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Topic 1.9Biology SL72 flashcards

Conservation of biodiversity

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Card 1 of 721.9.1
1.9.1
Question

Define biodiversity.

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1.9.112 cards

Card 1definition
Question

Define biodiversity.

Answer

The **variety of life** in an area — including **species, habitat and genetic** diversity.

Card 2definition
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Define species richness.

Answer

The **number of different species** present in a community.

Card 3definition
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Define ecosystem stability.

Answer

The ability of an ecosystem to **keep functioning and recover** after a disturbance.

Card 4concept
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Name the three levels of biodiversity.

Answer

**Species** diversity, **habitat** diversity and **genetic** diversity.

Card 5concept
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Why does high biodiversity make an ecosystem more stable?

Answer

Species' roles **overlap**, so if one species is lost **another can cover its role** — the ecosystem keeps working.

Card 6concept
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Give two ways biodiversity is valuable to humans.

Answer

It provides **food and materials**, **medicines**, and **ecosystem services** (e.g. pollination, water cleaning).

Card 7definition
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What is an ecosystem service? Give an example.

Answer

Free 'work' an ecosystem does for us — e.g. **bees pollinating crops** or wetlands cleaning water.

Card 8concept
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Why is extinction such a serious loss?

Answer

It is **irreversible** — a species' genes and its ecological role are gone **forever**.

Card 9concept
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Name three human causes of biodiversity loss.

Answer

**Habitat destruction**, **overexploitation** and **pollution** (also invasive species and climate change).

Card 10definition
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What is the 'sixth mass extinction'?

Answer

The current **rapid, human-driven** loss of species, happening far faster than the natural background rate.

Card 11concept
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In a 'Suggest why biodiversity matters' question, what should you link to?

Answer

Link **more species** to a **benefit** — usually greater **stability / resilience** or more **ecosystem services**.

Card 12concept
Question

Why does just saying 'there are more species' score no marks?

Answer

You must **link** the extra species to a **consequence** (stability, services); the variety alone is not the mark.

1.9.212 cards

Card 13definition
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Define biodiversity.

Answer

The **variety of living organisms** — the number of different species and the variety within them.

Card 14definition
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Define extinction.

Answer

The **permanent loss** of a species when its **very last member dies**.

Card 15concept
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Name the five human causes of biodiversity loss.

Answer

**Habitat loss, overexploitation, pollution, invasive species, climate change** (memory hook: HIPPO).

Card 16concept
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Which cause destroys the most biodiversity, and why?

Answer

**Habitat loss** — clearing a habitat removes the home of **every** species that depends on it at once.

Card 17definition
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Define habitat loss.

Answer

Destruction or fragmentation of the **natural place a species lives** (e.g. deforestation, draining wetlands).

Card 18definition
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Define overexploitation.

Answer

Harvesting or hunting a species **faster than it can reproduce**, so its population crashes.

Card 19definition
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Define an invasive species.

Answer

A **non-native** species, introduced by humans, that spreads and **harms native species** by competing with, eating or infecting them.

Card 20concept
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Why are islands especially vulnerable to invasive species?

Answer

Native island species often have **no defences** against a brand-new predator or competitor.

Card 21concept
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Give one way pollution causes biodiversity loss.

Answer

Harmful substances such as **pesticides or plastic** added to air, water or soil **poison or kill** wildlife.

Card 22concept
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How does climate change cause biodiversity loss?

Answer

Human-driven warming **shifts conditions faster than species can adapt** (e.g. coral bleaching as the sea warms).

Card 23concept
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Difference between extinction and biodiversity loss?

Answer

**Extinction** = one whole species lost forever; **biodiversity loss** = the **wider fall** in variety, including shrinking populations.

Card 24concept
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What does a 'Discuss the impact' question need to score full marks?

Answer

**Named impacts with reasoning** (a direct and a knock-on effect) — not just 'it is bad'.

1.9.312 cards

Card 25definition
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Define in situ conservation.

Answer

Protecting a species **within its natural habitat** (e.g. in a nature reserve or national park).

Card 26definition
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Define ex situ conservation.

Answer

Protecting a species **outside its natural habitat** (e.g. in a zoo, botanic garden or seed bank).

Card 27concept
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Give two examples of in situ conservation.

Answer

**Nature reserves / national parks** and **wildlife corridors** that connect them.

Card 28concept
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State the main advantage of in situ conservation.

Answer

The **whole ecosystem** is conserved together, so the species keeps a large population with **high genetic diversity** and behaves naturally.

Card 29definition
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What is a wildlife corridor?

Answer

A protected strip of habitat that **connects two separate reserves** so animals can move between them.

Card 30concept
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How does a wildlife corridor help biodiversity?

Answer

It lets animals **move, interbreed and recolonise** between reserves — keeping populations larger and genetically diverse.

Card 31definition
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Define habitat fragmentation.

Answer

The breaking up of one large habitat into **smaller, separated patches**.

Card 32definition
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What is the edge effect?

Answer

The **harsher conditions** (wind, light, predators, invasive species) found **near the boundary** of a habitat patch compared with its interior.

Card 33concept
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Which reserve shape protects the most species, and why?

Answer

A **large, rounded** reserve — it has **more sheltered interior** and **less exposed edge**.

Card 34concept
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Why is a long, thin reserve poor at protecting species?

Answer

It is **almost all edge**, so harsh edge conditions reach every part and few interior species survive.

Card 35concept
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Why does in situ conservation keep genetic diversity high?

Answer

The wild population stays **large**, so a wide range of alleles is kept (unlike a small captive group).

Card 36concept
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Why is in situ often preferred over ex situ?

Answer

It conserves the **whole habitat/ecosystem** and lets the species **behave and evolve naturally**, not just survive in captivity.

1.9.412 cards

Card 37definition
Question

Define ex situ conservation.

Answer

Protecting a species **away from its natural habitat** — e.g. in a zoo, botanic garden, seed bank or gene bank.

Card 38definition
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Define in situ conservation.

Answer

Protecting a species **inside its natural habitat** — e.g. a nature reserve or national park.

Card 39concept
Question

Give three ex situ methods.

Answer

**Captive breeding** (zoos), **botanic gardens**, and **seed / gene banks**.

Card 40definition
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What is captive breeding?

Answer

Breeding endangered animals **under human care** to raise their numbers, often to **reintroduce** them to the wild.

Card 41definition
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What is a seed bank?

Answer

A cold, dry store of seeds from many species kept as a **long-term genetic back-up**.

Card 42concept
Question

How does ex situ help raise numbers?

Answer

Animals breed **safely** (away from predators/poachers) under expert care, so the **population grows**.

Card 43concept
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How do gene/seed banks help conservation?

Answer

They **preserve genetic variety** so a species can recover even if wild populations are lost.

Card 44definition
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What is reintroduction?

Answer

**Releasing** captive-bred individuals back into a (protected) **natural habitat**.

Card 45concept
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Give two limitations of ex situ conservation.

Answer

It is **expensive** and holds **small numbers** (inbreeding risk); it also **does not protect the habitat**.

Card 46concept
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Why can captive-bred animals struggle after release?

Answer

They may **lack survival skills** learned in the wild, so they can struggle to find food or avoid predators.

Card 47concept
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Why is ex situ called a 'back-up'?

Answer

It keeps a species alive when its **wild habitat is too damaged**, but it does not protect that habitat — so it works **best alongside in situ**.

Card 48concept
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In situ vs ex situ — one key difference?

Answer

**In situ protects the habitat** (the species stays in the wild); **ex situ does not** (the species is held off-site).

1.9.512 cards

Card 49definition
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Define rewilding.

Answer

Restoring the **natural processes** of a degraded ecosystem so it becomes **self-sustaining**, often by reintroducing a **keystone species**.

Card 50definition
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Define a keystone species.

Answer

A species whose effect on its ecosystem is **far larger than its numbers** suggest (e.g. a top predator or a beaver).

Card 51definition
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Define a degraded ecosystem.

Answer

An ecosystem that has been **damaged** so it works less well (e.g. a cleared forest or drained wetland).

Card 52concept
Question

What is the flagship method of rewilding?

Answer

Reintroducing a **keystone species** to restart natural processes across the ecosystem.

Card 53concept
Question

Name a rewilding method that is NOT a keystone reintroduction.

Answer

Restore natural **water flow** (re-flooding), re-establish natural **grazing**, let **native plants** return, or reconnect habitats with **corridors**.

Card 54concept
Question

How does rewilding differ from ordinary conservation?

Answer

Conservation protects species and often needs **ongoing management**; rewilding restores **natural processes** so the ecosystem **manages itself**.

Card 55concept
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Why can reintroducing one keystone species restore a whole ecosystem?

Answer

Its activity (e.g. damming or predation) restarts a **chain** of natural processes that many other species depend on.

Card 56concept
Question

Give an example of a keystone reintroduction in rewilding.

Answer

**Beavers** — they build dams that restore water flow and create wetland that supports many species.

Card 57definition
Question

What does 'ecosystem restoration' mean?

Answer

Repairing a **damaged** ecosystem so its **natural processes** and **biodiversity** recover.

Card 58concept
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How does rewilding help minimise biodiversity loss?

Answer

By restoring natural processes in a **degraded** ecosystem, it **reverses** damage so more species can return.

Card 59concept
Question

Name two natural processes rewilding tries to restore.

Answer

Any two of: **grazing**, **predation**, **flooding/water flow**, **seed dispersal**.

Card 60concept
Question

In a 'rewilding methods other than keystone reintroduction' question, what must each method do?

Answer

Restore a **natural process** (not just add a species) — e.g. re-flooding or letting native plants return.

1.9.612 cards

Card 61definition
Question

What does EDGE stand for?

Answer

**Evolutionarily Distinct and Globally Endangered**.

Card 62concept
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What is the purpose of the EDGE programme?

Answer

To **prioritise** which species to conserve — choosing those that are both distinct and endangered when resources are limited.

Card 63definition
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Define 'evolutionarily distinct'.

Answer

Having **very few close living relatives** — a unique, long branch on the tree of life carrying unique evolutionary history.

Card 64definition
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Define 'globally endangered'.

Answer

At **high risk of extinction worldwide** (e.g. a very small or fast-falling population).

Card 65definition
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What is an EDGE species?

Answer

A species that is **both** highly evolutionarily distinct **and** globally endangered — so it is high priority for conservation.

Card 66concept
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Why must conservationists prioritise species?

Answer

There are **more endangered species than money, land and time** to save them all, so choices must be made.

Card 67concept
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A species is distinct but common. Is it a high EDGE priority?

Answer

**No** — it is distinct but not at risk, so it is not urgent.

Card 68concept
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A species is endangered but has many close relatives. High EDGE priority?

Answer

**No (lower)** — its loss is a smaller loss to the tree of life because similar species remain.

Card 69concept
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Why is losing an evolutionarily distinct species so costly?

Answer

It removes a **unique branch of the tree of life and unique genes** that **no other species can replace**.

Card 70definition
Question

Define biodiversity.

Answer

The **variety of life** — the range of different species (and genes and ecosystems) in an area.

Card 71definition
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Define conservation.

Answer

**Protecting species and habitats** so that biodiversity is maintained for the future.

Card 72concept
Question

Which TWO criteria must a top EDGE species meet?

Answer

It must be **evolutionarily distinct AND globally endangered** — high on both, not just one.

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