What happens to a predator population when prey numbers increase?

Increased prey provides more food for predators, leading to higher predator survival and reproduction, so predator numbers rise.

Explain the effect of rising predator numbers on the prey population.

As predator numbers increase, predation pressure on prey increases, causing the prey population to decline.

What occurs in a predator population when prey numbers decline significantly?

Reduced prey means less food for predators, causing predator numbers to fall due to starvation and reduced reproduction; this allows prey populations to recover.

Describe the characteristic pattern seen in predator-prey population graphs.

Both populations show oscillations over time, with predator population peaks lagging behind prey population peaks.

What is intraspecific competition?

Intraspecific competition is competition between individuals of the same species for the same resources.

OCR A-Level Biology H420

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Populations and Sustainability

Predator-prey cycles and competition

2 things to know
Components 02 and 03

Overview

The lag between predator and prey numbers and the pattern it produces on a graph, and interspecific and intraspecific competition.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Process

Explain predator-prey population cycles.

Key term

Define interspecific competition.

Questions from this subtopic

Each one with the model answer underneath.

1
What happens to a predator population when prey numbers increase?
Model answer
Increased prey provides more food for predators, leading to higher predator survival and reproduction, so predator numbers rise.
2
Explain the effect of rising predator numbers on the prey population.
Model answer
As predator numbers increase, predation pressure on prey increases, causing the prey population to decline.
3
What occurs in a predator population when prey numbers decline significantly?
Model answer
Reduced prey means less food for predators, causing predator numbers to fall due to starvation and reduced reproduction; this allows prey populations to recover.
4
Describe the characteristic pattern seen in predator-prey population graphs.
Model answer
Both populations show oscillations over time, with predator population peaks lagging behind prey population peaks.
5
Define interspecific competition.
Model answer
Interspecific competition is competition between individuals of different species for the same resources.
6
What is intraspecific competition?
Model answer
Intraspecific competition is competition between individuals of the same species for the same resources.

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