Course Content
GROWTH AND DEVELOPMENT IN PLANTS AND ANIMALS
Biology Form 3
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Study Question

  1. To estimate the population size of mosquitoes in Shikoti village, Kenya Medical Research Institute (KEMRI) researchers caught 400 mosquitoes which they marked and released. After 24 hours 200 mosquitoes were caught out of which 80 had the marks.

(a) Suggest the possible instrument that may have been used for capturing and marking the insects. (1 mark)

Capturing:

  • sweep net

Marking:

  • permanent/waterproof ink

(b) Estimate the population size of the mosquitoes in the village.

Population = (400 X 200)/80
Population = 200 mosquitoes

 

2. Use the illustration below to answer questions.

(a) Identify the method of population estimation shown above.

  • Capture-recapture method;

(b) Estimate the population of the beetles.

Population = (35 X 20)/7

(c) State one limitation of this method.

  • Beetles may migrate;
  • Released beetles may not mix freely due to mark;
  • Released beetles may not have enough time to mix;
  • The mark may alter animals’ behavior;

 

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