Monday, 28 June 2010

All's Relative

I want to dedicate this post to some basic popular science stuff; I feel it is necessary given the regular frustration I feel whenever the blatant ignorance of too many people around me in the basics of the theory of evolution becomes apparent. No wonder this happens; between religion, bad science education, and a culture that still regards humans as the center of the universe one cannot blame people for being ignorant; one can only try and educate, even if by a tiny bit.
To sum up what I would like to say, I'll start by stating what should be obvious: we are all relatives. I don't just mean that you and your mother are relatives; I mean the following:
  • You and every other human being that ever lived are relatives.
  • You and that chimpanzee you see in the zoo are relatives.
  • You and your pet dog are relatives.
  • You and the dinosaur whose fossil you see at the museum are relatives.
  • You and the fish you had for dinner are relatives.
  • You and the potatoes that made the chips you ate with that fish are relatives.
  • You and an e-coli bacteria are relatives.
The point is simple: every living thing identified upon this planet thus far shares a common ancestor with all other living things. In the case of you and the chimp, that common ancestor of ours is your great-great-great grandfather that lived around some six million years ago and probably looked very ape like (not that we don't look ape like; we are an ape type); that grandfather also happens to be the chimp's great-great-great grandfather, only on the other side of the family.
In the case of you and and your dog, that greater great-great-great grandfather of yours that lived some hundred million years ago (give or take; feel free refer to The Ancestor's Tale by Richard Dawkins for more refined estimates). That common ancestor probably looked like some sort of a shrew and it probably spent its life hiding from dinosaurs.
The same applies elsewhere, only that for your common ancestor with the potato you need to go significantly further in time; for the e-coli common ancestor you need to go back billions of years.

How do I know that? There's plenty of evidence to support all of the above, but the most effective way to demonstrate the certainty of the above is through a basic thought experiment.
Consider the following two facts, about which there is no controversy:
  1. Living things are complicated. Given their complexity they don't just pop up; we need to go through great lengths to explain how they come about. In other words, the probability for life just spontaneously appearing is small.
  2. All the living things we know use the same genetic code.
Now, consider this: If not all living things are related to one another, that immediately implies that life on earth has started twice or more. Not only that, those two or more living systems have evolved to have the exact same genetic code. Given that the probability for that happening is so incredibly small we can and should rule it out as impossible, which therefore leaves us with the inevitable conclusion that we are all relatives and that life as we know it has risen only once.

Scientists at the David Hillis lab came up with a radial tree of life (the above drawing) that shows exactly how, according to the evidence before us, all living things are related. Note how "mammals", the branch us humans belong to, are just another one of many branches along the tree of life. We're so elusive it takes time to find us!
This brings me to the conclusions we should be deriving from this true view of ourselves as one of many related living beings upon this planet. When living things are presented in a form such as the radial tree of life one is unable to identify any special supremacy in human beings compared to other living things. We like to think of ourselves as the pinnacle of "creation", but the reality is that we're just one branch. If anything, it's the microbes that are ruling this world, and they'll continue to be here long after we're past our due date: did you know, for example, that the number of microbes in the seas is estimated at 36,000,000,000,000,000,000,000,000,000,000? Our population of near seven billion appears a bit shy next to such a vast number.
My point is simple: when we look at the world through the correct evidence based view where all living beings are relatives of equal merit, the world looks different. Us chopping down trees, us treating the animals we eat in horrendous ways... Suddenly all these things appear bad. You wouldn't do them to your cousin, so why are you doing them to your remote cousin?

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