Neil Shubin Your Inner Fish Summary

Part II Inner Fish Interactive Video Summaries

Episode 1 – Your Inner Fish

Neil Shubin, fish paleontologist, believes the history of humans, and all other living creatures, begins with fish. Neil Shubin says the roadmaps to our own bodies can be seen in all other creatures, in particular, fish because of the shared ancestry. Even though humans don’t appear to look like fish, with a deeper look, Neil Shubin describes the similarities. He describes the underlying theme found in bones and skeletons in all creatures: one bone, two bones, a lot of bones, and then the digits. Shubin researches these connections by looking for fossils in Pennsylvania based on particular times in history. Both fish and human embryos have a head, a body, a tail,

and much more. Shubin sees this in his research on embryos. He also studies gill arches, which are found in both humans and fish. In the video, Shubin meets with a woman who actually does have a gill, like a fish, because of the development of her gill arches. A 12-week fetus, like a fish, has gonads in the top of their body and eventually drops to where they are on humans, which can lead to hernias. The Sonic hedgehog gene was discovered, with the help of chicken embryos and fruit flies, and showed a connection in digits found in limbs and fins. Hedgehog tells different cells to do different things in a particular order based on its closeness to the signal. When hedgehog is increased, extra digits (fingers) are created. Shubin discovers Tiktaalik in 2004 and this flat-headed fish with lungs and a neck is a major connector in the evolution of fish into humans via its hand.

Episode 2 – Your Inner Reptile
Neil Shubin says human’s skin, hair, teeth, and hearing can all be traced back to reptiles that were shaped by transitions in life and these transitions help shape humans today.

In Nova Scotia, Shubin finds a reptile, tritheledont, with an upper jaw containing a canine tooth and smaller teeth behind it making it part reptile part mammal. In early development of humans, we have a yolk sack, which is a remnant from the time when our ancestors laid eggs. Reptiles must evolve to have their eggs not dried out since they are not laid in water; they have fluid filled sacks, with an amnion, also found in human embryos. Ancestors eventually stop relying on yolk to feed their embryos. Our ancestors, reptiles, had to fight for food and territory when moving into land fully (eggs no longer laid in water like amphibians). Paleontologists find “mammal-life reptiles.” Teeth of fossils can tell so much about an animal of the past: what it ate, how they ate, who was prey, who was predator, and more. The elongation of the canine found in these reptile fossils is still found in mammals. Holes found in reptile fossils suggest whiskers, which can be found on cats and dogs, but no evidence of hair anywhere else, making it a split between reptiles and mammals. Many common features are found in the skin of reptiles and mammals too, for example the bearded dragon. Mammals inherit the genes, or the manufacturing process to build tissues, such as the skin. Lastly, reptiles give mammals a wide range

of hearing using the three parts of the ear. Hadrocodium, regarded as one of the first mammals, is a skull fossil that links all mammals to their origin. This fossil has teeth with cusps like other mammals and a lower jaw just like modern mammals. This suggests that the reptile jawbone has become part of the ear.

Episode 3 – Your Inner Monkey
Human’s shape of our hands, our color vision, the structure of our brain, and the way we walk are all connected to monkeys.

The coccyx, found in humans, is a remnant of tail left over from our monkey ancestors. Just looking at a monkey, you can see the relation to humans: their nails and the way they grasp objects with their hands. Monkeys are primates just like humans are. We did no evolve from the modern monkey, but we have a common ancestor with monkeys existing today. Before 23 million years ago, monkeys were colorblind. Three opsins are required to see full range of light. If only two are present, this animal would be colorblind. Unlike monkeys, humans stand up on two feet. Neil Shubin looks at bones of an ancient monkey that walked on two legs (it is bipedal). This monkey, Lucy, is bipedal, yet primitive and not human. Lucy tells us when our ancestors began walking on two legs, around 4.4 million years ago. The fossil Ardipithecus tells us why our ancestors began walking on two legs. Ardi’s feet she walked on had a big toe that could grasp. Shubin believes Ardi disproves the past theory that mammals began walking on two feet with climate change because she walked on two feet before climate change millions of years ago. With the study of fossils, scientists find the human back goes wrong a lot. Bad backs of humans are connected to our monkey ancestors. The architecture of the brains of fish and humans are found to be very parallel structures, too. Both human and shark

brains have a forebrain, a midbrain, and a hindbrain. The human brain is even similar to the very primitive amphioxus in the way of genes.

Part III It’s A Fishapod! Article
The article begins talking about Neil Shubin, a fish paleontologist. Neil Shubin was inspired at a young age by fossils and books. Through fossils and books Shubin and other colleagues are able to find a fossil called tritheledont, which is a transition animals between reptiles and humans. Shubin and his graduate student, Ted Daeschler, embark on many trips to look for fossils that connect humans to the past and in these trips (on a roadside) they find “a fish with fingers” (they find a fish fossil that has fins but these fins contain bones). They then find that this fish has the one bone, two bone, and then digits like the universal mammal today. The next trip for Shubin and Daeschler is Melville Island in the Arctic in search for Devonian deposits. Arctic terrain is very hard to work in and relatively expensive so the partners follow a paper written by two scientists who went to the Arctic in search for Devonian fossils over a four year time period. Melville Island is a desolate island, west of Ellesmere Island, with only 200 inhabitants and the trip served unsuccessful. Even though Melville Island was a bust, they try Ellesmere Island next. Here Jason Downs, one of Neil’s colleagues, discovered fossils of lungfish and placoderms. Later on in the trip they also find a flat-headed animal with scales, which was later named Tiktaalik. Three specimens were found, plastered, and sent back to the lab. This fish does not have a cone-head, but a flat one, like a crocodile) that connected to the body with a neck (something fish do not have). Lastly, this fish has bones that corresponded to the upper arm, the forearm, and the wrist; this fish could do pushups. Tiktaalik is part fish, part tetra-pod making it a fishapod. Tiktaalik is known as a major insight of history; it draws a link between fish and mammal or the shift from water-living creatures to land-living creatures.