Chapter 35 - Human Influence on then Environment Flashcards
Name 5 ways in which modern technology has been utilised to increase food production
- Mechanical methods (Machinery)
- Use of fertilisers increases crop yield
- Pesticides prevent destruction of crops
- Genetic engineering produce organisms resilient to disease
- Development of chemistry and processing techniques processes once-useless byproducts
Define deforestation
The removal of large numbers of trees and forests
Suggest causes for deforestation
- People wants to use the land for agriculture and urban use
- Uncontrolled fires
- Firewood
- Construction material
- Furniture and wood carvings
- Overgrazing
- Hunters burn trees to chase out animals
Describe the effects of deforestation
- More soil erosion
- Flooding
- Leaching causes infertile soil
- Less photosynthesis results in global warming and less rain
- Less rain (less transpiration)
- Destruction of habitats
- Extinction of species
- Extinct species means the loss of a medicine source
- Disruption of food chains and webs
- More pollution
- Less tourism (less income)
Describe a fertiliser
Concentrated source of plant nutrients in chemical or organic form. Fertilisers increase plant growth and crop yield. Fertilisers are also used where plants show nutrient deficiency
Describe the effects of the over use of fertilisers on the environment
- Leaching
- Algae bloom
- Algae block out light
- Eutrophication
- Aquatic plants die
- Decomposers use up oxygen
- Other species die or migrate
Name 4 alternatives to using industrially produced fertilisers
- Nitrogen fixing crops (Legume plants)
- Crop rotation
- Organic fertilisers
- Green manure
Describe the responsible use of fertilisers
Apply the correct amount, never apply when rain is in forecast, never spray near water sources and never spray on open fields
Name 5 advantages of crop rotation
- Improve yield
- Improve soil structure
- Less diseases
- Less pesticides required
- No leaching
Suggest one reason for which a farmer would replace industrial fertilisers with organic fertilisers
Less expensive and uses already availible materials
Define a pesticide
A chemical compound used to kill pests
Describe the negative effects of pesticides on the environment
- Pesticides are non-biodegradable
- Bioaccumilation, meaning pesticides become part of living organisms
- Biomagnification, which means pesticides become more concentrated along the food chain
- High concentrations of pesticides cause serious harm to animals and humans
- Wide-spectrum pesticides kill many organisms and not only pests
- Usefull organisms like pollinators can be killed
- Too much pesticides can cause pests to develop resistance to pesticides
Name two ways in which damage caused to the environment by pesticides can be reduced
- Fewer pesticides
- More specific pesticides
Describe biological control
The use of one species to control another. Control pests by using their natural enemies to disrupt their breeding cycle and reduce the pest’s numbers. The control organism must become part of the food chain and not a pest itself. The enemy must be very specific
Name three advantages of biological control
- Natural enemy only attacks pest
- Pest cannot become resistant
- Alternative to pesticides
