Lesson T4.2.4

T4.2.4 Adaptation, extinction and biodiversity Quiz: KS3 Biology, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T4.2.4, Adaptation, extinction and biodiversity: 20 multiple choice questions for the KS3 Biology (National Curriculum), Unit 4: Genetics and evolution, written with Revision Ninja.

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The 20 questions

  1. What is extinction?

    • When a species reproduces rapidly and fills its habitat
    • When all individuals of a species have died out
    • When a species changes its colour over many generations
    • When a species moves to a new habitat in search of food

  2. Why can a species become extinct when its environment changes?

    • The species is able to photosynthesise in the dark during winter nights
    • Individuals may be less well adapted and fail to survive and reproduce
    • The environment stops changing so the species never needs to adapt
    • The species becomes stronger and no longer needs to eat much food

  3. Which change is most likely to cause a species to become extinct?

    • Rapid destruction of its habitat with no suitable place to move
    • Gradual change that gives the species time to adapt and survive
    • A small rise in the number of its predators in a stable habitat
    • A slight increase in available food throughout the whole year

  4. What is biodiversity?

    • The number of decomposers living in the soil of a single habitat
    • The amount of sunlight that reaches plants in a temperate forest
    • The variety of living organisms in an area or on Earth
    • The total mass of organisms living in one habitat at one time

  5. Why is biodiversity important to humans?

    • It reduces the amount of light available to crops growing in fields
    • It provides food, medicines and ecosystem services that support life
    • It makes the air colder in the summer months across the whole planet
    • It stops humans from needing water to drink, cook and wash food

  6. What is a gene bank?

    • A laboratory where new species of animals are bred for sale to farms
    • A group of organisms that all feed on the same food source in a habitat
    • A store of seeds or other genetic material kept to preserve variety
    • A record of how many predators live in one area during each season

  7. Why are gene banks useful?

    • They prevent all species from changing, so no evolution can occur
    • They preserve genetic variety that could be needed in the future
    • They stop natural selection from happening in the wild populations
    • They make every plant identical so that crops grow in uniform rows

  8. Why is maintaining biodiversity important for food crops?

    • A wide range of genes stops photosynthesis, so crops need much less light to grow
    • A wide range of genes makes crops grow identically in every field and season
    • A wide range of genes removes the need for water, so crops need no irrigation
    • A wide range of genes gives crops more chance of resisting disease and climate change

  9. Which action would most likely reduce biodiversity?

    • Using seed banks to store plant varieties
    • Planting native trees in a wood
    • Destroying forests to build roads and farmland
    • Protecting wetlands for wildlife

  10. A species has very little genetic variation. Why is it at greater risk?

    • It cannot photosynthesise, so it must rely on food from other species
    • It cannot reproduce at all, so it never produces any new offspring
    • It may not have the variation needed to adapt to a change in its environment
    • It will always be the largest species in its habitat and its region

  11. Why does losing one species often affect others?

    • Losing one species always increases the number of others
    • Species are interdependent, so losing one can disrupt food webs
    • Species only compete for light
    • Species never interact with each other

  12. What is an endangered species?

    • A species that is no longer able to reproduce
    • A species that lives only in the sea
    • A species that is at risk of becoming extinct
    • A species that has no predators

  13. Which statement about extinction is correct?

    • Extinction is always caused by a single food shortage in the habitat
    • Extinction only happens in plants that are grown in large monocultures
    • Extinction is a natural process, but human activity can speed it up
    • Extinction never happens in nature because species always adapt in time

  14. Why are fossils useful for studying extinct species?

    • They give evidence of organisms that lived in the past and have died out
    • They reveal the future of the environment and where species will live
    • They prove all species are identical across different time periods
    • They show that extinct species are still alive in remote areas today

  15. Why does a larger number of species usually make an ecosystem more stable?

    • Larger numbers of species make the ecosystem colder and less productive
    • Larger numbers of species remove all predators from the food chain
    • Different species respond differently to changes, so the system is more resilient
    • Larger numbers of species stop natural selection from acting on populations

  16. What is a consequence of reduced genetic variety in a species?

    • It becomes more able to cope with every disease
    • It will reproduce more quickly in every habitat
    • It may be less able to adapt to a changing environment
    • It will develop photosynthesis

  17. Why do conservationists try to protect habitats as well as individual species?

    • Protecting habitats only helps decomposers living in the leaf litter
    • Protecting habitats makes species identical so they all look alike
    • Protecting habitats keeps the species from needing food and water
    • Protecting habitats protects many species that depend on that environment

  18. What is the link between evolution and biodiversity?

    • Biodiversity makes evolution impossible because species stop changing
    • Evolution removes all species from the planet over a long period
    • Natural selection over time produces the variety of species seen today
    • Evolution only happens in plants that grow in the wild habitats

  19. Which statement about biodiversity and survival is true?

    • Biodiversity has no effect on food webs
    • A low variety of species is always best
    • Only one species is needed for a healthy ecosystem
    • A variety of organisms helps ecosystems cope with change

  20. What does it mean for a population to be locally extinct?

    • It has died out across the whole world, with no survivors anywhere
    • It is growing faster than its habitat can support and so is declining
    • It has moved to a new continent and established a new population there
    • It has died out in one area although the species survives elsewhere

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