---
title: "Interspecific Competition — AP Enviro Definition & Exam Guide"
description: "Interspecific competition is when different species fight over the same limited resources, a selective pressure that can push native species toward extinction."
canonical: "https://fiveable.me/ap-enviro/key-terms/interspecific-competition"
type: "key-term"
subject: "AP Environmental Science"
unit: "Unit 9"
---

# Interspecific Competition — AP Enviro Definition & Exam Guide

## Definition

Interspecific competition is competition between two different species for the same limited resources such as food, territory, mates, or habitat, and it can act as a selective pressure that drives a less-fit species toward endangerment or extinction (EK EIN-4.B.1).

## What It Is

Interspecific competition is what happens when two different species need the same thing and there isn't enough to go around. Think shared food, the same nesting [territory](/ap-enviro/key-terms/territory "fv-autolink"), the same patch of habitat. "Inter" means "between" (between species), so this is the rivalry across species lines, not within a single one.

In [AP Enviro](/ap-enviro "fv-autolink") this shows up in [Unit 9](/ap-enviro/unit-9 "fv-autolink") as one of the ways a species ends up threatened. EK EIN-4.B.1 lists being "outcompeted by invasive species" as a major path to extinction, and that's interspecific competition in action. An invasive species arrives, uses resources more efficiently, and the native species loses access to the food or space it needs. If the native species can't adapt or move (EK EIN-4.B.2), its numbers crash. Competition is one of those selective pressures from EK EIN-4.B.3 that changes a population's fitness over time.

## Why It Matters

This term lives in [Topic 9.9](/ap-enviro/unit-9/endangered-species/study-guide/nPHB7UlREP5mNGlxRUfD "fv-autolink") (Endangered Species) under Unit 9: Global Change, and it directly supports learning objective AP Enviro 9.9.A, which asks you to explain how species become endangered and what strategies fight the problem. The CED specifically names being outcompeted by invasive species as a cause of endangerment (EK EIN-4.B.1). So understanding [competition](/ap-enviro/key-terms/competition "fv-autolink") is part of understanding the whole extinction-risk picture. It also ties into the big idea that not every species responds the same way to change. Species that can adapt or relocate survive the competition; specialists with narrow needs often don't.

## Connections

### Invasive Species and Extinction Risk (Unit 9)

Invasive species are the headline example of interspecific competition gone wrong. A non-native arrives, outcompetes the locals for food or space, and the native species' [extinction risk](/ap-enviro/key-terms/extinction-risk "fv-autolink") jumps. The competition is the mechanism; endangerment is the result.

### Habitat Specialists and Limited Diet (Unit 9)

EK EIN-4.B.1 pairs competition with narrow [habitat](/ap-enviro/key-terms/habitat "fv-autolink") needs and a limited diet. A specialist like a bamboo-only lemur is hit hardest by competition because it has no backup resource to switch to, so any rival eating its one food source is a direct threat.

### Adaptation and Mobility (Unit 9)

EK EIN-4.B.2 explains why competition doesn't doom every species. If a population can adapt or move to a new environment, it dodges the loser's fate. Competition only pushes toward [extinction](/ap-enviro/key-terms/extinction "fv-autolink") when the species is stuck and inflexible.

### [Protected Areas (Unit 9)](/ap-enviro/key-terms/protected-areas)

Setting aside protected areas is one strategy to reduce pressure on native species, including the pressure from competing or invasive species. It gives the native species space where its resources aren't being stolen.

## On the AP Exam

Expect this on MCQs that hand you a scenario and ask you to identify the cause of endangerment. The classic stem asks which scenario "most directly illustrates interspecific competition contributing to endangerment of a native species," and the right answer features two different species fighting over the same resource (often an invasive species crowding out a native one). Be careful: questions also test the contrast, like a habitat-fragmentation scenario for a K-selected mammal, which is loss-of-habitat, not competition. On FRQs under topic 9.9, you'd use interspecific competition to explain one cause of endangerment and then propose a strategy (protected areas, captive breeding) to counter it. The skill is matching the cause to the mechanism, not just naming the term.

## interspecific competition vs intraspecific competition

Interspecific competition is between different species (inter = between groups). Intraspecific competition is within one species, members of the same population fighting each other for the same resources. On the exam, if the scenario names two different species competing, it's interspecific; if it's one species fighting itself, it's intraspecific.

## Key Takeaways

- Interspecific competition is competition between two different species for the same limited resource like food, territory, mates, or habitat.
- Being outcompeted, especially by invasive species, is a listed cause of endangerment in EK EIN-4.B.1.
- It acts as a selective pressure (EK EIN-4.B.3), changing a population's fitness and pushing the weaker competitor toward decline.
- Specialists with a limited diet or narrow habitat needs suffer most because they can't switch resources when a competitor moves in.
- Species that can adapt or relocate (EK EIN-4.B.2) are less likely to lose to competition, so competition alone doesn't doom everyone.
- On the exam, the correct interspecific-competition scenario always involves two different species using the same resource.

## FAQs

### What is interspecific competition in AP Environmental Science?

It's competition between two different species for the same limited resource such as food, territory, mates, or habitat. In Unit 9 it's one of the factors that can push a native species toward endangerment, especially when an invasive species does the outcompeting (EK EIN-4.B.1).

### What's the difference between interspecific and intraspecific competition?

Interspecific is between different species; intraspecific is within the same species. So a native bird losing food to an invasive bird is interspecific, but two members of that same native bird species fighting over a nest site is intraspecific. Watch the prefix: inter means between, intra means within.

### Does interspecific competition always cause extinction?

No. Per EK EIN-4.B.2, species that can adapt to the change or move to a new environment are less likely to go extinct. Competition raises extinction risk most for specialists that can't switch resources or relocate.

### How do invasive species relate to interspecific competition?

Invasive species are the most tested example. They outcompete native species for shared resources, which is interspecific competition by definition, and EK EIN-4.B.1 names being outcompeted by invasive species as a direct cause of endangerment.

### How is interspecific competition tested on the AP Enviro exam?

Usually as an MCQ where you pick the scenario that shows two different species competing for the same resource and harming a native species. Don't confuse it with habitat fragmentation or a limited diet, which are separate endangerment causes under topic 9.9.

## Related Study Guides

- [9.9 Endangered Species](/ap-enviro/unit-9/endangered-species/study-guide/nPHB7UlREP5mNGlxRUfD)

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