Question

(a) Compare, giving reasons, the J-shaped and S-shaped models of population growth of a species.
(b) Explain "fitness of a species" as mentioned by Drawin. [5]

Answer 1

(a) Comparision between the J-shaped and S-shaped models of population growth is shown below: [0.5 mark for each point]
$\begin{array}{cc}\text{J-shaped}& \text{S-shaped}\\ \text{Resources are unlimited}& \text{Resources are limited.}\\ \text{Growth is exponential.}& \text{Logistic growth.}\\ \text{As resources are unlimited}& \text{The fittest individuals will}\\ \text{all individuals survive and}& \text{survive and reproduce.}\\ \text{reproduce.}& \end{array}$
Fig: J-shaped growth curve (red) and S-shaped growth curve (blue). [1 mark for drawing and 0.5 mark for equation]

(b) According to Darwin, 'fitness of a species" means reproductive fitness in which organisms evolve towards the most efficient reproductive strategy. When resources are limited, competition occurs between individuals. The fittest will survive and reproduces to leave more progeny. [2]