TASC Environmental Science Level 3 key terms

The variety of living things in a place, measured as the number of species, the genetic differences among them, and the range of habitats and ecosystems they form.

A community of living organisms interacting with one another and with the nonliving parts of their surroundings, such as soil, water, air, and sunlight, functioning as a unit.

The particular place or type of surroundings where a plant, animal, or other organism naturally lives and finds the food, water, shelter, and space it needs to survive.

The specific role an organism plays in its community, including what it eats, what eats it, when it is active, and how it uses resources, which reduces competition with other species.

All the individuals of one species living in the same area at the same time, which scientists study to track growth, decline, and the effects of environmental pressures.

The largest population of a species that a given environment can support over the long term without damage to the resources on which that population depends.

Any condition, such as food supply, water, shelter, disease, or predators, that restricts how large a population can grow or where a species can live.

The struggle between organisms for the same limited resources, such as food, water, light, or space, which can occur within one species or between different species.

An animal that hunts and eats other animals for food, which helps control the size of prey populations and shapes how those populations behave and where they live.

An animal that is hunted and eaten by another animal, often developing defenses such as speed, camouflage, warning colors, or group living to avoid being caught.

A close, long-term relationship between two different species living together, which may benefit both, benefit one while harming the other, or benefit one while the other is unaffected.

A symbiotic relationship in which two species both benefit, such as bees gathering nectar while carrying pollen that lets flowering plants reproduce.

An organism that lives on or inside another organism, called the host, and takes nutrients from it, usually weakening the host without immediately killing it.

A simple sequence showing how energy passes from one organism to another, starting with a producer and continuing through consumers and ending with decomposers.

A diagram of the many interconnected food chains in an ecosystem, showing how each organism may eat and be eaten by several different species.

An organism, usually a green plant or alga, that makes its own food from sunlight through photosynthesis and forms the energy base for the rest of the food web.

An organism that cannot make its own food and must eat other organisms, classified as primary, secondary, or tertiary depending on where it feeds in a food chain.

An organism such as a fungus or bacterium that breaks down dead plants and animals and wastes, releasing nutrients back into the soil for other organisms to use.

The process by which green plants, algae, and some bacteria use sunlight, water, and carbon dioxide to make sugar and release oxygen into the atmosphere.

The process by which living cells release energy from sugars, using oxygen and producing carbon dioxide and water, the reverse of photosynthesis in its overall chemical equation.

A model shaped like a triangle showing that only about ten percent of the energy at each feeding level passes to the next, so top predators are few.

The continuous movement of elements such as carbon, nitrogen, and phosphorus between living organisms, soil, water, and the atmosphere so they can be reused.

The ongoing exchange of carbon among the atmosphere, oceans, soil, and living things through processes such as photosynthesis, respiration, decomposition, and the burning of fuels.

The conversion of nitrogen gas from the air into compounds that plants can use, carried out by certain bacteria in soil and in the roots of legumes such as beans.

The series of steps by which nitrogen moves between the atmosphere, soil, water, and living organisms, including fixation, uptake by plants, decomposition, and return to the air.

A feature or behavior that helps an organism survive and reproduce in its environment, arising over many generations through natural selection acting on inherited variation.

The process by which individuals with traits better suited to their surroundings tend to survive and leave more offspring, gradually changing the characteristics of a population over time.

The change in the inherited characteristics of populations over generations, driven largely by natural selection and other processes such as mutation and migration.

A group of organisms that can interbreed and produce fertile offspring under natural conditions, and that is given its own scientific name.

A nonnative organism introduced to a new area where it spreads rapidly, often lacking natural enemies, and harms native species, ecosystems, or human activities.

A plant or animal that has lived in a particular region for a long time and evolved there alongside the other organisms in its ecosystem.

A species whose population has fallen so low that it faces a high risk of extinction throughout all or a large part of the area where it naturally occurs.

The permanent disappearance of a species from Earth when the last living individuals die and no descendants remain to continue the line.

Using resources in a way that meets present needs without reducing the ability of future generations to meet their own needs.

A natural resource that can be replenished by natural processes within a human lifetime, such as sunlight, wind, flowing water, or timber from managed forests.

A natural resource that exists in limited amounts and forms far more slowly than it is used, such as coal, oil, natural gas, and many metal ores.

The careful protection and planned management of natural resources, habitats, and wildlife so they are not wasted, damaged, or lost.

The addition to air, water, or soil of substances or forms of energy at levels that harm living things, damage materials, or reduce the quality of the environment.

A single identifiable place from which pollution enters the environment, such as a factory pipe or a sewer outfall, making the pollution easier to regulate and treat.

The overenrichment of water with nutrients, often from fertilizer or sewage runoff, which causes excessive algae growth and can leave the water low in oxygen.

All the land area whose rain and snowmelt drain into a particular river, lake, or other body of water, linking land use upstream with water quality downstream.

Water stored in the cracks and spaces within soil and rock beneath the surface, which supplies wells and springs and can become contaminated by pollutants seeping downward.

An underground layer of rock or sediment that holds and transmits enough water to supply wells and springs, and that can be recharged slowly by rain.

A gas in the atmosphere, such as carbon dioxide, methane, or water vapor, that absorbs and re-emits heat, warming the planet's surface and lower atmosphere.

A fuel formed over millions of years from the buried remains of plants and animals, such as coal, petroleum, and natural gas, which releases carbon dioxide when burned.

Long-term shifts in average temperature, rainfall, and weather patterns, currently driven largely by human releases of greenhouse gases from burning fuels and clearing land.