(a) (i) What is competition? [2 marks]
(ii)In a tabular form, state four differences between competition and succession [4 marks]

(b) A pure strain goat with black coloured fur was crossed with a pure strain goat with white coloured fur, all the offspring had black coloured fur.
(i) With the aid of a genetic diagram, determine the phenotypic ratio of the F2 generation if the F1 offspring are selfed. [10 marks]
(ii) What would be the outcome of mating a black heterozygote offspring from the F2 generation with the original black coloured parent? [4 marks]

Most candidates avoided this question and those that attempted it did poorly. The definition of competition was poorly attempted. The difference between competition and succession was also poorly attempted. In genetic crossing, some candidates just drew lines without corresponding the gametes with the F1 generation.

The expected answers are:

4 (a) (i) Definition of Competition
- a biological interaction/struggle between organisms of the same species/intraspecific or different species/interspecific;
- for the same resources/food, water, space, light, suitable temperature/warmth, mates, soil; which are in limited/scarce supply.

(ii) Differences between competition and succession

Competition	Deficient elements
-occurs in all places inhabited by organisms	occurs only in a particular area;
- is triggered off when resources are in short/ limited supply in an existing habitat	usually starts within new habitats;
- the replacement of an old population by a population is due to interspecific competition	old population is gradually being replaced with new dominant population;
- competition has no end/ it continues in Succession ends when a stable or a stable or climax community	Succession ends when a stable or a stable or climax community climax community has been attained;
- competition speeds up succession	Succession provides basis for competition;
- the replacement of one population byanother in a given environment in a competition is due to ‘survival of the fittest’	the replacement of onepopulation by another in a particular area (is transitory and) leads to a climax or stable community.

Note: Points must correspond to score.

(b)(i) Crosses

Note: All crosses must be correct to score.