Darwin 2 Essay Research Paper Natural SelectionCharles

Darwin 2 Essay, Research Paper

Natural Selection

Charles Darwin came up with the theory of evolution to explain the diversity, complexity, and origin of life. According to Darwin evolution takes place via Natural selection. Natural selection can explain diversity with in species, but I have yet to see anything that could make me believe that natural selection can create new species, or the origin of life.

Natural selection is a natural process in which animals better adapted to their environment tend to survive and produce more offspring. This increases the percentage of their genes in the gene pool. Animals which are lesser suited tend to die earlier and as a result produce fewer offspring, therefore the genes they carry tend to diminish within the population.

Natural selection helps species of animals survive. A species chance of survival increases because animals, which have defects, tend to die earlier thereby producing fewer offspring, while the animals with “beneficial” genes will tend to live longer and produce more offspring. Natural selection becomes most important when the environment of a species changes.

An example of natural selection is the legendry example of the pepper moth. England saw a great shift in the proportion of “black” to “white” peppered moths during the industrial revolution, going from predominately white to predominately black in a few years. The commonly believed cause for this change was that pollution had killed the lichens that covered the trees causing the tree trunks to turn dark. The white moths were easily spotted by predatory birds and were consumed by birds at a higher rate than the black moths. Because white moths were easy targets, the black peppered moths had a survival advantage that resulted in more black moths in succeeding generations. The process started with moths and ended with moths. The only change was the proportion of black moths to white moths. The Peppered Moth case is an example of how environmental pressures in nature can produce changes within an animal population.

Some people see this example as proof of evolution, and explains the origins of life. Although this does prove Darwin theory of natural selection, it does not prove that one species can be derived from another. Sure the moths are now mostly black but they are still the same species of moth. There was no new genetic material made, only a change in what genetic material was expressed. This change within a species is called microevolution.

Darwin had no clue how this change happened, but he tried to explain it anyways, it was called pangenesis. He thought that each cell from the parent gave off a gemmule to the offspring. Now he was sort of on the right track of DNA.

In contrast to microevolution, demonstrated by the peppered moth case and dog breeding macroevolution requires the changing from of one fundamental kind of animal into another. This process requires the generation of new genetic material. In the case of the peppered moths, there was no new genetic material created. Some moths had genes that produced black coloring, while others had genes that produced white coloring. The environment was acting on the population to change the proportion of black moths to white moth.

The real question is not whether microevolution happens. It does, but can microevolution be the cause for large evolutionary change. In order for a new species to evolve there must be creation of new genes that did not exist before. Natural selection just optimizes the existing gene variation with in a particular species. Science now days use microevolution to explain macroevolution.

It has been over 100 years since English naturalist

Charles Darwin first told the world his revolutionary concept about how livings things develop. Evolution through natural selection and adaptation was the basis of his argument, as it remains to this day a debated subject by many. Darwin s theory does explain the evolution within species, but it has yet been proven to be the generator of new species. If this was the case than there would be many different species of dog. Dogs have been bread for centuries to express desired characteristics. Despite their vast differences between breeds they are all still the same species, and share the same genetic make up. Many people assume that the many small changes with in a species can lead up to a new species. We have yet to observe microevolution long enough to see if it can result in a new species. Until then we should stop assuming that it is the cause for macroevolution.


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