GCSE · Biology · AQA · Spec 8461

Maintaining biodiversity

Building, farming, cutting down forests, burning fossil fuels: four very different activities. Follow each one far enough and nearly all of them end up in the same place.

Human impact on ecosystems

How do these activities end up reducing biodiversity?

Draw the links. For each activity (1 to 4), what does it lead to? Keep going until you reach lower biodiversity (7). One activity can have more than one arrow.

  1. Building, quarrying and dumping waste in landfill
  2. Merging small fields into huge single-crop fields
  3. Cutting down forests
  4. Burning fossil fuels
  5. More carbon dioxide and climate change
  6. Loss of habitat
  7. Lower biodiversity (outcome)
Add a link

No links yet.

Why biodiversity matters

?

Reason it through

So why does losing species matter, to ecosystems and to us?

Link 1 of 4

First link · your turn

Start with the word itself. What does biodiversity actually measure?

2
Locked — reveal the link above first
3
Locked — reveal the link above first
4
Locked — reveal the link above first

Same farm, two choices

Huge single-crop fields, hedges removedvsHedgerows restored, wild-flower margins sown

Read across each row. The land and the crop are the same; what changes is what is left around the edges.

Focus

What the farmer did

Huge single-crop fields, hedges removed

Merged small fields into one huge field of a single crop, removing the hedges between them, and used pesticides.

Hedgerows restored, wild-flower margins sown

Restored and managed the hedgerows, and sowed strips of grasses and wild flowers along the field margins.

The insight

Both are farms growing crops. This is not farming versus no farming; it is about what the farmer leaves for wildlife.

Somewhere to live

Huge single-crop fields, hedges removed

Hedges gone, and hedges are important habitats.

Hedgerows restored, wild-flower margins sown

Hedgerows give wildlife somewhere to live.

Food

Huge single-crop fields, hedges removed

The pollen, nectar and berries the hedges supplied are gone with them.

Hedgerows restored, wild-flower margins sown

Hedgerows supply pollen, nectar and berries that feed insects, birds and mammals. The wild flowers give pollinating insects pollen and nectar.

Places to nest

Huge single-crop fields, hedges removed

No wild-flower margins to nest in.

Hedgerows restored, wild-flower margins sown

The margin strips give insects, farmland birds and small mammals places to nest.

Effect on biodiversity

Huge single-crop fields, hedges removed

Lowered.

Hedgerows restored, wild-flower margins sown

Helps to maintain it.

Programmes that help

What does each programme give back?

Scientists and concerned citizens have set up programmes to reduce the harm humans do to biodiversity. For each one, decide what it does: protect or restore habitat, cut carbon dioxide, both, or neither.

  • A Protects or restores habitat
  • B Cuts carbon dioxide
  1. Breeding endangered animals in captivity, for example in zoos, then releasing them
  2. Setting rare habitats aside as protected nature reserves
  3. Regenerating damaged habitats
  4. Reducing deforestation
  5. Burning less fossil fuel
  6. Recycling instead of dumping waste in landfill

Your turn

Write it, then mark it

Describe one way humans reduce biodiversity and one programme that helps to maintain it. Explain how each one affects biodiversity. [4 marks]

0 words · your answer stays on this page and is not sent anywhere.

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

Lots of different human activities harm wildlife in the same way: they take away habitat. Most of the fixes work by giving it back.

What you need to know

  • What biodiversity is, and why high biodiversity keeps ecosystems stable
  • How human activities reduce biodiversity, and how several of them do it by taking away habitat
  • How programmes such as breeding, nature reserves, hedgerows and field margins, reducing deforestation and emissions, and recycling help to maintain biodiversity

The big picture

Biodiversity is the variety of all the different species on Earth or within an ecosystem. High biodiversity keeps ecosystems stable, and the future of humans depends on keeping it. Humans reduce biodiversity by taking land for building, quarrying, farming and landfill, by pollution, by cutting down forests and by burning fossil fuels. Many of these act through loss of habitat. Programmes to maintain biodiversity include breeding endangered animals, protecting and regenerating habitats, restoring hedgerows and field margins, reducing deforestation and carbon dioxide emissions, and recycling instead of landfill. Most of them work by giving habitat back.

Key points

1Biodiversity is the variety of all the different species of organisms on Earth, or within an ecosystem.
2High biodiversity makes an ecosystem stable by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment.
3The future of the human species on Earth relies on maintaining a good level of biodiversity.
4Building, quarrying, farming and dumping waste reduce the land available for other animals and plants. Pollution kills plants and animals.
5Cutting down forests destroys habitats and removes plants that absorb carbon dioxide. Burning fossil fuels gives off carbon dioxide, which drives climate change.
6Programmes that help: breeding endangered animals in captivity and releasing them, protected nature reserves, regenerating damaged habitats, restoring hedgerows and field margins, reducing deforestation and carbon dioxide emissions, and recycling instead of landfill.

Worked example

Problem

A town sends almost all of its rubbish to landfill. It decides to recycle much more instead. Explain how this change could help biodiversity.

⚠ Watch out

Thinking that maintaining biodiversity just means rescuing individual animals, for example breeding endangered animals in zoos. Breeding programmes are only one of several programmes. Most of the others work by protecting or restoring habitat, and even animals bred in captivity need suitable habitat to be released into.

🧠

Memory hook

Take away the home, lose the species. Give back the home, keep the species.

✓

Check yourself

Cover the page. Name two activities that take habitat away, one programme that gives it back, and the programme that does neither. What does that one still need?

Flashcards

(12)
What is biodiversity?
The variety of all the different species of organisms on Earth, or within an ecosystem.
How does high biodiversity make an ecosystem stable?
It reduces the dependence of one species on another for food, shelter and the maintenance of the physical environment.
Why does biodiversity matter to humans?
The future of the human species on Earth relies on us maintaining a good level of biodiversity.
Four activities that reduce the land available for other animals and plants
Building, quarrying, farming and dumping waste.
How does pollution reduce biodiversity?
It kills plants and animals.
Two ways cutting down forests harms the environment
It destroys habitats, and it removes plants that absorb carbon dioxide.
Why do huge single-crop fields often have low biodiversity?
Hedges, which are important habitats, are often removed to make them, and pesticides are used on the crop.
How does burning less fossil fuel help biodiversity?
It cuts carbon dioxide emissions and limits climate change, which helps protect habitats.
How does a breeding programme help an endangered species?
Animals are bred in captivity, for example in zoos, and later released into suitable habitat, which helps stop the species dying out.
How do nature reserves and regenerating habitats help?
They supply organisms with what they need to survive, so the species there are conserved.
What do restored hedgerows give wildlife?
Somewhere to live, plus pollen, nectar and berries that feed insects, birds and mammals.
What do strips of grasses and wild flowers along field margins provide?
Pollen and nectar for pollinating insects, and places for insects, farmland birds and small mammals to nest.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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