20. Human influences on ecosystems
A section of Biology, 0610
Listing 10 of 393 questions
For Examiner's Use Tropical rainforest is one of the habitats with the greatest number of species on the Earth but it is being rapidly destroyed. Table 5.1 shows data from six countries that have large areas of tropical rainforest. Table 5.1 country area of rainforest in 1990 / thousand ha area of rainforest in 2005 / thousand ha Brazil 520 027 477 695 Ecuador 13 817 10 853 Indonesia 116 567 88 497 Madagascar 13 692 12 855 Philippines 10 561 7 181 Venezuela 52 026 47 713 Which country had the largest area of tropical rainforest in 2005? Calculate the total area of rainforest lost in the Philippines between 1990 and 2005. answer = thousand ha In the space below calculate the percentage of tropical rainforest lost in the Philippines between 1990 and 2005. Show your working. answer = % For Examiner's Use One method of deforestation is to remove the large trees for timber and then burn the rest of the vegetation. Explain why deforestation is considered harmful to the environment.
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THEORY
2012
Paper 2, Variant 2
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For Examiner's Use Tropical rainforest is one of the habitats with the greatest number of species on the Earth but it is being rapidly destroyed. Table 5.1 shows data from six countries that have large areas of tropical rainforest. Table 5.1 country area of rainforest in 1990 / thousand ha area of rainforest in 2005 / thousand ha Brazil 520 027 477 695 Ecuador 13 817 10 853 Indonesia 116 567 88 497 Madagascar 13 692 12 855 Philippines 10 561 7 181 Venezuela 52 026 47 713 Which country had the largest area of tropical rainforest in 2005? Calculate the total area of rainforest lost in the Philippines between 1990 and 2005. answer = thousand ha In the space below calculate the percentage of tropical rainforest lost in the Philippines between 1990 and 2005. Show your working. answer = % For Examiner's Use One method of deforestation is to remove the large trees for timber and then burn the rest of the vegetation. Explain why deforestation is considered harmful to the environment.
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THEORY
2012
Paper 2, Variant 3
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For Examiner's Use The Galápagos Islands in the Pacific Ocean have many species of animals and plants that live nowhere else. Iguanas are large herbivorous reptiles. Four species of iguana live on the Galápagos Islands: • marine iguana, Amblyrhynchus cristatus • land iguana, Conolophus subcristatus • Santa Fe land iguana, Conolophus pallidus • pink land iguana, Conolophus rosada shows a marine iguana. Reptiles and mammals are both vertebrates. State three features of mammals that are not found in reptiles. For Examiner's Use The marine iguana, A. cristatus, feeds on seaweed and must therefore dive several metres into the cold waters that surround the Galápagos Islands. Iguanas can only stay in the water for a short length of time, until their body temperature drops too low. Mammals of an equivalent size, such as sea otters, can stay in cold water for a long time. Explain how some mammals are able to stay in cold water for a long time. Land iguanas live on Isabela, the largest island in the Galápagos. In 1986, some rangers from the Galápagos National Park found a population of pink land iguanas living at the northern end of the island. These iguanas have been studied in detail and are now classified as a new species, C. rosada. Define the term population. Suggest how a study of the DNA of iguanas helps to classify them. For Examiner's Use The International Union for the Conservation of Nature describes these iguanas as vulnerable. This means that their populations are likely to become extinct. Suggest two reasons why it is important to conserve individual species, such as the four species of iguana on the Galápagos Islands.
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THEORY
2012
Paper 3, Variant 1
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For Examiner's Use The red slender loris, Loris tardigradus, is a nocturnal mammal that feeds at night on flowers, fruit and a variety of small animals. It is found in forest ecosystems in South Asia. shows a red slender loris. Explain the meaning of the term ecosystem. State three ways in which mammals, such as the red slender loris, differ from other groups of vertebrates. For Examiner's Use The large eyes of the red slender loris show that it is well adapted for a nocturnal way of life. Suggest other features that the animal is likely to have that are adaptations to being active at night. Two species of slender loris are found in Sri Lanka, the grey slender loris, L. lydekkerianus, and L. tardigradus. The International Union for Conservation of Nature describes the red slender loris as endangered. Horton Plains National Park in Sri Lanka is one of the few places where L. tardigradus is found. Discuss why areas of land, such as the Horton Plains National Park, must be conserved. State how scientists could show that two populations of slender loris belong to the same species or to two different species.
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THEORY
2012
Paper 3, Variant 2
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F ig. 1.1 shows seven different species of amphibian. A B C D E F G not drawn to scale Use the key to identify each species. Write the letter of each species (A to G) in the correct box beside the key. One has been done for you. Key 1 long, narrow body, with or without legs go to 2 body not long and narrow, back legs are larger than the front legs go to 5 2 body without legs Gymnopis multiplicata B body with legs which are all of the same size go to 3 3 raised crest along the back of the body Triturus cristatus no crest along the back of the body go to 4 4 gills present Necturus maculosus no gills present Ambystoma tigrinum 5 skin is smooth go to 6 skin is not smooth Oreophrynella quelchii 6 digits end in swellings Polypedates leucomystax digits do not end in round swellings Rana temporaria Many amphibian species throughout the world are endangered. Suggest three reasons why many amphibian species are endangered.
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THEORY
2015
Paper 3, Variant 3
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shows an area of forest where some of the trees have been cut down. Explain the reasons why forests may be cut down as shown in . 1 9 The loss of forests from parts of the world is assessed by satellite imagery. Table 5.1 shows data on the forests in Indonesia and Malaysia, two countries in South-East Asia which have large areas of forest. Table 5.1 area / thousands of hectares type of forest country natural forest Indonesia natural forest Malaysia Calculate the percentage loss of natural forest in Indonesia between 1990 and 2010. Show your working and express your answer to the nearest whole number. % Use the data in Table 5.1 to compare the loss of natural forest in Indonesia with the loss of natural forest in Malaysia. [ 1 9 Many hectares of natural forest have been cleared in countries such as Malaysia and Indonesia for oil palm plantations. Both countries have also replanted forests to grow timber and other forest products. Suggest why replanted forests and plantations are less useful for conservation than natural forest. Discuss the effects of deforestation on areas of land. 1 9
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THEORY
2016
Paper 4, Variant 3
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Questions Discovered
393