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IBDP Biology: Measuring Biodiversity --- Part 1

Measuring Biodiversity

August 15, 2022

In this topic of IBDP Biology, we will learn about Measuring Biodiversity --- Part 1.

Measuring Biodiversity

  • Environment – The conditions, in which an organism lives, composed of both biotic and abiotic factors.
  • Habitat – a well-defined area, in which an organism lives.
  • Population – the number of individuals of one species within a defined area at a given time.
  • Community – all the populations of different species, interacting together in a habitat at a given time.
  • Ecosystem – the community plus its associated physical environment.
  • Biodiversity – variety of life in a region:
  • Ecosystem diversity – range of different habitats within an ecosystem
  • Genetic diversity – range of alleles present within a species
  • Species diversity:
  • The number of species in an ecosystem.
  • The abundance of each species.
  • IE the greater the number of species and the more even their relative abundance, the more diverse the community.

Species Diversity Index

  • Used as a measure of the range and numbers of species in an area.
  • When it comes to IBDP Biology, I\it takes into account:
    • The number of species present
    • The number of individuals of each species.
  • It can be calculated by the following formulae:

d =

N(N-1)/

Σ n(n-1)

Where:         

N = total number of organisms of all species in the area
d = index of diversity
n = total number of organisms of each species in the area

Σ = sum of

Example

Population in a pond:

crested newt

8

stickleback

20

Leech

15

Great pond snail

20

Dragon fly larva

2

Stonefly larva

10

Water boatman

6

Caddisfly larva

30

N =

111

 

d = (111 x 110) / (8X7) + (20X19) + (15X14) + (20X19) + (2X1) + (10X9) + (6X5) + (30X29)

D =

12210/

therefore d = 6.05

2018

In another pond there were:

crested newt

45

stickleback

4

Leech

18

Great pond snail

10

d  = 2.6

  • When it comes toIBDP Biology, comparing both indices, 6.05 is an indicator of greater diversity.
  • The higher number the greater the species diversity.

You get it now. Now you can proceed to Part 2.