19.2 Variation in population size

Question 1

Why does no population continue to grow indefinitely

Answer 1

Because certain factors limit growth, e.g. the availability of food, light, water, oxygen, and the accumulation of toxic waste, disease and predators.

Question 2

What are the examples of abiotic factors that influence the size of a population

Answer 2

1. Temperature - each different species has an optimum temperature at which its best able to survive
2. Light - light is the ultimate source of energy in an ecyosystem
3. pH - This affects the action of enzymes
4. Water and humidity