On a predator-prey graph, which peak comes first?

The prey peak, followed by the predator peak.

What is the time lag in a predator-prey cycle?

The delay between the prey peak and the predator peak.

Why does the predator peak come after the prey peak?

Predators need time to breed and grow after there is more food.

Why do predator numbers fall when prey numbers fall?

There is less food, so predators starve or fewer reproduce.

Why do prey numbers recover when predators decrease?

Fewer prey are eaten, so more survive and reproduce.

How do you find the length of a cycle on a graph?

Measure the time between one peak and the next.

How do eyes at the front of the head help a predator?

They help it to judge distances accurately.

How do eyes at the sides of the head help prey?

They give a wide field of view to spot predators.

Colouring or patterns that help an organism blend into its background.

How does camouflage help prey?

Predators are less likely to see it, so it survives and reproduces.

Name two adaptations of a predator for catching prey.

Streamlined body and powerful muscles for speed; sharp teeth and claws.

What is an adaptation?

A feature that helps an organism survive and reproduce.

Predator-prey relationshipsIB MYP Biology: Flashcards

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What is a predator?

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What is a predator?: An animal that hunts, kills and eats other animals.
What is prey?: An animal that is hunted and eaten by a predator.
On a predator-prey graph, which peak comes first?: The prey peak, followed by the predator peak.
What is the time lag in a predator-prey cycle?: The delay between the prey peak and the predator peak.
Why does the predator peak come after the prey peak?: Predators need time to breed and grow after there is more food.
Why do predator numbers fall when prey numbers fall?: There is less food, so predators starve or fewer reproduce.
Why do prey numbers recover when predators decrease?: Fewer prey are eaten, so more survive and reproduce.
How do you find the length of a cycle on a graph?: Measure the time between one peak and the next.
How do eyes at the front of the head help a predator?: They help it to judge distances accurately.
How do eyes at the sides of the head help prey?: They give a wide field of view to spot predators.
What is camouflage?: Colouring or patterns that help an organism blend into its background.
How does camouflage help prey?: Predators are less likely to see it, so it survives and reproduces.
Name two adaptations of a predator for catching prey.: Streamlined body and powerful muscles for speed; sharp teeth and claws.
What is an adaptation?: A feature that helps an organism survive and reproduce.

Exam questions on Predator-prey relationships

In a nature reserve in Canada, the populations of snowshoe hares (prey) and lynx (predators) were counted every year for 20 years. The hare population peaked at about 140 000 in year 4 and again in year 14. The lynx population peaked at about 60 000 in year 6 and again in year 16.
Explain why each lynx peak comes after the hare peak.2 marks
A cheetah hunts gazelles on an African grassland. The cheetah has a streamlined body, powerful leg muscles and eyes at the front of its head. The gazelle has eyes at the sides of its head, long legs for fast running and a brown coat.
Explain how the gazelle's brown coat helps it to survive.2 marks
A class investigates camouflage using paper 'insects' on a green lawn. In each trial the teacher scatters 20 green, 20 yellow and 20 red paper insects, all the same size, over the same area of the lawn. Ten students act as predators and each has 20 seconds to collect as many insects as they can. The trial is repeated three times with fresh insects. In total, the students collected 9 green, 24 yellow and 41 red insects.
Identify the independent variable, the dependent variable and one control variable in this investigation.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).