Species richness, genetic diversity and how to preserve biodiversity

Biodiversity The total diversity of alleles, species and ecosystems in an area. It is a combination of species richness and genetic diversity.

The importance of biodiversity in ecosystems Allows large ecosystems to function and self-regulate Bacteria and fungi decompose waste Air and water purified Transpiration of plants determines where rain will fall Plants grip soil particles with their roots reducing flooding Genetic diversity has enabled genetic engineering, cross breeding and the production of crops Plant species richness has given rise to many chemicals that are useful to humans

Biodiversity Species richness – number of different species within a particular area Genetic diversity – the number of different alleles within a gene pool of a species.

Definitions Population – all the individuals of one species living in an area Community – all the individuals of all species living in an area Habitat – the place an organism lives Ecosystem – the inter-relationship of all the biotic and abiotic factors in an area Gene pool – is all of the alleles in a species

Niche – the role of a particular species within an ecosystem E.g. A fox’s niche is that it lives in a den, feeds on small animals and rubbish. Fleas live on the fox. Biotic factors – living factors e.g. presence of prey, predators, disease caused by microorganisms Abiotic factors – non living factors – light intensity, temperature, soil pH, nitrate concentration of soil

Key ideas in preserving biodiversity The good functioning of most ecosystems depend on: Plant pollination Seed dispersal Soil quality Nutrient recycling e.g. N cycle

Some species are more important than others Organisms low in food chains: without plants (the producer) nothing else would exist. 2. Key stone species help preserve biodiversity e.g. otters eat sea urchins which helps preserve the population of kelp.

Some places are more important to conserve than others Tropical rainforest have the greatest biodiversity Biodiversity hotspots often have endemic species Coral reefs, bogs and wetlands Indicator species – are used as a measure of species richness e.g. many birds; lichens.

Species richness of amphibians

How to measure Species Richness Count the number of different species in an area. The higher the number of species the greater the species richness. You could also calculate Simpson’s diversity index. This takes into account of the different species and the number of individuals of each species.

Random Sampling Form a grid using two tape measures laid down at right angles Obtain random co-ordinates using random numbers generated by a calculator and place the quadrat at those coordinates. This reduces bias. This method can be repeated in two different habitats. It can be be used to compare the numbers of individuals, or the different number of species in two different habitats.

Measuring Abundance: the numbers of individuals of one species Abundance is the number of individuals of a species are within a given space. It can be measured by calculating frequency or percentage cover. Frequency – the likelihood a species occurs in a quadrat. If a species is in 10 of 40 quadrats it has an occurrence of 25%. Percentage cover – estimate of an area within a quadrat that a particular plant species covers. Useful when a species is particularly abundance (e.g.mussels) or difficult to count (e.g. lichen).

Species that are difficult to count

Genetic Diversity

http://ngm.nationalgeographic.com/2012/11/cheetahs/smith-text

Genetic Diversity Genetic diversity if the variety of different alleles in a gene pool of a species The larger the population, the more likely there will be greater different types of alleles present

Genetic Diversity in Horses

How to measure genetic diversity How to measure: observe the different phenotypes e.g. the different eye colours as a measure of the genetic diversity. Analyse the DNA - alleles will have slightly different orders of bases. The larger the number of alleles the greater the genetic diversity.

Why is genetic diversity important? The greater the genetic diversity, the greater the number of different alleles in the gene pool. This mean there is a greater chance of having a beneficial allele if the environment changes. This means the species is more likely to survive. There is more chance that a few individuals will be survive the disease or other change in the environment. * the total number of alleles for all genes for one species