Extinction is the cessation of existence of a species.
- Species become extinct when they are no longer able to survive in changing conditions, against superior competition or unable to move to a new environment where they can survive.
- Extinction becomes a certainty when there are no surviving individuals that are able to reproduce and create a new generation.
- Humans can cause extinction of a species through overharvesting, pollution, habitat destruction, introduction of new predators & food competitors, overhunting, and other influences.
- Some of the species(maintained only in zoos or other artificial environments) are functionally extinct, as they are no longer part of their natural habitat and it is unlikely the species will ever be restored to the wild.
When possible, modern zoological institutions attempt to maintain a viable population for species preservation and possible future reintroduction to the wild through use of carefully planned breeding programs.
- A number of organizations, such as the Worldwide Fund for Nature, have been created with the goal of preserving species from extinction.
- Governments have attempted, through enacting laws, to avoid habitat destruction, agricultural over-harvesting, and pollution.
Nature preserves are created by governments as a means to provide continuing habitats to species crowded by human expansion.
-Advocacy groups, such as The Wildlands Project and the Alliance for Zero Extinctions, work to educate the public and pressure governments into action.
- While many human-caused extinctions have been accidental, humans have also engaged in the deliberate destruction of some species, such as dangerous viruses, and the extirpation of other problematic species has been suggested.
- However, people prioritize day-to-day survival over species conservation; with human overpopulation in tropical developing countries, there has been enormous pressure on forests due to subsistence agriculture (including slash-and-burn agricultural techniques that can reduce endangered species's habitats).
- If humans speed up the extinction rate over the next 50-100 years, it would take at least 5 million years for natural speciation to rebuild the biodiversity we are likely to destroy this century.
- The extinction of a species of plant could be accompanied by a ten- to thirty-fold loss among other organisms due to the interrelationships that occur in an ecosystem.
- Series of chain reactions is by far the most destructive process that can occur in any ecological community.
- If we wish to guarantee the survival of species whose fates we care about, we have to stop thinking about them in isolation from their environments.
- We need to educate the local population about the effects they are having on their wildlife and about how they can help to protect it and help it flourish again.
- Dave Tilman (a member of the National Academy of Sciences, the country's top scientific body, the author of four books and more than 140 scientific papers) argues saving the planet's biodiversity will require modifying human preferences for driving bigger vehicles, eating more meat and generally consuming more of everything around us.
http://en.wikipedia.org/wiki/Species_extinction
http://answers.yahoo.com/question/index?qid=20070416112405AADA9B2
http://answers.yahoo.com/question/index?qid=1005121502450
http://news.minnesota.publicradio.org/features/2005/01/31_olsond_biodiversity/
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