Page 150 - SUBSEC October 2017_Neat

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02107020/CAPE/SPEC/KMS 2017
BIOLOGY
UNIT 1 – PAPER 02
KEY AND MARK SCHEME
Question 2 cont’d

Advantages

1. More efficient process in that higher yields are obtained
2. More cost effective/less expensive
3. No animals have to be slaughtered (cattle, pigs, salmon)
4. Faster, less tedious and less difficult process

Any 3 = 3 marks [8 marks]

(c) Isolating mechanisms

1. Temporal - individuals do not mate because they are active at
different times of the day or during different seasons. This may
have resulted from resource limitations or changes over time.

2. Behavioural / reproductive - potential mates meet but they do not
mate due to strict behavioural complexities e.g. mating dances or
vocalisations. This may occur where mate choice is not a
limitation.

3. Geographical / ecological - Individuals prefer to mate in their
desired habitat and therefore do not meet individuals of other
ecological preferences. This may happen, for example, when new
food sources become available in the habitat. Also, Physical
changes in landscape may result in physical barriers which may
separate populations.

4. Mechanical – structural differences mean that sex organs of males
and females of different species are incompatible.

3 marks for each mechanism fully discussed
1 mark for correct examples
[13 marks]

Total 30 marks