• Species: a group of organisms with similar morphological and physiological features, which can interbreed to produce fertile offspring and are reproductively isolated from other species.
  • Ecosystem: a relatively self-contained, interacting community of organisms, and the environment in which they live and with which they interact. Consists of biotic and abiotic parts
  • Niche: is the role of an organism in an ecosystem (it is how an organism fits into the ecosystem).


What is Biodiversity

Biodiversity: The variety of species in an area along with their variation within species and the genetic diversity between them.

The three levels of diversity

    • Variation in ecosystems or habitats
    • Number of different species in the ecosystem and their relative abundance
    • Genetic variation within each species


Importance of maintaining biodiversity

    • Maintains stability of ecosystem thus preventing extinction
    • Maintains large gene pool (genetic variation)
    • Ecosystems provide ‘services’ for humans
    • Species can be source of new medicines
    • Resource such as food and wood
    • Leisure for humans to see in zoos; ecotourism
    • Climate stability


Genetic Diversity

  • Is the diversity of the alleles within the genes in the genome of a single species
  • A species can all have the same genes, but different alleles for those genes. Genetic diversity is assessed by finding proportion of genes with different alleles and how many alleles there are per gene.

Species Diversity

  • The number of species in a community is known as species richness
  • Species diversity takes species richness into account, but also includes evenness of abundance of each species

In species diversity there are two points that need to be found: distribution and abundance of species.

To do this we use means of Random sampling such as:

  • Quadrat
  • Mark and release
  • Simpson’s Index of Biodiversity

The importance of random sampling is that a habitat may be too large for actual counting so a sample is quick and gives a representation of the whole habitat.


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