Skip to main content

First Ever Bilaterian Discovered

Humans, it’s been said, are like donuts. They have an opening at each end, and a single continuous hole running through their middle. (Note: This theory has yet to appear in a peer-reviewed journal.)

It’s a crude simplification of our species, sure, but look far enough back on the animal family tree and you’ll find an ancestor organism that’s little more than a digestive tract with some meat wrapped around it. Limbless and hungry like a sentient macaroni, this ancient creepy-crawler was the first bilaterian — an organism with two symmetrical sides, a distinct front and back end, and a continuous gut connecting them.

While bilaterians run rampant today (insects, humans and most other animals among them), the identity of that progenitor organism has long eluded discovery. Now, researchers believe they’ve found it in the fossil record for the first time.

In a study published March 23 in the journal Proceedings of the National Academy of Sciences, a team of scientists analyzed a chunk of rock containing an ancient undersea burrow found deep below Australia. They found several fossil organisms preserved near the burrows, each creature about the size and shape of a grain of rice and dating to roughly 555 million years ago.

Comments

Popular Posts

Too Cold To Handle: The Science Behind Brain Freeze

When you eat ice cream or something cold, you will probably experience brain freeze. It happens when you gulp a cold substance too quickly for your brain to cope with. Brain freeze is a way of telling your body to slow down and take it easy. It doesn’t feel particularly nice, but at least it works. Here’s how it happens: when you slurp up a really cold drink or eat ice cream too fast you are rapidly changing the temperature in the back of your throat, which feeds blood to the brain.  The brain can’t actually feel pain despite its many sensors, but actually brain freeze occurs on the outer layer of brain tissue, where the throat meets. When the cold hits, it causes a strange feeling which is what causes the pain you feel when you get brain freeze.