Intro to biodiversity - 3.1 - Coggle Diagram
Intro to biodiversity - 3.1
The amount of biodiversity per unit in area (the variety of living organisms in an area)
-- identofied by species, habitat and genetic diversity.
Leads to stability and resistance to change
Lost biodiversity cannot be replaced
Result of millions of years of evolution
Provides us with resources and services
Area of high biodiversity and endemism (a species only found in one area (koalas)). All hotspots are threatened areas. Conservation efforts are focused here. e.g. tropical rainforests
Number of different species and abundance of each species within a given area in a habitat
Includes amount of species (richness) + individuals of each species (evenness)
Counting number of different species in a given habitat. The more there are the richer the habitat. BUT it doesn't take into account the abundance of these in the habitat. Gives equal weight to all species found.
e.g. 1 buttercup has as much weight as 1000 daisy's
: Measure of the relative abundance of different species making up the richness of an area. A community where most species has high abundance is said to have high evenness - no single species dominates the area.
A highly diverse community has high evenness and richness.
A less diverse community may be dominated by a species.
Number of different habitats per unit area that an ecosystem or biome contains
(niches / unit area).
If habitat diversity is conserved, this usually leads to the conservation of species and genetic diversity.
variety of forests, deserts, grasslands, lakes, oceans, coral reefs...
The range of genetic material present in a species or population = gene pool
(different genes found in every individual species)
Individuals within a species differ = show variation.
Organisms that reproduce sexually, all individuals have a combination of different alleles. The greater the variety of genotypes the more biodiverse the species.
Should be conserved in order to allow the population to adapt to change
The higher the better
HIGH = more resistance to disease
LOW = indicator of low population size recently
Larger populations have higher genetic diversity = more potential for adaptation.
e.g. in CHETTAHS = low genetic diversity + poor sperm quantity make breeding and survivorship low.
The ability to assess changes to biodiversity in a given community over time is important in assessing the impact of human activity
It's dependent on many factors:
Diversity changes through succession
Greater habitat diversity leads to greater species and genetic diversity
A complex ecosystem, with its variety of nutrient and energy pathways, provides stability
human activities modify succession, e.g. logging, grazing, burning, mining
human activities often simplify ecosystems, rendering them unstable, for example, North America wheat farming versus tall grass prairie
an ecosystem’s capacity to survive change may depend on diversity, resilience and inertia.
Simpsons diversity index
High D = stable and ancient site
Low D = pollution, recent colonisation, agricultural management
The index can be applied to comparisons of diversity of any species.
Indices can be used to assess whether the impact of humans on the ecosystem is sustainable or not.
All species aren't equal, some have a bigger effect on their environment than others regardless of abundance or biomass.
The loss of a small population of keystone species could be the cause of the destruction of an ecosystem.
These are difficult to identify, are often predators or engineer species (beavers).
e.g. Beavers, they build dams and turn streams into swampy areas. Species then inhabit the swamp = elephant. Without the beaver there wouldn't be a swamp or a home for such species.