24.1 Population Size

Question 1

Describe & explain the stages of the population growth curve:

Answer 1

1. PHASE 1 - period of slow growth
   
   1. Only a few individuals present which reproduce. birth rate > death rate.
2. PHASE 2 - period of rapid growth
   
   1. Exponential growth ∵ no limiting factors.
3. PHASE 3 - stable state
   
   1. Population size remains fairly constant. Birth rate approx = death rate due to limiting factors.

Question 2

What are the 2 types of limiting factors which limit the rate of growth of a population?

Answer 2

BIOTIC - living factors

ABIOTIC - non-living factors

Question 3

What are examples of biotic factors affecting population size?

Answer 3

predators

disease

competition

Question 4

What are examples of abiotic factors affecting population size?

Answer 4

light

pH

humidity

oxygen availability

Question 5

What is carrying capacity?

Answer 5

Maximum population size

an environment can support

Question 6

What is immigration?

Answer 6

movement of individual organisms into an area

increasing the population size within that area

Question 7

What is emigration?

Answer 7

movement of individual organisms out of an area

decreasing the population size of that area

Question 8

What are density independent factors?

Answer 8

Factors which affect the whole population

regardless of its size