origin of species

Origin of species; Critical Evaluation of Darwinian Theory
Cristina Nava
North Salinas High School
Instructor: Mr. Zelensky

Charles Darwin implied in his book, On the Origin of Species (1859), a theory for evolution and its mechanisms. In his book Darwin intends to convey the reader that descent with modification and natural selection, part of the evolution theory, has occurred. He also writes about the “problem of purpose” idea and how evolution and natural selection solve that problem. Many who have been exposed to Darwin’s ideas have argued that natural selection transformed the art of natural history into the science of biology. After reading the first four chapters of his book it is concluded that natural selection is a very important part of Darwin’s theory of evolution.
Charles Darwin author of, On the Origin of Species (1859), clearly states that natural selection and descent with modification have occurred. Descent with modification as well as natural selection plays an important role in evolution. Through Darwin’s first four chapters he gives various examples. He explains effects of Habitat and of the use or disuse of parts. An example he uses for that principle is domesticated animals. For example he uses the domesticated duck, where the bones of the wings weigh less than the bones of the legs; and the cows and goats that are milked often they use those organs whereas in other countries they might not (Darwin C., 1859). He also enforces the domestic pigeon as an example and takes time to actually explain it thoroughly. It was also very difficult for Darwin to believe that all the different breeds of pigeons developed from a common ancestor. Despite that he was able to prove that, by the research he gathered. There are many different breeds of pigeons just as there are of other domesticated animals. In the breeds of pigeons there is a great variety of bone structures that these pigeons have developed. Some differences in the bone structure are the face length as well as the jaw

length, also the vertebrate and the number of ribs they have. His evidence are from observations he kept of almost any breed of pigeon there is, and of some experiments he conducted himself of crossing different types of pigeon breeds to see the outcome. Adaptation is also another example Darwin uses, he explains how horses have adapted to live on either cultivated land or mountain pasture (Darwin C., 1859). This is not only applied to the horse but also for cattle, sheep, and any other species that have been able to adapt so it will be able to pass down the selected traits to its offspring. Unconscious selection is just as important as natural selection. Both of these selections select for desirable traits and characteristics. Unconscious selection is when we as humans, breed animals to get certain characteristics to produce the best individual species. Natural selection selects characteristics that are best fitted to survive in that environment. For example the Galapagos birds, the birds that survived in the certain islands adapted and were selected to be able to feed off the available food. For unconscious selection we as humans do it all the time. We want everything better. We select for the biggest animals, because they provide the most meat. Fruit and vegetables have also been altered by us, bigger to have more of certain vitamins and minerals. We pick out the best seedlings, and keep doing that, yet we are never satisfied, we always want more and better.
Individual differences are also big parts that serve as an example. These differences can have either been inherited or been caused by mutations. It is a big part because it helps determine the next generation’s characteristics and traits. An individual difference is the separation between sexes. Males and females are definitely very distinct. In fact sometimes as said earlier, there is unconscious selection between the two sexes; generally this is caused by the females. The

females determine who they will pass on their genes with. This creates natural selection because the males that are not able to pass on their genes will die and none will be left. For example the peacocks have developed very big attractive eye like feathers. Generally the one with the more eye-like feathers are chosen by the female, so those pass on their traits and the ones with fewer eye-like feathers die off, leaving the other kind to strive. This is also known as sexual selection, another aspect that branches of both natural and unconscious selection.
Darwin also presents to us that species that live in larger population will have a lot more divergence than those living in smaller populations. He was able to provide evidence by conducting an experiment relating to plants of different countries. He was able to confirm his theory by his results which in deed where that; larger populations presented varieties. He calls this, divergence of character principle, which is the amount of differences there is between an offspring and its parent, compared to the difference between the populations (Darwin C., 1859). His evidence was the experiment conducted by H.C. Walter, which was to divide species into different parts of Great Britain, recording the varieties between the provinces.
Natural selection also occurs with species and plants, such as those plants that depend on insects to pass on their pollen. For example there is a type of orchid that needs to have an insect with a long mouth in order to reach its pollen. Otherwise as said before the orchids genetics will not be passed on the next generation. Natural selection is also known as survival of the fittest. The name basically explains is all, it is species striving to put their grain of sand into the next generation’s gene pool. Another example also provided by Darwin is the peppered moth. Before the industrial times there were mainly white moths and they blended in well with the trees, meaning that the black or peppered moths were eaten. This caused the divergence in the gene

pool to decrease. Later on when the industrial time came the trees began to become darker, because of the factories smoke. The small amount of the darker moths that were left, were able to survive. So then things change, yet the gene pool still had a lower divergence, but know it was in favor towards the darker moths. A big part that undergoes natural selection as well is the change in climate.
Also species should be fertile, otherwise even if they have the fittest characteristic, yet are not fertile then there is no point because the species will not be able to pass on its genetics. Another requirement is to have a fertile mate. Also plants need to have insects that are able to spread their pollen, as well as bring them pollen. Also the method of selection needs to be done right otherwise it will fail.
Another example that helps understand survival of the fittest is the tint some species have in order to survive. There is a butterfly to which birds through time have learned to not eat because of the taste. The birds are able to distinguish by the color of the butterfly. Species have learned to avoid certain colors of other species; they have learned this through their experiences.
Natural selection affects in ways that are significant. It may cause many difference from parent to offspring, and offspring to parent (Darwin C., 1859). It affects certain structures or characteristics an offspring will have. A custom that the parents have may be passed on to the offspring; the offspring will do it unconsciously. Even though that can occur, it will be a gradually process of modification.
After acknowledging and analyzing the previous examples and evidence Darwin provides, it is certain that descent with modification and natural selection has indeed occurred. This conclusion is acceptable to the extent that Darwin provides evidence for his theories. Also if

he himself did not conduct an experiment he would use someone else’s, the important part is that he made the results fit what he has to prove. He did not just say random thing to which he could not provide evidence. His evidence not only comes from experiments conducted by him and other scientist, he also uses much observational evidence. Another reason he is able to truly convince what he is trying to convey is because what he says is very reasonable.
The problem of purpose is basically a four step process of the things that occur. The first is why things occur, the second is what is it made up of, the third is what causes it to change and the fourth is what is it for (Wilkins J.S., 2013). When referring to “purpose” there is two definitions, one is God and the other is Nature. The God definition means that everything in this world is here for a reason that God had. In the Nature definition it means that things occur by themselves with no help from a supernatural force. Natural selection was a rather difficult idea for people to believe, this is because the effects of it, meaning afterwards was the new purpose of what occurred. Many could not understand why the purpose of things involved change or evolution. They believed in a God, because if things changed they believed it was because the God chose it to be that certain way. In the scientific way we always want to know why and how things occur.
In Darwin’s book, he is able to validate the “why” thing happen in this world. He uses and explains many examples to prove the mechanisms of what happens, happens for a reason. The natural selection and descent with modification clearly explain why things happen the way the happen. The only thing he does not address is where things truly originated from. Despite that he is a very important scientist because he was one of the first ones to explain evolution with mechanism evidence. In his book he does not clearly address the “problem of purpose”; neither

does he refer back to God of dealing with anything of evolution. He explains all of his ideas in a very scientific way, he uses logical evidence. Whereas the definition of God truly does not have any evidence nor does it have any relation to what truly goes on when thing occur. His research has gone through layers of interpretation and misinterpretation designed to influence our judgment of what he did. He has penetrated knowledge that was at one point obscure by religious beliefs. Many scientists believe that his theory of evolution by natural selection has been triumphantly correct, therefor providing a base for the modern attempt to understand the development of life on earth. Historians of science started a unique movement to reconstruct the process by which Darwin made his discovery. This has developed to such a degree that today it is proper to speak of a "Darwin industry." This is the result of a theory which specifies that natural selection marks a turning point in the overall development of modern science. But even within this industry, there are biologists who think Darwin 's ideas were wrong. They argue that Darwinian evolutionary theory needs to be modified or even be left if modern science is to advance at all. Darwinism has always had political implications. The political left still uses the expression "social Darwinism" as a label for any effort to claim that human nature is determined by our biological nature. Conservatives argue that the existing state of society is natural because it reflects our biological character. Socialists, meanwhile, suggest the memory of Darwin and the "struggle for existence" to show that even science can be shaped by its political environment. Darwin proposed the industrial model of a competitive society onto nature. Meanwhile, conservatives held the Darwinian model to claim that their values are truly natural. Darwin 's theory of evolution by natural selection triggers all modern biology. It allows us to read our genes and fight viruses, and to understand Earth 's fossil record and rich biodiversity. Simple

yet at times controversial, misunderstood and misused for social goals, the theory remains unchallenged as the central concept of biology. Darwin strongly changed our view of the natural world and our place in it. It gave us a good blueprint of how life came to be as it is and is used in medical research today. It allows scientists to trace genes and structures back and see why they came to be as they are, and give a base for where they might evolve next. Natural selection is important because it is a foundation for research, in that it hasn 't been proven a false theory to the question of our origins. Darwin had the right idea, but he was only a visionary; most of his work did not prove anything at all, so when he proposed his idea, people not only thought he was ridiculous , they set out to prove him wrong and couldn 't because his fossil records and data was at its best. So natural selection was never proven or disproven, and remains only a theory well after his dead, and to this day.

References

Darwin, C. (1859). Origin of Species by natural selection. John Murray: London
Reece, ., Urray, ., Cain, ., Wasserman, ., Minorsky, ., Jackson, . (2011). Campbell Biology (9th A.P. ed.). San Francisco, Pearson
Wilkins, J.S. (2013). God and Evolution 3: The Problem of Purpose A. evolvingthoughts.net. Retrieved from http://evolvingthoughts.net/2013/04/god-and-evolution-3-the-problem-of- purpose-a/

References: Darwin, C. (1859). Origin of Species by natural selection. John Murray: London Reece, ., Urray, ., Cain, ., Wasserman, ., Minorsky, ., Jackson, . (2011). Campbell Biology (9th A.P. ed.). San Francisco, Pearson Wilkins, J.S. (2013). God and Evolution 3: The Problem of Purpose A. evolvingthoughts.net. Retrieved from http://evolvingthoughts.net/2013/04/god-and-evolution-3-the-problem-of- purpose-a/