AS I write this, my BBC news app has just blinked on, announcing the discovery of ocean-like water on a far off comet.
Nothing too bizarre about that, except when you start thinking about the evolution of the Earth and how that was able to occur. The answer in short, is through water.
The most basic organisms on the planet, mere collections of cells, began their life in the world’s oceans. But when you think about it, where did the water come from?
There was none on the surface of the planet at its creation, some 4.5 billion years ago so how did it get here? Of course we can never be sure, but a few plausible theories have surfaced and one directly involves comets like the one spotted this week.
After the Earth’s formation, comet strikes were commonplace and impacts frequent.
Because comets are largely formed of ice, they may have given rise to the first water vapour on our planet, later to cool and settle as lakes and oceans. The other theory is that hydrogen and oxygen were released in vast quantities by volcanoes, as they do today. The two elements combined to make water.
Whatever wonderful way water came into being on Earth, we can be certain that the first life-forms evolved from that protective, primordial soup of oxygen and hydrogen.
Now one cannot mention evolution without uttering in the same paragraph, Darwin. As we all know, Darwin sailed the oceans 200 years ago in search of adventure and natural history. The east coast of South America fascinated him to a point by which he began thinking ‘outside the box’ and wondering whether or not “He created every living thing”.
Beetles fascinated Darwin. In one small patch of South American jungle he found dozens of different species, or as he would put it, variations on a single design.
But still the penny did not drop and it would not do so until he returned home to England. But when Darwin rounded the Cape of Good Hope and arrived at the Galapagos Islands, his theories were confirmed.
We all know about the famous finches, ‘Darwin’s Finches’, but in fact these birds were of little consequence to him at the time.
He shot and collected many of them and must have realised the similarities and subtle differences between them, but it was not until he spoke to a British resident of the Galapagos that he began to get really excited.
Today the islands’ most famous residents are the giant tortoises, but back then Darwin knew little of these creatures.
The man told the naturalist that one could determine which tortoise came from which island by the shape of the animal’s shell.
Those with a high arch in their shell came from dry islands, necessitating the need to reach high up and browse on shrubs and bushes, whereas tortoises from lusher islands could find their food at ground level and had no need for an arch over their neck.
These were obvious adaptations formed by natural selection. Darwin was onto the truth.
Today we can read Charles Darwin’s works and tick off the few outstanding assumptions, hopes and expectations that future evidence would be found to confirm as correct.
But we can also see the triggers for ourselves and we don’t have to travel to the Galapagos to do so.
I have more to say on this subject, but for now I will happily spend time watching the bullfinches with their petite bills, being bullied off the bird table by the green finches and their enormous ones and tuck my tortoise away for hibernation in the hope that he will bring me more lumbering, lethargic pleasure next spring.