Jeff Scudder
Honors Biology
Evolution Essay

	There is tons of scientific evidence that evolution, in fact really did occur, and is still in progress today. What is Evolution? It is the theory that the make-up of populations changes over time. This means that populations, over time, adapt to their changing environment in order to survive. Evolution can be described as the survival of the fittest. For example if a bunch of giraffes were born, but only a few were tall enough to reach the tree that held their food, then the shorter ones would die out. This would cause the tall giraffes' offspring to acquire the traits of being tall and surviving like its parents. This takes much time to happen. Sometimes hundreds of years. There is much evidence of evolution that has occurred.
	The first and most visible piece of evidence is called a Fossil. Fossils are mineralized or preserved remains of once living organisms. Fossils show that life has gone from simple forms, to complex forms. If an animal died and was frozen in a solid block of ice, and that ice was never unfrozen. We would still be able to find that organism today! Other examples of fossils include sedimentary rocks that layer, and dead things could be surrounded or make imprints as the rock is formed over time. Petrified wood and bugs or insects getting caught in tree sap and then the tree sap hardening into solid amber, is another example. Not so long ago, scientists have found a wooly mammoth frozen in the ice of the arctic. By looking at fossils, people can see older organisms and how they are different from today's organisms of the same kind. For example, through fossils, we discovered that Horses used to be the size of a dog, but they evolved to become bigger.
	The second piece of evidence is called Common Biochemistry. This is where all living things are made of the same elements and they share a common DNA code. This indicates that all life evolved from a common ancestor with the same genetic code. This also shows that through mutations and natural selection, we have received the variety of life that we see on earth today. Common Biochemistry has been proven, considering all organisms do in fact share the same genetic code. This means we all evolved from a single organism, or group of organism.
	Homologous Structures are very similar structures found in very different animals. This also shows that organisms share a common ancestor. One main example is that all animals have eyes, and many organisms on earth such as the human, the bat, the alligator, and a monkey, use the same basic structure for arm/leg bones. This is almost a rock solid piece of evidence that evolution really has occurred.
	Vestigial Structures are things that are still in our bodies or in organism’s bodies that have no use. For example, the human appendix had no use whatsoever to us anymore, but we believe in history that humans may have used it to help digest their food. Another example is that a Cobra snake has toenails on the end of its body. It obviously has no toes, but maybe it used to.
	Common Embryology is a great similarity in the early development of organisms. Embryos of fish, rabbits, and humans as well as other animals, all look almost exactly alike at their first stage. They all have a tale, and even gills. This definitely shows that at one point, we were all very alike. Until evolution occurred.
	Evolution never stopped, it is still occurring today. In fact there are many examples of Natural Selection going on in our world right now. Changing environmental conditions cause different traits to be selected and population’s change. This indicates that Natural Selection is a mechanism for change. Humans used to spray mosquitoes with a poisonous chemical known as DDT. Lately this chemical has not affected mosquitoes. It is because of evolution that they have developed immunity to this chemical. Also, many bacteria are forming resistances against the antibiotics that we use as medicines in the same fashion. As you can see, evolution is very real and with all this evidence, how could anyone not believe the facts of evolution and natural selection.