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Human Impact on the Environment - Endangered Species and Conservation…
Human Impact on the Environment - Endangered Species and Conservation
destruction of habitats + altering eco systems
agericulture
urban development
forestry
mining
pollution
Biodiversity Crisis
due to change in abiotic and biotic factors leading to extinction in some cases
Index
IUCN - International Union for the Conservation of Nature
Populations are assessed and given a code to indicate vulnerability
EX - Extinction
EW - Extinct in the Wild
CR - Critically Endangered
EN - Endangered
VU - vulnerable
NT - Near Threatened
LC - Least Consern
(DD - Data Deficient)
(NE - Not Evaluated)
Extinction
Natural process - recently it is the speed that is concerning - rate increased by human activity (in tropical areas by 1000 to 10000 times) - could be causing 6th mass extinction previous 5 by geological events
Reasons for extinction
Natural Selection
- occurs when individuals less suited to conditions reproduce less successfully. Human activities cause habitats to change faster that mutations needed for species to adapt and survive
Non-contiguous populations
- populations that are isolated so can't breed even if there is a large total number of species - lead to low genetic diversity
Loss of habitat
- deforestation, drainage of wetlands, hedgerow destruction
Overhunting
- trophy hunters, traditional medicines, overfishing
Competition from Introduced Species
- species are introduced to areas where they didn't evolve and without their natural predators e.g. grey squirrel + rats from ships ate dodo's eggs
Pollution
e.g. oil tanker accidents cause huge destruction
Floating oil prevents oxygenation of surface water
sticks birds feathers togethers
poisons shore dwelling animals
e.g. PCBs (polychlorinated biphenyls) banned but detected in wastewater near manufacturer (Cardiff)
ingested in food + act as neurotoxins, carcinogens
Conservation
The maintenance/planned preservation of the biosphere and enhancement of local biodiversity
Importance
ensures the conservation of existing gene pooles and prevents the loss of useful genes to the species and to man
e.g. genes for agriculture and horticulture - disease resistance, medical compounds
e.g. alleles that are advantageous to a species to adapt to environmental change
Economic
- provide resources that humans need e.g. rainforests provide drugs, clothes and foods
Social
- many ecosystems are enjoyed and used for activities e.g. birdwatching
Ethical
- organisms have a right to exist and humans have a moral responsibility to future generations
Strategies
Habitat Protection
- official designation of sites protects species by providing legal protection nd monitering of a habitat e.g. nature reserves, national parks, SAC's (special areas of conservation, SSSI (sites of special scientific interest)
International Cooperation Restricting Trade
- CITES (Convention of International Trade in Endangered Species) e.g. ivory +whaling
Gene Banks
- captive breeding programs by zoos (sperm banks) and botanic gardens (seed banks) and reintroduction programs e.g. Red Kites breeding pairs
Education
- WWF and Countryside Commission in the UK
Legislation
- prevent overgrazing, poaching, egg collection, picking wild flowers etc.
Ecotourism
- encouraged to help minimise effects of mass tourism + educate visitors about local environment + culture
Wild vs captivity
Wild (
In situ
)
Advantages
effective for species who have reached the point where they would not recover in the wild
Disadvantages
Small gene pool
Isolated so would not evolve with their environment - habitat may be gone even if species recovered
Captivity (
ex situ
)
Advantages
Bigger breeding population - higher biodiversity
Continue to evolve + adapt o their habitat
Disadvantages
Difficult to control illegal expoitation
if population is too small breeding may not take place