The Flip Side of Evolution?

Many people who visit the Galapagos have a fascination with Darwin, or Evolution, or Biology etc. And while there, Im sure that most people spend at least a little while thinking about the associated ideas in their own way... Im no different :)

And here is what I was thinking:

Apparently, about 70% of the plants and animals on the Galapagos are endemic... which means that they occur nowhere else but there... Amazingly high proportion of endemisme!

So, all those plants and animals must have arrived on the islands as castaways and as representatives of species from other places. Now, those parent populations are generally quite stable in their genetics (which is why they are species in the first place) Its the genetic diversity in the large parent populations that stabilise the species (rather than it being just a bunch of mutants!). So, it seems that a large population with the normal cross-breeding of "random mating pairs" seems to reduce the mutation rate... Im speculating a bit there but I think Im right.

In effect, any random genetic mutation that does occur is quite likely to disappear in the next generation or two as the interbreeding "dilutes" the mutative gene... That is unless there is strong selective pressure from the environment... in which case the "effective" breeding population is in fact the small number of mutant members who produce viable offspring (The others fail and are "selected out" !)
Alternatively, if the selective pressures are much more mild, it is still possible for species divergence if there is a "sexual selection" process acting at the same time and in the same direction... Which is to say that if the small group of individuals (with the mutation in question) in the larger population also "choose" to prefer to mate with each other rather than the "random" pairings of the larger group...
But, the combination of a "beneficial physical mutation (or at least not detrimental)" AND a "preferential mate selection mutation" is FAR less likely to occur than the single mutation... Hence the larger populations are quite stable.


So, the corollary to the large populations being stable and effectively discouraging speciation is that the smaller populations are less stable and encourage speciation.
But what I refer to as speciation is really just random mutations combined with selective environments... And, true enough, we are constantly reminded of the risks of too small a group of breeding individuals resulting in "in-breeding" and genetically inferior/weak off-spring. It happens quite a lot in specialised breeds of cats and dogs etc, and environmentalists are always very concerned about maximising the genetic variety in breeding programs for endangered species like Pandas and Cheetahs and Snow Leopards etc...

But, thats kind of my point, EVERY species MUST have originated from just a few individuals with a particular genetic mutation and from there they became numerous and stabilised into a species.
I think the issue is that if you want to "keep things from changing" then you want a large group and lots of cross breeding... But, if you want to encourage adaptation, then in fact you WANT a SMALL group with INBREEDING as well as strong external selective pressure!

The down side of this is that the chances are that a great many of the "random" mutations that occur in the in-bred group will in fact be detrimental to the survival of the "afflicted" individual and will result in it and its offspring being "selected out"!

Hmmm
... And this all has consequences for Humans I think!!!
Particularly if we consider that the same evolutionary process that results in physical changes in a species is also effective in Behavioural changes in a species (sexual selection being but one example)... Thats definite for behaviours that are hereditary (like mating displays in birds for example) but I think it still has a strong influence over learned behaviours too...

Now, if we humans need to adapt to a changing environment then the chances of us achieving that with the extremely large population base we have are Very low.... But we do appear to be rapidly changing our environment (... And those external selective pressures are "building" as the planets ecosystems are changed by our undoubtedly destructive habits)
And the human population continues to rise and the planet continues to decline in its environmental health/stability...

Of course, its all well and good to say "Yes, but we are Intelligent beings and we can choose to change our behaviours at will, and we can use our intelligence to adapt the physical world to us rather than us having to adapt to the world... So, what your talking about is just bunk!"

But,in fact, I dont think thats quite true.... Yes, we have the potential to do it, but if you take a good hard look at what we actually do then you will see that we rarely make the "intelligent" or rational choices, and we almost always make the emotive and instinctive choices... Even when its obviously Not rational.... The reality is that much of our behaviour is operating "outside" of our intelligence.

Back to my original theme...

Now, Nature always provides solutions!... And if a large population will not adapt to changing environment, then it WILL be reduced in size either to extinction or to the point where the smaller surviving population DOES adapt!
And as much as we might like to think that we are "outside" of the rules of nature; Truth is that we are not, and that this rule applies just as much to us as any other life on earth.


And so now Ill go for some WILD speculation... Unsupported by any real hard evidence and the product of my own prejudices :)))


Im pretty sure that within my lifetime, there is going to be a massive humanitarian crisis as population grows and environmental degradation accelerates and the inevitable result that food supplies for people are insufficient!
I strongly suspect that the human population will continue behaving as it has done (ie badly as far as sustainability is concerned) and will continue to increase in numbers, right up until the point where the "Unsustainability" problem is "brought home" in that completely unavoidable way that nature has!, And then the population will be forcibly and severely reduced in size (probably starting in the economically poorest, and environmentally most compromised parts of the world and spreading from there)... either to extinction, or to a size where the remaining population modifies its behaviours to be "sustainable"!

And how long will it all take?
Well, as I said, I think it will be well under way within my life time...
But it could take years or decades or centuries... I just dont know... But, there is a significant possibility that it could happen VERY quickly... Like Lake Atitlan in Guatemala suddenly turning green after many years of apparent "tolerance of pollution".


A couple of little examples of this "large stable, non-adaptive population" overwhelming an included "small adaptive population" sort of thing:

Environmental example:
On the shores of lake Atitlan there is a little restaurant. And the owner is an expat and he is thoughtful... and he grows his own veggies organically, and he has composting toilets and he does recycling, and has a minimal power usage etc... And his little restaurant is popular and moderately profitable.
In short, he cares and is aware of his impact on the environment.... The desirable adaptation.

But, he lives in amongst many many other people who are not aware and dont care... The undesirable but stable population group.

And, despite the presence of the desirable adaptation, (and despite his example and encouragement to others) it is swamped by the stable population and the lake is turned green regardless of how "well behaved" this individual is... Too bad, so sad!

Business example:
I worked in high-tech back in the days of the "Tech Boom". And when the "boom" was happening, companies were "growing" at incredible rates (quadrupelingin size in a year or less) and engineers were being hired as fast as they could get them to support this growth.... But to get the engineers the companies needed to grow, the companies had to offer them huge salaries... and promote junior people to senior positions way before they had the skills etc... It was all way out of control, and you could see that these hiring and promotion behaviours were incredibly bad for the companies in the long run... Im sure the executives in at least some companies were well aware of the future consequences of what they were doing...
BUT, they effectively had NO CHOICE...They were carried along with the "market".
As public companies, if they did not "grow" at the rates expected, then the stock market funding would not be given to them (it would go to the companies that did deliver on the expectations instead) and the "sensible" companies with "logical" hiring and promotion practices and moderate growth rates would have no funding and would doom themselves to "extinction"... and that certainly happened.
So, even companies who could see the crash would come and the consequences of poor hiring and promotion practices had to do it anyway in order to survive for the moment...and they doomed them selves to having to deal with the very unpleasant consequences of the crash when it came...
The problem was of course that no-one could predict exactly when the "crash" phase would actually occur... so they couldnt make good use of the desirable adaptation...




But, then again, What the hell do I know???
This is all just speculation :)))