Measuring genetic diversity

In a nutshell

Genetic diversity can be assessed, this can help scientists understand how humans impact global biodiversity. Human population growth, climate change and the increased used of monocultures all affect global biodiversity.

Genetic polymorphism

Genetic polymorphism can be used to measure genetic diversity. Polymorphism refers to a locus with two or more alleles. By using the below formula, you can calculate the proportion of polymorphic gene loci in an organism. The greater the proportion of polymorphic loci, the higher the genetic diversity in a population.

$proportion\ of\ polymorphic\ gene\ loci = {number\ of\ polymorphic\ gene\ loci\over total\ number\ of\ loci}$

Example

Calculate the proportion of polymorphic gene loci, if $10,000$ genes are sampled from a population and $3780$  are polymorphic.

Put the numbers in the formula:

${3780\over10000}=\boxed{0.378}$

$\underline{Therefore, the\ proportion\ of\ polymorphic\ gene\ loci\ in\ this\ population\ is\ 0.378}$

Human population growth

The human population has risen exponentially over the past few centuries. This has led to a reduction in global biodiversity for a number of reasons.

Reason	Explanation
Habitat loss	Humans have destroyed habitats to create land for housing and agriculture.
High demand	A higher population has meant a a greater demand for resources like food and energy. This means that these resources are required faster than they can be replaced. This can lead to low numbers of species that are food sources which reduced biodiversity.
Urbanisation	Large cities have led to the destruction of habitats and isolation of species in places where they might find it difficult to interbreed.
Pollution	Pollution can lead to destruction of habitats or death of a species.

Climate change

Definition

Climate change refers to the variation in the climate of the Earth.

Climate change can occur naturally but due to increasing emissions of greenhouse gases produced by humans, it is occurring at a much quicker rate. This affects biodiversity as some species are sensitive to changes in climate. This can lead to their migration (to somewhere with an ideal climate) or their extinction.

Example

Puffins are affected by a rise in sea temperature as fish are moving further North into deeper waters. This means they are struggling to feed their young and many of dying of starvation.

Monoculture

Definition

Monocultures are areas of land used to grow only one type of crop.

Monocultures reduce biodiversity as habitats are destroyed to clear fields for them. Also, the use of herbicides and pesticides is high in monoculture fields and this leads to a reduction in both plant and animal species.

Biology; Biodiversity; KS5 Year 12; Measuring genetic diversity