human impact (finished) Flashcards
(57 cards)
what is extinction?
the loss of species and a decrease in biodiversity
what is an endangered species?
a species that is seriously at risk of extinction
what are the reasons for species becoming endangered due to human impact?
- destroying habitats
- pollution of the environment
- introduction of alien species to an ecosystem
- monoculture
- building roads, houses or factories
- unsustainable harvesting
what is conservation?
the principles and practise of the science of preventing species extinctions
why can alien species disrupt an ecosystem?
- they may out-compete native species for food and space
- they might have no natural predators to control the population
- may also carry diseases that affect native population
how is conservation achieved?
- habitat protection by nature reserves and SSSI
- international co-operation between governments and organisations
- restricting activities and passing legislations that threaten endangered species
- breeding programmes
- sperm banks and seed stores
- reintroduction programmes
- pollution control
what is the SSSI?
sites of special scientific interest
how are gene pools conserved in the wild?
rare breeds, frozen zoos and sperm/seed banks
how are gene pools conserved in captivity?
captive breeding programmes which ensure the diversity of the species by maintaining the genetic diversity of the stocks of captive animals
why is conservation so important?
some organisms may have alleles that are useful to humans
- our domestic animals and plants all have wild relatives that have useful alleles that could be bred back into the domestic varieties and confer
- many plants also have medicinal properties
why is it important that genetic diversity is maintained?
it is critical for species to survive changing environments as natural selection is dependent on variation in the species
what is agriculture?
the means of producing food for human consumption in order to meet demand.
how do agriculturalists meet the growing demand of human consumption?
- created larger fields by removing hedges
- cultivated monocultures
- increased their use of fertilisers and pesticide.
why are hedges so important for wildlife?
they are valuable habitats and contain some pest species and their predators.
- also allows mobile species to travel to different areas to disperse species and find mates.
what is the advantages of using monoculture crops?
- grow crops that are easy to harvest mechanically
- guaranteed to yield disease-free seeds
what is the disadvantages of using monocultures?
- if pest species invade, this will spread rapidly
- reduces biodiversity of the area
what is a gene pool?
the sum of all the alleles for all the genes in a population
what is an example of a reintroduction programme?
red kite programme in wales
what are 3 of the legislations passed for conservation?
- the protection of endangered species
- prevention of over-grazing/fishing, hunting, collecting birds eggs and picking wild flowers
- international co-operation restricting trade e.g. ivory, whaling
how do agriculturalists meet the growing demand of food production?
- creating larger fields by removing hedges
- cultivated monocultures
- increased use of fertilisers and pesticide
what is the issue with fertilisers?
can cause eutrophication of nearby water bodies as any excess will leach into rivers
issues with pesticides?
they harm beneficial species and pests, and can cause them to decline in numbers
consequences of deforestation
- loss of habitats and biodiversity
- soil erosion > removal of vegetation
- lowland flooding (leaf litter usually acts as a sponge to soak up heavy rainfall)
- climate change
- less photosynthesis
- combustion of trees
management techniques for sustainability (forestry)
- coppicing
- selective cutting
- long rotation time
- planting trees
- protected areas
