Believe it or not, your ancestors were once fish. Evolutionary biologists have really good reason to believe that we all started from fish. We slowly evolved to land animals, and eventually evolved into the humans that we are today! So how can biologists prove that this is true?
Of course we can never fully prove that we evolved from fish, but we have good evidence that suggests we have. For example when a human baby is developing in a mother, it actually grows “gills” for a little while. Our DNA then directs these cells that are forming gills to stop and transform those into cheek muscles and bones. Based on this, we can infer that our ancestors used to live and thrive in the water. Biologists knew that we probably came from the water, but they couldn’t find the missing link of our evolution from water to land. At least until recently.
In 2006 biologists believed that they found this missing link between swimming and walking. It is a fish-like animal (named Tiktaalik) that is able to support its weight on land. This small evolutionary advantage allowed the fish to eat food that was stuck on land during low tides. They could crawl out of the water and eat while other fish still had to search for food. This gave them an advantage over the rest of the fish population which allowed for this gene to be passed on. In theory, these animals continued to evolve until they were not able to live in the water anymore. Eventually, these animals grew into what we are today! Check out the photographs of what these scientists think this fish looked like. What do you think about this evolutionary evidence? Comment below.