4.6 Biodiversity within a community Flashcards
Define biodiversity:
The variety of living organisms in an area
What are the 3 components of biodiversity?
- Species diversity – the number of different species and the number of individuals of each species within a community
- Genetic diversity
- Ecosystem diversity
Define habitat:
Places where an organism lives
Define community:
All the populations of different species in a habitat
What is local biodiversity?
The variety of species living in a small habitat e.g. pond / meadow
What is global diversity?
The variety of species living on Earth
What is global diversity?
The variety of species living on Earth
What is species richness:
The number of different species in a community
How do you measure index of diversity?
D / N(N-1)/Σn(n-1)
The greater the species richness and species evenness…
The higher the number (index of diversity)
Why is index of biodiversity a more useful measure of species diversity than species richness?
- As well as measuring the number of species, it also measures the number of individuals in a species (different proportions of species)
- So takes account for the fact that some species may be present in low/high numbers
What farming techniques that reduce biodiversity?
- Removal of woodland and hedgerows
- Monoculture e.g. replace natural meadows with one cereal crop
- Use of pesticides, herbicides and inorganic fertilisers
- Crops better competitors for resources e.g. light / nutrients