Advantages and Disadvantages of Sexual and Asexual Reproduction

1. 1 State [1 mark]

   State one advantage of asexual reproduction.

   Show answerHide answer

   Model answer

   Only one parent is needed, or it is faster, or it is more efficient.

   Mark scheme

   • A correct advantage — 1 mark
2. 2 Describe [2 marks]

   Describe how a strawberry plant can reproduce both sexually and asexually.

   Show answerHide answer

   Model answer

   It reproduces sexually by producing seeds from flowers, and asexually by growing runners, which form new plants.

   Mark scheme

   • Seeds, sexually — 1 mark
   • Runners, asexually — 1 mark
3. 3 Explain [3 marks]

   Explain why sexual reproduction gives a survival advantage when the environment changes.

   Show answerHide answer

   Model answer

   Sexual reproduction produces variation in the offspring. If the environment changes, some of the offspring may have characteristics that are better suited to the new conditions. These survive and reproduce, by natural selection, and pass on their genes.

   Mark scheme

   • Variation in the offspring — 1 mark
   • Some are better suited to the new conditions — 1 mark
   • They survive and reproduce, natural selection — 1 mark
4. 4 Explain [3 marks]

   Explain why malarial parasites reproducing sexually in the mosquito may make malaria harder to treat.

   Show answerHide answer

   Model answer

   Sexual reproduction gives variation, with new combinations of genes. Some of the parasites may be resistant to a drug. These survive the treatment and reproduce, so the resistant parasites become more common.

   Mark scheme

   • Sexual reproduction gives variation — 1 mark
   • Some are resistant to the drug — 1 mark
   • They survive and become more common — 1 mark
5. 5 Explain [4 marks]

   A daffodil can reproduce by bulb division and by seeds. Explain one advantage of each method.

   Show answerHide answer

   Model answer

   Bulb division is asexual, so it needs only one parent, and it is faster and gives many identical plants, which will all flower and grow well in the same conditions. Seeds are produced by sexual reproduction, which gives variation, so if the environment changes some of the plants may survive.

   Mark scheme

   • Bulb division needs one parent, or is faster — 1 mark
   • Many identical plants, favourable conditions — 1 mark
   • Seeds give variation — 1 mark
   • Survival if the environment changes — 1 mark
6. 6 Evaluate [6 marks]

   A rare plant species can be grown from seed, or from cuttings. A conservationist wants to increase the number of plants quickly. Evaluate the two methods, and suggest which would be better in the long term.

   Show answerHide answer

   Model answer

   Cuttings are asexual reproduction, and need only one parent, so many identical plants can be made quickly, and each will have the same characteristics as the parent, which will be well suited to the habitat. This is a quick way of increasing the number of plants. However, all the plants will be clones, with no variation, so a disease or a change in the environment could kill them all. Growing from seed is sexual reproduction, which is slower, because the plants have to flower and be pollinated, but the seeds produce variation, so some of the plants may be resistant to a disease, or suited to a changed environment. In the long term, the variation from seeds is better for the survival of the species, but cuttings could be used first to increase the number quickly.

   Mark scheme

   • Cuttings are asexual and quick — 1 mark
   • Identical plants, same suited characteristics — 1 mark
   • No variation, so all affected by disease or change — 1 mark
   • Seeds are sexual and slower — 1 mark
   • Seeds give variation, so some survive — 1 mark
   • Conclusion with a reason — 1 mark

Quick check

1. 1

   Which is an advantage of sexual reproduction?

   1. AOnly one parent is needed
   2. BIt is faster
   3. CIt produces variation in the offspring
   4. DIt makes identical clones
   Show answerHide answer

   C: It produces variation in the offspring

   It produces variation in the offspring.

2. 2

   Which is an advantage of asexual reproduction?

   1. AIt is more time and energy efficient
   2. BIt produces variation
   3. CIt needs two parents
   4. DIt is slower
   Show answerHide answer

   A: It is more time and energy efficient

   It is more time and energy efficient, because no mate is needed.

3. 3

   Where do malarial parasites reproduce sexually?

   1. AIn the human liver
   2. BIn the mosquito
   3. CIn the red blood cells
   4. DIn water
   Show answerHide answer

   B: In the mosquito

   In the mosquito.

4. 4

   How do fungi reproduce asexually?

   1. ABy seeds
   2. BBy runners
   3. CBy bulbs
   4. DBy spores
   Show answerHide answer

   D: By spores

   By spores.

5. 5

   How do strawberry plants reproduce asexually?

   1. ABy runners
   2. BBy seeds
   3. CBy pollen
   4. DBy spores
   Show answerHide answer

   A: By runners

   By runners.

6. 6

   How do daffodils reproduce asexually?

   1. ABy runners
   2. BBy spores
   3. CBy bulb division
   4. DBy fertilisation
   Show answerHide answer

   C: By bulb division

   By bulb division.

7. 7

   Why does variation help a species when the environment changes?

   1. AAll individuals die
   2. BSome individuals may be better adapted and survive
   3. CIt makes the environment stop changing
   4. DIt makes clones
   Show answerHide answer

   B: Some individuals may be better adapted and survive

   Some individuals may be better adapted, and survive.

8. 8

   Which of these is a disadvantage of asexual reproduction?

   1. AIt needs two parents
   2. BIt is slow
   3. CIt needs a mate
   4. DThere is no variation in the offspring
   Show answerHide answer

   D: There is no variation in the offspring

   There is no variation in the offspring.

9. 9

   How can humans speed up natural selection?

   1. ABy selective breeding
   2. BBy mitosis
   3. CBy fertilisation
   4. DBy photosynthesis
   Show answerHide answer

   A: By selective breeding

   By selective breeding.