4.6 Biodiveristy Within A Community Flashcards
What is biodiversity?
- Variety of living organisms (species, genetic and ecosystem diversity)
- can relate to a range of habitats, from a small local habitat to the Earth
What is a community?
All populations of different species that live in an area
What is species richness?
A measure of the number of different species in a community
What does an index of diversity do?
Describes the relationship between:
1. The number of species in a community (species richness).
2. The number of individuals in each species (population size).
Suggest what index of diversity is more useful than species richness
- Also takes into account number of individuals in each species
- So takes into account that some species may be present in small or high numbers
What is the formula for index of diversity?
D = N(N-1) / sum of n(n-1)
N = total number of organisms of all species
n = total number of organisms of each species
Describe how index of diversity values can be interpreted
- High –> many species present (high species richness) and species evenly represented
- Low –> habitat dominated by one/a few species
Explain how some farming techniques reduced biodiversity
- Removal of woodland and head rose, monoculture (growing one type of crop), use of herbicide to kill weeds
- Reduces variety of plant species, so few habitats and niche, less variety of food sources - Use of pesticides to kill pests- predator population of pest decreases
Explain the balance between conservation and farming
- Conservation required to increase biodiversity
- But when implemented on farms, yield can be reduced, reducing profit/income for farmers
- To offset loss, financial incentives/grants are offered
Give examples of how biodiversity can be increased in areas of agriculture
- re-introduction of field margins and rose, reduce use of pesticides, growing different crops in the same area, using crop rotation of nitrogen fixing crops instead of fertilisers
