18. Classification, biodiversity and conservation
A section of Biology, 9700
Listing 10 of 184 questions
The tiger, Panthera tigris, is classified as an endangered species by the International Union for the Conservation of Nature and Natural Resources (IUCN). The IUCN publishes an annual list of endangered species called the Red List. shows the number of tigers in the wild between 1900 and 2010. 100 000 90 000 80 000 70 000 60 000 50 000 40 000 30 000 20 000 10 000 1900 1910 1920 1930 1940 1950 1960 year number of tigers in the wild 1970 1980 1990 2000 2010 Calculate the overall rate of decrease in number of tigers between 1900 and 2010. Give your answer to the nearest whole number. answer tigers per year Describe the reasons why a named species has become endangered.
9700_w13_qp_42
THEORY
2013
Paper 4, Variant 2
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Explain the meaning of the term biodiversity. The Javan gibbon, Hylobates moloch, is an endangered species. shows a female Javan gibbon with an infant. Javan gibbons live in fragmented patches of undisturbed forest in western Java, Indonesia. Habitat loss has reduced the population of wild gibbons to around 4500 individuals. Suggest why the separation of their habitat into small fragments, rather than a single large area, poses a threat to the long-term survival of this species. Several zoos in Java keep Javan gibbons, but few of these are involved in breeding programmes. Suggest how, other than through captive breeding programmes, zoos in Java could contribute to the conservation of the Javan gibbon.
9700_w15_qp_41
THEORY
2015
Paper 4, Variant 1
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Explain the meaning of the term biodiversity. The Javan gibbon, Hylobates moloch, is an endangered species. shows a female Javan gibbon with an infant. Javan gibbons live in fragmented patches of undisturbed forest in western Java, Indonesia. Habitat loss has reduced the population of wild gibbons to around 4500 individuals. Suggest why the separation of their habitat into small fragments, rather than a single large area, poses a threat to the long-term survival of this species. Several zoos in Java keep Javan gibbons, but few of these are involved in breeding programmes. Suggest how, other than through captive breeding programmes, zoos in Java could contribute to the conservation of the Javan gibbon.
9700_w15_qp_42
THEORY
2015
Paper 4, Variant 2
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shows a red squirrel, Sciurus vulgaris. This species is native to the British Isles, meaning it has lived there for at least 10 000 years. In the 1800s a related but slightly larger species, the grey squirrel, Sciurus carolinensis, was introduced from North America. A history of the interaction between red squirrels and grey squirrels includes these facts: • Grey squirrels, which occupy a similar niche to red squirrels, expanded their range rapidly after introduction. • Grey squirrels carry a virus that does not harm them, but which kills red squirrels. • Red squirrels became extinct in many parts of the British Isles. • Recently some areas have seen a reversal of this trend. There has been a decrease in numbers of grey squirrels. Red squirrels have re-colonised their former areas of habitat. • This has happened in areas where protection of a native predator species, the pine marten, Martes martes, has resulted in an increase in the number of these predators. • Analysis of pine marten faeces shows that they catch and eat many more grey squirrels than red squirrels. Use the information given to identify the causes of the extinction of red squirrels in many parts of the British Isles. Describe how the level of molecular similarity between the two species, S. vulgaris and S. carolinensis, can be investigated. Explain how the differing effect of pine marten predation on red and grey squirrel populations is due to natural selection and the separate evolution of each squirrel species.
9700_w17_qp_41
THEORY
2017
Paper 4, Variant 1
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shows a snow leopard, Panthera uncia. The habitat of the snow leopard is the high mountains of Central Asia. Snow leopards usually live and hunt alone. Their main prey is grazing herbivores, such as wild sheep and wild goats. They will also hunt domesticated animals and livestock. The number of snow leopards has decreased dramatically in the last 40 years. Predict the consequences to the ecosystem if the number of snow leopards continues to decrease. In 2003, the total number of snow leopards was estimated to be between 4080 and 6590. Suggest one reason why the actual number of snow leopards in 2003 may have been higher than the estimated number. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an agreement between the governments of most countries. The snow leopard is endangered and is listed on this agreement. Describe the actions taken by participating governments that help to conserve endangered animals, such as the snow leopard. State how a decrease in the number of snow leopards will affect the genetic diversity of the species. Outline the possible future consequences of this change in genetic diversity. In 1775 the snow leopard was classified as the only species in the genus Uncia and was known as Uncia uncia. More recently, new techniques showed similarities to the tiger, Panthera tigris, and so in 2006 the snow leopard was reclassified in the genus Panthera. Suggest the type of evidence used to classify the snow leopard in 1775.
9700_w17_qp_42
THEORY
2017
Paper 4, Variant 2
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shows a red squirrel, Sciurus vulgaris. This species is native to the British Isles, meaning it has lived there for at least 10 000 years. In the 1800s a related but slightly larger species, the grey squirrel, Sciurus carolinensis, was introduced from North America. A history of the interaction between red squirrels and grey squirrels includes these facts: • Grey squirrels, which occupy a similar niche to red squirrels, expanded their range rapidly after introduction. • Grey squirrels carry a virus that does not harm them, but which kills red squirrels. • Red squirrels became extinct in many parts of the British Isles. • Recently some areas have seen a reversal of this trend. There has been a decrease in numbers of grey squirrels. Red squirrels have re-colonised their former areas of habitat. • This has happened in areas where protection of a native predator species, the pine marten, Martes martes, has resulted in an increase in the number of these predators. • Analysis of pine marten faeces shows that they catch and eat many more grey squirrels than red squirrels. Use the information given to identify the causes of the extinction of red squirrels in many parts of the British Isles. Describe how the level of molecular similarity between the two species, S. vulgaris and S. carolinensis, can be investigated. Explain how the differing effect of pine marten predation on red and grey squirrel populations is due to natural selection and the separate evolution of each squirrel species.
9700_w17_qp_43
THEORY
2017
Paper 4, Variant 3
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The Hawaiian archipelago is a group of volcanic islands in the Pacific ocean. shows the relative locations of five of these islands. O’ahu Lana’i Moloka’i Maui Hawai’i Table 4.1 shows the size and age of these five islands and the total number of Mecyclothorax ground beetle species and their species density, on each island. Data for the island of Maui is shown as two distinct regions, West and Haleakalã. This is because they formed at different times from two separate volcanoes. Table 4.1 island area / km2 age of island / million years total number of Mecyclothorax species species density / number of species per km2 Hawai’i 10 433 0.4 0.003 Lãna’i 1.3 0.008 Maui (West) 1.3 0.061 Maui (Haleakalã) 1.1 0.081 Moloka’i 1.9 – 1.8 0.064 O’ahu 3.7 – 2.6 shows a ground beetle of the genus Mecyclothorax. All the beetle species of this genus on the Hawaiian archipelago form a monophyletic group, descended from one original colonising species that reached Maui from Australia. Complete Table 4.1 by calculating the density of Mecyclothorax beetle species on the island of O’ahu. Use Table 4.1 to explain why the island of Hawai’i has the lowest density of Mecyclothorax beetle species. Use and Table 4.1 to suggest why O’ahu has a lower number of Mecyclothorax beetle species than Moloka’i. The rate of speciation of Mecyclothorax beetles on the slopes of the volcano Haleakalã, on Maui, is the highest recorded for any genus or location on earth. The volcano last erupted 400 years ago. This produced lava flows which cut through ancient forest and vegetation, dividing it into many separate microhabitats. Explain how the large number of Mecyclothorax beetle species on Haleakalã developed.
9700_w18_qp_41
THEORY
2018
Paper 4, Variant 1
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Questions Discovered
184