Life on earth combines an amazing 40 millions different species. Insects, animals and vegetation normally spread in areas where their morphology can deal with the climate and where they can better feed themselves. This is known as the ecological niche and it can be destabilized.
Some species have the ability to spread almost everywhere on earth, like ants, which can be found in extreme weather such as the tundra or the African desert. Rats are another example as they are able to feed on almost anything. In general, the species that have the capacity to branch out in their eating habits have a much better chance to survive.
Humans are the perfect example as they adapt easily to the environment and have a multiplicity of things from which to feed from. The ability to cook and eat all kinds of food has led the population to grow, as we know today.
However, not all species on Earth are able to spread out as much as humans, rats or ants. Some species are extremely dependant of their ecological niche and depend on just a few things to survive, like the panda for example, which feed mostly on bamboo. This animal because of its unique diet and is inability to reproduce quickly and massively, became the symbol of endangered species.
Some species have become extinct, meaning that all of their kind, up to the last one, died. In the history of our planet, 99.9% of all species got extinct. Many different causes can lead to the extinction of a species, like the change of an environment, a superior competitor, sterilization, diseases, hunting abuse and poaching. Consequently, since all living things are part of a food chain, extinction has a direct impact on the interaction between species and is a big problem for biodiversity. Today, 30 million species are interconnected.
Painting by Dave Todaro, http://nuvango.com/davetodaro
Extinction is a natural phenomenon that can be minor or massive. For instance, the disappearance of dinosaurs 65 million years ago was massive. Geologists can now count up to five phases of massive extinction in the history of the planet. Since the last one, the rate of lost species has been quite constant. However, extinction rate has jumped abnormally as human activity keeps growing.
The destruction of natural habitat and climate change are the main cause for the alarming extinction rate we have reached today, one which has gone up to 1000 times the normal rate of the past years. At this rhythm, the planet is on its way to lose almost one third of its species, at a pace never seen or reached before. A generation to come might be the next spectator of a sixth massive extinction on planet Earth.