The largest extinction in Earth’s history marked the end of the Permian period, some 252 million years ago. Long before dinosaurs, our planet was populated with plants and animals that were mostly obliterated after a series of massive volcanic eruptions in Siberia. Fossils in ancient seafloor rocks show a thriving and diverse marine ecosystem, then a swath of corpses. Some 96 percent of marine species were wiped out during the “Great Dying,” followed by millions of years when life had to multiply and diversify once more.
Some 65 million years ago the greatest asteroid impact in a billion years may have sown life throughout the solar system, even as it ravaged life on Earth. Blasted debris escaped Earth’s gravitational force forming irregular orbits around the sun, eventually finding its way to the planets and moons of the solar system. Mars was eventually dusted with the debris and according to a 2013 study in the journal Astrobiology, the 14-kilometer-wide object ejected tens of thousands of pounds of impact rubble that may have landed on Saturn’s moon, Titan and on Europa and Callisto, which orbit Jupiter – all satellites that scientists believe harbor promising habitats for life. Mathematical models indicate that at least some of this debris still carried living microbes.
Fossils of a giant new species –the Tyrannosaurus rex of the Cambrian–a long-extinct group of sea creatures called trilobites have been found on Kangaroo Island, South Australia. Around 540 million years ago, the most important moment in the history of evolution, the Cambrian Explosion, the spectacular supernova of biology, detonated, and the world of animal life—creatures that move around and eat other organisms for a living—was born.
Scientists propose that a supernovae eight-million years ago created atmospheric ionization that triggered an enormous upsurge in cloud-to-ground lightning strikes, igniting forest fires around the globe. These infernos could be one reason ancestors of homo sapiens developed bipedalism—to adapt in savannas that replaced torched forests in northeast Africa leading proto-humans to walk on two legs, “eventually resulting in homo sapiens with hands free to build cathedrals, design rockets and snap iPhone selfies.”
There have been about 15,000 generation of human beings on our planet, and some 500,000 generations of cockroaches. Now we learn that the inglorious bedbug has been a parasitic companions with other species aside from humans for more than 100 million years, stalking their hosts at the same time as dinosaurs.
“The evolution of the planet and the life on it are intertwined. We can’t understand one without understanding the other,” says Caltech assistant professor of geology Claire Bucholz about a new study that provides fresh evidence for just how deep—literally—the strong connection is between the geology of Earth and the ocean life that flourishes on it.
