It is 200 years since Charles Darwin, the biologist and pioneer of evolutionary thought, was born. British television and radio have been running a series of programmes on him.
Evolution is such an obvious concept that it is difficult to imagine today how shocking it was to many of the experts of his day. Such are intellectual revolutions - shocking at the time, but often obvious and natural afterwards.
I recently read on Wikipedia about DNA. To a non-biologist like myself, the way its basic structure combines to form and control life is surprisingly easy to understand. The organisation of sub-molecules in the big DNA molecule makes them convenient to rearrange. Some rearrangements are novel, so you can get new species. Cancer can be caused by things getting in the way of the rearrangements, which is why some chemicals are carcinogens. And there are lots of other logical molecular events like that corresponding to medical events. I hope I haven't misrepresented DNA and biology. As mentioned, I am no biologist.
I do have a couple of questions. Perhaps readers know the answers.
The first is that it has been said that DNA is the basis of life (replication and development or some sensible arbitrary definition) throughout the universe. Are there no other molecules which serve the same function in natural occurrence? RNA seems to do something analogous, although admittedly for simpler organisms and with a very similar structure. And silicon based organisms are possible, no? Self-replicating computer programs would be life by some definitions. And other long-chain molecules could serve, either by manufacture or natural occurrence?
The second is that dogs show much wider variation in shape than cats. Is their DNA much more flexible in its organisation, like having a building block which consists of three distinct detachable shapes rather than a block which consists of three shapes where two of them are identical?
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2 comments:
You seem to have a lot of beliefs about evolution without much knowledge.
Perhaps you should do some more reading, starting with how the first organism began and what it had for food.
Advanced organisms presumably require increasingly concentrated sources of energy. Carbon based compounds, with their strong long chain links and weak cross chain links, are convenient sources of energy by breaking their weak links, which may account for why animals eat other carbon based things rather than, say, rocks. The weak/strong bond combinations helps also explain why carbon is a basis for advanced life. Consideration of the chemical orbital shells could establish the uniqueness of carbon in this respect. It is not clear to me that non-elemental long chain molecules could not have the same property.
DNA could also be subject to similar uniqueness identification analysis through examination of necessary properties for complex life, like replication, mutation, formation of acids and bases and catalysts, and molecular weight. Given the unlimited number of molecules and the fact that chemical properties are often not inherited from their components, demonstrating universal uniqueness looks like a big job.
Conceivably, cats show greater binding strength than wolves on the parts of their genome expressing appearance phenotypes, accounting for the larger number of dog species. The genomes are probably on the internet so the guess could be tested. One could theoretically calculate the number of species of both for a given breaking energy applied to the molecules.
Thanks for the post, I may have taken weeks to reach the conclusions above in its absence.
Best wishes.
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