Evolution on essay


The origins of mankind is an extremely controversial issue within today’s society. Scientists have a host of different theories pertaining to man’s inhabitance of earth. Many disagreements arise between scientists who have different beliefs pertaining to where and how mankind arose. One such argument is the conflict involving the theory of evolution versus the theory of creation. After extensive scientific research, it is apparent that the theory of evolution is correct.

Evolution is the theory that life arose by natural processes at an early stage of the earth’s history and that complex organism developed from simpler organisms by a process of slow change (Coren 209). It’s the idea that new species arise from older species after thousands of years of gradual chemical, environmental, and genetic change (Coren 142).

Evolution can also be described as the complex processes by which living organisms originated on earth and have been diversified and modified through sustained changes in form and function (“Evolution”). Scientists, looking for an explanation for the origin of man and other organisms created this evolutionism theory, which also presented answers to the many asked questions dealing with similarities between species.

Unlike the theory of creation, which states that the complexity of life and different species can only be explained in terms of a supernatural creator or god who placed life on earth, the theory of evolution has a plethora of evidence proving it to be true (“Creation”). There are several different types of observations that support the theory of organic evolution as an explanation for the similarities and differences among species. One such observation is in the geologic record.

The geologic record is the rock scheme found within the earth’s outer crust. By means of radioactive dating, the ages of rocks in many places on earth have been determined. It’s a timetable of the earth’s geologic history. This combined with the fossil record, another observation supporting the evolutionary hypothesis, has produced an apparent sequence of life forms from the most simple to the most complex during the history of the planet.

Fossils are any remains or traces of a once-living organism, which are formed by preservation, petrifaction, or sedimentation. Organisms can be preserved and protected against decay by being trapped in amber, tar, or frozen in ice. The hard parts of an organism, such as shells or bones, can be preserved when the flesh of an organism has decayed away. In other cases, the materials of a dead organism may be gradually washed away and replaced by minerals from the water causing the organism to petrify, or harden. Imprints, molds, or casts left by an organism after it is enclosed in sedimentary rock and decomposed are also fossils, as well as footprints and tracks.

The fossil record is the timetable of fossils found within the earth’s geologic record. Since the upper layers of sedimentary rocks are assumed to have been laid down over lower layers, the upper layers are younger than those deeper into the earth. Therefore, fossils found within the upper layers are also younger than those found within the lower layers. This combination of geologic and fossil records shows the progression of species as time also progressed (Coren 142). In reiterating the definition of evolution, we are reminded that gradual changes in one life form’s anatomy, cytology, embryology, or biochemistry could cause a new species to originate.

Similarities in these categories link species together and are therefore studied to support evolutionism. In comparing anatomy, the structures of different organisms often show unexpected similarities. Cell organelles, such as cell membranes, ribosomes, and other structures found within cells, are also similar in organisms of all kinds, showing that comparative cytology can also shows signs of evolution. When comparing the embryos of different organisms, comparative embryology, similarities can be seen in the early stages of embryos that are completely different at maturity.

Finally, comparative biochemistry, which is the comparing of biochemical compounds, such as amino acids, can also show similarities in species, reinforcing the idea of evolution (Coren 143). As curiosity rose throughout much of the world, scientists began to question the existence of organisms and why some are so alike in so many ways and so diverse as well. Several theories have been proposed in the past to account for the diversity and similarity of species.

One scientist by the name of Lamarck proposed that changes in species occurred basically as the result of a striving of organisms for improvement. One main point of this theory was use and disuse. New organs appear in a species as a result of a need for them, and they increase in size or effectiveness through repeated use. Organs not needed a decrease in size or strength as a result of disuse.

A second idea included in his theory was the transmission of acquired characteristics. This means that a trait acquired during the lifetime of an organism, including improvements of existing traits, can be transmitted to its offspring (Coren 145). Later in scientific history, it was Charles Darwin who came up with the most convincing theories of adaptation and development. In 1859 he published The Origin of Species, introducing the theory that species evolve from others, including man’s development from apes (Lampton 48).

Darwin proposed that evolution occurred as the result of natural selection. Natural selection is the process by which environmental effects lead to varying degrees of reproductive success among individuals of a population of organisms with different characteristics and traits. It’s the idea that organisms with favorable variations are better able to survive and reproduce than organisms not well adapted (“Natural Selection”). Overproduction is the main idea of Darwin’s theory. He believes that more offspring are produced than can survive, because of limitations in living space and food supply. He also believes in competition, where individuals of each generation compete for available food and opportunities to mate and reproduce.

The third idea of Darwin’s evolution theory is variation, meaning some individuals are better fitted to survive than others, because of variations in characteristics. Survival of the fittest was how he explained the fact that individuals better fitted to survive are more likely to live longer and reproduce. Darwin’s idea of the transmission of favorable characteristics modified the earlier idea presented by Lamarck. Charles believed offspring of the fittest individuals would inherit only the favorable variations that enabled their parents to survive and reproduce (Coren 145).

Explaining this idea, Charles Darwin stated, “Beneficial variations of all kinds will thus, either occasionally or habitually, have been preserved, and injurious ones eliminated” (Thomas 130). In the end, Darwin expressed his idea on the evolution of species saying that the accumulation of favorable variations will gradually lead to the appearance of new species better adapted to their environment. Another scientist, DeVries, later added to Darwin’s theory that mutations were the source of new traits that permitted evolution to occur. These scientists put together today’s basis of thinking and questioning evolutionary processes (Coren 145).

Once these new scientific explanations were introduced into society, people began questioning not only animal origins but also the beginnings of mankind itself. Through years of research, experimentation, and applying the theories of evolution, it has been suggested that man derived from the ape, and there is an endless amount of evidence to prove it. The first step in proving that man derived from apes is to compare the two organisms from head to toe, and from anatomy to embryo development. Similarities between the two organisms would provide some facts helpful in proving that humans and apes are related.

In comparing anatomy, a multitude of similarities is present. Both humans and apes have diversified teeth, meaning a variety of tooth types such as molars, incisors, and canines. This also confirms that humans and apes are omnivorous, eating both meat and vegetables. Both lack an external tail and both are capable of reaching an upright posture as well as bipedal locomotion, walking on two legs.

Humans and apes both have an appendix, which is an appendage that is believed to be used for the digestion of rocks, sticks, and tree bark. Humans do not have a need to digest rocks; therefore their appendix is fairly small and useless. The theory of evolution would lead us to believe that human ancestors did have to digest stones and needed a strong appendix, but as a result of disuse, the appendix in modern humans has shrunken and weakened and is not needed.

Other similarities in anatomy between man and apes include stereoptic vision, which is the ability to see in three dimensions, and similarities in cranial structure. In comparative embryology, a similarity in the length of the gestation period is observed. Fetal development in both humans and apes is between 250 and 280 days. In biochemistry, the two species reach sexual maturity between the ages of 8 and 15 years due to the secreting of hormones. They also have similar blood types. The most intriguing similarities are those that have to do with behavior and psychology.

Both men and apes have similar personality ranges. They interact in small social units, families of two to six members, and they have the ability to invent their own culture, for example, tool making (Moore 185). Even with all of the information about similarities between man and apes, there is still more evidence proving the theory of evolution. Determined and curious scientists, archeologists, and anthropologists began to study the geologic and fossil records in order to obtain actual remains of human ancestors.

The fossil evidence for the immediate ancestors of modern humans is divided into the genera Australopithecus and Homo and begins almost 5 million years ago. Australopithecus originated in Africa, which was believed to be the place of origin of man’s ancestors, and were most primitive. The Genus Homo pertained to the more modern and complex ancestors who began to spread through and eventually out of Africa (“Human Evolution”). Scientists’ discoveries are hard evidence supporting the evolution theory as well as helping to date the beginnings and stages of mankind.

One such discovery was the finding of Australopithecus Ramidus. Ramidus, meaning root, is thought to be the missing link between man and ape. It was given that name because it is the beginning of man, man’s roots. Dated to be 4.4 million years old, it is the oldest hominid, human ancestor, ever unearthed. Tim White, from the University of California, discovered Australopithecus Ramidus in 1992, near Aramis, Ethiopia.

This hominid was more apelike than manlike, but not completely ape (Thomas 136). An amazing discovery that had a large impact on the scientific world of evolution was the discovery of Lucy. Lucy was Australopithecus Afzrensis that dated back 3.5 million years. Found by paleoanthropologist, Donald Johanson, in Hadar, Ethiopia, on November 30, 1974. The reason why it was such a huge find was that the 3 ½ foot tall female hominid skeleton was the most complete, best-preserved skeleton of any erect-walking human ancestor that has ever been found.

The completeness allowed for an accurate idea of how she should have been pieced together, what she looked like, and how old she was (Johanson 86). Until the discovery of Lucy and Australopithecus Ramidus, the oldest known human ancestor was Australopithecus Africanus, known as the Southern Ape from South Africa (Thomas 136). It was a little more than 3 million years old and was thought to be the missing link until the later discoveries (Lemonick 82). Raymond Dart discovered Australopithecus Africanus near Taung, South Africa, in 1925 (Thomas 69).

Another important finding was of ER-1470. ER-1470 was the oldest known Homo, Homo Habilis. Named after its discovery sight, ER-1470 was the oldest most complete representative of Homo Habilis. Richard E. Leakey located the skeleton near Lake Turkana in Kenya. It was named Homo Habilis because that meant skillful person. The 1.8 million-old skeletons featured a large cranial capacity, meaning it was more intelligent than the older ancestors, with a compact face, and small teeth.

This species had grown a foot and a half since Lucy, reaching 4 1/2 to 5 feet tall. Its cranial capacity was 50 cubic inches, which was also a great amount larger than the older ancestors. Homo Habilis was the first to use tools, which were found, at the site. That’s just another reason for its title of skillful person (Thomas 140). Before Homo Sapiens, modern-day humans, there was the Neanderthal Man. Its discovery was also extremely important discovery because of its young, 1 million-year-old age.

Discovered in a small cave in the Neander Valley near Dusseldorf, Germany, Homo Neanderthalensis was 5 ½ feet tall with an even larger cranial capacity than Homo Habilis. Neanderthals made tools and controlled fire, two major achievements for a primitive man (Thomas 44). These discoveries make up strong evidence proving the theory of evolution. As more and more discoveries of primitive skulls and bones of human ancestors were made, an evolution scale could be created.

The scale is a timeline of human ancestors beginning at the most apelike and moving to the most humanlike until the modern-day human is finally reached. Starting 4.4 million years ago Australopithecus Ramidus and ending with Homo Sapiens Sapiens, the anatomically modern human being.

As the scale moves from oldest hominid to youngest, the species become taller and more erect in their posture, and their cranial capacity increases, indicating an increase in intelligence (Lemonick 82). These facts are just more evidence supporting the evolution theory. As scientists attempted to prove their ideas of adaptation and development, others still believed in the idea of creation. On May 7, 1925, in Tennessee, a popular schoolteacher by the name of John Scopes was arrested. He was charged with teaching the theory of evolution to his class on April 24.

In court, Scopes’ strong defense penetrated the prosecution’s case when they stated that the Bible could not always be taken literally and that there was no way the world could have been created in six days. Even though Scopes was found guilty of contradicting creationism and the Bible’s teachings, the persuasion of the defense’s case brought up the major question of evolution versus creation.

In 1996, the issue was revisited and now teachers have the right to teach both theories. The Attorney General said the constitutional separation of church and state would be violated if both theories were not acceptable. This trial was a major step for those who believed in evolution. The outcome eventually allowed people to open their eyes and accept new ideas. The theory of evolution proved to be true (“Monkey”).

The controversy over whether evolution or creation is the correct answer to human origins is a major topic of discussion and argument in today’s society. People are entitled to their beliefs, but a great deal of evidence and supporting information has confirmed the theory of evolution to be factual and accurate. By combining all of this information along with comparisons between man and ape and the discoveries of humanlike fossils, the truth is apparent. The theory of evolution is correct.