Ecology Key Terms: Biotic, Abiotic, and Ecosystem Concepts

Abiotic

Non-living chemical and physical parts of the environment that affect living organisms.

Biotic

Living components of an ecosystem, such as plants, animals, and microorganisms.

Niche

The role or function of an organism or species within an ecosystem, including its habitat, resource use, and interactions with other organisms.

Organism

Any individual living entity that can react to stimuli, reproduce, grow, and maintain homeostasis.

Population

A group of individuals of the same species living in a specific area at the same time.

Community

An assemblage of different populations that live together in a defined area.

Ecosystem

A biological community of interacting organisms and their physical environment.

Biome

A large geographical biotic unit, a major community of plants and animals with similar life forms and environmental conditions.

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem, including species diversity, genetic diversity, and ecosystem diversity.

Ecological Equivalent

Species that occupy similar niches but live in different geographical regions.

Food Chain

A linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Keystone Species

A species that has a disproportionately large effect on its environment relative to its abundance.

Carrying Capacity

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

Habitat

The natural home or environment of an organism, providing the necessary resources for survival.

Exponential Growth

A growth pattern where the number of individuals increases rapidly over time, typically when resources are unlimited.

Logistic Growth

A growth pattern that starts exponentially but slows as the population reaches the carrying capacity of the environment.

Interspecific Competition

Competition between different species for the same resources in an ecosystem.

Intraspecific Competition

Competition among individuals of the same species for limited resources.

Predation

The interaction where one organism (the predator) kills and eats another organism (the prey).

Symbiosis

A close and long-term interaction between two different species, which can be beneficial, neutral, or harmful.

Mutualism

A type of symbiotic relationship where both species benefit from the interaction.

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 organism benefits at the expense of another.

Limiting Factor

An environmental factor that restricts the growth, abundance, or distribution of a population.

Food Web

A complex network of feeding relationships among various organisms in an ecosystem, illustrating how energy and nutrients flow.