2.3.5+Simpson's+Diversity+Index

20/11/08   To measure species diversity of an ecosystem/ habitat...we need to take into account the number of species and their relative abundance. •We can use the **Simpson diversity index** It is sometimes useful to have an overall measure of species richness in an ecosystem. The Simpson diversity index is one of the most commonly used. Diversity is often considered to be a function of both the number of different species present and the number of individuals of each species. A high index indicates high species diversity, whilst a low number indicates low diversity. ** D = __N(N-1)__ **** Σ n(n-1)  ** ** N= ** Total number of organisms ** n= ** Number of individuals of each species. •The highest the number, the higher the species diversity. • From the table we see that A has the higher diversity and C has the lowest Diversity.
 * Diversity **
 * EXAMPLE **
 * ** ECOSYSTEM  ** || **  A  ** || **  B  ** || **  C  ** || **  D  ** ||
 * Kidney Beans  ||   17   ||   3   ||   8   ||   31   ||
 * White Beans  ||   31   ||   -   ||   2   ||   12   ||
 * Chick Peas  ||   19   ||   28   ||   54   ||   24   ||
 * Penne Pasta  ||   1   ||   9   ||   3   ||   2   ||
 * Macaroni Pasta  ||   1   ||   -   ||   -   ||   -   ||
 * Sunflower Rice  ||   15   ||   -   ||   3   ||   9   ||
 * Rice  ||   -   ||   2   ||   3   ||   -   ||
 * ** TOTAL  ** ||   84   ||   42   ||   73   ||   78   ||
 * ** DIVERSITY  ** ||   3.97   ||   2.06   ||   1.79   ||   3.56   ||