Image credit: R.B. Pedersen/Centre for Geobiology, Bergen, Norway
By Nell Greenfieldboyce
Scientists have discovered a group of microbes at the bottom of the Atlantic Ocean that could provide new clues to how life went from being simple to complex.
There’s good evidence that life appeared soon after our planet formed — some 4.5 billion years ago — but the Earth wasn’t very hospitable. “The microbes that lived back then had to cope with completely different conditions,” says Thijs Ettema, a biologist at Uppsala University in Sweden. The life forms that eked out a living were bacteria, plus another group of microbes called the archaea.
“These are, typically, very small cells that look very simple,” Ettema says.
Then, starting about 2 billion years ago, much more fancy cells appeared — the kind of cells in your body and in all plants and animals.
These cells are larger, and their genetic material is wrapped inside a nucleus. Plus, they’ve got all kinds of little organs, like energy-producing mitochondria. In these cells, Ettema says, there’s just a whole lot of complicated business going on.
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