Populations and Sustainability 6.3.2 Flashcards
factors that determine the size of a population
Limiting
- abiotic
- temp
- light
- pH
- water availab.
- biotic
- predators
- disease
- competition
Migration
- immigration
- emigration
carrying capacity
the max population size that an environment can support
pop size remains relatively stable, births ≈ deaths
density independent factors
factors that have an effect on the whole population regardless of its size
eg. earthquakes, fires
interspecific competition
competition between different species for the same resource
results in reduction of resource available to both species, and one species going extinct (competitive exclusion principle)
intraspecific competition
competition between individuals of the same species
results in fluctuations in the no. organisms present in a particular pop. around the carrying capacity
competitive exclusion principle
if two species are competing for the same finite resource, the less well adapted species is likely to be outcompeted
what’s the difference between conservation and preservation?
conservation involves human action to help maintain biodiversity, while preservation restricts or bans human interferance
conservation
maintenance of biodiversity through human action or management so that the natural resources in them can be used without running out
includes ecosystem management and reclamation
dynamic
preservation
protection of an area by restricting or banning human interference, to keep the ecosystem in its original state
why is conservation important?
Economic
- ecosystems provide lots of valuable resources eg. rainforests provide medicines, clothes, and food which can be traded locally and globally
Social
- aesthetic reasons, relaxation and exercise
Ethical
- all organisms have the right to exist, not our choice to decide if they live or die
- moral responsibility to future generations
coppicing
tree trunk is cut close to the ground, and new shoots form from cut
rotational coppicing
woodland is divided into sections and trees are only cut in a section until all have been coppiced. then you move to another section while the trees groow
maintains biodiversity as the trees never grow enough to block out light, so succession does not occur
pollarding
tree trunk is cut higher up that in coppicing so deer and other animals can’t eat the shoots
how can companies make sure large scale timber felling is sustainable?
- selective cutting (only removing largest trees)
- replanting
- plant far apart to reduce competition
- manage pests and pathogens
- leave areas of forest for indigenous ppl
how is sustainable fishing done?
- Common Fisheries Policy (EU) puts limits on no. fish that can be caught in diff areas
- nets with diff mesh sizes to allow young fish to escape
- limit to certain times of year
- fish farming
How is the Masai Mara managed to balance the conflict between conservation/preservation and human needs?
Traditional grazing and cultivation has led to removal of vegetation and increased soil erosion = reliance on fertilisers
Masai people being encouraged to make money from Ecotourism which supports conservation and local communities
Poaching has also been discouraged (laws, deterrents), saving black rhino
How is the Terai region of Nepal managed to balance the conflict between conservation/preservation and human needs?
Large areas of forest have been cleared, which increases the effects of monsoon flooding and damages wildlife
- improved irrigation
- growth of nitrogen fixing crop to improve soil quality
- provide ppl with solar heaters to reduce reliance on wood for fuel
How are peat bogs managed to balance the conflict between conservation/preservation and human needs?
Bogs are very acidic and water logged (anaerobic). They act as carbon sinks and are home to many different plants (lots of Sphagnum moss). Also help control floods.
Peat is used as a fuel which releases CO2 and damages ecosystems. Also used by farmers to improve soil acidity.
- ditches to allow water run off
- removal of seedling trees from area
- controlled grazing
the effects of human activities on the Galapagos Islands
- giant tortoise was hunted to extinction for food
- non-native plants and animals have been introduced which have affected native species
- fishing has affected sea life
- tourism has led to development, which has damaged the ecosystem
- eradication has removed non-native species like wild dogs
- marine protected area established around the islands which puts limits on fishing
- you cannot visit the islands without a lisensed guide
the effects of human activities on Antarctica
- seal hunting
- sewage dumping
- fishing
- oil spills
- The Antarctic Treaty
- commercial whaling and seal hunting banned
- limits on fishing
- all waste taken away by ship for disposal abroad
- tourist restrictions
the effects of human activities on Snowdonia and the Lake District
- footpath erosion from tourism
- vegetation is trampled
- water pollution
- conservation charities undergo repair work
- walkers told to not take shortcuts which increase erosion
- improved sewage treatment
explain why the reintroduction of wolves into the yellowstone national park is an eg. of conservation (2)
1 restoring the ecosystem (to its original form) or maintains biodiversity ; 2 helps the (global) wolf population ; 3 active / dynamic / sustainable, management / maintenance ; 4 prevents over-population by the elk ; 5 prevents over-grazing or damage to, habitat / ecosystem ;