AQA A Level Biology

Revision Notes

4.6.2 Species Richness

Species Richness

  • Species richness is the number of species within a community
    • A community is a group of populations of different species living in the same place at the same time that interact with each other
  • Species richness is the simplest way to measure species diversity
  • A community with a greater number of species will have a greater species richness score
    • For example, a tropical rain forest has a very high number of different species so it would be described as species-rich
  • Species richness can be a misleading indicator of diversity as it does not take into account the number of individuals of each species
    • For example, habitat A has 10 different plant species and habitat B has 7 different plant species
    • Habitat A would be described as being more species-rich than habitat B
    • However, in habitat A there is only one individual of each plant species present (10 individuals present) while in habitat B there are over 20 individuals of each species present (over 140 individuals present)
    • This example illustrates the limitations of species richness
  • Conservationists often favour the use of an index of diversity as it takes into account species number and evenness

Author: Lára

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

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