Variation And Natural Selection

9.Explain how antibiotic resistance can develop in a bacterial population.

10.Which of the following is a step in artificial selection?

11.Selective breeding is also known as artificial selection.

12.Complete the sentence about selective breeding:

13.Which of the following is an example of artificial selection?

14.Match each type of variation with its correct example.

15.Place the following steps of natural selection in the correct order.

16.Which of the following are examples of discontinuous variation? (Select all that apply.)

17.Mutation results in the formation of new alleles.

18.In a population of bacteria, some individuals have a mutation that makes them resistant to an antibiotic. When the antibiotic is applied, what is the most likely outcome?

19.Which of the following is NOT a step in artificial selection?

20.Which of the following are true about natural selection? (Select all that apply.)

21.Match each term with its correct description.

22.Place the following steps of selective breeding in the correct order.

23.In a population of wildflowers, flower colour shows continuous variation. Which of the following statements about this population is correct?

24.Mutations always result in a change to the phenotype of an organism.

25.Match each type of variation with its correct description.

26.A farmer selectively breeds cows to increase milk yield. Which of the following is the most likely long-term consequence of this practice?

27.Which of the following is the source of new alleles in a population?

28.Artificial selection always leads to organisms that are better adapted to their natural environment.

29.Which of the following are necessary conditions for natural selection to occur in a population? (Select all that apply.)

30.In a laboratory experiment, a student investigates the effect of an antibiotic on two bacterial strains: one resistant (R) and one non-resistant (S). Equal numbers of each strain are mixed and grown on a nutrient agar plate containing the antibiotic. After 24 hours, the plate is examined. Which of the following results would best demonstrate natural selection?

31.Which of the following is a correct definition of variation?

32.Place the following steps of natural selection in the correct order from first to last.

33.Natural selection always results in organisms that are perfectly adapted to their environment.

34.Match each type of variation with its correct characteristic.

35.Place the following steps of selective breeding in the correct order from first to last.

36.Which of the following is an example of continuous variation?

37.A farmer selectively breeds cows for increased milk yield. After 20 generations, the average milk yield has increased by 40%. However, the cows are now more susceptible to a common disease. Which statement best explains this observation?

38.Which of the following are examples of continuous variation? (Select all that apply.)

39.Place the following steps of natural selection in the correct order from first to last:

40.A population of 1000 birds lives on an island. Their beak sizes show continuous variation, with a mean of 10 mm. After a drought, only seeds with hard shells are available. The average beak size in the next generation is 12 mm. Which statement best explains this change?

41.Variation is defined as differences between individuals of the same species.

42.Discontinuous variation shows a range of phenotypes with no clear categories.

43.In natural selection, individuals that are better adapted to their environment have a higher chance of survival and reproduce more, passing on their alleles.

44.Complete the sentence about variation:

45.In a population of bacteria, 5% initially carry a resistance allele. After exposure to an antibiotic, 80% of the surviving bacteria carry the resistance allele. If the total population before exposure was 10,000 and 90% died, how many bacteria survive?

46.Define the term 'selective breeding' (artificial selection).

47.Complete the sentence about variation.

48.In a population of 1000 bacteria, 10% have a mutation that confers antibiotic resistance. After exposure to an antibiotic, 80% of the surviving bacteria carry the resistance allele. If 500 bacteria survive, how many resistant bacteria were there initially?

49.Define the term 'variation' as used in biology.

50.In a population of 500 insects, 20 have a mutation that makes them resistant to a pesticide. The pesticide is sprayed, killing all non-resistant insects. What percentage of the surviving insects are resistant? Give your answer to one decimal place.

51.Describe how natural selection can lead to the development of antibiotic resistance in bacteria.

52.Explain how artificial selection differs from natural selection.

53.Explain how the development of antibiotic resistance in bacteria is an example of natural selection.

54.Explain how natural selection can lead to the development of antibiotic resistance in bacteria.

55.In a population of bacteria, 5% initially carry a resistance allele. After exposure to an antibiotic, 80% of the surviving bacteria carry the resistance allele. If the total population before exposure was 10,000 and 90% died, how many bacteria survive?

56.In a population of 1000 bacteria, 10% have a mutation that confers antibiotic resistance. After exposure to an antibiotic, 80% of the surviving bacteria carry the resistance allele. If 500 bacteria survive, how many resistant bacteria were there initially?

57.In a population of 500 insects, 20 have a mutation that makes them resistant to a pesticide. The pesticide is sprayed, killing all non-resistant insects. What percentage of the surviving insects are resistant? Give your answer to one decimal place.