It starts with embryos, which go through the same early stages of development, regardless of the animal type. Light generates the image in our eyes, and it travels through the lens to be reflected by light-sensitive cells at the back of our eyes (or retinas). Then they search for sedimentary rocks, which are most likely to contain fossils. The Eusthenopteron has one bone and two bones, just like us! The parts (brain, heart, stomach, and so on) have different functions. Placozoa are sometimes found in aquarium tanks and appear similar to bacteria, but they have a cellular structure with specialized cells that resemble modern-day humans. From the Arctic Circle, to China, to Nova Scotia, Greenland and the American West Shubin was ready to pack his gear an go anywhere where he might be able to find more answers to the question that he was determined to have answered. 1) Sticking Together: Some of the earliest bodies were multi-celled creatures that lived in the seas 600 million years ago. Preface. Interactive exercises: apply the book's ideas to your own life with our educators' guidance. First, tiny buds protrude from the embryonic body, then the tips develop into paddles. Here’s an example of how descent with modifications works in a family of clowns (assuming in the example that clown features are heritable): Actual human traits can be traced the same way, although it’s more complicated because humans and animals typically change more than one trait with each... We can trace most ailments of modern life to the fact that our bodies were built to be active predators on the hunt for food, or gatherers and agriculturalists—yet today, most of us spend our days sitting. Search: The plunger goes up and down, moving around the gel in the snail-like structure. Copyright © 2020 Public Broadcasting Service (PBS), all rights reserved. Humans have all these same smell receptors as other mammals but some are rendered useless because we rely more on sight than smell. However, this chapter explains that while our ears are complex, parts evolved from simpler creatures: reptiles, fish, and sharks (remember gill arches?). Further research shows this gene exists in every limbed animal. Through Lucy, we trace our primate history; Tiktaalik tells us our history as fish. Keep reading with Blinkist Start your free Blinkist trial to get unlimited access to key ideas from Your Inner Fish and over 4,000 other nonfiction titles. It was modified over time for making different kinds of skin structures—scales, feathers, skin, and mammary glands. In 2004, on Ellesmere Island in the Arctic, Shubin’s team found a 375-million-year-old fossil fish with a neck, a flat head, and fins capable of propelling it on land, making the creature a key link in the evolutionary chain from fish to land animals. First, tiny buds protrude from the embryonic body, then the tips develop into paddles. However, in 2004, Shubin discovered his new species of Tiktaalik. Shubin begins by explaining the human body plan. Shubin explains that he first became interested in fossil finding by finding early mammalian tooth fossils as a child and it took him years to learn how to identify possible fossil sites in the field with help from his advisor Jenkins, expert fossil hunters Bill Amaral and Chuck Schaff, and finally his own research into mammal-like reptiles’ development into mammals. DNA contains the “recipe” that builds human or animal bodies from an egg. Search String: Summary | However, Charles Darwin argued the skeletal pattern meant that animals share a common ancestor. Scientists are researching and experimenting on DNA in order to discover why cells with all the same genetic code can differentiate themselves into different types of cells that perform different functions. Shortform summaries help you learn 10x faster by: Here's a preview of the rest of Shortform's Your Inner Fish summary: Shubin’s exploration of our primitive connections started in the Canadian Arctic, where he and colleagues discovered a key link in the chain from the earliest creatures to humans: a 375-million-year-old fossil fish,... Finding important clues to our human past in fossils seems improbable when you consider that: Nonetheless, for hundreds of years, scientists like Shubin have been uncovering fossils of worms and fish that, combined with clues from DNA studies, go a long way toward explaining the structure of our bodies. Humans have a very unique structure to their hands that is unlike any other land animals. Eventually, descendants of Tiktaalik probably moved out of water and became amphibians. - Mike Novacek, author of Terra: Our 100 Million Year Ecosystem and the Threats That Now Put It at Risk. The blocks are a platform holding the brain, with arteries and nerves running through it. You've just tried to add this show to My List. Unlock the full book summary of Your Inner Fish by signing up for Shortform. But where was the evidence? Click here and be the first to review this book! The book begins with the author remembering a fossil he saw in China. Mammalian teeth are far more complex than reptilian teeth. The hands of fish are also different from those of humans, but some fish have a simple structure similar to human’s hand. 240 pages First, through the function of teeth. A first generation of clowns has a mutation giving them a red nose. To form bodies, cells have to be able to: 1) attach to each other to create specific materials like bone, and 2) communicate with each other. Later, biologists found that the same gene exists in humans and mice. While fossils are sometimes stumbled upon accidentally by scientists and laypeople, their locations often can be predicted with surprising accuracy. The first two chapters of Your Inner Fish describe one of Shubin’s most important scientific contributions: the discovery of Tiktaalik, an ancient fish that lived around 375 million years ago. Using fossils, embryos and genes, he reveals how our bodies are the legacy of ancient fish, reptiles and primates — the ancestors you never knew were in your family tree. Animals as diverse as humans, fish, lizards, birds, amphibians, and mammals all have symmetrical bodies of the same design—with a front/back, top/bottom, and left/right, plus a head, spinal cord, and organs in specific places. Shubin proved that these same genes are active in sharks and skates as well; though fish have radically different limb-like structures than land animals like humans do. "Your Inner Fish" connects our limbs, necks and lungs to a fish with limbs that crawled onto land 375 million years ago. Many of the features in human cells can be found in primitive organisms such as placozoa. Although the human body is made up of hundreds of different kinds of cells, which make our bones, organs, nerves, and tissues function differently, all cells contain the same DNA. These mechanisms predated the various body plans and patterns we can trace back through DNA and fossils. This chapter explains how embryos develop key body structures. But first, we need you to sign in to PBS using one of the services below. He knew it existed. We can remove the first show in the list to add this one. The author takes us through a story about how he discovered the fossil of a fish that reframed the transition between fish and land animals. In the 1990s, scientists found genes that control smell in fish. Jaw bones and two ear bones—the malleus and incus—develop in the first arch, while the second arch forms “the third small ear bone (the stapes), a tiny throat bone, and most of the muscles that control facial expression”. Your Inner Fish: Chapter 1. It explains how we were able to smell with a single gene that corresponds to each odor we can detect. The inner workings of the human ear function like a Rube Goldberg machine. The first germ layer, ectoderm, creates structures on the outside of the body such as skin. The paddles contain millions of cells that ultimately become the limb’s skeleton, nerves, and muscles. Shubin also explains mitochondria, bacteria from another species that live within our cells today. There’s even a worm that has both kinds of eyes! In the fourth chapter, Shubin talks about how fossil records show that mammalian teeth have existed for millions of years.