My question is about the adaptation (or seemingly so) processes. For example the camouflage features in certain species seems too specifically ‘designed’ to have resulted from a purely random mutations. I read about the ‘intermediate advantage’ arguments; but I still feel the possible number of mutations should be too huge a number for mutations alone to have produced such specific outcomes - even after taking into account the grand nature of evolutionary time scale (millions of years).


My question is -- Is it really that I am failing to appreciate the truly grand scope of this time-length or is there some ingenuity (details) in the process of mutation that causes some bias towards generating genotypes that are not necessarily random? I understand natural selection does the trick, but my problem is, for natural selection to have picked the ‘good’ ones they must have first been present in the gene pool resulting from a purely random process (mutation) - which leaves me somewhat unconvinced.

Thanks a lot for reading.

Yes, you are failing to appreciate the effect long time scales can have. Even slight advantages, like partial camouflage, can go to fixation over long enough time scales. Of course, over those same time scales further mutation and selection occurs, resulting in a kind of feedback loop making the camouflage better and better adapted.

All organisms contain mutations that their parents didn't have, including you. These don't need to be beneficial to persist, just neutral, which is almost all of them. Benefit/detriment is of course contextual, so a mutation which is neutral or bad under one circumstance can become beneficial in another. In the case of camouflage, I can easily imagine how small variations in pelt/feather/skin colour and patterning can occur within a population. How many different coloured dogs or cats or rabbits or chickens or pigeons are there? Or humans for that matter?

Lets say that a pack of wild dogs are dislodged from their planes territory and into a more wooded area. This new circumstance could make their existing camouflage somewhat less effective, and so selection would favour new camouflage patterns or colours. This selection would initially occur from that existing variation, and in subsequent generations this would tend to be further refined with the new mutations each generation inevitably produces. Over the long time scales at which evolution operates this produces camouflage adapted to the local environment.

These same principles apply to pretty much every aspect of the organism in question; limb length, size of teeth, litter size, method of spore dispersal, leaf size and composition, amount of water required......