Human Impact on the environment Flashcards
Endangered species
A species that due to a loss of a habitat or rapid decrease in population numbers is at risk of extinction.
When is a species described as extinct?
When all members of the species are dead.
Potential causes for the extinction of a species:
- Natural selection due to pressures
- Loss of habitat
- Pollution
- Over hunting by humans
- Introduction of new competitors
- Non-continuous populations.
Conservation
The maintenance of ecosystems and biodiversity through human action in order to preserve the Earth’s resources.
How can conservation be achieved?
- Protection of habitats.
- Protection of endangered species.
- International cooperation restricting trade
- Species reintroduction.
- Gene and sperm banks.
- Seed banks.
- Education (awareness campaigns)
- Ecotourism (recognises mass travel is harmful)
Why is the conservation of gene pools important?
- Many plant species are yet to be discovered and may contain chemicals that could be used in future medicines.
- Protection of potential future food sources.
- Some alleles may provided selective advantages, preventing extinction.
- Each species and its genes are precious.
Agricultural exploitation
The increase in efficiency and intensity of food production in order to meet growing demands.
Deforestation
The removal of trees from land which is subsequently used to grow crops or provide space for cattle.
Consequences of deforestation
- Loss of biodiversity
- Climate change
- Habitat loss
- Soil erosion
- Desertification
- Lowland flooding
What do managed forests involve?
Sustainable replanting and regeneration. Examples of methods include; coppicing, selective cutting and long rotation time.
Overfishing
The excessive fishing of an area at a rate which exceeds potential replenishment of the species.
What are the methods employed to regulate fishing?
- Using lines rather than nets.
- Regulating net size.
- Fishing quotas and exclusion zones.
- Avoiding overfishing species, fishing non-traditional species.
- Limiting fishing fleet sizes.
- Consumers choose to only eat fish with Marine Stewardship council certification.
- Fish farming
Fish farming
The breeding of fish commercially in enclosures for food to combat overfishing.
What are the problems with fish farming?
- Rapid spread of disease
- Escape of farmed fish: spread of disease to wild populations, larger so outcompete wild populations.
- Bioaccumulation of pesticides.
- Farmed fish contain high concentrations of toxic chemicals.
Sustainability
Using resources in a way that also maintains them for future generations.
