600 Million-Year-Old Secret: How Your Eyes Evolved From a Tiny Sea Worm

• New research reveals the surprising evolution of vertebrate eyes from a single-eyed, worm-like ancestor 600 million years ago.
• Our ancient ancestor, a sedentary sea worm, initially lost its paired eyes, developing a single, primitive 'median eye' in the middle of its head.
• This median eye, unable to form clear images, could distinguish day from night and sense up/down, aiding survival in the deep ocean.
• As ancestors adopted an active lifestyle, two new eyes re-evolved from parts of this median eye, explaining the unique structure of human eyes.
• The pineal gland in our brain, which regulates sleep, is a remnant of this ancient median eye, connecting our sleep cycle to a 600-million-year-old ancestor.