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3.1 An introduction to biodiversity - Coggle Diagram
3.1 An introduction to biodiversity
Types of biodiversity
Genetic diversity
: range of genetic material present in a gene pool or population of a species
small population normally has a lower genetic diversity than a larger one because of the smaller gene pool
different populations of a species need to be conserved to conserve maximum amount of genetic diversity
humans can alter genetic diversity by artificially breeding or genetically engineering populations with reduced variation in their genotypes or even identical genotypes
Habitat diversity
: range of different habitats per unit area in a particular ecosystem or biome
Species diversity
: communities is a product of two variables, the number of species (richness) and their relative proportions (evenness)
alters from habitat to habitat
Hotspots
biodiversity hotspot is a region with a high level of biodiversity that is under threat from human activities
Endemic species: species that is only found in a particular location
Places of biodiversity hotspots
about ten in tropical rainforest but also regions in most other biomes
tend to be nearer the tropics because there are fewer limiting factors in lower latitudes
threatened areas where 70% of habitat has already lost
habitat contains more than 1,500 species of endemic plants
cover only 2.3% of the land surface
tend to have large densities of human habitation nearby
naming hotspots may be misleading
focus on vascular plants and ignore animals
do not represent total species diversity or richness
focus on regions where habitats, usually forest, have been lost and ignore whether that loss is still happening
do not consider genetic diversity
do not consider value of services (eg water resources)
Biodiversity
an indicator of ecosystem health
advantages of habitat with high biodiversity
genetic diversity so resistance to diseases
some plants there will have deep roots so can cycle nutrients and
bring them to the surface making them available for other plants
resilience and stability due to the range of plants present of which some will survive drought, floods, insect attack, disease
high biodiversity does not always equate to healthy ecosystem
managing grazing can be difficult as plant species have different requirements and tolerance to grazing
some stable and healthy communities have few plant species so are an exception to the rule
diversity could be the result of fragmentation (break up) of a habitat or degradation when species richness is due to pioneer species invading bare areas quickly