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13.6Chapter 13: Variation and Natural Selection

What can we do? — Alhussan Biology - Stage 9 Revision Notes & Topical Questions

5 min read 9 parts Lesson 6 of 8 2 quizzes

📚 Alhussan Biology - Stage 9 Hub / Topical Revision
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13.6 What can we do? — Conservation, Seed Banks and Captive Breeding — Alhussan International Academy — Biology (Stages 7–9) notes: Describe and evaluate strategies for protecting endangered species and their habitats, including conservation and weighing the costs of solutions su…

  • Biodiversity
  • Ecological reasons
  • Economic reasons
  • Ethical reasons
  • Two approaches
  • Protected areas

Section 1 of 9Why conserve

Biodiversity
  • Biodiversity conserving species protects it.
Ecological reasons
  • Ecological reasons each species has a role in food webs, pollination and nutrient cycles.
Economic reasons
  • Economic reasons tourism, medicines and genetic resources for crops.
Ethical reasons
  • Ethical reasons all species have a right to exist.
Two approaches
  • Two approaches in situ conservation protects wild populations in their natural habitat, and ex situ conservation works away from it.

Section 2 of 9In situ methods

In situ methods
Protected areas
  • Protected areas national parks and nature reserves restrict building, farming and hunting, and wildlife corridors link habitat patches.
Laws and treaties
  • CITES and similar agreements restrict trade in endangered species and products such as ivory.
Anti-poaching patrols and community involvement
  • Anti-poaching patrols and community involvement local people benefit from tourism.
Habitat restoration
  • Habitat restoration replanting forest and restoring wetlands.
Sustainable management
  • Sustainable management fishing and forestry with quotas and replanting.

Section 3 of 9Captive breeding

Method
  • Method animals are bred in zoos and wildlife parks and paired to maximise genetic variety and avoid inbreeding, using studbooks that record family trees.
Release
  • Release young animals may be released into protected habitat, as with the Arabian oryx and the California condor.
Disadvantages
  • Disadvantages it is costly, animals may lose survival skills and a suitable habitat must exist for release.

Section 4 of 9Seed banks

1Storage
  • Storage seeds of wild plants and crop varieties are kept at low temperature, around −20 °C, and low humidity so they stay alive for decades.
2Svalbard Global Seed Vault
  • Svalbard Global Seed Vault in Norway it stores copies of seeds from around the world as insurance against disasters.
3Advantages
  • Advantages seeds need less space than whole plants and can be grown later.
4Limits
  • Limits not all seeds can be stored this way, and some plants must be kept as tissue cultures or in botanic gardens.

Section 5 of 9Evaluating conservation

StrategyAdvantageLimitation
ReservesProtect an entire ecosystemNeed enforcement and land; animals may leave
Captive breedingBoosts numbers; researchExpensive; loss of wild behaviour
Seed banksCheap, compact; preserve genetic varietyDo not protect habitats
LawsReduce hunting and tradeHard to enforce
  • Best plans
    • they combine methods and involve local communities, so people have a reason to protect wildlife.

Section 6 of 9Weighing solutions: hydroelectric power

Questions to ask
  • Questions to ask we must ask whether we can do something and whether we should do it.
  • A solution to one problem can produce another, so advantages and disadvantages must be weighed.
Benefits
  • Benefits about two thirds of the world's electricity comes from burning fossil fuels, which add carbon dioxide and increase global warming.
  • Hydroelectric power uses water, a renewable resource trapped behind dams, and produces no greenhouse gases.
  • It provides relatively cheap electricity, and in Latin America 70% of electricity is hydroelectric.
  • Four hydroelectric dams on the Mekong river in China produce more than 8800 megawatts, equivalent to burning over 7 million barrels of oil.
Costs
  • Costs dams change river flows and may cause drought.
  • They flood land in reservoirs, which can remove indigenous people and destroy ecosystems.
  • They prevent fish moving up and down rivers to breed.

Section 7 of 9Threats to freshwater fish

Scale
  • Scale nearly one third of freshwater fish species are threatened with extinction, and 16 species became globally extinct in 2020 alone.
  • Populations of migratory fish such as salmon and eels have fallen by 75% in the last 50 years.
  • Megafish, which weigh over 30 kg and live many years, such as the Mekong giant catfish, are seriously threatened.
Causes
  • Causes dams, pollution by sewage, farming and industry, draining of rivers and wetlands, and overfishing.
    • (which may destroy all life or cause bioaccumulation)
Wider effect
  • Wider effect where fish go extinct, other species are threatened as well.

Section 8 of 9Key terms

TermMeaning
ConservationProtecting species and habitats so they survive.
In situIn the natural habitat.
Ex situAway from the natural habitat, such as in a zoo or seed bank.
Captive breedingBreeding endangered animals under human care.
Seed bankA store of seeds kept at low temperature and humidity.
Hydroelectric powerElectricity generated from flowing water trapped behind dams.

Section 9 of 9Exam technique

1
Saying zoos can solve extinction alone.
2
Forgetting that habitats must be protected for release.
3
Thinking seed banks store plants rather than seeds.
4
Forgetting to involve local people.

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