Evolution deals with the origin of life. The alteration in the DNA or genetic material of an organism over a generation gives rise to an all new generation of an organism. The changes occur in both flora and fauna, which might take millions of years to manifest. Such evolution gives rise to biodiversity that further breeds animals with diversified characters and variations. Origin of life deals with common ancestry. Those animals with common ancestors are considered to have evolved from the same species. This phenomenon of origin of life forms the greatest essence of Darwin’s theory. According to Darwin, though the ancestors might have existed during different periods of time, geological existence very much correlates to the biological history. For example, whales, bats, cheetahs and humans, in short all mammals share similarities in terms of bones of forelimbs and thereby have common ancestors. These forelimbs may perform different functions in these mammals according to their adaptation to a function. Such kind of similarity gives way to divergent evolution, whereas the flippers of penguins and dolphins share same function, but different structure, thus giving rise to convergent evolution. Such evolution is in terms of anatomical structure. There are evolutions that originate from the long existing fossil records. This is called pale ontological evidence. So far large number of species has evolved, which till date continue to leave evidence and many of them have also become extinct. By far dinosaurs are the only animals that have become extinct much prior to human civilization. But recently fossil eggs were found in China that bear similarity to the eggs of the dinosaurs. They were 22 in number having a diameter of 10-12 centimeters.
So far we have talked about how different organisms evolve through different mediums.
Now let’s talk about how this evolution gives way to the survival/existence of organisms on earth. What are the factors that help them to survive with a healthy mind and body? Talking about Darwin, the first thing that comes to our minds is ‘Survival of the fittest’. It says those who are physically and mentally healthy fit better into the environment. The term ‘survival of the fittest’ very much goes hand in hand with the term natural selection. In the natural habitat competition occurs between closely related animals that share same habitat and feed on the same food. But the same competition can also take place among totally unrelated species. The term ‘competition’ here plays a very significant role because in such cases competition reduces the efficiency of an organism due to presence of other species. The best example of such struggle could be seen in the Galapagos Islands. In these Islands, the Abingdon tortoise became extinct as soon as the goats were introduced as they were much competitive because of greater browsing efficiency.
Such is the world of competition, which exists in both mammals and other breeds, where only one of the two competitive species survives. Other ways of survival include defense mechanisms. Defense is a mechanism adapted by both plants and animals. There are plants that make use of both morphological and chemical defenses. Plants such as touch-me-not bend down as soon as they come in contact with a stranger in order to protect themselves. There are even plants that contain toxic substances in order to get rid of enemies. With animals, it’s not the same. Animals have the power of motion and ability to understand threat. Animals such as tortoises on sensing some stranger or enemy near by tend to behave as lifeless objects, precisely stones. Other animals have other capabilities to fight their predators.
There have been numerous ways by which organisms tend to evolve and at the same time survive. This theory correlates to the theory of ‘natural selection’ and ‘survival of the fittest’. These two theories are further based on the theory of heredity that brings down required or healthy genes to the progeny from their parents. The capability to survive in hostile conditions depends entirely on the innate ability that is the genes of the organism. Thus, biological evolution differentiates between the organisms on the basis of their metabolic capability or genetic basis. Though science has achieved a lot over the years and far more developments are taking place. But ‘man being a social animal’ is going to remain forever in the biological history. We have evolved from the apes and other homo sapiens like the Homo habilis and Homo erectus. These evolutions have always been an important part of man’s life. In fact, some religious groups believe that evolution has been a way of creating life on earth by God. Beliefs also include the emergence of life from chemicals called ‘Biogenesis’. So, there have been numerous theories regarding the evolution and such will keep on continuing till the mankind’s last breath. Thankfully, science has done a lot of research and so, today we know who our ancestors are and from where we have originated. The evolution is not a thing of everyday use. But, it is important to learn about our biological history after all it’s a hidden treasure in man’s paradise.