How can we define biodiversity?

· The biosphere is the layer of the earth where there is life and it includes part of the atmosphere and lithosphere.

· Biological diversity- variability among living organisms, testerial, marine and aquatic ecosystems and the ecological complexes of which they are a part

· Biodiversity is ecosystem, genetic and species diversity, although richness is perhaps the most easily measure- tell the interactions between species and between species and their environments need to taken into account for a true understanding

Ecosystem diversity

Genetic diversity

Species diversity


















Looking at the diversity range

Looking at variety within species from molecular level up to population

Looking at the range and variety of species from kingdom down to individuals





Species diversity

Linked to species richness- the number of species in a given area

· A good measure of biodiversity

· Better if a range indicator species is specified ones that suggest a richer system if they are present

· Take care when assessing area as larger areas tend to be more diverse

· Many species are yet undiscovered

· Species richness does not cover the distribution of the species or the interactions between species

Genetic diversity

Genetic variation within species, in populations that have been separated geographically but also amongst individuals within single populations. Variation in genetic makeup more easily allows populations to adapt to changing environments

· Allows an accurate picture of the diversity within a population

· Helps explain how isolated groups have adapted to new environments

· Difficult to assess without high level biological skills as DNA has to be analysed

Ecosystem diversity

Variety of different ecosystems or habitat that occur within an area and takes into account biotic and abiotic components

· Useful when assign areas to protect as has a wider focus than the other two diversity

· Difficult to know where to place the boundaries for an area under investigation

What factors influence biodiversity?

· Biodiversity is not evenly spread out across the earth

· The size of the area is important as generally more species can live and interact with a larger area.

· A growth in population has an impact on biodiversity because we are in competition with other species for space and resources as human number increase; the biodiversity will decrease if there is a lack of management

· There are also certain human activities- hunting that target specific species which can lead to extinction if unregulated

· As humans practice agriculture, the multi-layered natural system is changed into a single-layered one, a monoculture and thus reduces biodiversity in an area.

· Most important impact on the level of biodiversity is the locations climate- regarded as a limiting factor

· Overall there is an increase in the number and variety of organisms towards the Tropics and this is also true for marine ecosystems

· Nearer the equator, the climate


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