Will we stand by and DENY the truth of our climate?
The Sixth Extinction: Sounds so much like scare tactics that politicians use or something you see on late night TV. Unfortunately, some of the great minds of our times are suggesting just such a thing. Scientists like Richard Leakey, of the first family of paleontology Leakeys, teamed up with Roger Lewin on a book of the same name.Leakey's Book Or Niles Aldredge and his permanent Displayl. Karen Lips, in her shocking and eye opening Essay showed how a simple frog could point the way. It is time to listen. The warnings are clear, we are losing species daily. Many Paleoarcheologists and anthropologists tell of the horror and poignant sadness of finding a handful of wonderful new species in Borneo, South America or Madagascar, only to find we are too late, and they are gone. Please help to stop this Sixth Extinction. We have to listen and participate, before it is too late....Jeff Darling
The five Mass Extinctions
End of Cretaceous
5)The most recent of the Five mass extinctions of Earth's history is The end of the Cretaceous. The K/T boundary, as it is known in Geological/ Paleontological circles, is marked by a thin layer of Iridium(an element usually found in space) that is in the same strata of rock everywhere in the world. The iridium is what originally tipped off scientists to the Impact event that many think sealed the fate of the Dinosaurs. This boundary marks the end of the Dinosaurs in the Geologic record.
4)The end of the Triassic. (J/T boundary) This one is mostly a mystery. As in all of the Mass Extinction Events, many species were lost. The Earth lost about 40% of all genera, 20% of all families. There are clues, but they range on both sides. In all likelihood the climate was hot after cold in at least one succession, maybe many. In any event, there is little evidence of new life forms coming about with any regularity. Needless to say, it doesn't sound like a great time to be alive.
3)The Permian Extinction (The Great Dying). This was the granddaddy of them all .This was the closest life has ever come to completely ending. The Earth lost 83% of all species in the Permian extinction. The oceans lost 96% of all its species. The land lost 70%. It is almost certain an event of this magnitude had more than one cause. We know the creation of the enormous Siberian Traps probably put a huge inflow of carbon dioxide into the atmosphere, enough to affect the stability of the climate. As the supercontinent Pangaea was just taking shape, it is a good bet that the changes in the ocean currents, with temperature changes and salinity events probably have their share in the causal event.
2)The Devonian Extinction Is thought to have more than one part to it. The marine die-offs and loss of coral-builders leads scientists to believe there was a cooling of the Ocean and coastal ares. The land plants had spread to most land areas by this time. This spread could have caused the opposite of what we see now. They could have put so much oxygen into the atmosphere and taken so much CO2 out, that they cooled the earth enough to have wreaked havoc before a balance was restored. Scientists think several things worked together to form this extinction. About Half of all species were still lost. We know that predators had emerged, along with the jawed fish. These forerunners to us all tell a lot of the story of life.
1)The Ordivician is the first Mass Extinction event, and as with all the Geologic Records , the farther back in the record the less to distinguish. There were no land animals yet. The extent of the Ordivician extinction, with over 100 Families extinguished, is probably due to the fact that when the ocean cooled, the tropical species had nowhere to run. Finding root causes is even harder. We know a great deal about how the plants and animals lived 445 Million Years Ago, and that is a lot.