DNA (Deoxyribonucleic acid)
Are We Just Mere Mortals Or Just Mere Mutants?
DNA (Deoxyribonucleic acid) |
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Mutation
Define Mutations:The cell, through the use of enzymes, has a built in proof-reading mechanism to correct any errors in the DNA copying process. However, it is not fool-proof and mistakes do occur. Mutations are the result of these mistakes and are basically the imperfections resulting from this process of copying or replicating.
So the chemical result of a mutation would be a change in the base sequence in a piece of DNA. For instance a base can be accidentally skipped, inserted, or incorrectly copied, or the chain is trimmed, or added to. Any of these errors or a combinations of these errors can result in a mutation.
In fact if the DNA copying process performed as it was supposed to, there would be no such thing as evolution. No copying errors means no evolution. Life on Earth would be in its most fundamental state.
How do they happen: Mutations do not occur spontaneously. There is always a cause. The main causes of mutations are;
Mutations can occur naturally in the environment or can be administered deliberately in our laboratories. The rate at which this process takes place may be accelerated by exposure to chemicals or radiation. Most mutations have no effect with regard to reducing or increasing an organisms ability to survive or reproduce (neutral mutations).
What are the consequences: Mutations are considered one of the driving forces of evolution. Mutations may disrupt or prevent the production of proteins, which disturbs the genes and the functioning of the organism as a whole. Since mutations can affect the way a gene works, this may in turn cause changes in an animal's appearance or behaviour.
The process of Natural Selection dictates that less favorable mutations are removed from the gene pool, while more favorable ones tend to accumulate. Sometimes, the resulting new gene variant may mean the animal is better adapted to its surroundings, improving its chances of survival. So this animal is more likely to have offspring, which will inherit the beneficial gene variant. Natural Selection is a vital part of the whole process of evolution since mutations originally occurring in an individual rely on this process where conferred benefits spread within a population.
As previously stated, without DNA mutations, life on Earth could not have evolved. We'd all have remained as microbes in the primordial soup. So in effect, we are all just mutants !
Is a more complex organism necessarly a better survival machine? Are humans a better survival machine than bacteria? After all Bacteria has existed far longer than us humans and are much more likely to out-survive us and most complex life forms. Is this a contradiction? After all the 'goal' of evolution is about survival. And as time passes natural forces appear to ensure that at the top of the food chain you will always find the more complex organisms. Yet the top of the food chain would appear to be most exposed or vulnerable to extinction when compared to the bottom of the food chain.
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