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18.3. Conservation
A subsection of Biology, 9700, through 18. Classification, biodiversity and conservation
Listing 10 of 69 questions
The Ethiopian wolf, Canis simensis, is a member of the Canidae family of carnivores. shows an Ethiopian wolf. Ethiopian wolves evolved from an ancestor similar to the grey wolf that crossed into Northern Africa from Europe about 100 000 years ago. They live in the alpine grasslands and heathlands at, or above, 3000 m altitude in Ethiopia. State the most likely type of speciation that led to the evolution of the Ethiopian wolf. A population of Ethiopian wolves is called a pack. Heterozygosity has been found to be low in all of the packs of Ethiopian wolves that have been studied. Suggest why the heterozygosity may be low in Ethiopian wolf packs. The Ethiopian wolf is classified as an endangered species by the International Union for the Conservation of Nature and Natural Resources (IUCN). It publishes an annual list of endangered species called the Red List. Complete Table 1.1 to summarise four of the main reasons, with further explanation, as to why the Ethiopian wolf has become an endangered species. Table 1.1 reason explanation an activity that accompanies human expansion and reduces the size of the wolf habitat rabies, a lethal viral disease of wolves a human activity to control wolves, considered to be pests the result of wolves breeding with domestic dogs According to the Red List, the number of endangered mammal species in 2007 was 349 and in 2008 was 448. Calculate the percentage increase in endangered mammal species between 2007 and 2008. Give your answer to the nearest whole number. Show your working. answer %
9700_w11_qp_41
THEORY
2011
Paper 4, Variant 1
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The Ethiopian wolf, Canis simensis, is a member of the Canidae family of carnivores. shows an Ethiopian wolf. Ethiopian wolves evolved from an ancestor similar to the grey wolf that crossed into Northern Africa from Europe about 100 000 years ago. They live in the alpine grasslands and heathlands at, or above, 3000 m altitude in Ethiopia. State the most likely type of speciation that led to the evolution of the Ethiopian wolf. A population of Ethiopian wolves is called a pack. Heterozygosity has been found to be low in all of the packs of Ethiopian wolves that have been studied. Suggest why the heterozygosity may be low in Ethiopian wolf packs. The Ethiopian wolf is classified as an endangered species by the International Union for the Conservation of Nature and Natural Resources (IUCN). It publishes an annual list of endangered species called the Red List. Complete Table 1.1 to summarise four of the main reasons, with further explanation, as to why the Ethiopian wolf has become an endangered species. Table 1.1 reason explanation an activity that accompanies human expansion and reduces the size of the wolf habitat rabies, a lethal viral disease of wolves a human activity to control wolves, considered to be pests the result of wolves breeding with domestic dogs According to the Red List, the number of endangered mammal species in 2007 was 349 and in 2008 was 448. Calculate the percentage increase in endangered mammal species between 2007 and 2008. Give your answer to the nearest whole number. Show your working. answer %
9700_w11_qp_42
THEORY
2011
Paper 4, Variant 2
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Lancaster Sound in the Canadian Arctic is a very productive marine environment and supports large populations of sea birds and marine mammals. Studies of the area have shown the importance of Arctic cod, Boreogadus saida, in the flow of energy to marine birds, such as guillemots and fulmars, and marine mammals, such as narwhals and belugas. Arctic cod forms the main, or only, source of food for many such animals. The flow of energy through the food web in Lancaster Sound is shown in . gull polar bear human guillemot narwhal Arctic cod copepods amphipods arrow worms walrus bivalve molluscs algae kelp phytoplankton detritus harp seal fulmar Note: detritus is dead and decaying matter ringed seal beluga Name the trophic levels occupied by the following organisms in the food web in : kelp arrow worms narwhals. The population of polar bears in the Lancaster Sound area is quite small in comparison to populations of animals that feed on Arctic cod. Using only the information shown in , explain why the population of polar bears is small. Populations of many fish species are under threat of extinction as a result of over-fishing. Explain the likely consequences of over-fishing of Arctic cod.
9700_w12_qp_21
THEORY
2012
Paper 2, Variant 1
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In some ecosystems, certain species fulfil important roles in maintaining biodiversity in communities. These species are often known as keystone species. The sea otter, Enhydra lutris, is found in waters of the northern and eastern coasts of the Pacific, where it occupies a niche as a predator. These coastal waters are rich in kelp communities. Kelp are very large seaweeds that form ‘underwater forests’. In the 19th century the sea otter was hunted for its fur, with the result that populations decreased. A consequence of this reduction in numbers was the disappearance of much of the kelp. Conservation measures in the 20th century restored the numbers of sea otters. shows the food web for this ecosystem. sharks sea otters large carnivorous fish starfish (sea stars) abalones large crabs small carnivorous fish and invertebrates scallops and sessile invertebrates microscopic floating animals detritus kelp (very large seaweeds) smaller seaweed phytoplankton small herbivorous invertebrates small herbivorous fish sea urchins Explain the meaning of the terms niche and community. niche community With reference to the food web in , suggest why sea otters are considered to be a keystone species. Suggest how the efficiency of energy transfer from kelp to sea urchins could be determined.
9700_w13_qp_21
THEORY
2013
Paper 2, Variant 1
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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_41
THEORY
2013
Paper 4, Variant 1
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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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The endangered Californian condor, Gymnogyps californianus, is the largest flying bird in North America. Condors feed on dead bodies of large mammals, such as cattle and deer. shows the Californian condor. The population of these condors fell to just 22 in 1982 and this led to the California Condor Recovery Program (CCRP), a captive breeding programme, being set up in different zoos in the United States and Mexico. Owing to the success of the captive breeding programme there are now over 300 condors. Many of these have been released as part of the programme. Outline the advantages of captive breeding programmes such as CCRP. Suggest why animals in captive breeding programmes may not always breed successfully. When animals that have been bred in captivity are released, their survival rate is low. Suggest two reasons why many of these animals are unable to survive in the wild. Bullets containing lead are commonly used by hunters. Hunting for pleasure means that hunters often leave the killed animals, such as deer, bears and antelopes, in the area where they have been shot. Suggest why this is a threat, rather than an advantage, to the Californian condor.
9700_w14_qp_43
THEORY
2014
Paper 4, Variant 3
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The St. Lawrence river in Canada has been identified as an area with very high biodiversity. Explain how the term biodiversity can be considered at different levels. The St. Lawrence river is rich in species of aquatic mammals, especially whales. In spring, thousands of whales swim from the Atlantic ocean up the St. Lawrence river. Thirteen different species of whale have been recorded. One of these is the blue whale, Balaenoptera musculus. is a diagram of a blue whale. dorsal fin Photographs of blue whales are analysed by computer so that individual whales can be identified and population abundance can be estimated. Each blue whale is different in colour and in the shape of dorsal fin. Different whales also have different patterns of scarring. State the two sources of phenotypic variation in the blue whale population. Suggest one reason why it is difficult to measure the actual population size of the blue whale. The St. Lawrence river runs through very busy industrial areas. It has many ports for cargo ships, a good fishing trade and many whale-watching boat trips for tourists. Decades of whale hunting has caused a large decrease in whale population sizes. Since whale hunting was banned, whale populations have not recovered. Seven of the thirteen whale species in the St. Lawrence river have been rated as endangered species. Suggest two reasons why the populations of whales have not recovered since the ban on whale hunting. Fat samples from under the skin of individual whales of several different species were taken. These were analysed and the concentrations of the toxins DDT and PCBs were measured. Suggest why whales were found to have accumulated very high concentrations of DDT and PCBs in their fatty tissues. Algal blooms sometimes occur in the area of the Atlantic ocean near the St. Lawrence river. These result from rapid population growth of unicellular algae such as Alexandrium tamarense. A. tamarense produces saxitoxin, a neurotoxin that causes muscle paralysis by acting on voltage-gated sodium ion channels in neurones. Saxitoxin can kill whales. Suggest how saxitoxin results in the death of a whale. Algae, such as A. tamarense, used to belong to the kingdom Plantae but are now classified in the kingdom Protoctista. State one reason why A. tamarense is classified in the kingdom Protoctista and not in the kingdom Plantae.
9700_w17_qp_41
THEORY
2017
Paper 4, Variant 1
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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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Questions Discovered
69