Why types die out?the Last research of group of the American and Mexican scientists who declared that on our planet the sixth mass extinction of types began did a lot of noise. But when occurred what represented and in what the reasons previous to five?
Authors of work consider that from - for activity of the person the speed of extinction of vertebrata within last century was 100 times higher than usual. According to researchers, our influence was avoided by no uniform corner of the planet therefore under the threat existence of a third of all terrestrial corals, sharks and slopes, the fifth part of reptiles and a quarter of mammals. The earth can already lose them by the end of the current century.
The forecast is catastrophic, but studying of fossils shows that our planet saw times worse. However, they were not connected with activity of one certain type of terrestrial inhabitants.
That the world is threatened by the next wave of mass extinction researchers from University of California in Berkeley in 2011 for the first time came to a conclusion. Having analysed data on number of the disappeared types and speed of their disappearance, scientists came to a conclusion that to take measures and to stop approach of the next apocalypse not late.
For five periods of the mass extinctions which happened for the last half a billion years three quarters of all types died out. Of course, types constantly disappear also “in itself“, without the special reasons. However background indicators are much lower than peak.
The most known of the five of biological crises of the planet - so-called swept - paleogenovy extinction, happened about 65 - 66 million years ago. This period is known to inhabitants on mass disappearance of dinosaurs, and together with them cephalopods, the flying pterosaurs and large sea reptiles. At that time 70 - 80% of all types inhabiting Earth died. Collision of the planet with a comet with a diameter about 10 km or with an asteroid became the cause of accident, most likely. It is possible to challenge the space version of cataclysm, but unambiguous arguments against it, however, as well as for at anybody is not present.
Three quarters of types are, undoubtedly, it is a lot of. But earlier accident was even more mass. During great Perm extinction 95 - 97% of all terrestrial types died (251 - 252 million years ago).
Except listed, Earth endured three more mass extinctions: Triassic during which a half of all types died out 200 - 201 million years ago; Devonian (375 million years ago) when 50% of sea types died; ordoviksko - Silurian (444 million years ago), led 60% of types of sea invertebrates to disappearance.
Whatever were the reasons which caused them consequences of mass extinctions are always huge. So, the reef ecosystems which disappeared in Devon were restored throughout 100 million. years after that.
Researchers put forward various theories explaining why from time to time the incalculable quantity of types completely disappears. Usually among the reasons call climate changes, fluctuations of level of the seas, volcanic activity and extraterrestrial influences.
Some experts are inclined to consider mass extinctions as the inevitable periodic phenomena, perhaps, caused by our movement in the Universe. On one of theories of this sort Nemesis - the mysterious and still not found star - the dwarf, white, red or brown is guilty of everything. It is supposed that Nemesis - a star - the partner of our Sun who is from it at distance of 0,8 - 1,5 light years. The partner has a nasty character. Each 26 million years it, allegedly, throw away comets which serve as the reason of terrestrial disasters.
One more fantastic theory explains mass extinctions with galactic features. In the center of our Milky Way, most likely, there is a supermassive black hole. Rotating together with all Galaxy, the Solar system periodically rises above and falls below the plane of the main disk that causes changes in a stream of space radiation and increases probability of collision with comets.
Scientists from Yale university in 2014 published the views of the reasons of terrestrial cataclysms. They believe that the prime cause in mysterious dark matter. Its thin layer penetrates all disk of the Milky Way and makes the gravitational impact, sufficient on all space objects to break stable orbits of comets and to direct them towards Earth. As a result of influence of dark matter our planet each 35 million years (or about that) gets to the real cometary storm. However, traces any more - less regular space bombings are not revealed yet.
Unlike the previous five mass extinctions taking place far back in the past, the reasons of the sixth if it really approaches, are called in advance. This pollution of the nature caused by activity of the person, climatic changes and destruction of habitat of types.
Perhaps, not all is lost? Protect the nature!