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20. Human influences on ecosystems
A section of Biology, 0610
Listing 10 of 393 questions
shows seven lizards that are at risk of becoming extinct. A C B E D F G not to same scale Name the vertebrate group that contains lizards. 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 feet with three toes go to 2 feet with five toes go to 3 has a collar or crest on head go to 4 has no collar or crest on head Chalcides minutus spikes along back go to 5 no spikes along back go to 6 ridges extend along back and tail Brookesia perarmata no ridges along back or tail Calumma parsonii blunt, rounded head Amblyrhynchus cristatus elongated head Cyclura lewisi large raised scales on skin Abronia graminea scales on skin are not large or raised Varanus komodoensis D The effect of humans on the environment has caused the populations of the lizard species in to decrease. Explain why conserving lizards is important. Zookeepers report that isolated female Komodo dragons, Varanus komodoensis, have produced offspring asexually. This is very unusual in vertebrates. State two disadvantages of asexual reproduction. State two disadvantages of sexual reproduction. Sexual reproduction requires meiosis to occur. Define the term meiosis. Explain the significance of meiosis to the survival of endangered species of lizards.
0610_w15_qp_31
THEORY
2015
Paper 3, Variant 1
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Fish called trout and other fish used to be caught commercially in the Great Lakes of Canada. However, canals built between the lakes before 1900 allowed a predator fish, the lamprey, to enter the lakes. The lamprey feeds on trout. It caused the fishing industry to collapse. shows fish catches over 65 years. 1900–1904 1905–1909 1910–1914 1915–1919 1920–1924 1925–1929 1930–1934 1935–1939 1940–1944 1945–1949 1950–1954 1955–1959 1960–1964 years total fish catch / × 106 kg State in which five year period: the greatest mass of fish was caught the smallest mass of fish was caught Between 1900 and 1904, 37.4 × 106 kg of fish were caught. Between 1960 and 1964, 23.4 × 106 kg of fish were caught. Calculate the reduction in fish catches between 1900 and 1964. Show your working. In 1944 barriers were placed in the canals to stop lampreys entering the lakes. Suggest whether the barriers were effective. Explain your answer. Studies have shown that human activities can affect trout numbers. Suggest three human activities that could cause the trout numbers to drop. Describe two methods of conserving endangered species.
0610_w16_qp_31
THEORY
2016
Paper 3, Variant 1
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Giant tortoises are an endangered species living on the Galapagos Islands, 600 miles from the coast of South America. shows a giant tortoise. For over 300 years sailors hunted the slow-moving giant tortoises as a source of food. They also left goats on the islands to provide food for sailors to eat in the future. Giant tortoises and goats are both herbivores. Use this information to suggest and explain two reasons why giant tortoises became an endangered species. Outline two ways that an endangered species can be conserved. The loss of one species can affect other organisms living in the same environment. Suggest how the loss of one species of secondary consumer from a food web might affect other organisms in the same food web.
0610_w16_qp_33
THEORY
2016
Paper 3, Variant 3
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Cheetahs, Acinonyx jubatus, are carnivores found in the dry grasslands and woodlands of southern Africa. Cheetahs hunt for food during the day. They eat deer and antelope. The cheetah is the fastest mammal on land but can only run at high speed over a short distance. Its hunting strategy is to creep up on prey and then sprint to catch them. is a photograph of a cheetah in its natural habitat. Suggest how these adaptive features enable cheetahs to survive in their natural environment. fur colouring streamlined body shape The king cheetah is a rare variety of A. jubatus that has inherited striped fur markings. shows a cheetah with spots and a king cheetah. cheetah with spots king cheetah Define the term inheritance. shows a pedigree diagram of a population of cheetahs. male king cheetah female king cheetah male cheetah with spots female cheetah with spots Key: ? Deduce the genotype of cheetah 11. Predict the probability of cheetah 14 being a king cheetah. Describe how a breeder could determine the genotype of cheetah 17. When the king cheetah was first discovered it was thought that it was a new species. Pedigree diagrams of cheetahs proved it was not a new species. Suggest one type of evidence, other than pedigree diagrams, that can be used to determine how closely related organisms are. Cheetahs are at risk of becoming endangered. Suggest why the cheetah is at risk of becoming endangered. Describe how species like the cheetah can be conserved.
0610_s20_qp_42
THEORY
2020
Paper 4, Variant 2
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Questions Discovered
393