18. Classification, biodiversity and conservation
A section of Biology, 9700
Listing 10 of 184 questions
Mole rats, Spalax ehrenbergi, are mammals that live in groups in underground burrows. They are blind, and communicate with each other through sound and scent. Males make a purring call when they are attempting to persuade females to mate with them. In Israel, the mole rats found in different parts of the country all look identical. However, there are actually four different populations with different chromosome numbers, which live in different climatic regions. These are shown in Table 5.1. This table also shows information about the purring calls used by the males in each population. The calls of the males were analysed by measuring the number of sound pulses per second, and also the frequencies of the sounds that they made. Table 5.1 chromosome number of population climatic region in which population lives cool and humid cool and dry warm and humid warm and dry purring call made by males mean number of pulses per second 21.0 25.3 23.9 23.2 mean major frequency / kHz Explain why the chromosome number of each of the four populations of mole rats is an even number. Researchers investigated how female mole rats from each of the four populations responded to purring calls made by males from the same population, and by males from different populations. A female was placed midway between two loudspeakers, and recorded calls from two males were played to her simultaneously. The researchers noted which loudspeaker the female moved towards. This was repeated with many different females from each population. The results are shown in Table 5.2. Table 5.2 population chromosome number percentage of females preferring the purring call of males from their own population With reference to Table 5.2, describe the extent to which female mole rats show a preference for the purring calls of males from their own population. With reference to the data in both Table 5.1 and Table 5.2, discuss whether these four populations of mole rats should be classified as different species.
9700_s15_qp_41
THEORY
2015
Paper 4, Variant 1
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Mole rats, Spalax ehrenbergi, are mammals that live in groups in underground burrows. They are blind, and communicate with each other through sound and scent. Males make a purring call when they are attempting to persuade females to mate with them. In Israel, the mole rats found in different parts of the country all look identical. However, there are actually four different populations with different chromosome numbers, which live in different climatic regions. These are shown in Table 5.1. This table also shows information about the purring calls used by the males in each population. The calls of the males were analysed by measuring the number of sound pulses per second, and also the frequencies of the sounds that they made. Table 5.1 chromosome number of population climatic region in which population lives cool and humid cool and dry warm and humid warm and dry purring call made by males mean number of pulses per second 21.0 25.3 23.9 23.2 mean major frequency / kHz Explain why the chromosome number of each of the four populations of mole rats is an even number. Researchers investigated how female mole rats from each of the four populations responded to purring calls made by males from the same population, and by males from different populations. A female was placed midway between two loudspeakers, and recorded calls from two males were played to her simultaneously. The researchers noted which loudspeaker the female moved towards. This was repeated with many different females from each population. The results are shown in Table 5.2. Table 5.2 population chromosome number percentage of females preferring the purring call of males from their own population With reference to Table 5.2, describe the extent to which female mole rats show a preference for the purring calls of males from their own population. With reference to the data in both Table 5.1 and Table 5.2, discuss whether these four populations of mole rats should be classified as different species.
9700_s15_qp_43
THEORY
2015
Paper 4, Variant 3
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The Sulawesi macaque, Macaca nigra, is found on the large island of Sulawesi in Indonesia. The Sulawesi macaque is also found on other smaller islands close to Sulawesi, such as the island of Bacan. shows a Sulawesi macaque. The International Union for Conservation of Nature (IUCN) is the world’s largest global environmental organisation. The IUCN Red List of Threatened Species™ evaluates the conservation status of plant and animal species. The Sulawesi macaque is categorised as critically endangered on the IUCN Red List. Table 1.1 shows the numbers of humans and the numbers of Sulawesi macaques on Sulawesi and Bacan. Table 1.1 island area / km2 number of humans number of humans per km2 number of macaques number of macaques per km2 Sulawesi 174 600 17 360 000 99.43 Bacan 60 741 31.97 90 000 47.37 Calculate the number of macaques per km2 for Sulawesi. Write your answer in Table 1.1. Comment on the data shown in Table 1.1 and suggest reasons for the pattern shown. Suggest ways of protecting the Sulawesi macaque.
9700_s18_qp_43
THEORY
2018
Paper 4, Variant 3
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Table 8.1 shows the total number of plant species, the total number of insect species and the number of habitats in three areas, A, B and C. Table 8.1 area total number of plant species total number of insect species number of habitats A B C Identify the area with the highest biodiversity. Give reasons for your choice of area. area reasons Identify the area that is likely to be affected the most if the environment changes. Give a reason for your choice of area. area reason State one reason why it is important to conserve biodiversity in all three areas.
9700_s19_qp_41
THEORY
2019
Paper 4, Variant 1
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Sampling is used to find out the variety of species in an ecosystem and the size of the population of each species. A study was carried out to investigate the biodiversity of two fields, A and B. Field A had not been used for growing crops for 10 years. Field B had been used for growing crops until one year before the study. Random sampling was carried out. Describe how random sampling could be carried out on plant species in the two fields. Table 8.1 shows the results of the sampling of field A. Table 8.1 species number of individuals Scabiosa columbaria Centaurea centaurium Primula veris Trifolium pratense Leucanthemum vulgare Silybum marianum Anacamptis morio total number of individuals (N) Simpson’s Index of Diversity (D) is a value of the species diversity in an area. The formula for this is: D N n = -f d n p / ! = sum of n = number of individuals of a species N = number of individuals of all species Complete Table 8.2 for Primula veris. Table 8.2 species n N n N n 2 Trifolium pratense 0.32 0.10 Leucanthemum vulgare 0.10 0.01 Silybum marianum 0.04 0.00 Anacamptis morio 0.07 0.00 Use the data in Table 8.2 to calculate Simpson’s Index of Diversity (D) for field A. Show your working and write your answer to two decimal places. D = The value of D for field B was 0.45. Comment on the values of D for both fields.
9700_s20_qp_41
THEORY
2020
Paper 4, Variant 1
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Sampling can be used to find the distribution and abundance of species in an area. Students sampled a rocky shore from a high tide area to a low tide area. They decided to use a belt transect. Describe how you would carry out a belt transect to assess the distribution and abundance of organisms in an area. The results of an ecological investigation may suggest that there is a relationship between two variables, for example the abundance of a plant species and light intensity. Scattergraphs can be drawn between the two variables. shows three scattergraphs, A, B and C. y x A y x B y x C State which scattergraphs show a relationship between the two variables, x and y. Name a statistical test you would carry out to assess the strength of any relationship between two variables.
9700_s20_qp_43
THEORY
2020
Paper 4, Variant 3
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The Great Lakes, in North America, lie between the USA and Canada. A survey of birds of the Lake Ontario area has shown the relative abundance of birds between 1995 and 2005. Table 1.1 shows the feeding habits and the relative change in numbers of some of the birds in the survey. Table 1.1 name feeding habit percentage change in numbers between 1995 and 2005 mallard Anas platyrhynchos amphibia, plants +10.0 tree swallow Tachycineta bicolor flying insects – 6.2 blue-winged teal Anas discors aquatic insects, molluscs, plants –12.3 pied-billed grebe Podilymbus podiceps amphibia, aquatic insects, fish –15.9 black tern Chlidonias niger aquatic insects, fish, flying insects –18.7 Using the information in Table 1.1 suggest reasons for the changes in numbers of these birds. An ecosystem that has a wide range of species has a high biodiversity. Explain the benefits of maintaining biodiversity.
9700_w10_qp_41
THEORY
2010
Paper 4, Variant 1
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Questions Discovered
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