2 of 2 people found the following review helpful
An Insightful and Challenging View,
This review is from: The Extended Phenotype: The Long Reach of the Gene (Popular Science) (Paperback)
The Extended Phenotype is Dawkin's second book after the Selfish Gene. It was written, I believe for two purposes. Firstly, to address critics of the ideas in the Selfish Gene and secondly, to expound Dawkin's ideas to an audience of professional biologists. This latter point is important for potential readers of this book. This is not an easy book to read: it is assumed that the reader is familiar with some fairly advanced biology. Do not worry though, the writing is of a high standard and the ideas are presented logically and reasonably. It is likely that you will need to re-read some paragraphs and think about what has been written. A book that makes you think is generally a good one.
The first chapters of the book discuss and expand the idea of the "selfish gene", an idea much misunderstood by its critics. In essence, the term means that the basic unit of selection is the gene, i.e. natural selection acts at the level of the gene rather than the individual, or the species (group selection). This is actually perfectly logical, since the gene is the basic replicating unit. For example, a gene for antibiotic resistance in bacteria can be transferred linearly to daughter cells and also horizontally to other bacterial species through conjugation. Clearly, it is the resistance gene that is being selected for. The essentially mathematical idea of the evolutionary stable strategy (ESS) is mentioned here, as it was in more detail in the Selfish Gene. This is an idea from game theory that demonstrates how ecological strategies can arise. The notion of group selection is a misunderstanding that can be overcome by applying game theory. A group of animals may cooperate by gathering food for the whole group, but natural selection would tend to favour an individual who simple took food that was collected by other individuals, with no expenditure for itself. Such "selfish individuals" would tend to have higher reproductive success. Eventually, the group would become extinct (i.e. with no ability to gather food). Thus, in a successful species, an ESS would arise that would be some compromise between the extremes. Thus selection in a sucessful species would favour genes that enable this compromise to exist.
There is an interesting chapter on how genes "behave" in the "ecosystem" of a genome. There is a rare (for Dawkins) and brief foray into molecular biology. The possible evolutionary role of "junk" DNA (non-coding sequences) is discussed. I feel an understanding of molecular biology is essential to undestanding evolution, especially with the gene's eye view of evolution. Although Dawkins is an ethologist (the study of animal behaviour), I feel more attention could be given to molecular biology in evolutionary writing (of which Dawkins is one of the best writers).
Towards the end of the book, the discussion moves onto the extended phenotype, essentially how genes can act at a distance beyond the cell or even organism that contains them. I found the discussion on the interaction of host and parasite genes fascinating, and an excellent demonstration of the extended phenotype idea.
Exactly why do complex multicellular organisms such as ourselves exist? This question is addressed but no clear answer can yet be given. Clearly, groups of differentiated clones i.e. organisms are successful from an evolutionary point of view. It would seem genes "co-operate" in an evolutionary stable way to form a multicellular complex.
Daniel Dennett, the philosopher of biology has added an afterword, and I agree with another reviewer that it may be a good idea to read this before the main text. It provides a helpful overview of the book as a whole.
Overall, I commend this book to those who wish to further their understanding of life on this planet and its myriad complexities. Be prepared to think and question though! I am grateful that the publishers enabled this work aimed at the professional biologist to be published and made available to the general public.