Studying Fish Anatomy

Studying fish anatomy is a good way to learn about human anatomy because it can help us learn how we evolved. This is because often some of the anatomy in our bodies is also seen in other creatures, such as fish. These connections in anatomy are found in fossils that are inscribed in stone. By using these fossils to learn about ancient fish it reveals similarities between the fish and human anatomy. For example, the basic nerves in fish are similar to those found in the human head. Fish are also the first creatures with bony skeletons so they have backbones and skulls just like humans. By studying the similarities between human and fish anatomy it can help us recognize and gain a better understanding of how we evolved.

Fish were the first creatures with a backbone/spinal column. About 400 million years ago fish were swimming in water. Then about 40 million years later there were amphibians. Amphibians were the first vertebrates to walk on land but could only reproduce in water so they stayed close to water. After amphibians were the reptiles. Some reptiles lived in water but most lived on land. About 200 million years ago reptiles were followed by mammals and long after mammals were followed by primates

In the hand the there are complex connections between the bones, muscles, and tendons but the tiny muscles in our hand that run along the tendon are what really distinguishes us as primate/human.

Sir Richard Owen, an anatomist in the 19th century, is credited for the major discovery that all animals had bones that followed the same pattern but were changed to perform different functions. This pattern was: 1 bone, 2 bone, little bones, then digits. This was found because at the time, it was the age of discovery so people were discovering many different types of creatures. These different creatures were brought to him where he studied them and found their common bone pattern.

Jenny Clack and Stephanie Pierce were looking to understand the animal that was in between having fins and having limbs. It was called the ichthyostega, a tetrapod. In order to understand this animal they looked into how it lived and wanted to see how much movement was possible at each of the limb joints and how it compared to modern animals.

In the present day, the Arctic area in which Neil Schubin and his colleagues searched for fossils is a valley carved by glaciers. It has red and green rocks that are tilted and stacked one on top of the other. Millions of years ago the rocks were extended across the valley and were straight not tilted. The valley also used to be a giant flood plain filled with rivers, swamps, and streams. It was full of all kinds of different forms of life.

It is useful to study fish embryos when understanding the evolution of vertebrates because fish, the first vertebrate, have embryos with the basic body plan that become our own bodies, the last vertebrate. Even though the fish were on earth far before humans, the fish and the human embryo look almost identical. They both have a head, a body, a tail, a neck area, and gill arches. Because the fish is an ancestor of humans the vertebrates that are are in between should also have similar embryos and by studying fish embryos it allows you to find how they may have evolved into humans.

Cliff Tabin’s work investigated how digits like fingers formed. He used chick embryos by looking into the process of development before limbs form. By probing what is important in the embryo to see what disrupts the process or figuring out what things would do if moved around he was able to find out what gene altered how digits formed. He found that the gene sonic hedgehog was the source of the signal responsible for forming digits.

Fruit flies are relevant to evolution and development because they show how individual genes can do complex things like guiding the formation of entire body parts. There was one gene called hedgehog. In fruit flies the hedgehog gene would send out an organizing signal that told cells to do different things depending on how close they were to the signal. By looking at how these genes play a role in other animals it can help scientists figure out how they evolved and mutated to form other animals and show how different genes affect the development process of animals when they are changed.

The scientific reasoning behind Kamani’s six fingers is because in his stages of forming he had a mutation that altered the effect of his sonic hedgehog gene. The sonic hedghog gene alters the number of digits or fingers and animal or person has. The Sonic hedgehog gene sends out a pattern to shape out digits, if it is increased more fingers can form and if it is decreased less fingers can form. Because of Kanani’s gene mutation when he was forming it increased the sonic hedgehog gene which increased the number of fingers he has.

Tiktaalik is unique because it has features that resemble fish and others that are seen in future animals and even humans. Like fish the Tiktaalik has scales, fins, and gills but it also has lunges for breathing air. It has a wrist which is the first signs of a link to the human hand and is the earliest animal to have a neck like ours. It could use its neck to hunt small prey and look out for predators. Additionally, the Tiktaalik also follows the same one bone, two bone, many bones, digits pattern we see in animals today.