Your Inner Fish by Neil Shubin explains how our ancestors that may look very different from us gave us many of our characteristics today. Fish are the most distant ancestors of our modern hands. They were the first to show the system of one bone, two bones, many bones in limbs/fins. Scientists studied fish embryos and found many fossils to support this. Many organisms look the same during early stages in development until Hox genes turn on and specialize the cells to grow into whatever the organism is.
The sonic hedgehog gene emits a signal to tell cells where they are in the body. Based on that, they grow certain limbs and fingers. The closer the signal, the pinky finger grows and the furthest the thumb. This is related to the specialization of cells. The sonic hedgehog gene may have developed through natural selection as organisms started becoming more complex. I wonder how the sonic hedgehog gene works in detail and how it came about. Would having extra finger through mutation actually become favored?
The tiktaalik is one of the greatest finds connecting fish to land animals. It swam mostly, but its fins could support its body weight enough so it could walk on land. This trait came through natural selection - favoring stronger fins and wrists. Tiktaalik could also move its neck to watch for predators. It was the transitionary fossil between fish and amphibians. The first fossil was almost a rare specimen, which is a very lucky find. I wonder how one scientist was so lucky that he discovered so many breakthroughs in science? How did it stay intact for millions of years? How did the scientists know where to look? If it had a favored trait then why did it die out?
The video also talks about mammals and reptiles- how they passed down their sense of hearing. There was one jawbone and one ear bone. Over time, the ear bone and parts jawbone formed the ear. Mammals also developed their hair because of the cold and a way to communicate with other animals. The parts of our body we use everyday and almost every second come from our ancestors that look nothing like us.
The sonic hedgehog gene emits a signal to tell cells where they are in the body. Based on that, they grow certain limbs and fingers. The closer the signal, the pinky finger grows and the furthest the thumb. This is related to the specialization of cells. The sonic hedgehog gene may have developed through natural selection as organisms started becoming more complex. I wonder how the sonic hedgehog gene works in detail and how it came about. Would having extra finger through mutation actually become favored?
The tiktaalik is one of the greatest finds connecting fish to land animals. It swam mostly, but its fins could support its body weight enough so it could walk on land. This trait came through natural selection - favoring stronger fins and wrists. Tiktaalik could also move its neck to watch for predators. It was the transitionary fossil between fish and amphibians. The first fossil was almost a rare specimen, which is a very lucky find. I wonder how one scientist was so lucky that he discovered so many breakthroughs in science? How did it stay intact for millions of years? How did the scientists know where to look? If it had a favored trait then why did it die out?
The video also talks about mammals and reptiles- how they passed down their sense of hearing. There was one jawbone and one ear bone. Over time, the ear bone and parts jawbone formed the ear. Mammals also developed their hair because of the cold and a way to communicate with other animals. The parts of our body we use everyday and almost every second come from our ancestors that look nothing like us.
Fish fin developed into hand
No comments:
Post a Comment