6626907 83-population-ecology

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6626907 83-population-ecology

  1. 1. 8.3 Population Ecology
  2. 2. What is meant by population ecology?  A branch of ecology that studies the structure and dynamics of population.  Population density – number of organism per unit area of habitat  Affected by abiotic and biotic factors, birth rate, death rate, immigration and emigration.
  3. 3.  Direct counting – method to estimate the size and density of population (impractical due to the size of ecosystem, the number of plants involved and the movement of the animal).  Sampling technique – more practical way, enable us to estimate the total population size of the organism.
  4. 4. The quadrat sampling technique  Used in estimating the size of plant population and immobile animal.  A quadrat – metal, wooden frame or PVC pipe frame which form a square of a known area (1 m2 ).  Placed randomly in an ecosystem where sampling is carried out.
  5. 5. The quadrat sampling technique
  6. 6.  Used to determine: (a) Frequency – number of times a particular species is found present when a quadrat is thrown a certain number of time The quadrat sampling technique
  7. 7. (b) Density – the mean number of individuals of species per unit area (c) Percentage coverage – an indication of how much the area of quadrat is occupied by a species The quadrat sampling technique
  8. 8. The capture, mark, release and recapture technique  Used to estimate mobile animals (small mammals, butterflies, birds and insects)  Procedure: 1. Animal sample is captured 2. Marked 3. Released 4. Second sample captured & number of marked animal recorded.
  9. 9.  Population size of the animal in the area can be estimated using the formula below: The capture, mark, release and recapture technique
  10. 10. The abiotic factors which influence the distribution of an organism  What are abiotic factors?  How the abiotic factors influence the distribution of an organism?
  11. 11. Exercise  Do Focus Practice 8.3 on page 188 in the textbook.

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