Richard Dawkins - The Selfish Gene (The Replicators)

in this chapter talking talks about the general idea of evolution and he describes Darwin's idea of survival of the fittest as a more general law of survival of this table when a collection of atoms is common or permanent enough to deserve a name we call it a stable thing this thing might be matterhorn or a raindrop or what-have-you everything we see around us be they rocks galaxies or ocean waves for all to a greater or lesser extent stable patterns of atoms before the coming of life on earth some rudimentary evolution of molecules could have occurred by ordinary processes of physics and chemistry there is no need to think of design or purpose or directedness if a group of atoms in the presence of energy falls into a stable pattern it will tend to stay that way the earliest form of natural selection was simply a selection of the stable forms and rejection of unstable ones there is no mystery about this it had to happen by definition but all of these examples are just some tales of their slow building up of molecules by just relying on such an explanation you won't be able to build something as we will during an complex as a human this is where Darwin's theory takes over now imagine the early Earth among the plausible materials that you may have found where water carbon dioxide methane and ammonia chemists have tried to imitate the chemical conditions of the young earth they have put these simple substances in a flask and supplied the source of energy such as ultraviolet light or electric sparks after a few weeks of this something interesting is usually found inside the flask a weak Brown soup containing a large number of molecules more complex than the ones originally put in in particular amino acids have been found these complex molecules under the further influence of energy such as ultraviolet light from the Sun combined and give rise to even more complex molecules at some point a particularly remarkable molecule was formed by chance that had extraordinary property of being able to create copies of itself this molecule is what's called the replicator think of the replicator as a template this large molecule is consisted of a complex chain of various sorts our building block molecules now consider the possibility that each building block has affinity not for its own kind but the reciprocal if for one particular other kind in this scenario the replicator would act as a template not for an identical copy but for a kind of negative which would instead we make an exact copy of the original positive for our purposes it doesn't really matter if this remaking is a positive positive process for a positive negative one but the modern equivalent of the first replicator the DNA molecules use positive negative replication what matters here is that suddenly a new kind of stability came into the world and when this happened the replicator started to spread its copies throughout the seas here you should keep in mind that this copying process is not perfect and there will be occasional mistakes interestingly enough these errors are in bad rather improvements in a sense imagine you're copying a book like people did a thousand years ago no matter how cautious you may be there will be occasional errors for instance if you are sitting and copying the Gospels even though there might be some random mistakes the meaning of the original sentence you're copying isn't very likely to change dramatically but what if what you're copying from were copied from other copies and those copies from other copies after a reasonable period of time the impact of these random mistakes will inevitably be dramatic not that I'm using the word dramatic rather than say terrible of course in this case since there are fanatics will believe whatever they've told and they don't ponder upon anything the mistakes of copied Gospels can lead to horrifying consequences but since we're talking about biology are not science fiction we can consider that some of these errors can be improvements in other words it is essential for the progressive evolution of life that some errors were made thanks to these errors the new replicators were not identical replicas but several varieties of molecules all descended from the same ancestor now some of these replicas have high longevity and were more stable than others as a logical consequence it followed that they became more numerous but longevity isn't the only important property that a replica could have other things such as the Conda T of molecules also mattered if you have two types of replicators and one of them makes copies of itself at the pace of one copy a week and the other one copy an hour it's not hard to see which replicator will outnumber the other there's also a third factor remember when I said how erratic copying can be a good thing in an evolutionary sense well now imagine two types of replicators x and y both of them have the exact rate of longevity and fecundity what makes them distinguishable is the numbers of mistakes that they make dude in each copying process it's not hard to see if X makes a mistake on average every tenth replication while Y makes a mistake only every hundredth replication Y will obviously become more numerous how shall we reconcile this paradoxical point with what we've already described as an improvement Dawkins answers although evolution may seem in some vague sense a good thing especially since we are the product of it nothing actually wants to evolve evolution is something that happens willy-nilly in spite of all the efforts of the replicators to prevent it happening to simplify errors have they occurred for evolution to happen but there is an equilibrium needless to say what I've explained to us for about longevity fecundity and copying fidelity happens through natural selection now that we've covered the first important link in the argument let's talk about competition the primeval soup was not capable of supporting an infinite number of replicates of molecules replicators need their building blocks and there are only a finite number of these building blocks although the primeval soup was rich in these building blocks after a while these resources must have been used up and consequently they became scarce and precious as an upshot different varieties of replicators began to compete for them and this is why as a result the less favoured varieties went extinct what follows is that after a world molecules began to develop strategies such as obtaining the ability to break up other molecules of rival varieties chemically and use the building blocks or a list for making their own copies or they discovered how to protect themselves against the rival molecules and other strategies this may have been how the first living cells appeared as a tactic they built survival machines for themselves what you should bear in mind is that all of this happened completely unconsciously all of this is a matter of becoming more stable the story didn't end by building those simple survival machines they have come a long way those replicators now they go by the name of genes and we are their survival machines

Channel: Existentialist Dasein

Views: 9,236

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Keywords: Richard Dawkins, selfish gene, biology, zoology, natural selection, replicators, replicator, evolution

Id: VqXGv1CMDx8

Length: 7min 40sec (460 seconds)

Published: Sat Sep 14 2013