7.1 Adaptations, interdependence and competition

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Question 18
Medium

Biologists investigated the population density of the freshwater crustacean Gammarus pulex in an artificial research flume.

They used the following sampling method:

  1. Collect 1 dm3 of water from a randomly selected section of the flume.
  2. Filter the water sample through a fine mesh and count the number of Gammarus pulex retrieved.
  3. Repeat the process to obtain five samples in total.

Table of Results

Sample numberNumber of Gammarus pulex in 1 dm3 of water
121
234
37
418
545
a.

Calculate the mean number of Gammarus pulex in 1 m3 of the flume water. (Note: 1 m3=1000 dm31\text{ m}^3 = 1000\text{ dm}^31 m3=1000 dm3)

[2]
b.

The flume is a rectangular channel with the following dimensions:

  • length=6.4 m\text{length} = 6.4\text{ m}length=6.4 m
  • width=1.5 m\text{width} = 1.5\text{ m}width=1.5 m
  • water depth=0.25 m\text{water depth} = 0.25\text{ m}water depth=0.25 m

Calculate the estimated total population of Gammarus pulex in the flume. Give your answer in standard form.

[3]

7.1 Adaptations, interdependence and competition Questions

  1. GCSE
  2. /Biology
  3. /7.1 Adaptations, interdependence and competition