A lot of talk recently about the danger of asteroids causing a mass extinction, but we have already had our fair share of catastrophic events here on Terra that have plagued life throughout the history of our world!
Sure there was the disaster that wiped out the dinosaurs 65 million years ago, and an even bigger one 250 million years ago, but as far as we know the granddaddy of them all was almost half a billion years ago during the Ordovician mass extinction.
This wiped out anything bigger than small bugs and simple celled organisms except one particular life form.
Sponges may be simple creatures, but they basically ruled the world a new study finds.
Roughly 95 percent of all species died in the Ordovician mass extinction, the first of the world's five known mass extinctions. (The other mass extinctions are the Late Devonian, End Permian, End Triassic and End Cretaceous.) However, while the Ordovician mass extinction wiped out many of these ancient creatures, one group actually prospered: sponges.And ours was not the only planet that was subjected to calamities of this magnitude!
"We think the sponges thrived because they can tolerate changes in temperature and low oxygen levels, while their food source (organic particles in the water) would have been increased enormously by the death and destruction all around them," lead study author Joe Botting, a paleontologist at Nanjing Institute of Geology and Paleontology in China, said in a statement.
Usually, mass extinctions decimate animal life, with the surviving ecosystems holding only small, stunted species that somehow managed to survive. In contrast, thousands of fossils indicate that the sponges in the Anji Biota were large and complex. Moreover, while some sponge species lived only in certain areas, others were so plentiful, they formed forests on the seafloor, the fossils show.
Mars and Venus were at one time much the same as our home here on Terra, with blue skies and oceans as well as lush green continents full of life.
Unfortunately Venus was destroyed through runaway climate change that boiled the planet and made it into a toxic, searing inferno, while Mars lost its protective magnetic shield when the planet's interior cooled enough to solidify..., and this burned away the atmosphere and killed everything on the surface.
Mater of fact, we can now say with a great degree of certainty that the "Red Planet" is entirely inhabited by robots, and nothing more!