Evolution is a process witnessed in living entities wherein gradual changes are observed in the characteristics of species over generations attributed to the process of natural selection. Charles Darwin was the first person who observed the process and formulated the scientific theory of evolution.
It is based on the very fact that all species are related and eventually undergo changes over a period of time. It is also dependent on genetic variation in a population that has an influence on the phenotype of an organism. This change which occurs is usually in a much better and more complex form. In response to the environment, an entity becomes more sophisticated over a period of time. It is a biological mechanism driven by natural selection.
Darwin’s theory states that evolution occurs through the process of natural selection. An individual is able to exhibit changes in his phenotype or physical characteristics because of the differences in his genes. It was deduced that those entities with attributes that are best suited to their surroundings have more chances to survive, resist diseases, avoid predators and hence be able to find food. These are the entities that are more likely to pass their genes to the next generation via the biological process of reproduction. On the contrary, entities that are poorly adapted to their surroundings are less likely to reproduce and survive and thus their chances of passing on genes to the next generation are comparatively lower. Hence those who survive and reproduce evolve eventually.
Role Of Genes In Evolution
The process of evolution works at the genomic level. Alteration in the sequences of the DNA affects the way genes are expressed which forms the basis of inheritance. A study of DNA sequences reveals our evolutionary history as the human genome is influenced by the genetic changes that affected our ancestors. Evidence of different species sharing ancestors is observed when their genes and DNA look similar. For instance, the fruit fly and humans have much of their DNA in common, as much as 75% of the genes that cause diseases in fruit flies are also found in humans. Accumulation of DNA over a period of time causes changes which can either be harmful or beneficial.
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