Evidence of Evolution Essay Sample
- Word count: 1426
- Category: evolution
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Evidence of Evolution Essay Sample
Evidence from different fields of study suggest the same story: all living things once evolved from a common ancestor millions and millions of years ago, a suggestion that I agree with. The theory of biological evolution suggests that all living things are related and that the evolution of living things is powered by natural processes. Evidence from comparative anatomy, DNA comparisons, embryology, and fossil records, all back up the suggestion that all things evolved from a common ancestor. There are about 8.7 million species alive today, biologist claim that cetaceans, one of the branches in the evolutionary tree that includes whales, dolphins, and porpoises, are all related and evolved from an ancient land mammal.
Comparative anatomy is the study of differences and similarities between living things. Whales live in water, like fish, but although they appear to look like large fish they are very different. Whales like land mammals, but unlike fish, have placentas, give live birth, nurse their young, are warm blooded and do not have gills instead, they breath with two fully developed lungs much like we do.
Whales and dolphins have blowholes to breath out of when they come to the surface for air, they do not have noses like mammals. Some whales have two blowholes that almost look like nostrils, while dolphins only have one, but when looking at the skull it splits into two passages, could blowholes be a modified version of a nose like that of a mammals? Like mammals, whales have hair as well that can be seen on top of their heads and other places on their body but it is not everywhere. Looking at the bone structure is more evidence of evolution, whales have arm, wrist, hand, and finger bones in their front flippers. These same bones exist in bats, hippos, and humans. Modern whales do not have legs but they have what appears to look like hip, thigh ,and shin bones where back legs would be, they even have a ball and socket joint, biologist believe they could be left over from the four legged land mammals they once evolved from .
Embryology, the study of how creatures develop before being born or hatching, is more evidence of evolution. Dolphins and human embryos look similar at around the same stage of development, they both appear to have arm and leg buds. Humans later develop legs but in dolphins they grow for a while then stop and eventually fade away and the rest of the whale continues to grow and develop. In the early stages of development dolphins have two nostril openings which develop into one blowhole in later stages.
Fossil records of two species of extinct basilosaurid whales that lived about 34 – 40 million years ago act as a third source of evidence. The skulls of these extinct creatures show that their nasil opening was not located at the top of the head like whales of today and were not located in the front like land mammals, instead it was located in the middle. Like the small hind leg bones in whales, the basilosaurid had leg, ankle, feet, and toe bones. Though these legs were not made for walking because they were too small they could have been used for mating or scratching itchy skin. Maiacetus, another creatures who lived about 47.5 million years ago, had hip bones strong enough to use for walking but was considered a whale. Maiacetus was considered a whale for the following reasons, her bones were found with the fossils of sea creatures, indicating she lived in water, she had short legs, long flat fingers and toes that indicate she would have been a swimmer with webbed hands and feet, her teeth matched the teeth of the basilosaurid whale and matching ear bones with basilosaurid and whales of today. Maiacetus was considered to be a kind of walking whale. With fossils similar to whales being found it is becoming difficult to distinguish the four legged land mammals from the aquatic whales, making evolution a considerable explanation.
The DNA of whales has been compared to many other animals like, fish and sea lions but has only been closely matched to the DNA of a hippo. This does not mean that whales evolved from them but it could mean they share a common ancestor from about 54 million years ago. Whales have similar features with the hippopotamus like the distinct structure of the ancient walking whales ankles, which are found in hippos and in their close relatives. Hippos also give birth and nurse underwater, they both have multi chambered stomachs that most herbivor have, and both also have internal testicles that only few mammals on earth have. Bird wings have been discovered to be modified claws and arms, they are believed to have been evolved from dinosaur-like ancestors. Bat wings are believed to have been evolved from five fingered hands like those of a monkey, humans and chimpanzees share a common ancestor as well. Many other different creatures have been linked, mammals evolved from reptile creatures, those reptile creatures evolved from amphibian creatures, those amphibians evolved from fish and if one were to go far back enough, fish are believed to be evolved from segmented worms.
“ Evolution is a religion not science.” Creationist, those that believe in biblical accounts of creation from the book of genesis, argue that evolution is flawed and poorly supported. They believe that the creation of all living things took place in six days as stated in the bible. Many creationist have taken school districts to court in order to prevent them from teaching evolution to their children. Creationist have offered up “intelligent design” as an alternative to teaching evolution. Intelligent design has not successfully won because teaching it in U.S. public schools is “unconstitutional” because it is based around religion not science. Intelligent design is intended to start conversations about God in schools. But why isn’t intelligent design a scientific theory ? It’s because there is no evidence gathered through research for it.
An argument that creationist bring forward often is the gap in the fossil record. This gap means we’re missing a fossil that shows evidence of a certain step of a transition in evolution, this means we do not have a complete timeline of every step. However this missing link only accounts for a very small portion in the fossil record. The similar flaw in creationism is the lack of detailed evidence of the six days God put into creating the anatomy of a particular mammal. No creationist will claim to one day find this evidence, where scientist are constantly debunking potential evidence of the missing fossil in the record. Biologist can confirm many evolutionary transitions, such as our own from the bipedal ape. Biologist J B S Haldane was once asked what would prove evolution to be false to which he answered, \”Fossil rabbits in the pre-Cambrian.\” The theory of evolution has always tried to be proven false, like most theories, but has always had sufficient proof of it.
Another argument used is by creationist or anti-evolutionist “you can\’t prove evolution.” Biologist have discovered DNA similarities between plants, animal, and humans, they can prove that things have evolved and do evolve. Humans are closely related to Hominidae, which include, orangutans, chimpanzees, gorillas, and bonobos. We share 98.8% of our DNA with chimpanzees and their close relatives. Humans share a percentage of their DNA with mice, fruit flies, and even yeast.
In conclusion, no one has been able to disprove evolution much less without using the bible as a main source. The evidence of evolution is there and is only developing more over time as new discoveries are made. The evidence from different fields of study all tie together to conclude that all living things are related through a common ancestor from millions of years ago. Creationist continue to argue that evolution is not how life came to be on earth, though they do not understand that evolution is not the reason life came to be it is only a theory or an idea that a species evolved to adapt to their surroundings and continued to evolve until they were fit to be in their environment. Evolution is strongly supported idea with backup evidence from comparative anatomy, DNA comparisons, embryology, and fossil records all leading to the suggestion that all living things evolved from a common ancestor.
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