Topic 15 Practice Paper: Variation and selection — question paper

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

1. 1

   Which pair of examples shows continuous variation?

   1. ABlood group and seed colour
   2. BBody mass and body length
   3. CSeed shape and blood group
   4. DTongue-rolling and eye colour
   ( )
2. 2

   Discontinuous variation is usually caused by

   1. Athe environment only
   2. Bgenes and the environment
   3. Cdiet alone
   4. Dgenes only
   ( )
3. 3

   Mutations are important in evolution because they

   1. Aare always helpful
   2. Bprevent reproduction
   3. Ccreate new alleles for selection to act on
   4. Dhappen only in bacteria
   ( )
4. 4

   Which factor increases the rate of mutation?

   1. ALoud sound
   2. BCold temperatures
   3. CBright light
   4. DIonising radiation
   ( )
5. 5

   In natural selection, which individuals are most likely to reproduce?

   1. AThose best adapted to the environment
   2. BThe largest
   3. CThe youngest
   4. DThose with the most mutations
   ( )
6. 6

   The struggle for survival is caused mainly by

   1. Avoluntary exercise
   2. Bcompetition for limited resources
   3. Cgenetic engineering
   4. Doversized habitats
   ( )
7. 7

   Sunken stomata and rolled leaves are adaptive features of

   1. Ahydrophytes
   2. Binsectivorous plants
   3. Cxerophytes
   4. Dannual weeds
   ( )
8. 8

   In water plants, xylem tissue is often much reduced. The reason is that

   1. Athey photosynthesise in the dark
   2. Btheir stomata are sunken
   3. Cxylem would float them away
   4. Dsurrounding water removes the need for much water transport
   ( )
9. 9

   Antibiotic-resistant bacteria illustrate natural selection because the antibiotic

   1. Aselects pre-existing resistant variants to survive and reproduce
   2. Bcreates resistance deliberately
   3. Cmutates all bacteria equally
   4. Dfeeds the resistant ones
   ( )
10. 10

    Selective breeding differs from natural selection because in selective breeding

    1. Ano alleles are inherited
    2. Bhumans choose which individuals breed
    3. Cvariation is unnecessary
    4. Dthe environment selects
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 11

   A class investigates variation in humans.

   1. (a)

      Define variation.

      [1]
   2. (b)

      The class measures height (to the nearest cm) and records blood groups. State which measurement shows continuous variation and which shows discontinuous variation.

      [2]
   3. (c)

      Describe the expected shape of each set of results when plotted.

      [2]
   4. (d)

      State the causes of continuous and discontinuous variation.

      [1]
2. 12

   Natural selection changes populations over generations.

   1. (a)

      List four sources of genetic variation in a population. (Extended)

      [2]
   2. (b)

      Explain how natural selection leads to better-adapted individuals becoming more common.

      [4]
   3. (c)

      Define adaptation. (Extended)

      [1]
3. 13

   Insecticide P was sprayed on a crop every week for several years. The spray is now much less effective at killing the pest insects. (Extended)

   1. (a)

      Explain how the pest population became less affected by insecticide P.

      [4]
   2. (b)

      State the name of this type of selection and who or what carries out the selection.

      [2]
   3. (c)

      Suggest one change in farming practice that would slow the development of resistance, and explain why it helps.

      [1]