# 15: Climbing Mount Improbable
Richard Dawkins
This book has been sitting on my shelves, gathering dust for probably about a year. I finally got to reading it and have re-kindled my interest in evolution. I first starting reading Richard Dawkins in and right after college - the Selfish Gene is a classic. I hope that I will continue to read up on the subject, and maybe even find an on-line course or two to take. But as you know, there is often a difference between what one would like to happen, and what actually does happen.
Anyway, onto the book. He starts by talking about the fig, and how figs can be considered one of the pinnacles of evolution. A highly improbable peak that has been climbed very slowly and surely by the combination of heredity, variability, selection pressure and lots and lots of time.
This is Dawkins major point, he uses the metaphor of slowly climbing a mountain as an explanation for how the theory of evolution explains all the complexity and diversity of life. There are many, many intermediate steps - each providing for more "fitness" than the previous one - there can be no sudden leaps upward, and no going downhill. It is all very gradual, and the culmination of all these steps is the life we see around us. The reason all of this is so interesting to me is that, in a way, it addresses the meaning of life.
He address all sort of issues - spending many pages to show eyes have evolved anywhere between forty to sixty different times. This is a major challenge, because even Darwin had some doubts. Then he show how easy it is (relatively) for many species to develop flight, and pointing out that before the full fledged flight of an eagle, there is floating and gliding. There are "gliding" snakes to go with the frogs, lizards and squirrels in the forest. And in the water, not only flying fish, but even flying squid! All can be explained by small steps, going up the mountain slowly.
He admits that there is much more work to be done, and many mysteries remain to be solved. One of the interesting questions (chapter 6) is the debate between selection pressure and genetic variation. Is the pressure of selection enough to create anything? These are the selectionists. The other side agrees that selection drives evolution, but argue that it must have enough raw material (genetic variation) to work with. To the question as to why pigs do not have wings - the first camp would say that it is not an advantage for them to have wings, the other extreme would be to say that even if the pressure existed they would not have wings because there were never any "mutant wing stubs" for natural selection to work upon. This leads Dawkins to discuss his multi-dimensional "Museum of all Possible Animals", somewhat based on Borges' idea of a library with all the possible books in the world. He leans towards the selectionists, and feels that the empty corridors and space in the museum probably exist because selection did not go there. He also discuss magnets or "attractors", introducing the idea that there are pockets of "types" of animals or "types" of design which have been "created" by natural selection.
He then focus on the evolution of evolvablility - kaleidoscopic embryology - in chapter 7. He suggests that certain species may have a type of "embryology" that in some sense may be 'better' at evolving than others (224). These species in general work through segments and cluster of segments that are usually symmetrical and are arranged in a line from front to rear. His examples are the arthropods, mollusks, echinoderm and vertebrates. This "structure" provides a fruitful playing field for evolution to work on.
In Chapter 8 and 9 he re-hashes the "Selfish Gene" theory. In which he points out that the point of DNA is to replicate itself, and that you can make the argument that an elephant, bird, bee or flower is just an intermediate step used by the DNA to replicate itself. It is amazing to think that DNA is shared by all living beings - there are so many different ways for it to replicate itself.
And in the 10th chapter, he returns to the figs .. telling a truly amazing story of the complicated symbiosis between figs and wasps and underlying how evolution (going step by step) can climb the tallest, complex and improbable peaks.
Some other ideas that are worth following up:
Convergent Evolution: how different species arrive at the same general "effective" design in different environments
How Bill Bryson starts the brief history of time .. that everything alive can be traced back in a direct line for billions of years, back to the beginning of life. Our genes form an unbroken chain for all this time, and that we are all related to everything else that exists. Truly does blow the mind!
Pre-Adapatation: Is when an organ (or something else) is originally used for some purpose and then later in evolution is taken over for another purpose.
Natural selection can be a force against extreme perfection. If a species is trapped in a foothill and must go "down" before going up, it will never be able to escape to higher ground. Not too sure how this one works, might need to follow up.
People to read and follow up on:
- Robert Trivers
- John Maynard Smith: The Theory of Evolution
- SJ Gould and the theory of punctured equilibrium
- Some of the founders of Neo-Darwinism: Sewall Wright, R.A. Fischer, and J.B.S. Haldane.
This book has been sitting on my shelves, gathering dust for probably about a year. I finally got to reading it and have re-kindled my interest in evolution. I first starting reading Richard Dawkins in and right after college - the Selfish Gene is a classic. I hope that I will continue to read up on the subject, and maybe even find an on-line course or two to take. But as you know, there is often a difference between what one would like to happen, and what actually does happen.
Anyway, onto the book. He starts by talking about the fig, and how figs can be considered one of the pinnacles of evolution. A highly improbable peak that has been climbed very slowly and surely by the combination of heredity, variability, selection pressure and lots and lots of time.
This is Dawkins major point, he uses the metaphor of slowly climbing a mountain as an explanation for how the theory of evolution explains all the complexity and diversity of life. There are many, many intermediate steps - each providing for more "fitness" than the previous one - there can be no sudden leaps upward, and no going downhill. It is all very gradual, and the culmination of all these steps is the life we see around us. The reason all of this is so interesting to me is that, in a way, it addresses the meaning of life.
He address all sort of issues - spending many pages to show eyes have evolved anywhere between forty to sixty different times. This is a major challenge, because even Darwin had some doubts. Then he show how easy it is (relatively) for many species to develop flight, and pointing out that before the full fledged flight of an eagle, there is floating and gliding. There are "gliding" snakes to go with the frogs, lizards and squirrels in the forest. And in the water, not only flying fish, but even flying squid! All can be explained by small steps, going up the mountain slowly.
He admits that there is much more work to be done, and many mysteries remain to be solved. One of the interesting questions (chapter 6) is the debate between selection pressure and genetic variation. Is the pressure of selection enough to create anything? These are the selectionists. The other side agrees that selection drives evolution, but argue that it must have enough raw material (genetic variation) to work with. To the question as to why pigs do not have wings - the first camp would say that it is not an advantage for them to have wings, the other extreme would be to say that even if the pressure existed they would not have wings because there were never any "mutant wing stubs" for natural selection to work upon. This leads Dawkins to discuss his multi-dimensional "Museum of all Possible Animals", somewhat based on Borges' idea of a library with all the possible books in the world. He leans towards the selectionists, and feels that the empty corridors and space in the museum probably exist because selection did not go there. He also discuss magnets or "attractors", introducing the idea that there are pockets of "types" of animals or "types" of design which have been "created" by natural selection.
He then focus on the evolution of evolvablility - kaleidoscopic embryology - in chapter 7. He suggests that certain species may have a type of "embryology" that in some sense may be 'better' at evolving than others (224). These species in general work through segments and cluster of segments that are usually symmetrical and are arranged in a line from front to rear. His examples are the arthropods, mollusks, echinoderm and vertebrates. This "structure" provides a fruitful playing field for evolution to work on.
In Chapter 8 and 9 he re-hashes the "Selfish Gene" theory. In which he points out that the point of DNA is to replicate itself, and that you can make the argument that an elephant, bird, bee or flower is just an intermediate step used by the DNA to replicate itself. It is amazing to think that DNA is shared by all living beings - there are so many different ways for it to replicate itself.
And in the 10th chapter, he returns to the figs .. telling a truly amazing story of the complicated symbiosis between figs and wasps and underlying how evolution (going step by step) can climb the tallest, complex and improbable peaks.
Some other ideas that are worth following up:
Convergent Evolution: how different species arrive at the same general "effective" design in different environments
How Bill Bryson starts the brief history of time .. that everything alive can be traced back in a direct line for billions of years, back to the beginning of life. Our genes form an unbroken chain for all this time, and that we are all related to everything else that exists. Truly does blow the mind!
Pre-Adapatation: Is when an organ (or something else) is originally used for some purpose and then later in evolution is taken over for another purpose.
Natural selection can be a force against extreme perfection. If a species is trapped in a foothill and must go "down" before going up, it will never be able to escape to higher ground. Not too sure how this one works, might need to follow up.
People to read and follow up on:
- Robert Trivers
- John Maynard Smith: The Theory of Evolution
- SJ Gould and the theory of punctured equilibrium
- Some of the founders of Neo-Darwinism: Sewall Wright, R.A. Fischer, and J.B.S. Haldane.
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