20.1. Food supply
A subsection of Biology, 0610, through 20. Human influences on ecosystems
Listing 10 of 61 questions
Complete the sentences about human influences on ecosystems. Use words from the list. Each word may be used once, more than once, or not at all. deforestation fertilisers herbicides insecticides livestock monoculture pectinases pollinate pollute When one type of crop of the same species is grown on a large scale it is called a . Chemical add mineral ions to the soil to increase the yield of crops. Weeds can be killed by . Crop damage by insects can be reduced by the use of . One disadvantage is that this kills useful insects which flowers. State the names of two greenhouse gases that are produced as a consequence of farming.
0610_w20_qp_32
THEORY
2020
Paper 3, Variant 2
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Researchers investigated four different insecticides to determine how effective they were at removing three different species of insects, A, B and C, from crop plants. They tested different concentrations of each insecticide to find the minimum dosage required to remove 95% of each insect population in two hours. Each insecticide had the same cost per gram. The results are shown in Table 6.1. Table 6.1 species of insect minimum dosage required / mg per dm3 insecticide 1 insecticide 2 insecticide 3 insecticide 4 A B C Use the information in Table 6.1 to decide which one of the four different insecticides and which dosage would be the best choice for removing insects A, B and C from a field of crop plants. Explain your choices. insecticide dosage explanation Discuss factors, other than dosage, that should be considered to prevent the insecticide damaging the environment. Describe the advantages to farmers of using insecticides. Farmers also use other chemicals on their crop plants. State the names of chemicals, other than insecticides, that are used by farmers on crop plants and explain their benefits. Insecticides are often made from chemicals that occur naturally in plants. Tobacco plants are one example of this. Suggest why having a natural insecticide is an adaptive feature of plants. Describe why people find it difficult to stop smoking tobacco. State the names of two diseases that can be caused by smoking tobacco. State the name of the component of tobacco that can damage alveoli.
0610_w20_qp_43
THEORY
2020
Paper 4, Variant 3
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shows how some uses of land have changed from the year 1500 to the year 2000 in one country. year percentage of land used Key farming forests and wild plants housing Using the data in : Identify the years when there was the largest increase in the percentage of land used for farming. from to State the trend for the percentage of land used for housing. State the year when the percentage of land used for forests and wild plants was equal to the percentage of land used for farming. Deforestation is one of the consequences of using land for farming. Outline the undesirable effects of deforestation. State one way humans can damage aquatic environments.
0610_w24_qp_31
THEORY
2024
Paper 3, Variant 1
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is a photograph of intensive egg production on a chicken farm. In 1905, each chicken produced a mean of 120 eggs per year. In 2021, each chicken produced a mean of 300 eggs per year. Calculate the percentage increase in mean egg production per year. Space for working. % Egg production has increased due to selective breeding and intensive farming. Describe the disadvantages of intensive livestock farming. Complete the flowchart to describe how egg production in chickens is increased by selective breeding. identify the chickens that use these chickens to observe the offspring for improvement in egg production repeat this process over many Selective breeding is also used to increase crop plant production. State two other ways to increase crop plant production.
0610_w24_qp_32
THEORY
2024
Paper 3, Variant 2
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Questions Discovered
61