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Question 18N.2.HL.TZ0.c

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Date November 2018 Marks available [Maximum mark: 7] Reference code 18N.2.HL.TZ0.c
Level HL Paper 2 Time zone TZ0
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 7]
18N.2.HL.TZ0.c

Explain how evolution occurs and which factors can cause the process to be rapid.

[7]

Markscheme

a. evolution is a change in the heritable characteristics «of a species» ✔ 

b. natural selection «causes evolution» ✔

c. overpopulation/over-reproduction/more offspring «than the environment can support» ✔

d. competition «for resources/mates» ✔

e. variation in population/species ✔

f. mutation/meiosis/sexual reproduction contributes to variation ✔

g. adaptation increases chance of survival ✔

h. reproduction/offspring produced «by the better adapted/by those that survive» ✔

i. characteristics passed to offspring by reproduction/variation is heritable ✔

j. allele frequencies/number of organisms carrying a gene changes/gene pool changes ✔

k. environmental change stimulates/triggers/speeds up natural selection/evolution ✔

l. increase in rainfall/introduction of antibiotic/pollution on tree trunks/other valid example of environmental change/new selection pressure ✔

m. artificial selection/selective breeding can speed up evolution ✔

 

Mark points can be awarded if explained using an example.