18.3. Conservation
A subsection of Biology, 9700, through 18. Classification, biodiversity and conservation
Listing 10 of 69 questions
The wild Bactrian camel, Camelus ferus, lives only in the desert regions of Mongolia and northern China. shows a wild Bactrian camel. The wild Bactrian camel is at risk of extinction in the wild and is categorised as critically endangered by the International Union for Conservation of Nature (IUCN). There are only 950 wild Bactrian camels left in their natural habitat. Suggest reasons why the wild Bactrian camel has become critically endangered. Outline the role of the IUCN. Some zoos use assisted reproduction techniques, such as embryo transfer, in their captive breeding programmes for endangered species. Embryo transfer has resulted in domesticated dromedary camels giving birth to wild Bactrian camel calves. Describe the procedure of embryo transfer in a mammal such as a camel.
9700_w22_qp_41
THEORY
2022
Paper 4, Variant 1
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The wild Bactrian camel, Camelus ferus, lives only in the desert regions of Mongolia and northern China. shows a wild Bactrian camel. The wild Bactrian camel is at risk of extinction in the wild and is categorised as critically endangered by the International Union for Conservation of Nature (IUCN). There are only 950 wild Bactrian camels left in their natural habitat. Suggest reasons why the wild Bactrian camel has become critically endangered. Outline the role of the IUCN. Some zoos use assisted reproduction techniques, such as embryo transfer, in their captive breeding programmes for endangered species. Embryo transfer has resulted in domesticated dromedary camels giving birth to wild Bactrian camel calves. Describe the procedure of embryo transfer in a mammal such as a camel.
9700_w22_qp_43
THEORY
2022
Paper 4, Variant 3
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The red ruffed lemur, Varecia rubra, is a mammal found only in the rainforests of the Masoala region in north east Madagascar. shows a red ruffed lemur. The International Union for Conservation of Nature (IUCN) Red List of Threatened SpeciesTM states that the red ruffed lemur is critically endangered. Suggest why the red ruffed lemur has become critically endangered. Many zoos around the world operate captive breeding programmes for the red ruffed lemur. shows the numbers of captive‑born red ruffed lemurs in North American zoos from 1970 to 2020. year number of captive-born red ruffed lemurs Describe the results shown in . Captive breeding programmes for endangered mammals such as the red ruffed lemur can vary in their success rate. Suggest problems that may affect the success of captive breeding programmes of mammals like the red ruffed lemur. Occasionally, wild‑caught red ruffed lemurs are introduced into captive breeding programmes. Suggest why this is done.
9700_w24_qp_42
THEORY
2024
Paper 4, Variant 2
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Use Couples who are unable to conceive naturally may be able to have fertility treatment involving in-vitro fertilisation (IVF). Outline the technique of IVF. Table 6.1 shows the success rate, in terms of live births, for IVF using eggs from women of different ages. Table 6.1 age of woman percentage success rate of IVF under 35 27.6 35 to 37 22.3 38 to 39 18.3 40 to 42 10.0 above 42 less than 5.0 Suggest reasons for the trend shown in Table 6.1. Examiner’s Use The cost of one IVF treatment is about US$ 5000. In some countries, in-vitro fertilisation is offered free of charge to couples who have not conceived within two years of trying. With reference to Table 6.1, put forward an argument against the public funding of in-vitro fertilisation to all couples who request it.
9700_w07_qp_4
THEORY
2007
Paper 4, Variant 0
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Many couples who are not able to have children naturally are treated using in-vitro fertilisation (IVF). Describe how and where fertilisation occurs during IVF. The embryos resulting from IVF are transferred into the mother’s uterus. This is sometimes done after 3 days, and sometimes after 5 days. Suggest one advantage and one disadvantage of transferring the embryos after 5 days rather than 3 days. advantage disadvantage Many IVF clinics usually transfer two or more embryos to the mother’s uterus, to increase the chances of a successful pregnancy occurring. However, this increases the risk of more than one embryo developing in the uterus, which in turn increases the risk of problems with the pregnancy or birth. A study was carried out to compare the success rates of transferring: • a single embryo that had been carefully chosen as being of ‘top quality’ • a non-selected single embryo • two or more embryos. shows the results of this study. 1559 IVF treatment cycles 1464 embryo transfers 105 pregnancies 19 pregnancies 366 pregnancies 299 transfers of a single top-quality embryo 86 transfers of a single, non- selected embryo 1059 transfers of two of more embryos With reference to , explain why transferring a single top-quality embryo is now considered to be the best method to maximise the chance of a successful pregnancy. State one ethical implication of transferring single top-quality embryos in IVF.
9700_w12_qp_43
THEORY
2012
Paper 4, Variant 3
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The European hedgehog, Erinaceus europaeus, is a small omnivorous mammal. Its body is covered in spines, which are usually brown. A rare variant, which lacks the brown pigment, has blonde (pale yellow) spines. This characteristic is coded for by a recessive allele. shows a European hedgehog with blonde spines. Alderney is a small island between the UK and France. Hedgehogs were not found on Alderney until the 1960s, when three pairs of hedgehogs were introduced to the island. The hedgehogs started to breed and some of the offspring had blonde spines. By 2017, the population of hedgehogs, including individuals with brown spines and individuals with blonde spines, had increased to approximately 600. Suggest reasons why the population of hedgehogs increased to such a large number. A survey taken in 2017 showed that 60% of the hedgehogs on Alderney had blonde spines. Suggest and explain reasons why the proportion of hedgehogs with blonde spines was so high. The hedgehogs on Alderney are an example of an invasive alien species. Explain why it is sometimes important to control invasive alien species.
9700_m22_qp_42
THEORY
2022
Paper 4, Variant 2
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The passage outlines one method of estimating the size of an animal population. Complete the passage by using the most appropriate scientific terms. The size of a population of animals can be estimated using the mark-release-recapture method. A sample of animals is captured using a humane trap and is counted. The animals are marked using a method that does not harm them. This can be done using a small tag or . The marked animals are released into the area where they were captured. Time is allowed for the marked animals to mix into the population. This period of time must be short so that emigration, immigration, migration or do not occur. A second sample of animals is then captured and the number of marked and unmarked animals is counted. The population size can be estimated using the Index. For reliability, the method should be . Himalayan balsam, Impatiens glandulifera, is an annual plant native to Pakistan, India and Nepal. It was first introduced into the United Kingdom (UK) in 1839 because of its attractive flowers. Individual plants can produce thousands of mature seeds. These can be dispersed for long distances when the capsules that contain the seeds burst. shows Himalayan balsam growing in a woodland. Himalayan balsam has now become established in the UK. It is listed as an invasive alien species and attempts are being made to eradicate the plant. Not all alien plant species are considered to be invasive. Suggest why Himalayan balsam has been listed as an invasive alien species in the UK.
9700_w23_qp_42
THEORY
2023
Paper 4, Variant 2
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The polar bear, Ursus maritimus, lives in the Arctic regions of the USA, Canada, Norway and Russia. Polar bears move across the Arctic ice sheet to hunt prey such as seals. shows a polar bear. The area over which the Arctic ice sheet extends varies throughout the year. shows the variation in the extent of the Arctic ice sheet for the months of July to November for the years 1979 and 2009. July Aug Sept month Oct Nov extent of Arctic ice sheet / km2 × 106 Key Calculate the percentage reduction in the area over which the ice sheet extends between 1979 and 2009 for the month of September. Give your answer to the nearest whole number. Show your working. answer % In 2008 the government of the USA classified U. maritimus as an endangered species because it is under threat of extinction. Suggest what has caused U. maritimus to have become endangered. U. maritimus is a eukaryote. Beneficial bacteria, which are prokaryotic cells, live in the gut of U. maritimus. State three differences between the cells of U. maritimus and its gut bacteria. 1. 2. 3.
9700_s11_qp_41
THEORY
2011
Paper 4, Variant 1
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Questions Discovered
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