(a) Explain the term adaptation in relation to the mode of life of an organism.
(b) Explain how each of the following structures adapt the organisms that possess them to their modes of life:
(i) succulent leaves in Aloe sp
(ii) succulent stems and reduced leaves in cactus plants
(iii) short, strong beaks in fowls
(iv) counter shading in fish
(v) tiny scale leaves on needle-like branches of pine trees.
(c)(i) What is population?
(ii) State five effects of overpopulation on a community.
Explanation
(a) Adaptation: These are special features/characteristics that an organism possesses, which enable it to live/ survive successfully in an environment
(b)(i) Aloe: -
- The succulent leaves are adaptations for water storage.
- They are also adapted for surviving high temperatures and drought.
(ii) Cactus: Stems are thick and succulent for water storage, while leaves are reduced to conserve water, by reducing rate of transpiration.
(iii) Fowl: The beak is short/ strong/straight for picking insects/seeds, earthworms/small pieces of food, pecking of feathers.
(iv) Fish: The dorsal side is dark while the ventral side is silvery/counter shading. - This dual coloration protects the fish from predators, looking at them from above and below the water.
(v) Pines: The needle like leaves reduce water loss by transpiration. - Also conserves water for use in the long dry season.
(c)(i) Population: This is the total number of individuals of the same species, living together in a habitat, at a given time.
(ii) Effects of over population: -
- Competition for limited resources.
- Predation/cannibalism.
- Spread of diseases.
- Food shortage.
- build up toxic waste in the environment.
- Limited space for individual dwellings.
- High mortality/mortality rate.
- Increase of social vices/behaviour.