I don’t understand how evolution works. And I am not sure if I believe in evolution at all.
Perhaps I should go and read a good book about it, which I haven’t had the good fortune to do for all these years. But as things stand, my layman interpretation of evolution leaves large holes which are slowly overwhelming my schoolboy belief in evolution itself.
The big question I have is about the dynamics of evolution. Sure, I get the idea of the ‘survival of the fittest’ – it’s obvious that if there are a group of a thousand creatures, ostensibly of the same species but in which one group had a higher chance of success, that group would eventually dominate (and perhaps exterminate) the other group.
The hookey parts of evolution come up when people start talking about ‘random mutations’ causing adaptations. This is wholly unbelievable to me.
I heard an example many years back – in my school days – and I do not know if it is factually correct, but it nonetheless is a good example of fallacious reasoning about evolution. Apparently, a tribe living in the Amazon rain-forests carried wood through large tracts of jungle as part of their livelihood. In some convoluted fashion (which I cannot remember), this wood-carrying ability was critical in their ability to eke out a living in their hunter-gatherer way of life. The way this tribe would carry timber was to balance logs on their shoulders, resting them just below the neck.
As the story goes, when this tribe was studied by anthropologists, it was found that they had abnormally thicker skin in the shoulder area, which was much more resistant to chafing or injury. This was held up (for me) as a classic story of evolutionary adaptation. The hypothesis was that a group of people in this tribe had thicker skin (for random reasons), and this created a higher chance of survival, therefore the trait for this was propagated through the entire community over a few generations.
(I am reminded of a racist joke that one of my friends told me some years back about why some Africans are so tall – because they have to jump for food aid packets dropped from airplanes, the taller ones have the evolutionary advantage.)
A more credible example is the high prevalence of sickle-cell anemia among people living in those parts of Africa that have a high risk of malaria; while sickle-celled RBCs have health risks, these are more than offset by the benefit of having a lower chance of contracting (and dying from) malaria, so it confers an evolutionary advantage. And according to evolutionists, while the first sickle-cell person was a random mutation, this conferred such an evolutionary advantage that a majority of the population eventually acquired this characteristic.
My concern with this theory is the extrapolation from ‘increased chance of survival in one organism’ to ‘widespread prevalence in the species’. I think this would be true only in the most extreme cases, where the conferred ability is so dramatic that it somehow creates a ‘superman’. In the timber-carriers example, imagine that one individual suddenly and randomly was born with thicker shoulder skin. Yes, this confers an increased chance of life and procreation – but how much increase? Considering that there are probably a million other factors that affected this individual’s longevity and fertility, I would say the increase is likely to be less than 1%. It would be a miracle, more or less, for this 1% to pay off in the form of enough discrimination in life and reproduction that it becomes widespread among the entire species.
So the chance that an adaptation is propagated because of a single mutated individual is low.
Another objection is the precise nature of gene mutations that cause such a specific ‘enhancement’ to occur. Is it a single gene that governs sickle-cell production in a human being? It seems a bit unlikely. And if the mutation hit more than 1 gene, what is the likelihood that the only effect of the mutation is a single, specific enhancement? It seems far more possible that, instead, the mutation would cause a disability – the inability of the individual to perform certain acts – rather than an enhancement. So this whole random mutation concept has a stink of improbability around it.
What if mutation took ‘multiple paths’? That is, instead of originating in a single individual, it originated as a mutation in, say, 1% of the population over 1 generation. Then the chances of the 1% advantage in 1% of the population eventually translating into improved ability to live and multiply is much higher. The risk is lower, the chances work out.
But for this to happen, there is an important missing link. And that’s the causal link between the environment and the mutation.
The theory of evolution would be much more compelling if there was a mechanism by which the livelihood of a wood-carrier somehow worked its way into that individual’s DNA over a period of time. For example, if repeated (non-fatal) malaria attacks somehow caused the mutation rather than the other way round (viz. that the mutation caused the malaria attacks to be non-fatal). In other words, the human body (or more generally, any living being) has a feedback cycle by which an environmental factor – such as lighting, or stress, or cell death – finds its way into the DNA as a sort of ‘micro-mutation’. The body would either keep or reject this micro-mutation through a process of internal Darwinian survival, until eventually this mutation was transmitted to the next generation. The key here is that since the mutation is not random, it happens in multiple organisms within the species simultaneously (albeit randomly) and therefore dramatically increases the survival differential between the haves and the have-nots (so the speak).
I have long been fascinated by this possibility for a very selfish reason – because if such a feedback cycle exists, it represents the holy grail of Engineering. That is what we should mimic as engineers – a design process that somehow triggers mutations in existing organisms, causing them to ‘develop’ better solutions to the problems that their environments throw at them.
More on this in a later post. But I am very eager for reading material – if anyone has a reading list for evolution, please send it to me!