Organism

An individual living thing.

Population

A group of individuals of the same species living in the same area.

Community

All the different populations that live together in an area.

Ecosystem

Includes all the living (biotic) and nonliving (abiotic) things in an area.

Biome

A large geographic area characterized by specific climate conditions, animal and plant populations.

Biotic factors

Living things, such as animals or plants.

Abiotic factors

Nonliving things like wind, sunlight, or water.

Producers

Organisms that get their energy from abiotic resources, meaning they make their own food.

Consumers

Organisms that get their energy by consuming other organisms.

Herbivore

An organism that eats only plants.

Carnivore

An organism that eats only meat.

Omnivore

An organism that eats both plants and animals.

Trophic levels

The different feeding positions in a food chain or food web.

Primary consumer

An organism that eats producers (plants).

Secondary consumer

An organism that eats primary consumers.

Tertiary consumer

An organism that eats secondary consumers.

Decomposer

An organism that breaks down dead plants and animals.

Food chain

A linear sequence of organisms through which nutrients and energy pass.

Food web

A network of interconnected food chains.

Energy pyramid

A graphical representation of the energy flow in an ecosystem, showing the tiers from producers to tertiary consumers.

Biomagnification

The increasing concentration of a substance in the tissues of organisms at successively higher levels in a food chain.

Symbiosis

Any type of close and long-term biological interaction between two different biological organisms.

Commensalism

A relationship in which one organism benefits and the other is neither harmed nor helped.

Mutualism

A relationship in which both organisms benefit.

Predation

A relationship in which one organism (the predator) kills and eats another organism (the prey).

Parasitism

A relationship in which one organism (the parasite) benefits and the other organism (the host) is harmed.

Habitat

The place where an organism lives.

Niche

The role an organism plays in its environment.

Exponential growth (J-curve)

Population increases rapidly without any limitations.

Logistic growth (S-curve)

Population growth slows down as it reaches carrying capacity.

Density-dependent factor

A factor that limits population growth more strongly as population density increases.

Density-independent factor

A factor that limits population growth regardless of population density.

Carrying capacity

The maximum number of individuals of a species that an environment can support.