Seeing as I did not get a chance to go through the last two
chapters of the Blind Watchmaker on Tuesday, I thought in
this email I would give a quick, not too subjective, overview
Chapter 10. ^—One Tree^“
This chapter is about the idea that all forms of life on the
planet today (be they plants, fish, mammals etc.) are all
descended from one common ancestor. That is, if we traced
back through countless generations of all the species today,
we would find that they are all the product of one very
simple organism, probably living millions of years ago.
Dawkins^“ reasoning for this, is that even though every
species today has a different DNA code to buld themselves,
the fact that they all use ^—DNA^“ (or DNA dictionary - as he
calls it) as a method for transmitting their individual
characteristics, shows that everything must be descended from
something that originally used DNA coding.
The quote below (p.270), sums the point up nicely.
^—[I]t is a fact of great significance that every living
thing, no matter how different from others in external
appearance it may be, ^—speaks^“ almost exactly the same
language at the level of the genes. The genetic code is
universal. I regard this as near-conclusive proof that all
organisms are descended from a single common ancestor. The
odds of the same dictionary of arbitrary ^—meanings^“ [DNA]
arising twice are almost unimaginably small. As we saw in
chapter 6, there may once have been other organisms that used
a different genetic language, but they are no longer with us.
All surviving organisms are descended from a single ancestor
from which they have inherited a nearly identical, though
arbitrary, genetic dictionary, identical in almost every one
of its 64 DNA words.^“
Chapter 11. ^—Doomed Rivals^“
In this chapter Dawkins describes a few of the rival theories
of modern Darwinian Natural Selection, and how those theories
fail in their attempt to explain how organisms came to be
here, and why many of them are so complex.
1) ^—Lamarckism^“ Theory - characteristics acquired in ones
lifetime are inherited by the next generation. That is, a
giraffe gets its long neck because in previous generations
individual giraffes had to stretch to get to high leaves,
which stretched their neck muscles and bone. These stretched
muscles were passed onto the giraffes offspring, thus, the
next generation were born with necks longer than the ones
before. But the problem here, states Dawkins, is that things
that happen in an organisms lifetime cannot influence its
genetic code. No matter how high a giraffe stretches, its DNA
code will not reorganize itself so that the offspring will
have a longer neck.
* - He then goes on to say that the way to see DNA and genes,
is as a recipe (epinergic); rather than as a blueprint
(preformationistic). In a recipe, you have step-by-step
instructions to make something which have to be followed in
the correct sequence. In a blue print you have an overall
picture of what you are making. Making things from a DNA code
is in a step-by-step process, in which steps cannot be missed
2) Mutationism Theory - that changes that have occurred
in a species during their evolutionary history are all due to
random mutations. Giraffes got longer necks because of
mutation in neck length. But, the theory also states that
mutation is biased towards improvement - giraffe neck
mutation was biased towards longer necks - though it does not
say ^—why^“ mutation is biased towards improvement.
3)Creationist Theory - the idea that all the complex
organisms on the planet today were put there by some divine
being (God, Aboriginal Ant Eater, Buddah, etc.). Or that
divine intervention has occurred at times during evolutionary
history to push one species in a certain direction - for
example, made humans rulers of the animal kingdom. Dawkins,
the atheist, ridicules the creationists ideas, and pokes
humour at them - this humour poking is a common trend
throughout the book - which I think is totally unnecessary.
Modern Darwinians see Natural Selection as the only way to
explain the existence of complex structures - like the eye -
and complex organisms - like human beings - which exist in
the world today. The Dawkins way of thinking of natural
selection (if I got it right) is that:
1)Through reproduction, random mutations are ^—offered up^“
into the population of a species.
2)These mutations are not totally random but are under the
confines of physics, and embryo development - otherwise
evolution would have offered up things like ^—dragons^“ for
3)Also, mutations are usually in the direction of
what existing matter the organism has already - stumps turn
into fingers over a period time - rather than just creating
something totally random.
4)And, the mutation is never massive - such as a man with
5)Those mutations ^—offered up^“ into the population which are
helpful in aiding the species to reproduce or survive in that
environment, will then be passed onto the next offspring -
simply because they are successful (^—nothing succeeds like
6)Those mutations offered up into the population
that do not help, or even hinder, the individual to survive
in their environment will not be passed on because that
mutation has died within that part of the population.
I hope this is the correct view?
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