Fact. If you look at an embryo of a fish, lizard, bird, horse or man you will notice how similar we all are to each other. As the embryo develops, so do our differences and similarities. A fish develops gills which it will use to breath. For mammals our inner ear develops from the same components as the gill to make our ear including the canal, incus and staples. Birds have similar three chambered ears as mammals where as reptiles use their lower jaw to hear. As we develop and become mammals, fish become fish, birds became birds and reptiles became reptiles.We all have so much in common, a spine and four limbs and a head to name a few.
If you look at skeletons of birds you will find they have 5 fingers as part each of their two wings same goes for bats, horses have five fingers except they are formed differently and are elongated into a hoof, all mammals, birds and reptiles have four limbs as do whales and dolphins.
Our heads are an enlarged vertebra which protects our brain; our fingernails are made of the same substance as fish and reptile scales. The same substance (keratin) makes feathers on birds’ horns on rhino and hair on our heads.
We share a lot of our genes with insects, worms, fleas, spiders and vegetables the only difference is that they are sequenced differently and when activated they build different traits. In theory we could by turning on the right DNA sequence produce humans with wings and beaks, tusks or scales or humans with gills and webbed feet, long necks like giraffes and with the trunk of an elephant
In 65 million years little mouse like creatures (our ancestors) thrived due to the demise of dinosaurs and were responsible through evolution for humans, whales, dogs, cats, apes and cows to name a few.
360 million years ago mammals, including dinosaurs (reptiles) evolved from amphibians and migrated onto land as it was probably safer to lay its eggs on Terra Firma than in the water, if we go back millions and millions of years earlier again fish evolved from shrimp like creatures then shrimp like creatures from tiny plankton all the way back to little microbes and singular cell organisms.
So what does it all mean! Not much to most of us, but thanks to human knowledge of our genetic past which is a history book of our existence contained in our own DNA, it can help us understand more about our bodies, help create new better medicine for the prevention of disease which improves quality and length of life.
For me it just makes the natural world that bit more fascinatingFor further reading, this book is great - Your Inner Fish by Neil Shuban http://tiktaalik.uchicago.edu/book.html
