4.2- Calculating biodiversity Flashcards
What is Simpson’s index of diversity?
It’s a measure of the diversity of a habitat. It takes into account both species richness and evenness.
D=1-[SUM OF(n/N)^2]
n is the number of individuals of a particular species (percentage cover of species) and N is the total number of all individual of all species (total percentage cover for plants)
How can Simpson’s index of diversity be interpreted?
High value of Simpson’s index of diversity indicates a diverse habitat. Such a habitat provides a place for many different species and many organisms to live.
What happens if there’s a small change to the population for high biodiversity?
A small change may affect one species. If this one species is only a part of the habitat, the total number of individuals affected is a small proportion of the total number present. Therefore the effect of the whole habitat is small. The habitat tends to be stable and able to withstand change
What does a low value for diversity suggest?
Suggest a habitat is dominated by a few species. In this case a small change to environment that effects on of those species could damage or destroy the whole habitat. Such small change could be a disease or predator.
How can measuring the genetic diversity asses the value of the population?
Isolated populations such as captive animals in zoos, rare breeds or pedigree animals may be small. Therefore, their genetic diversity may be limited. Assessing their genetic diversity can help to asses the value of that population as a resource for conservation.
What is a simple way of measuring genetic diversity?
A simple assessment of genetic diversity can be made by looking at the observable features if the individuals. If a particular feature shows variation between the individuals, then it suggests there may be genetic variation.
Where is genetic diversity found?
Genetic diversity is found where there is more than one allele for a particular locus. This will lead to variations between individuals that may be easily observable. More importantly, perhaps it means there will be more genetic differences between the gametes (sperm and egg) produced by members of the population.
How can genetic diversity be calculated?
Genetic diversity can be estimated by calculating the number of loci in one individual that are heterozygous (i.e. that contain two different alleles). However, this does not give a good measure of the value of the population as a genetic resource
Which other way can genetic diversity be calculated?
Another measurement of genetic diversity involves calculating the percentage of loci in the population that have more than one allele. For example, in a species that has 10, 000 loci, if 2000 loci have more than one allele then the genetic diversity would be given the equation:
Genetic diversity= (2000÷10,000) *100%=20
Some loci have more than 2 alleles, these are known as polymorphic gene loci. Having more than two alleles at a locus increases genetic diversity.
