18. Variation and selection
A section of Biology, 0610
Listing 10 of 190 questions
A farmer grows different varieties of dates, which are a type of fruit. The table shows some features of the dates he grows. variety colour texture yield size Barhee amber soft high small to medium Dayri dark reddish brown semi dry variable medium to large Hayany purplish black soft medium large Maktoom amber soft medium medium to large Thoory straw coloured dry medium medium to large The farmer would like to produce a new variety of date using selective breeding. He wants a medium sized date that is straw coloured and soft, with a high yield. Which two varieties could the farmer breed together to get the variety he wants?
0610_w18_qp_11
MCQ
2018
Paper 1, Variant 1
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Coat colour in horses is controlled by genes. The allele for black coat (E) is dominant. The allele for red coat is recessive. Place ticks () in the table to show the coat colours of horses with each of the following genotypes. genotype black coat red coat EE Ee ee Modern horse breeds look very different to each other, but still belong to the same species. shows three different horse breeds. Thoroughbred Shetland Shire State the term used to describe the difference between individuals of the same species. Shire horses have been produced by selective breeding. They are strong and can pull heavy loads. Describe the process of selective breeding. Describe how natural selection differs from selective breeding.
0610_w18_qp_33
THEORY
2018
Paper 3, Variant 3
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Many crop plants are grown as monocultures. shows the destruction of a monoculture of maize as a result of drought. Describe the negative impacts to an ecosystem of large-scale monocultures, such as the one shown in . The fruits of maize are produced on structures called cobs. Each cob has many fruits. shows how the maize cobs have changed over thousands of years as a result of selective breeding. maize cob time length of maize cob fruit State two desirable features, visible in , that have been selected from the more ancient varieties of maize. The process of selective breeding involves a series of steps, as shown in . Step 1 select two plants with desirable features Step 2 transfer pollen from the flower of one plant to a flower on the second plant Step 3 use bags to cover the flowers that are pollinated Step 4 collect the seeds, germinate them and wait for the plants to grow Step 5 select the plants from step 4 that have the desirable features Step 6 continue step 2 to step 5 for many generations Explain why the flowers are covered with bags in step 3. Explain why the seeds in step 4 need oxygen to germinate. Explain why some of the plants in step 5 may show features not visible in the parent plants. Suggest why selective breeding should continue for many generations (step 6). State how new features, which did not exist in ancient varieties of a crop plant, could appear.
0610_w21_qp_41
THEORY
2021
Paper 4, Variant 1
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Questions Discovered
190