Before going on with this blog I will make one point; I am
an undergraduate and I’m by no means an expert – in fact I am trying to make it
clear that I am not claiming to be an expert. I write this blog based on my
understanding of biology and my current knowledge of the scientific literature.
If anybody notices errors then please feel free to let me know. Also, to explain all the background in careful
detail here would take many thousands of words. I would encourage anyone who
hasn’t done so to read The Selfish Gene for themselves, and ideally other books
about natural selection and evolution.
I was inspired to write a blog on this when I happened upon
a section in an old Open University course book on Human Biology. I remember
being a bit confused by this section at the time I first read it, but
re-reading it now made me realise that confusion about Dawkins’ work even seems
to have crept into university student literature. I don’t wish to criticise the
Open University as I found them to be an excellent organisation, and this is
only 2 pages in a 200 page book. Neither am I suggesting they are challenging
evolutionary theory, this section appears in a chapter in which they talk about
Darwinian evolution and natural selection. There are a few strange arguments
laid forth in this short section, I will deal with one in this blog post and
may follow up with some further posts about some of the other points they make.
An issue with this section becomes clear with the heading
entitled ‘Nature and nurture revisited’. They talk about whether anything “... in
addition to genetic inheritance should
also be taken into account when considering evolutionary change” (italic
emphasis is theirs and not mine). They then go on to say “There is at one
extreme, a gene-centred theory of evolution popularized by the biologist
Richard Dawkins in his book The Selfish Gene (1976), which views organisms as
nothing more than vehicles for ensuring the survival of genes. In this highly
reductionist account, all the characteristics of an organism (behavioural, psychological
and physical) can be traced to the activity of its genes”.
I realise now, as I start to write more on this, it would
actually take a very long time to pick this apart and explain where I am coming
from. I will focus on making two points. Firstly, by including this in a
section about nature and nurture, I think this shows the author’s desire to indicate that Dawkins’ work reflects a theory
of genetic determinism – that it is an extreme view. They wish to suggest that
Dawkins says that genes are the be all and end all - environment, social
interactions and learning are all inconsequential because everything is
explained by the genes. This is the old nature vs. nurture dichotomy, but it is
a false dichotomy and the view is not held by Dawkins or any other major biologist
whose works I have read. Yes, Dawkins argues that it is differences in the
genes that lead to differences in the organism that are then subjected to
natural selection – but he is not espousing genetic determinism nor is his an
extreme view. He is not trying to say that everything that we see in an
organism is a product of the genes alone – in fact if he were to say that (or
if any biologist were to say it) he would be going against masses of evidence
that organisms often show phenotypic plasticity – simply meaning that the same
genes can lead to differences in an organism if they are subjected to different
environments. Dawkins knows full well, and if you read The Selfish Gene (or most of his other major work) you will see, that genes and environment always interact during the
development of any organism.
But, if Dawkins argues that it is the genes that are subject
to natural selection, then isn’t that genetic determinism because the differences
must lie in those genes? No, it is not. By definition the reason for the differences
must lie in the genes, and I would love anybody to explain how we can get heritable change in any form outside
the genes. It is the genetic code that is inherited vertically from one
generation to the next, even a small change in a tiny part of the genetic code could make a net difference in some trait of that organism (although changes in non-coding DNA would not); if the altered trait gives an organism an advantage in its environment it may lead to evolutionary change
within that species (over many generations). If an organism gains an advantage
due to some change of a non-genetic kind (perhaps the organism happens to
source a particularly fruitful food supply which he can monopolize) then he may
survive better than other organisms and have more children. But, here is the
key point, do his children necessarily inherit the food supply? They may do,
they may not. The parent may have depleted it, some other organism may find it,
the environment may change and the food supply may disappear. It is only genes
that are fully heritable (Dawkins calls them replicators); offspring do not inherit
the environment in the broader sense of the word – although, of course they are
likely to live in the same environment as their parents.
Having said all that, any gene whatsoever needs a complex
interaction with all kinds of environmental variables; such as nutrient supply,
hormones during development, temperature, social interaction, the action of
other genes and much more. An organism may inherit a gene that has the
potential to produce a morphological (physical) difference, let’s say in a
kangaroo’s leg musculature to improve jumping, but without the right
nutritional input at the right developmental stages it may not develop any stronger
legs than other kangaroos without the altered gene. In the gene centred view of
evolution nobody is arguing that only genes are involved – but instead they
argue that it is the genes that contain the heritable variation that produces
differences in individuals on which natural selection can act.
And so to my final point (I promise). Later in the section
there is reference to “ ...the holistic view of evolutionary change”, let’s lay
aside this odd terminology as I’ve never heard the term before in terms of
biology, and see what they are driving at. I quote “This approach to an
understanding of evolution asserts, just as Darwin did, that whole organisms
are subject to natural selection”. Hmmmm. Does Dawkins not agree with Darwin? I
doubt you will find many more committed Darwinists working today in
evolutionary biology than Richard Dawkins. More to the point, does the ‘Selfish
gene’ theory suggest that whole organisms are not subject to natural selection? No. It states no such thing. The
point being made is quite subtle, of course Dawkins realises that it is the
actual organisms which live or die; the point is that it is differences at
the level of their genes which provides those differences in organisms on which
natural selection can act. I may be repeating myself or restating an earlier
point, but I think it worth doing so because it seems that this point is often
accidentally, or wilfully, misconstrued.
Well, I’ve gone on for long enough. I feel better for
getting that off my chest – not that I’m kidding myself than anyone is likely
to read all this! However, if anyone reads some, or all of it, then many thanks
for reading! Comments, as always, are welcomed.
Dominic
