Physical Anthropology

What is Evolution



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Evolution through Natural Selection

The Merriam Webster's Collegiate Dictionary has many definitions of evolution, one could go and look at each individual definition and find a certain amount of information revolving around each particular. This question seems to orbit around the dynamic of theory, in particular the theory of Evolution. Evolution has been rendered as how organisms came to be, not to be confused with why. A scientist must be objective in his/her approach toward evolution, objective is defined: of, relating to, or being an object, phenomenon, or condition in the realm of sensible experience independent of individual thought and perceptible by all observers: having reality independent of the mind (1).

The best way to take the objective approach in accordance to evolution is by the similarities between species, humans share more traits with apes, less with monkeys, even less with birds and plants, however we share similarities with all of the above. Take humans and plants for example, plants and humans share similar cell structures, nucleated cells having mitochondria where each cell is stacked and performs a specific function, we have more in common with plants than bacteria, bacteria do not have a nucleus nor do they contain mitochondria. The approach is called cladistics: cladistics is a way of analyzing relationships among organisms in a fossil record by using newly derived traits or characteristics (3). So then how did these organisms gain these similarities?

There have been many different aspects of evolution, from the Greek philosopher Aristotle's "Natural philosophy" (384-322 BC) to the current Charles Darwin and Alfred Russel Wallace's "Natural Selection", and many in between. Evolution through natural selection has been under the most scrutiny, in comparison, since its inception some 150 years ago. Natural Selection remains steadfast under the scrutiny of science. It is the paradigm of Biology, under inspection Natural Selection has withstood test after test in attempt to disprove its credibility and time after time it has been proven not false to the timbre of theory. To better understand this phenomenon one needs to understand what a scientific theory is: A theory is a set of facts, propositions, or principles analyzed in their relation to one another and used, especially in science, to explain phenomena (2). A theory is made a theory through the scientific method: An individual first makes an observation of a phenomenon, and then s/he asks a question based upon the observation. The individual then makes a hypothesis based upon the question s/he asked. S/he then makes a prediction based upon her/his hypothesis. S/he then tests to disprove the hypothesis; the test limits the amount of variables to gain an unbiased account of the observation. The individual then collects the data from the test and examines then summarizes the results. S/he then draws a conclusion based upon the results of the test. The individual then repeats the test. If proven not false (a hypothesis cannot be proven true) by the individual then the individual reports the finding so that other scientists can perform the same test. If proven not false under an extreme amount of testing then the hypothesis becomes a theory. To give you an example of how stringent this method is one need only look at evolution through natural selection, it has been proven not false for 150 years, and as one reads this essay natural selection is tested to be disproven.

What is evolution through natural selection? Natural Selection is the theory which explains the origin and diversity of species on earth. This theory provides scientists with a way to make predictions about organism evolution, biology, and behavior and to test their predictions against observations made in nature (3). Natural Selection can best be described as an organism that lives long enough to pass the organisms traits off to its offspring thus ensuring that the organism's species will survive. An organism is subject to its environment which can be many things based upon the organism's observed situation; there is a social environment and a physical environment. The social environment could be a number of situations from sexual to predator/prey relationships to moral or ethical stands and the like. The physical environment would be the sun, climate, terrain, and the proximity of other species. Through all of these situations arises diversity.

Another proponent to Evolution is mutation. A mutation is a change in genetic material through a random variation in a gene or chromosome resulting in a new trait or characteristic that can be inherited (2). Mutations can be beneficial, neutral, or deleterious in nature. It is worth note here that most mutations are harmful to the species success and the least amount of mutations are beneficial. This could be the actual reason why it has taken so long in the stretch from single celled bacteria to Humans. I digress; mutations are the reason for such variance among species.

Let us take a look at how this theory actually works. Humans have evolved more around the social aspect of the environment, or the environment they have created, rather than the physical environment. The physical aspect involving the sun has made adaptations toward skin color, in the case of Caucasians; they live in a cyclic climate where exposure to the sun varies between seasons. Because of the variance, Caucasians have white colored skin; they have been selected for less exposure to sunlight giving them the adaption of white skin which, when struck by sunlight, replenishes vitamin D into their system. In the case of dark colored individuals, they have been selected for constant exposure to the sun these individual's skin is dark to protect them from the harmful radiation emitted by the suns constant glare. There are many different scenarios of the variance betwixt appearance between each race of human, but these scenarios have taken a back seat to the social environment. Humans have risen above natural selection (one would think). A person no longer needs to be physically fit to make it in society (it sure doesn't hurt). A person does not need to be all that physically attractive, but of course it doesn't hurt to be attractive. People take care of each other (in a broad sense); we have programs that keep people alive, case and point the population dynamic. But have humans really risen above nature? Have we quit adapting? Have we beat evolution? On each question stated the answer would be no. Humans have not quit evolving, they evolve differently. They are still held in check by their social environment; the trait that is selected for in this environment would be the trait of charisma. How socially accepted one is would promote their traits to be passed on to the next generation, a person does not need to have constitution, a person does not need to be physical in any aspect (other than sexual). It could be argued that a person does not need to be clever. The more successful an individual is the more charismatic or charming s/he is. Now whether or not humans are devolving remains to be seen. This has arisen from the invention of communication, both speaking and writing, and the Gun. After all one does not need to be physically fit to pull a trigger nor speak nor write. Governments and politics have come into being because humans need one so called voice. This voice would be a representative of the people, even in the case of kings and queens. The best representative would promote human endeavors which in turn would promote the human species and survival.

Natural Selection then is how an individual survives, which means that an individual would need to adapt or change to whatever stressor inhibits an individual's success.




Sources:
1. Miriam Webster's Collegiate Dictionary Eleventh Edition. 2003
2. Encarta dictionary
3. Biological Anthropology: A Synthetic Approach to Human Evolution Second Edition. Noel T. Boaz. Alan J. Almquist. 2002.

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