3.6 - Human Impact Flashcards
What is the definition of an endangered species?
A species that due to a loss of habitat or rapid decrease in population numbers is at risk of extinction.
What is meant by extinction?
When all members of a species is dead, no chance of revival.
What are 6 causes of extinction?
- natural selection due to selection pressures
- loss of habitat
- pollution (eg oil)
- overhunting by humans
- introduction of new competitors
- non-contiguous populations
What are the 6 ways conservation can be achieved?
- protection of habitats (eg nature reserves)
- protection of endangered species (eg hunting laws)
- international co-operation (restricting trade)
- species re-introduction
- gene and sperm banks
- seedbanka
What is meant by the term ‘conservation’?
Maintenance of ecosystems and biodiversity by humans in order to preserve the earths resources
Why is it important to conserve gene pools? (4 reasons)
- plant species used for future medicine
- protection of future food sources
- alleles may provide selective advantages
- each species and its genes are morally precious
What is meant by the term ‘agricultural exploitation’?
The increase in efficency and intensity of food production in order to meet growing demands
What is meant by ‘deforestion’?
The removal of trees from land which is subsequently used for growing crops or to provide space for cattle.
What are the consequences of deforestion?
- loss of biodiversity
- climate change
- habitat loss
- soil erosion
- desertification
- lowland flooding
What is meant by the term ‘overfishing’?
The excessive fishing of an area at a rate in which exceeds potential replenishment of the species.
What are 6 methods that are employed to regulate fishing?
- using lines rather than nets
- regulating netsize (reduce bycatch)
- fishing quotas and exclusion zones
- avoiding overfished species, fishing non traditional species
- limiting fishing fleetsizes
- marine stewardship council certification
- fishfarming
What is meant by the term ‘fishfarming’?
The breeding of fish commercially in enclosures for food to combat overfishing.
What are the problems associated with fishfarming?
- rapid spread of disease
- escape of farmed fish (spreading disease to wild populations, larger fish can outcompete wild populations)
- bioaccumulations of pesticides
- farmed fish contain high concentrations of toxic chemicals
What 2 strategies are used to manage forests and what 3 processes are common practice?
Replanting and regeneration
- coppicing
- selective cutting
- long rotation time
What is the meant by the term ‘sustainability’?
Using resources in a way that also maintains them for future generations.
