Formative Practice 9.2 (Form 5 Biology Textbook Exercise and Answer)

Question 1:
An ecosystem has a population size, population density and population distribution.
(a) What is the difference between population size and population distribution?
(b) State the factors that can affect population distribution.
(c) State the patterns of the population distribution. Explain.

(a) Population size is the number of organisms present in a population whereas population distribution is the number of individuals of a species per unit area of habitat.

(b) Temperature, water, pH of soil, salt content, mineral content, reproduction place and food supply

(c) Clumped – Clumped organisms forming separated groups because of uneven distribution of resources.
  Random – Organisms are in a free pattern in an area due to lack of interactions with each other.
  Uniform – Organisms scattered all over the area because every individual competes for limited resources in an area.

Question 2:
Quadrat sampling can be used to find the coverage percentage of plants in the school field. You are supplied with a quadrat which consists of a square-shaped wood frame.
According to your biology teacher, the quadrat needs to be modified to obtain a more accurate estimation. Explain.

Divide the quadrat into smaller square parts of the same size using wires or strings. Small squares which are covered by species either half or more are counted as having coverage whereas lesser than half are ignored.

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