WE delved into planet Earth’s turbulent history of the last billions of years, the most difficult part of which had been the search of origins of life. What seems to be a relatively easy job turned out to be a pretty hard nut to crack! Many scientists and researchers hold differing views on various parts or portions of the causes that culminated into what is called, or understood, as the origin of life. Nevertheless, there is a broad agreement on the ‘final outcome’. That is the story as I pieced it together for you.

We now fully understand that things like viruses, bacteria, eukaryotes and prokaryotes etc., are our earliest precursors, or ancestors that go back a couple of billion years or so (give or take a few million years!). And I tried to tell you how it took more than half that time for life to ‘develop’ into millions of complex and bizarre, but also, beautiful forms, probably the most intelligent and vibrant form is us, the Homo-sapiens.

Most of you know about dinosaurs — those terrible ‘lizards’ of yore, that they were complete animals but could not do anything in their own defence when it was time for them to bow out catastrophically. It is believed that an item belonging to outer space struck them suddenly, wiping them out nearly in total, some 65 million years ago. Strong geophysical evidence points in the direction of a large comet, or an asteroid as most likely the culprit.

While I tend to agree to this hypothesis, I also hold the ensuing lasting ‘winter’ that must have lasted for 50-100 years, raising dust and fine debris into the atmosphere, blocking sunlight that feeds all kinds of grasses and flora which may have ended up the feed for these great animals and support animals too. The absence of flora resulted in the giant animals’ tragic elimination (which opened the way for the gradual growth and planet — wide proliferation of mammals, starting probably with the shrews); until such time when gravity overpowered the suspended clouds of dust and debris bringing them down to Earth where they actually belonged. But by that time it was too late for the hapless dinosaurs.

So, the place of the irrepressible Dinos was usurped by the vast variety of mammals. Some species of dinosaurs have managed to survive to this day (such as tortoise, alligators, lizards of all kinds etc.,) and are likely to co-exist with the remaining beasts, without coming into conflict with each other in a big way.

However, it may be noted that all descendants of fish that ventured out on land, and evolved further there over the next hundreds of millions of years, these amphibian animals, reptiles, birds and, later on, mammals, all of them possess internal skeleton. The mystery as to why almost all land and water (aquatic) animals have vertebrae or internally placed skeletons whether made of bones or cartilage (except some worms, wasps or a few others) defies my imagination except as a means to obtain locomotion to escape, or to hunt their prey.

The earliest vertebrates may have first appeared about 500 million years ago. Then these characteristics spread thick and fast among the other existing groups of animals, until it became a “universal” phenomenon.

What is evolution after all?

Evolution can best be described as: the gradual development of a living organism which consciously select and choose the best of the available features for itself, with the passage of time. They either perish if they cannot cope with the ominous change, or, adapt themselves to the said change.

The first time I actively thought about it was in the early 1990s during my first visit to Sri Lanka, that beautiful country full of animals. They had (and still have them!) a large population of crows, each with a large and elongated beak, much larger than our crows. How else this can be explained except for the reason that they ‘need’ it in order to survive.

Again, evolution, as you might agree. Animals, as people, may differ with difference in area, or region, or, call it habitat. For the same reason, the Australian cows are visibly bigger and larger than their cousins in Pakistan, for instance.

Compared with other theories, or laws, the laws governing evolution provide us with far more food for thought, and are appealing in their content and substance too. But it is for you to work out one way or the other. Study all laws until you reach a conclusion of your choice. Keep in mind the billions of years available to us to play around with evolution.

Near the end of debate carried on in a large number of articles on planet Earth, we shall discuss the appearance of Man. The 4.6 billion years versus a mere four million years set aside for the most intelligent, the most crafty, the most resourceful, occasionally the most devious of all animals — determined to wrest control of the blue planet from all animals, without meeting any resistance worth the challenge. Poor animals! See you in the next issue!