I’ve become intrigued by how we’ve managed to evolve the complexity of the human being, particularly after reading the following: “The inner ear is where the receptors for hearing (and balance) are contained. Specifically, the cochlea is a liquid filled (snail-like) spiral structure that internally widens in the middle such that different vibration frequencies will have heightened energy at different (specific) locations along the structure that cause the membranes to be displaced. Inside the cochlea, liquid filled tubes (scala) are separated by membranes, one of which (the basilar membrane) contains rows of hairs (the stereocilia) that cause neural activity when the membrane is displaced nearby.”

I thought it would be interesting to do a rough calculation of how long it would take for us to get from our originating bacteria to where we are today based on my top-of-the-head estimates of the number of mutations required and how many entities were contributing to them.

W: Number of mutations required: 10 million – 610 million: average 310,000,000

X: Number of generations required for a successful mutation on top of a previously successful mutation: 10,000 – 210,000: average 110,000

Y: Number of entities/couples contributing to generations: 1 – 100,000,000: average 50,000,000

Z: Number of years between generations: 0.01 – 20: average 10

Using the averages:

For W mutations to occur, taking X generations for each one, would take 310,000,000 x 110,000 generations

If there were Y contributing entities/couples, this would take (310,000,000 x 110,000)/50,000,000 generations

If there were an average of Z number of years per generation, the overall process would take     [(310,000,000 x 110,000)/50,000,000)] x 10 years = 6,820,000 years

Despite this being a possible result (considering the earth is apparently 4.5 billion years old), it is clearly wrong since the earliest microbes found in rocks are estimated to be 3.7 billion years old. Anyway, I’m feeling distinctly uncomfortable about all the assumptions I’ve made in the above calculations – essentially every element is totally flawed and the whole calculation is worthless. In any case, I’m still left with the feeling that, to have evolved such a huge set of such very highly complex and interworking physical mechanisms, completely by chance, seems to be highly unlikely. So, I’m left with a lurking suspicion that somewhere in the originating DNA, or early equivalent, was a programme of instructions….

POSTSCRIPT: Quite by chance I watched part of “Attenborough: 60 years in the wild” on the BBC this morning – the day after I posted the above material. The programme is highly relevant and I recommend it.