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lord of the files Science 10 ecology project ① Extinction of species  A species becomes extinct when its last representative dies.  Extinction is forever - Once a species become extinct will never been seen again.  This has happened quite a lot of times on Earth.  Due, in many cases, to colonization and hunting by humans.  People feel that extinction is very sad, and try to protect life-forms on the brink of extinction by naming them "endangered species" and being nice to them.  Each living organism which humans force into extinction is a tragedy for nature.  Over fishing or excessive hunting by humans can reduce the populations of certain organisms on Earth.  Animals are hunted for their fur, meat or other valuable parts of their bodies. http://www.galactic-guide.com/articles/2R84.html http://www.saburchill.com/hfns02/chapters/chap019.html 1. lost of habitat  Sometimes human activities destroy the habitats of living organisms. The habitat of an organism is its home: where it lives, feeds, and reproduces.  Many species have become extinct because humans have destroyed or modified their habitats, polluted their environment  Human influences on the environment can be considered as being influences on the habitats of living organisms.  Any time humans alter the hydrosphere, lithosphere, atmosphere or biosphere, habitats are modified  Survival can become more challenging (or even impossible) for the organisms which live there.  When hunters miss their target, the lead shot which comes out of the gun is left behind in nature. Lead is a toxic metal.  The main component of a panda's diet is bamboo. Bamboo forests have been cut down by humans for centuries. http://www.saburchill.com/hfns02/chapters/chap020.html http://www.saburchill.com/hfns02/chapters/chap021.html 2. lost of biodiversity  This collection of vastly varied living organisms is our planet's biodiversity.  The richest parts of the planet's biodiversity are also the least well-known. It is estimated that 97% of all species on Earth live in the oceans below the zone where sunlight penetrates the water.  On the continents, it is estimated that 50% of all land-dwelling species live in tropical rainforests.  Throughout the history of the Earth, as new species evolve, other species become extinct. Overall, as time has progressed, there are more and more different kinds of organisms.  Human activities today are exterminating species up to 10 times faster than they would naturally disappear.  As the numbers of people increase, the numbers of species decrease.  http://www.saburchill.com/hfns02/chapters/chap024f.html 3. Introduction of exotic species  Humans have helped to spread many species across the world.  More often, however, species are introduced accidentally and have a negative impact.  Plant species used in agriculture, for example, have been deliberately introduced to new areas by humans.  Sometimes wild animals are introduced for hunting as a sport.