The evolution of a head has been traced back surprisingly far back our ancestral line

[Still Waters]

What's in a head? According to new research, a little bit of our ancestors' tails.

In the early days of complex, multicellular life on Earth, animals started out without any spines or brains. They only had a network of neurons spread throughout their body. Over the course of millions of years, however, that system somehow became concentrated on one end. But how?

Tunicates, or 'sea squirts', are the closest living relatives of vertebrates, and they don't have a true head.

https://www.sciencealert.com/the-evolution-of-the-head-has-been-traced-back-to-our-closest-blob-like-ancestors

The study was published in Nature.

https://www.nature.com/articles/s41586-022-04742-w#Sec5