Effects of human activities:
Extinction: The death of the last member of a species.
Endangered species: the population of teh species is so low, that likely risk of extinction.
Biodiversity: The number of variety of species to be found in the world, the differnet genes they contain and the variety of habitats in which they live.
Number of species falling? why?: Habitat destruction: clearing woodlan for building developments/ agricultre land, growing single cash crops: deforrestation, to grow oil palms. Over hunting: reduction in fish stocks in north sea. Use of insecticides: killing pests/ insects: also killing benifical insects and impact the food chain. Pollution: eg acid rain. Introduction: for foregn species to a new habitat, eg introduction of rats. Climate change due to global warming.
Reasons for conserving biodiversity:
Ecological reasons: Prevents disruption of food chains, eg: loss of plant species means loss of animals whihc feed on it. The more diverse a habitat is the more stable it is. Each species is dependent on other if one species is lost others will also be reduced.
Economic reasons: The gene pool should be conserved because some species: may have gene products whihc may prove to be useful, many medicines are produced by plants. Different plants and animals could be utilised for food, eg: different species of fish could become more popular.
Ethical reasons: Humans have a moral responsibility to stop the loss of biodiversity which is resulting from human activities. To preserve biodiversity for future generations, some tribal human groups are losing there tradioinal way of life.
Aesthetic reasons: observing beautiess of the natural world brings pleasure.
Reasons for conserving biodiversity in argricultur
Use of clones and selective breeding in agriculture reduces genetic diversity in cropm plants. If new diseases appear there is less liklihood of alleles whihc cod =e for resistance being present. Wild strains of plants have genetic resistance to disease and pests; these can be crossed with food crops to increase hardiness and yeilds. Different species offer a;ternaive food sources.
The consequences of climate chnage on biodiversity in agriculture: climate change will result in changes to temperature and rainfall. Certain crops will no longer be able to grwo. Domestic plants and animals have been seleceted to adapt to specific conditions, low genetic biodiversity. Some areas will become to arid for crops to grow. Soe areas which are now too cole for cultrivation may become warmer, more fertile. Low lying areas will become flooded as sea levels rise: salt marshes will disapear.