AQA · GCSE · Combined Science

Course version: 8464 · Version from Sept 2018

Communities: the importance of interdependence and competition in a community.

Q: How do I revise Communities: the importance of interdependence and competition in a community. for GCSE?

Read the notes on Communities: the importance of interdependence and competition in a community., then test yourself without looking. Answering questions and checking what you missed builds recall faster than re-reading.

Q: Is this Communities: the importance of interdependence and competition in a community. guide aligned to the AQA specification?

Yes. This guide is linked to the Communities: the importance of interdependence and competition in a community. topic in the AQA GCSE specification.

In a community, every population depends on others.

2 key terms

Study notes

From the checked teaching notes for this specification point.

The idea

In a community, every population depends on others. Interdependence means that organisms rely on each other for food, shelter, pollination, seed dispersal and other needs. For example, bees depend on flowers for nectar while flowers depend on bees for pollination; if the bees disappear, the plants may not reproduce. Competition happens when organisms need the same limited resource. Plants compete for light, water, space and mineral ions; animals compete for food, mates and territory. Competition can be between members of the same species or between different species. Both interdependence and competition affect which organisms survive and reproduce, so they help determine the size and distribution of populations in a community. Removing or adding one species can therefore affect many others.

What earns the marks

Interdependence is the reliance of organisms in a community on each other for resources and processes such as food, shelter, pollination and seed dispersal.
Competition occurs when organisms require the same resource that is in limited supply.
Plants compete for light, water, space and mineral ions; animals compete for food, mates and territory.
Competition may be between individuals of the same species or between different species.
Interdependence and competition influence survival and reproduction, and therefore affect population sizes and distribution.
A change to one population, such as a fall in bee numbers, can affect other populations because of interdependence.

Common mistakes and how to put them right

Treating interdependence as one-way, such as saying bees depend on flowers but ignoring that flowers depend on bees.
Put it right: The relationship works in both directions.
Assuming competition only happens between different species.
Put it right: Members of the same species also compete for the same resources.
Saying competition always kills the weaker organism.
Put it right: It reduces the resources available, affecting growth, survival and reproduction rather than always causing immediate death.

Exam tips

Use the phrase 'limited resource' when defining competition, because competition only matters when supply is short.
Give named examples of what plants and animals compete for rather than writing 'resources' alone.
For interdependence questions, state the benefit each organism gains, such as food for the bee and pollination for the flower.

Try the lesson

The start of the Communities: the importance of interdependence and competition in a community. lesson, made from checked teaching notes for this specification point.

Have a go first

In a community, what does interdependence mean?

Tip: press 1 to 4 to choose

See it

A top-down flowchart. The top node is Community, which branches into two nodes: Interdependence and Competition. From Interdependence a node reads Organisms rely on each other, leading to Food, shelter, pollination, seed dispersal. From Competition a node reads Same limited resource needed, which branches into Plants: light, water, space, mineral ions and Animals: food, mates, territory. Competition also leads to a node reading Same species or different species. Both Interdependence and Competition lead to Survival and reproduction, which leads to Population size and distribution, which leads to Change in one population affects others. — It shows how interdependence and competition in a community affect survival, reproduction and population size and distribution.

Key words

Say what each word means before you turn the card.

Interdependence

Try answering aloud or in your head before turning the card.

Competition

Try answering aloud or in your head before turning the card.

See every definition

Interdependence: The reliance of organisms in a community on each other for resources and processes such as food, shelter, pollination and seed dispersal.
Competition: Occurs when organisms require the same resource that is in limited supply, and may be between individuals of the same species or between different species.

Label the diagram

Some boxes have lost their names. Pick the right name for each number.

The diagram again, with 3 boxes numbered instead of named. A top-down flowchart. The top node is Community, which branches into two nodes: Interdependence and Competition. From Interdependence a node reads Organisms rely on each other, leading to Food, shelter, pollination, seed dispersal. From Competition a node reads Same limited resource needed, which branches into Plants: light, water, space, mineral ions and Animals: food, mates, territory. Competition also leads to a node reading Same species or different species. Both Interdependence and Competition lead to Survival and reproduction, which leads to Population size and distribution, which leads to Change in one population affects others.

1Box 1
2Box 2
3Box 3

0 of 3 labelled

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