10.3. Species diversity and human activities Flashcards
What has the effort to provide enough food for the human population caused
A reduction in biodiversity
What is the index of diversity of a natural ecosystem
High due to complex communities with many individuals of a large number of different species
Why are agricultural ecosystems different to natural ecosystems
Because they are controlled by humans
What do farmers do within agricultural ecosystems
Select species of particular qualities that make them more productive
Why does the encouragement of selective growth reduce biodiversity
Because the number of species and genetic variety of the alleles they possess is reduced to the few that express the desired features
How is farming made economic
By adopting a large number of these desirable species
What is the impact on biodiversity from a large number of desirable species
Biodiversity is reduced because species have to compete for the remaining space. Many will not survive this type of competition and the biodiversity is reduced
What do farmers also use as a means of providing economic farming
Pesticides
Why are pesticides used
To destroy plants that aren’t of the select species because they compete for minerals, light, space and food.
What methods have increased food production
- Improved genetic variation of plants
- Greater use of chemical fertilisers and pesticides
- Greater use of biotechnology
What is the impact of using these methods to increase food production
Biodiversity is reduced
What direct practices have reduced species diversity
- Removal of hedgerows
- Filling in of ponds
- Over-grazing of land
What indirect practices have reduced species diversity
- Use of pesticides
- Use of inorganic fertilisers
- Absence of crop-rotation and lack of intercropping
What methods have been developed to combat the practices that reduce species diversity
- Using ORGANIC fertilisers, not inorganic
- Plant hedges rather than fences as field boundaries
- Maintain ponds
- Rotate crops sufficiently
- Maintain existing hedgerows in an A-shape
Why is the use of these methods to combat the practices that reduce species diversity not favourable to farmers
Because they make the production of food more expensive