs without compromising future generations.