What Really Killed the Dinosaurs?

Squeaky the Squirrel

http://www.slate.com/articles/health_and_science/animal_forecast/2013/02/dinosaur_extinction_was_an_asteroid_the_only_cause_of_the_cretaceous_mass.html

Sixty-five million years ago, an asteroid killed the dinosaurs. Not that the ruling reptiles made it easy—Tyrannosaurus, Triceratops, and company didn’t stand in one place, stoically waiting for the inevitable. Rather, the six-mile-wide chunk of extraterrestrial rock struck the Earth with such force that it sparked a global firestorm followed by a thick dust shroud that slowly choked whatever life persisted through the first onslaught. A reign of more than 160 million years ended in just a few days or weeks, leaving behind a charred world open to exploitation by our shrewd mammalian forebears.



That’s a nice fairy tale. But it’s not accurate. It’s more of the “based on a true story” version of what really happened as the curtain fell on the Cretaceous.

Ancestor of All Placental Mammals Revealed

drunkmonkey

Horse Burgers?

Squeaky the Squirrel

drunkmonkey wrote: »

Horse Burgers?

Capt'n Midnight

Results suggest that the ancestor of all placental mammals evolved less than 400,000 years after the mass extinctions that wiped out the dinosaurs, the researchers report online today in Science. The hypothetical creature, not found in the fossil record but inferred from it, probably was a tree-climbing, insect-eating mammal that weighed between 6 and 245 grams—somewhere between a small shrew and a mid-sized rat. It was furry, had a long tail, gave birth to a single young, and had a complex brain with a large lobe for interpreting smells and a corpus callosum, the bundle of nerve fibers that connects the left and right hemispheres of the brain.

The period following the dinosaur die-offs could be considered a "big bang" of mammalian diversification, with species representing as many as 10 major groups of placentals appearing within a 200,000-year interval, O'Leary says.

Rafting across the Atlantic would have been easier when it wasn't as wide, also I'm guessing there were islands along the mid Atlantic ridge too.

There have been lots of explosions of evolution, one being the molluscs that lived in the Inland Sea that covered Hungry after the last Ice Age. Or the well know examples of the fish in the Rift Valley lakes.

The main back pressure to evoultion is a stable ecosystem with no empty niches to exploit ?