Unit 1: The Living World: Ecosystems | Module 1: Introduction to Ecosystems

Community Ecology

The study of interactions between species.

Symbiosis

Two species living in close and long-term association with one another in an ecosystem.

Biosphere

The region of our planet where life resides.

Competition

The struggle of individuals, either within or between species, to obtain a shared limiting resource.

Competitive Exclusion Principle

The principle stating that two species competing for the same limiting resource cannot coexist.

Resource Partitioning

When two species divide a resource based on differences in their behavior or morphology.

Predation

An interaction in which one animal typically kills and consumes another animal.

Parasitoid

A specialized type of predator that lays eggs inside other organisms—referred to as its host.

Parasitism

An interaction in which one organism lives on or in another organism, referred to as the host.

Pathogen

A parasite that causes disease in its host.

Herbivory

An interaction in which an animal consumes plants or algae.

Mutualism

An interaction between two species that increases the chances of survival or reproduction for both species.

Photosynthesis

The process by which plants and algae use solar energy to convert carbon dioxide (CO₂) and water (H₂O) into glucose (C₆H₁₂O₆) and oxygen (O₂)

Commensalism

An interaction between two species in which one species benefits and the other species is neither harmed nor helped.

Native species

A species that lives in its historical range, typically where it has lived for thousands or millions of years.

Exotic Species/Alien Species

A species living outside its historical range. Also known as alien species.

Invasive Species

A species that spreads rapidly across large areas and causes harm.