6.3 BIODIVERSITY
Biodiversity is the sum total of genetically based variety of all organisms in the biosphere. Ecosystem diversity includes the variety of habitats, communities, and ecological processes in the living world. Species diversity refers to the number of different species in the biosphere. Genetic diversity refers to the sum total of all the different forms of genetic information carried by all organisms living on Earth today. Biodiversity is one of Earth's greatest natural resouces. Species of many kinds have provided us with foods, industrial products, and medicines including painkiller, antibiotics, heart drugs, anti depressants, and anticancer drugs.
Humans activity can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environment. Extinction occurs when a species disappears from all part of its ranges. Endangered species is a species whose population size is declining in a way that places it in a danger of extinction. If a population of an endangered species declines, the species is more likely to become extinct.
Habitat fragmentation is a process in which development splits ecosystems into pieces. The result is the pieces of habitat become biological "islands". These islands are not surrounded by water but can also be surrounded by other habitats.
Pollution can threaten biodiversity. The most serious problems can occur when toxic compounds accumulate in the tissue of organisms. DDT is the first widely used pesticides, DDT can be drained into streams or rivers after being sprayed. The two factor that makes DDT dangerous in high doses is that it can not be broken by metabolic systems. Second is when DDT is picked up by other organisms, they can not be eliminate from their bodies. Biological magnification is when concentrations of harmful substance increase in organisms at higher trophic levels in food chain or food web. Biological magnification can effect an entire food web, but carnivores at the top of the food chain are at a higher risk. Humans throughout the history had hunted animals until extinction. Today, some endangered animals are protected but some are still hunted to extinction because some people want food, skin, and horns.
An important threat to biodiversity today is when harmless animals and plant are transported by humans to other places. Invasive species happens when animals or plants are introduced into new habitats where they will soon reproduce rapidly. They reproduce rapidly because there are now parasites or predators that can stop them in their new area or "home". These animals will then compete with native animals which could make native animals die off slowly.
Conservation is used to describe wise management of natural resources, including the preservation of habitats and wildlife. Today, conservation efforts focus on protecting entire ecosystems as well as single species. Protecting an ecosystem will ensure that the natural habitats and the interactions of many different species are preserved at the same time. Protecting species may be a problem, scientists and government now are doing there best on this topic, some of the ideas are making "hot spots" for endangered animals. Some of the conservation challenges are making regulations for fishing which can make financial hardships and many fishers will not agree. But if we don't take act now, resources may disappear forever.
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