Your Surprisingly Close Marine Relative

You share a closer evolutionary ancestor with a simple, stationary sea squirt than you do with almost any other invertebrate. Despite their blob-like appearance, these creatures are actually our closest living invertebrate cousins.

Tunicates belong to the same group as humans called chordates, which are animals that possess a nerve cord at some point in their lives. While adult tunicates look like rubbery sponges anchored to the seafloor, their larvae reveal a hidden truth. These tiny swimmers possess a primitive backbone called a notochord, which is the exact same structure that eventually develops into a human spine. It is a humbling reminder that complex vertebrate life emerged from humble, ocean-drifting roots.