8 Facts That Show You're Part Fish, Reptile and Primate!

How did the human body become the complicated, quirky and amazing machine it is today? Find out in the new series, Your Inner Fish, based on the best-selling book by Neil Shubin. Premieres on PBS April 9th, at 10/9c. Join the conversation on Facebook and Twitter using #InnerFishPBS and get your picture added to this mosaic!

You're Part Fish, Make No [Back]Bones About It.

You may not think you have much in common with a fish, but Neil Shubin sees a family resemblance. Fish were the first creatures with bony skeletons, and they have backbones, just like humans.

One Bone, Two Bones, Little Bones, Fingers.

The skeleton of every vertebrate walking the Earth today has the fundamental pattern of one bone, two bones, little bones and fingers. Why is that the case? At some point in the distant past, we all had a common ancestor.

PhilanGEEZ, this is how fingers take shape.

Proteins made from a gene called "sonic hedgehog" send out a signal to shape the pattern of our digits. When the signal is strong, a pinky forms. And as it weakens -- one by one -- different fingers are made until we end up with five. When scientists turn down Sonic Hedgehog, fewer fingers are made. Increase it, and we would get extra fingers. Joe Hanson from It's Okay to Be Smart sat down with Neil Shubin to learn more.

Listen up! Mammal ear bones were reptile jaw bones.

This is the skull of the gray short-tailed opossum. When it's born, it only has one ear bone, just like a reptile. As the opossums grow, two more bones disconnect from the jaw, shrink and move up to become the three bones of the mammal ear. They go through 300 million years of evolution in the span of one lifetime!

Color Me Amazed!

The ability to see the world in color is one most people take for granted. But our earliest primate ancestors lacked this ability. When and how did we gain the ability to see the world the way we do? Neil Shubin pays a visit to vision expert Jay Neitz to learn where our color vision comes from.

This is quite possibly the cutest cousin we have.

In a sense, this squirrel monkey is a distant cousin of ours. We got the placement of our eyes, the shape of our skulls, and the ability to grasp things with our hands from our common ancestor. Thanks, inner monkey!

Lucy: the original runway model.

Meet Lucy, a 3.2-million-year-old ancestor of ours. Though she looks like an ape, her knees were close together, just like a human’s! That positioned her feet directly under her body and made walking easier.

Epic Tail Fail.

There’s a reason it hurts when you fall on your rear end! We all have something called a coccyx at the base of our spines. It’s a remnant from a time when our ancestors looked like monkeys, complete with tails. That thing can really hurt!

Learn more with Neil Shubin as he introduces us to Tiktaalik and your inner fish, reptile and primate.