Neil Shubin, a world-renowned paleontologist who surprised the academic world with the discovery of the legged fish 'Tiktaalik', traces the history of the human body from the bodies of seemingly unrelated creatures such as fish, flies, and bacteria.
The ultimate question pursued by biology and evolution is how the human body was created and why it is shaped this way.
Because, along with the genuine desire to discover our own identity, the answers can reveal why our bodies break down in certain ways.


This book unravels the mystery of human evolution through the fossil of a footed fish discovered on Ellesmere Island in the Arctic in 2004.
The author suggests two paths to find the answer: 'Fossils and Paleontology' and 'DNA and Evolutionary Developmental Biology'. By examining fossils and DNA, he cites various pieces of evidence and reveals that the anatomical structures of our bodies, fish, reptiles, and other creatures are surprisingly similar.
That is, it proves that human hands resemble fish fins, the human head is organized like the head of a long-extinct jawless fish, and the human genome functions similarly to the genome of bacteria.

Life has existed on Earth for 3.5 billion years, and this long and fascinating history is embedded in the structure of our bodies.
Neil Shubin, who claims that "humans are upgraded fish," presents a fascinating account of the evolutionary journey from single-celled to multi-cellular and from water to land in this book.

Find the fish inside me
There is no field guide to Arctic paleontology.
Friends and colleagues recommended all sorts of gear, and we read a lot of reference books, but we felt completely unprepared for the experience ahead.
The moment I realized this most painfully was when the helicopter first landed us in some remote part of the Arctic.
The first thing that came to mind was a polar bear.
And countless times I looked around, watching for any movement of a whitish speck.
When you suffer from anxiety, you start seeing hallucinations.
During the first week of work in the Arctic, one of the expedition members noticed a white blob moving around.
It seemed like there was a polar bear 0.4 kilometers away.
We scrambled to grab our guns, flares, and whistles like some silly cops from a 1920s silent movie, but on closer inspection, we realized the bear was a white Arctic hare, standing about 20 feet away.
In the North Pole, there are no trees or houses to judge distance, so you lose your sense of perspective.
The Arctic is a vast and empty space.
The rocks we were interested in were exposed for a whopping 1,500 kilometers.
On the other hand, the creature we were looking for was about 1.2 meters long.
Somehow, I had to pinpoint the small lump of rock that would preserve the fossil.
The people who review research grant applications are incredibly picky, so they bring up these difficulties like ghosts.
A committee member who previously reviewed Parish's Arctic expedition grant application made a striking statement:
To paraphrase the judges' comments (which, let's face it, were not very positive), the odds of finding new fossils in the Arctic are "lower than finding a needle in a haystack."
We only found our needle after exploring Ellesmere Island four times over six years.
That's what luck is.

Pages 38-39

A single pattern that makes up the hand and arm
There is a certain pattern to the human arm skeleton.
That is, there is one bone in the upper arm, two bones in the forearm, and nine small bones in the wrist, from which five branches extend to form the fingers.
The arrangement of human leg bones is similar to this.
One bone, two bones, several round bones, five toes.
Owen compared this pattern to various animal skeletons around the world and discovered something surprising.
He did not focus on the differences that make the various skeletons different from each other.
That was Owen's genius.
Owen discovered surprising similarities between creatures as disparate as frogs and humans, and he preached this fact in lectures and books.
The limbs of all living things follow a common design.
It doesn't matter whether the limbs are wings, webbed feet, or hands.
First, there is one bone, such as the humerus in the arm or the femur in the thigh, then two bones are connected to it by joints, then several small, round bones are attached to it, and finally, the fingers or toes are connected.
This pattern underlies the structure of all limbs.
Want to make bat wings? Just stretch your fingers out really long.
Want to make a horse? Just lengthen the middle finger and toes and shorten or eliminate the rest.
So what about frog legs? Just take the leg bones, stretch them, and then fuse them together into a single mass.
Differences between living things lie in the shape and size of their bones, and in the number of round bones or fingers and toes.
Although the shape and function of the limbs may be drastically different, the underlying blueprint is always the same.
Pages 57-58

There are teeth everywhere
If teeth had never developed in the first place, there would never have been scales, feathers, or breasts.
This is because the tools used to create skin structures are modified versions of teeth-forming tools.
Teeth, feathers, and breasts may seem like unrelated organs, but in a deep sense, they are intertwined in a single history.
So far, we have discussed the topic of how to track a single organ in various organisms.
Chapter 1 discusses how we can find deformed versions of human organs in ancient rocks and even predict such excavations.
Chapter 2 discussed the existence of similar bones in all animals, from fish to humans.
In Chapter 3, we discussed that the genetic recipes that direct organ formation among the DNA passed down from organism to offspring are generally similar regardless of the type of organism.
In Chapter 4, we saw that there is a consistent theme that runs through teeth, mammary glands, and feathers.
The biological processes that create different organs are actually variations of one process.
Given the profound similarities between various organs and bodies, the various creatures of the world are merely variations on a single theme.

Page 132

The origin of the human head
There is one more thing that humans and these little bugs have in common.
It's the gill palace.
Each arch corresponds to a small cartilaginous ridge, and like the cartilage that forms part of the human jaw, ear bones, and larynx, the cartilaginous ridges of crucian cartilages support the gill slits.
So, the essence of the human head can be traced back to that of an insect.
And that too, as a headless bug.

Page 154

Conditions for becoming a body
When our distant ancestors evolved from single-celled organisms to become living organisms with bodies, their cells would have had to learn new cooperative mechanisms.
Actually, that happened a billion years ago.
Cells needed to communicate with each other, combine in new ways, and create new materials.
For example, we had to know how to create molecules that would give each organ its own unique characteristics.
So the glue that holds cells together, the way they 'speak' to each other, the way they make special molecules—these properties are key extensions of the toolbox needed to build every body on Earth.
The invention of these tools was nothing short of revolutionary.
When single-celled animals transformed into animals with bodies, a whole new world opened up.
New creatures with new talents have appeared.
Organisms grew larger, became able to move around, and developed new organs for sensing, eating, and digesting.

Page 186

The past of the fish and tadpole that caused hiccups
The problem is that the brainstem was originally used to control the fish's breathing.
After some modification, it came to control the breathing of mammals.
Sharks and bony fish also have areas in their brainstems that provide rhythmic movement to the muscles around the throat and gills.
Nerves from that area control the neck and gill areas.
This type of neural arrangement has been observed even in the most primitive fossil fish.
Among the fossils of armored fish found in rocks from 400 million years ago, there are some with brains and cranial nerves preserved as cast fossils, and looking at them, we can see that the nerves that control breathing are coming out of the brainstem, just like in modern fish.
This structure may work well for fish, but it is truly annoying for mammals.
In fish, the nerves that control breathing do not have to travel very far from the brainstem.
This is because the gills and throat usually surround the brainstem.
But mammals are different.
Breathing in mammals is controlled by the muscles of the chest wall and the diaphragm, a membrane-like muscle that separates the chest from the abdomen.
The diaphragm contracts to control inhalation, and the nerves that control the diaphragm come from the brain.
As in fish, these are the vagus nerve and the phrenic nerve, which come out of the brainstem near the neck.
The two nerves that extend from beneath the skull must pass through the rib cage before reaching the chest area and diaphragm, which control breathing.
Following such a twisted path is bound to lead to problems.
In a rational design, the nerves should emerge near the diaphragm rather than in the neck, but unfortunately that is not the case.
So while the nerves are making their long journey, something can occasionally interfere with their function and cause them to spasm.

Pages 289-290

The shark's past as a cause of hernias
The reason why humans are prone to hernias is because they created the mammalian body by kneading the body of a fish.
At least that's the case with hernias in the inguinal area.
The gonads of fish extend to the upper chest, almost close to the heart, but this is not the case in mammals.
That's the problem.
Of course, it's a good thing that the human gonads aren't in the chest, near the heart (if they were, it would be a weird feeling every time we pledge our allegiance to the flag).
If our gonads were in our chests, we might not be able to reproduce.

Page 292

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