Section 17. Selection and evolution for Biology, A Level - revisedeck

17. Selection and evolution

A section of Biology, 9700

Listing 10 of 104 questions

Several different processes can affect allele frequencies in populations. Outline the processes that may affect allele frequencies in wildlife populations. The process of selective breeding changes allele frequencies in a population. Plant breeders use selective breeding to improve crop plants such as maize. Explain how selective breeding can be used to obtain a variety of maize where the plants are vigorous and of uniform height.

9700_w24_qp_42

THEORY

2024

Paper 4, Variant 2

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Anaerobic bacteria are abundant in waterlogged soils. Which effect does this have on soil fertility and why?

9700_s11_qp_12

MCQ

2011

Paper 1, Variant 2

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A farmer grows a different crop in a field each year for three years. In the fourth year the farmer plants a leguminous crop and then ploughs this into the soil. The next year the rotation starts again. Which microorganisms will increase by the time the rotation starts again?

9700_s14_qp_11

MCQ

2014

Paper 1, Variant 1

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A gardener has a waterlogged garden showing poor growth. He decides to drain it in an attempt to reduce the numbers of some harmful bacteria. Which type of bacteria would he be attempting to reduce in number?

9700_s14_qp_12

MCQ

2014

Paper 1, Variant 2

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Strains of Mycobacterium have been found that are: • multiple drug-resistant (MDR) – resistant to the drugs most commonly used to control tuberculosis (TB) • extensively drug-resistant (XDR) – resistant to the drugs most commonly used to control TB and to some of the drugs less commonly used to control TB • totally drug-resistant (TDR) – resistant to all known drugs used to control TB. Comparisons of some of these strains of Mycobacterium found differences in the thickness of their cell walls, as shown...

9700_s15_qp_13

MCQ

2015

Paper 1, Variant 3

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In what order do the following processes occur to produce a population of bacteria that are resistant to a new antibiotic?

9700_s17_qp_13

MCQ

2017

Paper 1, Variant 3

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A population of bacteria is exposed to the antibiotic penicillin. Most of the bacteria die. However, some bacteria in the population have an allele coding for an enzyme that breaks down penicillin. These bacteria are able to survive. Which could explain how these bacterial cells acquired this allele?

9700_s20_qp_11

MCQ

2020

Paper 1, Variant 1

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A farmer grows a different crop in a field each year for three years. In the fourth year the farmer plants a leguminous crop and then ploughs this into the soil. The next year the rotation starts again. Which microorganisms will increase by the time the rotation starts again?

9700_w10_qp_11

MCQ

2010

Paper 1, Variant 1

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A farmer grows a different crop in a field each year for three years. In the fourth year the farmer plants a leguminous crop and then ploughs this into the soil. The next year the rotation starts again. Which microorganisms will increase by the time the rotation starts again?

9700_w10_qp_13

MCQ

2010

Paper 1, Variant 3

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Decomposition of organic matter can cause the concentration of ammonia to rise in a fish tank. High concentrations of ammonia in the tank are toxic to fish. Bacteria may be added to remove the ammonia. Which type of bacteria should be added?

9700_w13_qp_11

MCQ

2013

Paper 1, Variant 1

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Questions Discovered

104