Darwin theory of Evolution Assignment Help
According to the English Dictionary, Evolution is the slow and gradual process by which different kinds of living organism are believed to have developed from earlier forms during the history of earth. Whether we term evolution as the slow process, a biological model or the heritable change of life forms, whatever is the definition but in a simple and clear language we can state that evolution helps us to learn about the life forms and their diversity since the time they are present on the earth. Therefore, this process of evolution is very well described and presented by Darwin after several pros and cons in theories given by scientist before him.
When the clouds of doubts covered all the theories of evolution assignment and several questions were still left unanswered, it was Charles Darwin who put forward the concept and idea of evolution that was based on research, logic and time. It is the book named Origin of Species through which he revealed the complete concept of evolution and the process that goes on in nature.
Charles Darwin was born in Shrewsbury. From his early childhood he had a very deep interest in nature. When he was eighteen years old his father sent him University of Edinburgh to study medicine but due to lack of interest in the subject he left the place and went to Cambridge University to become a clergyman. There he met a botany professor, John Henslow. Under the guidance and help of professor, Darwin got an opportunity to go on HMS beagle on a voyage of different places with Robert Fitzroy. During the journey, where Robert Fitzroy was busy with his work, Darwin felt the nature and observed many species of birds and animals, thus discovering many interesting facts about it. He noticed that species living in temperate region of South America closely resembled the species living in South America tropics rather than temperate region of Europe. Beside nature and species, Darwin also had keen interest on geology therefore, on his journey he also looked upon lots of geographical facts and figures. When he reached Galapagos, his interest got deepened when he saw unusual creatures there. Galapagos is one of the young volcanic islands where he saw many finches and noticed some extraordinary things about them. He saw that some finches looked quite similar but where totally different species whereas other was unique to Individual Island and even some species were distributed to many other such islands nearby. This differences in finches lied in their beak and their feeding habit but he failed to figure out exact reason behind it at that moment, thus when he returned to England he found out that the some species in that island were similar to the finches living in south America but other were not found anywhere in the world, thus from this Darwin hypothesized that the finches from south America has migrated there and then diverged to many other places.
To get the answer for his questions Darwin gave a deep thought on the Natural selection and Origin of Species. Thus finally when every single of the obtained information was linked to both this concepts, a conclusion was drawn i.e. these species has adapted themselves as per the environment they live on, finches adapted their beaks as per the available food at that place so as to survive on the earth. Thus, this was the first step for Darwin to go for many more of depth studies on evolution.
Unfortunately, due to his bad health, Darwin could not publish his ideas, but more or less he has already worked out with his theory of natural selection by collecting several evidences in support of his theories and ideas. He asked his wife to publish all his articles and essay when he dies. At the same time, Yell (one of the famous scientist) asked Darwin to publish all his findings, theories and evidences before anyone does it. On the other side, Alfred Russell Wallace a young British scientist was also working in the theory of natural selection and he asked Darwin to evaluate all his findings and forward it to Yell for further publication and Yell published Russell paper along with Darwin extracts. After sometime, Darwin's book Origin of Species was published and within a decade almost all the biologists were convinced with the ideas on evolution by Darwin.
Origin of species: the ideas on origin of evolution given by Darwin are:
- 1) Descend with modification: According to Darwin, all the organism present today are descended from the past ancestor, just like the tree that have several branches spread In different ways.
- 2) Natural selection and Adaptation: connection of natural selection with adaption was dissected by Ernst Mayr from Darwin's observations thus dividing it into different subheads:
- Overproduction: The entire organism has power to reproduce and if successful, population will increase tremendously.
- Struggle for existence: though the capacity to reproduce is maximum by every individual but still there is stability in nature because only certain numbers of offspring are produced. Since all the offspring's have to fight against all the natural disasters or environmental conditions to survive or stay alive. Thus, in this case only some succeeds while other remains behind.
- Survival of fittest: after struggling with natural condition, offspring's have to fight with each other for food and all other available resources and in this race only those survives who comes out to be the fittest.
- Inheritance: survival of offspring also depends on inherited trait; the traits that are advantageous increase the rate of survival.
- Variations: the variations acquired in one generation by particular group of species are inherited to the offspring as well. Therefore, if these variations serve as advantage for upcoming generation, it increases the rate of survival whereas alternative happens in other case.
- Natural selection: nature selects only those species that wins the race for available factors and possess an advantageous trait living other behind.
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These are some of the facts discovered by Darwin, and to verify all his ideas and result he collected lots of evidences that support his theory. In fact he carried many experiments to prove his hypothesis and yet come out with correct result.
Though Darwin's work was appreciated and accepted still some questions were still unclear and doubtful. Like the variations that Darwin talked about was micro variations but he didn't talk about macro variations that results due to mutation. Likewise, he did not know the genetics basis for heredity, thus his points were weak at this area.
After ten years of publication of Origin of Species, Darwin reinstituted an old theory of pangenesis that describes that a reproductive cell contains gemmules or invisible germs derived from individual cell from every part of organism and these gemmules are the bearer of the hereditary attributes. Since there were no proper evidences in support of this theory, this theory was not accepted by most of the scientist.
When several doubts emerged regarding the theory of natural selection given by Darwin, mutational theory by de Varies and Mendel's work on genes and their recombination provided a deep insight into Darwin's concept. In fact many supporter of Darwin worked together to interpret his theory of natural selection and thus their theories along with Darwin's work on natural selection gave rise to Neo- Darwinism. Many researchers like Haldane, Huxley, fisher derived Neo-Darwinism from the overall concept of Darwin's theory, Mendel's law, Mutation theory by Varies and Germplasm theory. Therefore, they figure out that there are five basic factor involved in the process of organic evolution such as gene mutation, change in chromosome number and structure, genetic recombination, natural selection and reproductive isolation. These entire factors are responsible in brining variations in genetic materials and thus carrying out the process of evolution.
This way Charles Darwin started the journey to describe evolution and its theories and slowly with the help of many other biologist and scientist his ideas were clearly revealed and thus are the important part for our education. We can now understand why two offspring are quite similar and others are totally different, how and why new born die and only some survive, how changes in gene and chromosome can serve advantage or disadvantage for any individual.
With every passing time, science is developing and several unanswered and hidden facts are disclosed. Therefore, the journey started century back is still in progress, since then many more of research on evolution has been carried on where fossils serve as important evidence.