We are a really big comet
Last edited Tue Jun 26, 2012, 02:43 PM - Edit history (1)
In the geological/palentological record there's little difference between ten years and ten thousand years... both appear to be geological instants.
If mankind died out and alien researchers arrived here a billion years later they would be going through the fossil record and noting a series of mass extinctions. Okay, here's some geothermal event... and here's so climatological catastrophe having to do with the changing composition of the atmosphere... and here's a big comet strike... and here's another big comet strike, and there go the dinosaurs... and here's the sudden extinction of almost all the large mammals... hmmmm.... but where's the crater?
The rise of Homo Sapiens was a mass-extinction event similar to the end of the dinosaurs. Not the end of life, but the speedy disappearance of most large animals in the fossil record.
And we didn't need industry to do it. Most of the big animal extinctions were accomplished with stone implements. We were an absolute terror! (And not just us. Pre-sapiens hominids did a lot of damage too.)
The larger the animal the longer the gestation period and lower the population... and the less evolved fear of relatively small animals like us. Big animals are easy extinction targets. Monkeys had never been a threat for millions of years, and then in the blink of an eye they are suddenly going around on two feet setting coordinated wildfires to panic your herd into running off a cliff!
There are various theories about some of the decline of large mammals, of course. There are surely some climatological contributions but the climate has always been doing something or another, and we don't see these kind of losses all the time. One way or another most of them went away in the last million years at the same time a new natural enemy was arising. Seems unlikely to be coincidence, but either way, whatever the cause, we are in the midst of a geological mass-extinction event that will jump out in the fossil record as a sudden calamity.
It did take some semi-modern technology to get at the large mammals in the ocean. From the perspective of a billion years from now it will appear that a pandemic virus must have struck whales. Their population collapses in the blink of an eye. And that sudden and global effect wasn't due to our most modern technology. It was accomplished by people in wooden boats throwing sharp pieces of metal at whales! (If we had evolved whaling over a million years whales would have evolved a diferent attitude toward ships, but it was way too sudden. I suspect that is why there are more huge mammals in Africa than in the Americas. Evolving alongside humans is different from having them suddenly rush across the Bering land bridge with fire and spears. People could probably walk right up to giant mammals in the Americas.)
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