Thursday, February 12, 2009

Darwin 200: Let us remember a great Scientist and a revolutionary theory



Today the World is celebrating the bicentenary of the birth one of the greatest Scientist it has ever seen, Charles Robert Darwin (1809-1882).

His theory of evolution by natural selection, now the unifying theory of the life sciences, explained where all of the astonishingly diverse kinds of living things came from and how they became exquisitely adapted to their particular environments. Darwin demonstrated that the difference between humans and other animals is one of degree not kind. Darwin's writings produced profound reactions in geology, zoology, taxonomy, botany, palaeontology, philosophy, anthropology, psychology, literature and theology, many of which are still ongoing.
Darwin presented compelling evidence for evolution in On the Origin of Species [1959] and, since his time, the case has become overwhelming. Countless fossil discoveries allow us to trace the evolution of today's organisms from earlier forms. DNA sequencing has confirmed beyond any doubt that all living creatures share a common origin. Innumerable examples of evolution in action can be seen all around us, from the pollution-matching peppered moth to fast-changing viruses such as HIV and H5N1 bird flu. Evolution is as firmly established a scientific fact as the roundness of the Earth.





And yet despite an ever-growing mountain of evidence most people around the world are not taught the truth about evolution, if they are taught about it at all. Even in the UK, the birthplace of Darwin with an educated and increasingly secular population, one recent poll suggests less than half the population accepts evolution. Even lesser number of US citizens believe in it.In US controversy regarding Creation and theory of intelligent design continues. Many Islamic Countries[Saudi Arabia,Sudan] do not teach it in Schools.


Some misconceptions about Evolution


Evolution must be the best-known yet worst-understood of all scientific theories. Here are some popular misconceptions


Natural selection explains everything we see today
There are two fundamental mechanisms of evolution. Natural selection is only one of them. The less realised mechanism is the random genetic drift. The anti-evolutionists fail to recognise genetic drift. Darwin did not know about it either.
Genetic drift is the random change in the genetic composition of a population due to chance events. It all boils down to how the two alleles, one inherited from each parent, get affected. The smaller a population, the bigger the role of genetic drift.


Evolution always increases the chances of survival


The theory of survival of the fittest is widely misunderstood.
Evolution does not always increase the chances of a species’ survival. Mutations, which provide the vital mechanism for natural selection, need to be helpful.
Detrimental mutations are a common phenomenon. Species may not survive if such mutations happen rapidly and if they keep accumulating.
Again, if the rate at which mutations happens is slow, then a species may not be able to cope with changing environmental conditions.


'Survival of the fittest' justifies 'everyone for themselves'


Fittest does not always go with the most aggressive or strongest species. On the contrary, the ‘fittest’ label may be more appropriate to animals that are the most co-operative like the bees, the best camouflaged or the cleverest. The "fittest" can be the most loving and selfless, not the most aggressive and violent.
The ‘lowly’ sponge and the jellyfish with a few simple cell types have persisted from the Precambrian, and have changed very little. It is the same with fungi, mosses, sharks, and horseshoe crabs.


Man occupies the pinnacle


Till recently scientists believed that “modern invertebrates, fish, amphibians, reptiles, birds, mammals and humans were living representatives of successive evolutionary steps toward a more complex brain,” (Scientific American, December 2008).
But the fact is that complex brains — and sophisticated cognition — have evolved from simpler brains multiple times independently in separate lineages.
This can be seen in molluscs such as octopuses; in bony fishes such as goldfish and, separately again, in cartilagenous fishes such as sharks and manta rays; and in reptiles and birds.

On his birthday today let us applaud the contribution of this great scientist to humanity.


Adapted from Darwin online and New Scientist.Click here for more misconceptions

2 comments:

  1. Indeed complicated..lol..Sorry..

    I rememeber reading(studying) all this is detail,hell I tried to crack Kerala CAT twice.Both times,ended up in Ayrveda and Homeopathy..Joined BHMS and went for some time..Afetr second try,joined for Engg,but biology is my fav subject.

    loo..why did i tell this now,just recalled all my memories down the lane,where Sunny Sir (PC Thomas) would shout all this ..lol..

    Can i ask something-Why didn't all monkeys become humans?

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  2. Nimmy, so that is how the World missed out on a compassionate doctor -: Sad story.

    I think I made the post complicated.Sorry.Will edit and make it more understandable when I get time.
    Evolution never took place in a linear fashion.Humans did not evolve from monkeys. Humans are more closely related to modern apes than to monkeys, but we didn't evolve from apes, either. Humans share a common ancestor with modern African apes, like gorillas and chimpanzees. Scientists believe this common ancestor existed 5 to 8 million years ago. Shortly thereafter, the species diverged into two separate lineages. One of these lineages ultimately evolved into gorillas and chimps, and the other evolved into early human ancestors called hominids. More information from http://www.pbs.org/wgbh/evolution/index.html

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