Fish

It is surprising to see how many similarities fish have with all other vertebrates considering how different they physically appear to be. One of these similarities is their bony skeleton that also consists of a skull which is something that is found in both vertebrate and fish. Fish have been present for around four hundred million years as opposed to mammals who have been around for 200 million years. Although they have been around for drastically different times their similarities do start after conception. A piece of evidence of evolution can be found in an embryo. All animals start their earliest development the same way, as a single cell. A fish embryo and a human embryo look almost identical with one another. Small ridges can be found in both of embryos in fish they develop into gills and for humans they become the portion of the lower jaw as well as middle ear and voice box. To bridge the gap between land animals and water animals a Tiktaalikfossil can be examined. Although fish do not have necks they can be found in the Tiktaalik, although it is an extinct fish it had many features of a tetrapod. Including the bone ratio of one bone, two bones, little bones that is also found in humans which is why this animal helps fill the gap.