All animals–from Corgis to Greenland sharks, from dog ticks to toucans to you–descend from a common ancestor. The fossil record of animals, which runs back over 600 million years, can help us travel back some of the way through animal evolution towards the origin of the kingdom. But those early rocks contain precious few remains of animals, and so fossils alone can’t tell us what our common animal ancestor looked like.

Scientists can add to their supply of clues by studying living animals. And it now looks as if some of the most important clues to how animals got their start come from a beautiful creature called the comb jelly. This video from the Monterey Bay Aquarium is a good introduction to their luminescent loveliness.

Continue reading “In Search of the First Animals” →

Evolution drives relentlessly forward, leaving behind a messy wake. One of the best places to survey its sloppy creativity is inside your nose.

When you smell a lily or a cigar or a jug of spoiled milk, you are grabbing their molecules out of an ocean of air. You have exposed nerve endings dangling deep inside your nostrils, each of which is studded with proteins called olfactory receptors. Each neuron is covered in one type of receptor, the shape of which allows it to grab tightly onto certain odor molecules and weakly to others, while letting many others drift by.

Continue reading “The Smell of Evolution” →

I can still remember back in 1997 being shocked that a team of scientists had managed to extract a few hundred bases of DNA from a 40,000 year old Neanderthal fossil. Neanderthal DNA! In the years that followed, scientists made huge advances in recovering ancient DNA, with the entire Neanderthal genome published in 2010. But for all that amazement, I had to learn to be resigned that scientists probably wouldn’t get human DNA older than about 100,000 years. Beyond that vintage, the DNA was just too busted up to be recoverable.

Wrong. Very wrong.

Continue reading “An Ancient, Mysterious Scrap of Human DNA” →