Conservation (Cambridge (CIE) A Level Biology): Flashcards
Exam code: 9700
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Define extinction.
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Define extinction.
The permanent loss of a species, when all of its members have died out.
State four causes by which populations and species can become extinct.
Climate change
Competition
Hunting by humans
Degradation and loss of habitats
How can climate change cause a species to become extinct?
Conditions may change faster than the species can adapt or migrate, and its habitat or food sources may be lost — so numbers fall until it dies out.
How can competition lead to extinction?
A species may be outcompeted for resources (e.g. by an invasive species) and so its population declines until it dies out.
How does habitat loss and degradation cause extinction?
It reduces available food, shelter and breeding sites and fragments populations, so numbers fall below a viable level.
How can hunting by humans cause a species to become extinct?
Individuals are removed faster than they can reproduce and be replaced, so the population falls below the level needed to survive.
The permanent loss of all members of a species is called .
The permanent loss of all members of a species is called extinction.
Give economic reasons for the need to maintain biodiversity.
Species provide food, medicines and raw materials, and generate income through ecotourism.
Give ecological reasons for maintaining biodiversity.
It keeps ecosystems stable and maintains ecosystem services such as pollination, nutrient cycling and climate regulation; it also preserves a genetic resource for the future.
Give ethical or aesthetic reasons for maintaining biodiversity.
Humans have a moral duty to protect species, which have a right to exist, and biodiversity provides beauty and enjoyment for present and future generations.
Define ecosystem resilience.
The ability of an ecosystem to return to its original state after a disturbance.
Why does high biodiversity make an ecosystem more resilient?
With more species and more interlinked food webs, the loss of any one species has less impact, so the ecosystem can recover more easily from change.
How can biodiversity be a source of future medicines?
Undiscovered species may contain useful chemical compounds or genes that could be developed into new drugs.
Greater biodiversity generally makes an ecosystem more to environmental change.
Greater biodiversity generally makes an ecosystem more resilient to environmental change.
Define in-situ conservation.
Conserving a species in its natural habitat (e.g. national parks and marine parks).
Define ex-situ conservation.
Conserving a species outside its natural habitat (e.g. zoos, botanic gardens, seed banks).
Outline the role of zoos in conservation.
Captive breeding programmes to increase numbers and maintain genetic diversity (using studbooks), reintroduction to the wild, plus research and education.
Outline the role of botanic gardens in conservation.
Growing and conserving rare or endangered plant species, storing seeds, researching propagation, and supplying plants for reintroduction.
Outline the role of conserved areas (national parks and marine parks) in conservation.
They protect habitats and species in their natural environment (in-situ), restricting damaging human activities such as building, hunting and fishing.
What is a 'frozen zoo'?
A store of frozen genetic material — such as gametes, embryos and tissue/DNA — from endangered animals, kept for future breeding.
Outline the role of seed banks in conservation.
Storing seeds of many plant species in cool, dry conditions as a backup against extinction and to preserve genetic diversity.
A store of frozen gametes, embryos and tissue from endangered animals is known as a zoo.
A store of frozen gametes, embryos and tissue from endangered animals is known as a frozen zoo.
State the three methods of assisted reproduction used in the conservation of endangered mammals.
IVF (in vitro fertilisation)
Embryo transfer
Surrogacy
Define IVF (in vitro fertilisation).
An egg is fertilised by sperm outside the body (in a dish) to produce an embryo.
Define embryo transfer.
An embryo (e.g. produced by IVF) is transferred into the uterus of a female so that it can develop.
Define surrogacy in conservation.
An embryo is implanted into a surrogate female (of the same or a closely related species) who carries the pregnancy but is not the genetic mother.
How does IVF help conserve endangered mammals?
It allows breeding when natural mating is difficult, can use stored gametes, and increases the number of offspring and the genetic diversity of the population.
Why might a surrogate of a closely related species be used?
When there are too few females of the endangered species available to carry the pregnancies themselves.
The fertilisation of an egg by sperm outside the body is known as .
The fertilisation of an egg by sperm outside the body is known as IVF.
Define an invasive alien species.
A non-native species introduced to an area that spreads rapidly and causes harm to the native ecosystem.
Explain why invasive alien species need to be controlled.
They outcompete native species for resources, may prey on them or introduce disease, and so reduce the biodiversity of the area.
Why do invasive species often spread so rapidly in a new area?
They have no natural predators, competitors or diseases to keep their population in check.
How can an invasive species cause a native species to become extinct?
By outcompeting it for resources or preying on it, until the native population collapses.
State methods used to control invasive species.
Physical removal (e.g. culling, trapping), chemical control (pesticides/herbicides) and biological control (introducing a natural enemy).
A non-native species that spreads rapidly and harms an ecosystem is described as .
A non-native species that spreads rapidly and harms an ecosystem is described as invasive.
True or False?
Invasive alien species usually increase the biodiversity of the area they invade.
False.
Invasive species usually reduce biodiversity by outcompeting, preying on or introducing disease to native species.
What does IUCN stand for?
The International Union for Conservation of Nature.
Outline the role of the IUCN in conservation.
It assesses the conservation status of species and publishes the Red List, coordinates and funds conservation projects, and advises governments on protecting biodiversity.
Define the IUCN Red List.
A global list that classifies species according to their risk of extinction (e.g. vulnerable, endangered, critically endangered).
What does CITES stand for?
The Convention on International Trade in Endangered Species of Wild Fauna and Flora.
Outline the role of CITES in conservation.
An international agreement that regulates or bans trade in endangered species and their products, to prevent overexploitation.
How does CITES help conserve endangered species?
By banning or licensing international trade, so that demand for animals, plants and their products does not drive species towards extinction.
The IUCN publishes the List, which ranks species by their risk of extinction.
The IUCN publishes the Red List, which ranks species by their risk of extinction.
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