Conservation + Endangered species

Why may some species be endangered or extinct?

• natural selection

• habitat destruction

• pollution - inc greenhouse gas emissions

• over-hunting

• competition between non-native + domestic species

How can competition between non-native + domestic species result in endangered/extinct species?

• species introduced to area it didn’t evolve in

• without natural predators + pathogens = increase in numbers → out-compete native species = numbers decline

What is the aim of conservation?

aims to maintain biodiversity by conserving existing gene pools

Explain methods of conservation

• Habitat protection - nature reserves + SSSIs to protect ecosystems

• International cooperation to restrict trade of endangered species + reduce pollution

• Zoos - protect + breed endangered species and reintroduction of species

• Seed + sperm banks - conserve gene pools for future

What is meant by agricultural exploitation?

increase in food production efficiency + intensity to maximise yield from land to meet human needs

What aspects of modern agriculture affect biodiversity?

• Mechanisation - use of large machinery needs large fields so removal of hedgerows = reduces biodiversity

• Monoculture - growing single crop variety over large area = increased use of inorganic fertilisers (as same nutrients used from soil then not replaced) → eutrophication

  • leads to ideal conditions for pests = increased use of pesticides = reduces biodiversity

What are the consequences of deforestation?

• habitat loss = biodiversity loss

• loss of valuable plant chemicals

• soil erosion + flooding - no tress to take up water during transpiration

• less CO2 intake so more CO2 in atmosphere

Explain methods to sustainably use tress?

• Coppicing - stem of young tress cut down to ground level so tree not killed and new shoots can grow from stump

• Selective cutting - oldest largest trees removed to reduce impact of soil erosion

• Plantations - where fast-growing species planted and new planted when they are cut down

Consequences of overfishing

capture of young fish so less remain to breed so population declines

Methods to regulate fishing

• larger mesh size of nets - small fish can escape to reproduce

• exclusion zones - prevents fishing in overfished areas

• fishing seasons - prevent fishing during breeding seasons

• fishing quotas

What are issues with fish farming?

• quick spread of diseases as pop densely packed - may spread to wild fish

• use of antibiotics may lead to antibiotic resistance

• if escape may outcompete wild fish or interbreed with them

• excess waster + food may escape nets causing eutrophication