Travel back far enough in your genealogy, and you will run into a fish.

Before about 370 million years ago, our ancestors were scaly creatures that lived in the sea, swimming with fins and using gills to get oxygen from the water. And then, over the course of millions of years, they began moving ashore, adapting to the terrestrial realm. They became tetrapods, a lineage that would eventually produce today’s amphibians, reptiles, birds, and mammals. As scientists have unearthed fossils from those early days, one lesson has come through ever more loud and clear: the transition was not a single leap. Instead, it was drawn out and piecemeal. Continue reading “How We Got On Land, Bone by Bone” →

On Monday I wrote here about how scientists could retrace the history of evolutionary change in bacteria they raised in their lab by thawing out ancestors and comparing them to their descendants. That’s a much harder thing to pull off in the wild, but under the right conditions it can be done. Continue reading “After Seven Hundred Years, Crustaceans Rise Again to Show Us How We Steer Evolution” →

It’s hard to believe that Escherichia coli could have any secrets left.

For over a century, scientists have picked the microbe apart–sequencing its genes, cracking its genetic code, running experiments on its metabolism, earning Nobel Prizes off of it, and turning it into, arguably, the most-studied organism in history.

But as deep as scientists dive, they have yet to touch bottom. That’s in part because Escherichia coli is not fixed. It continues to evolve, and even in the most carefully controlled experiments, evolution leaves behind a complicated history. Continue reading “Evolution Hidden in Plain Sight” →