May 23, 2007

Evolution and the role of Humans as initiators

In his book titled 'Prey', Michael Crichton talks about evolution in organisms initiated by the pressures of survival. He has elaborated more on this topic in his more famous book, 'The Lost World'. The Darwinian theory of life evolving to adjust to the environment has been studied at large, with the implications of behavioural changes now emerging as a major cause of evolution. Peer pressure has been acknowledged to majorly contribute to the changes a species undergoes.

A scientific report of an isolated female shark giving birth at a zoo in Nebraska has been filed recently. The report cites the case of a female Hammerhead shark which came to the zoo as a baby and been grown ever since in isolation from male sharks. This report gains significance as it is the first recorded event of its kind. But the phenomenon could be more common in the natural world. Pressures induced by humans coupled with natural threats could result in many such changes occurring in the ecological system. The deprivation of a male partner or the rapid dwindling of a population might mount pressure on the females of a species, forcing it to evolve an ability that enables it to reproduce on its own. Scientists feel that such evolutionary actions to sustain life could be against the principle of natural selection, which emphasizes the concept of the survival of the fittest. In an environment where natural order prevails, the passing on of genes to the next generation is reserved for the mightiest of the lot. It is a well documented fact that males compete with one another to establish dominance. Females mate more frequently with dominant males than the others. These natural orders ensure that during the course of evolution, the genes of animals that are most healthy and most adapted to conditions, are passed on more frequently than that of animals that are not. Thus over a period of several generations the dominant genes take over from the lesser ones and this also allows the species to have a natural tendency to adapt to the surroundings as they have acquired the dominant genes.

But artificial pressures created by factors such as humans increase the survival pressure on every species, leading to such instances of 'parthenogenesis'. Hermaphroditism is not uncommon in nature. But it is not widely prevalent either. Suppression of life could force characteristics like hermaphroditism to surface. This reminds me of the classic scene in Jurassic Park, where Alan Grant (Sam Neill) states that 'Life finds a way', when they discover that some of the female Dinosaurs released from captivity begin to change sex and starts to reproduce.

Genetic studies have shown that the difference between the genes of many animals are so few. So the question of how two widely different species could share as much as 90% of genes (if not more) is largely unanswered. It is reasonable to suppose that between species that share genes, differences in characteristics and behaviour are influenced a lot by the living environment. So a radical change in the environment could activate the hitherto inactive genetic characteristics bringing about an evolution in the species.

A conception that Crichton seeks to remove in 'Next' is the common understanding of the time period of evolution. Contrary to popular beliefs of evolution occurring over a period of million years, he states that evolution is continuous. Life continuously evolves in tune with dynamic changes of its environment, which is true.

Humans have altered the environment in a large way. Rainforests have been destroyed, water bodies polluted, air composition being changed. Many species have become extinct or are on the brink of it, thanks largely to mass killings by humans for reasons of profit and the likes. We have been altering the face of the earth and changes have been happening right before our eyes. An interesting outcome of the behavioural theory is that the changes in the behaviour of one species will alter that of every species that interacts with it. Thus no change is isolated and behavioural alterations are bound to have worldwide repercussions. Maybe its the turn of the humans to bring about another major shuffling of the Earth's biosphere.

2 comments:

Filarial June 1, 2007 at 10:32:00 PM EDT  

that is not something that i can agree with .. evolution cannot be forced by isolatng a shark in a tank.. there must be something "fishy" and surely it has not been scientifically validated..

I used to be a stauch believer tht we are the root cause for all environmental changes but after getting here and being exposed to more scientific thnking I have started to doubt tht.. tht doesnt mean tht i believe rain forests should be wiped out and all! but changes tht happen around us are a constant the last ice age wasnt caused by humans and ppl havnt studied the environment over say even 1000 years to be any kind of experts as to predict the next ice age say.. they are just comparing it with thngs that happend a couple of centuries which i feel is not enough of a time period to give any kind of concrete info..

nice tht provoking post man!!

Santhosh C June 1, 2007 at 11:49:00 PM EDT  

I am not saying we are responsible for evolution or that a shark confined will start to evolve immediately.
But issues like survival pressure, isolation, etc., can trigger hitherto suppressed genes (which also depends upon how innately aggressive the animal is, for it to fight for its survival) and result in the animal developing new characteristics according to its living environment. After all it is such small changes like these which when spread out over million years constitute evolution.

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