The Selfish Gene was published in 1976.
___________________________________________________________________________________
Thesis: The book explores the biology of selfishness and altruism.
Chapter 1: Why are people?
Dawkins starts his book by explaining what his book is and is not about. He starts out by saying that we are machines made up of genes, whose predominant qualities include ruthless selfishness. This selfishness, more often than not, will give rise to selfishness in human behavior. The book is essentially about explaining how this behavior arises and why. However, it is not about advocating a morality based on evolution. This is often confused by confusing what something is from what something ought to be. The important thing to note here is that descriptive claims do not entail prescriptive claims.
He then goes on to define a broad definition for both altruistic acts and selfish acts. Namely, an entity is said to be altruistic if it behaves in such a way as to increase another such entity's welfare at the expense of its own, where welfare is defined as 'chances of survival'. Selfish acts, quite evidently, have the opposite effect. After giving examples for both types of acts, he goes on to clear a common misconception about evolution, namely that species don't commit altruistic acts (mostly seen on parents of species to their young) for 'the greater good of the species' or 'for the perpetuation of the species. In fact, much of the animals' lives are devoted to reproduction and reproduction alone, and perpetuation of the species comes as a consequence of this devotion to reproduction.
All in all, he concludes that the best way to look at evolution (and he does this in the book) is through the lowest level of selection, which is not the individual level, but the gene level.
___________________________________________________________________________________
Chapter 2: The Replicators
This chapter consists of talking about abiogenesis, citing the earliest experiments that have been conducted to pursue this phenomenon, which of course are the Miller-Urey primordial soup experiments. (Of course, biochemistry has long since advanced its experiments and yielded much more exciting and convincing results since the experiments done in the early 50's and 60's. One must note that this book was published in 1976.) He goes on to speculate that in order for an evolutionary process to occur, there must have been the creation of a 'replicator' in early planetary conditions, which is a molecule that makes copies of itself. Of course, the molecule had to be prone to errors (as genes are today), otherwise there can be no potential for variability and evolution. He ends the chapter by saying that these replicators are essentially the great descendants of genes today.
___________________________________________________________________________________
Chapter 3: Immortal Coils
The chapter starts by talking about DNA, its functions and its importance in making proteins. Talking about genes, he notes that there are some genes dependent on others, so in one sense it may make more sense to talk about genes as a 'gene complex' rather than an individual gene. In addressing this, he makes his main argument for the chapter, namely that one gene may be regarded as a unit that survives through a large number of successive individual bodies. This is because the combination of genes that is any one individual may be short-lived, but the genes themselves are potentially long-lived, because their paths constantly cross and re-cross down the generations.
He goes on to explain the facts of sex, through mitosis, and crossing over via meiosis. This is to illustrate how genes in chromosomes are transferred from parent to offspring. The definition he uses for gene is one used by G.C. Williams.
- Gene - A gene is defined as any portion of chromosomal material that potentially lasts for enough generations to serve as a unit of natural selection.
The shorter a genetic unit is, the longer in generations it is likely to live. This is because it is less likely to be split by any one crossing-over. The smaller the gene is, the more likely it is to be present in other individuals, or even species, in the forms of copies.
He goes on to explain the concepts of point mutations, inversions, gene linkages, and mimicry.
On the case of mimicry, he notes that a butterfly for example, can mimic a certain species of poisonous butterfly, so as to warn off predators, but he cannot mimic two species of poisonous butterfly. It either mimics species A or species B. But since mimicry involves multiple genes such as shape, color, spot pattern, and rhythm of flight, the large cluster of genes that are responsible for this join in a tight linkage, and act as one gene. In fact, the other corresponding allele that allows the butterfly to mimic species B rather than A comes in form of another gene cluster.
In terms of its natural selection and evolution, the gene does not grow senile. Through copying itself, it can live through millions of years. He brings up questions that are still debated in modern biology (even though more convincing theories have been proposed since the late 70's), like the question of why we age, and why is there sex? (As opposed to species survival via mitotic reproduction). Through a gene-centric view of natural selection, these questions make more sense.
___________________________________________________________________________________
Chapter 4: The Gene Machine
This chapter is about behavior. He talks about neurons muscles and neurons acting as a motor for movement. This neural complexity eventually leads to 'consciousness.' He points out that the common misconception about genes is that genes control behavior. Genes do not control behavior, in the same way that programmer does not control the choices and behavior of a computer that plays chess. The computer instead is given the program (which would be the gene in the analogy), and after that, the computer is on its own. When the programmer writes the code for the chess-playing computer, it does not give it every single possible combination known to exist in chess, this is impossible. Instead it gives it the instruction of how the pieces move, and other 'advice' like "keep your king guarded" and techniques like knight forks and what not. In the same way, genes give 'advice' to animal brains to aid in survival. In some sense, it is an 'educated' gamble.
___________________________________________________________________________________
Chapter 5: Aggression: Stability and the Selfish Machine
This chapter is about the misunderstood topic of aggression. Each individual is a survival machine, and to a survival machine, other survival machines (which are not the children or parents of the individual) are part of that survival machine's environment. In other words, other survival machines are in the way and can be potentially exploited. At first glance, a problem arises through this view. Through a selfish gene theory scope of evolution, it seems sensible to kill off all the rivals and take away their resources for one's own gain. However, the selfish gene theory still holds if you recognize that if species B and species C are both your rivals, killing off species B will probably help out species C, so it would be much better if you don't kill species B in hopes that species C might kill species B off instead, saving you time and energy.
In collaboration with G.R. Price and G.A. Parker, J. Maynard Smith use Game Theory to help explain these evolutionary behaviors. The essential concept is the evolutionarily stable strategy, or ESS. An ESS is defined by a strategy, which if most members of a population adopt it, cannot be bettered by an alternate strategy. ESS's will tend to evolve, and an ESS is not the same as the optimum that could be achieved by a group conspiracy. In sum, common sense can be very misleading when thinking about game theory strategies.
"The gene pool is the long-term environment of the gene. 'Good' genes are blindly selected as those that survive in the gene pool. This is not a theory; it is not even an observed fact: it is a tautology. . . The gene pool will become an ESS of genes, defined as a gene pool that cannot be invaded by any new gene. Occasionally a new gene does succeed in invading the set: it succeeds in spreading through the gene pool. There is a transitional period of instability, terminating in a new ESS - a little bit of evolution has occurred. . . For understanding aggression it was convinient to treat individual animals as independent selfish machines. This model breaks down when the individuals concerned are close relatives - brothers and sisters, cousins, parents and children. This is because relatives share a substantial proportion of their genes. Each selfish gene therefore has its loyalties divided between different bodies."
___________________________________________________________________________________
Chapter 6: Genesmanship
A question that arrives in this chapter is: Are there any plausible ways in which genes might 'recognize' their copies in other individuals? The answer is yes. Close relatives have a much higher chance of sharing genes. This is why altruism is seen, majorly in parents to their young. This applies to other kin, like brothers, sisters and cousins. If one of these kin sacrifices their lives to save 10 other kin, then that individual's genes may have died, but there is a great chance that it saved multiple of its copy genes through its other kin.
He points out the mathematics of gene selection, namely that if you trace that if you drew a genetic family tree and wanted to know how much you share genetically with a certain family member, the answer is (1/2)^g where 'g' is generation distance. For example, in the case of parents (g=1), one shares 50% of their genes with their moms and dads. Brothers and sisters also share 50% of their genes with each other. With aunts and uncles (g=2) the number lowers down to 25%, with first cousins it's 12.5% etc. He makes it a point to note that this kin selection is not a special case of group selection, but a special consequence of gene selection.
One example used in the book to illustrate the type of altruistic behavior he is alluding to includes an example of an animal finding food reserves. There are two choices. Keep the food reserves all to himself, or to make a food call and share the food with the rest of his kin. Using a game theory device by assigning arbitrary relative numbers to each action, it turns out that sharing the food would turn in a higher result, and would help the survival of the selfish gene best. It seems quite the paradox, that the altruistic act ultimately turns out to be the underlying most selfish act; but as mentioned before, this kin selection is a special consequence of gene selection. Through this reasoning, individuals tend to act less altruistically to their third cousins than to their first cousins.
Also given this line of reasoning comes the notion that twins should theoretically value their twin's life as much as their own. However, aside from degrees of genetic makeup, degrees of certainty should also be taken into account. How does a kin know that its twin is actually its twin, rather than an individual who happens to look a lot like himself? It doesn't. Therefore although it's willing to sacrifice for that individual (more so than it's willing to sacrifice for its child or brother), it won't make as equal a sacrifice as it would for itself, simply because although its twin supposedly has it's same genetic makeup, he is not 100% completely certain that he is his twin, and moreover is 100% certain that he is himself. Therefore, the self takes ultimate priority. Taking this degree of certainty into account, an individual may sacrifice more for their children than for its brother or sister (simply because it's easier to tell one's self from it's child, through size for example, than from its brother or sister, and thus would have a higher degree of certainty, regardless if their genetics are a 50% relation in both cases. Also, in the case of some species, because the child will have a longer life, since it's younger, than its brother or sister.)
___________________________________________________________________________________
Chapter 7: Family Planning
This chapter is about Wynne-Edwards theory on group selections. Dawkins claims that he is right in his theory, but for the wrong reasons. Wynne-Edwards gets it right that certain characteristics such as pure altruism cannot in fact be materialized through natural selection alone. Dawkins cites the fact that natural selection, for whatever reason, favors females who reduce their birth-rate when their population is over-crowded.
"Wynn-Edward's answer is clear. Group selection favors groups in which the females measure the population and adjust their birth-rates so that food supplies are not over-exploited. . . What does the selfish gene theory say? Almost exactly the same thing, but with one crucial difference. You will remember that, according to Lack, animals will tend to have the optimum number of children from their own selfish point of view. If they bear too few or too many, they will end up rearing fewer than they would have if they had hit on just the right number. . . Obviously, if a female is presented with reliable evidence that a famine is to be expected, it is in her own selfish interests to reduce her own birth rate. Rivals who do not respond to the warning signs in this way will end up rearing fewer babies, even if they actually bear more. We therefore end up with almost exactly the same conclusion as Wynne-Edwards, but we get there by an entirely different type of evolutionary reasoning."
"Our conclusion from this chapter is that individual parents practice family planning, but in the sense that they optimize their birth-rates rather than restrict them for public good. They try to maximize the number of surviving children that they have, and this means having neither too many babies nor too few. Genes that make an individual have too many babies tend not to persist in the gene pool, because children containing such genes tend not to survive to adulthood.
___________________________________________________________________________________
Chapter 8: Battle of the Generations
The chapter starts off with the question "Should a mother have favorites, or should she be equally altruistic towards all her children?" It's important to note that the word 'favorite' carries no subjective connotation, and the word 'should' no moral ones. He cites R.L. Trivers, who uses the concept of Parental Investment (P.I.) to define any investment by the parent in an individual offspring that increases the offspring's chance of surviving, and hence reproductive success, at the cost of the parent's ability to invest in other offspring. However, a parent's investment in any one child should ideally be measured in terms of detriment to life expectancy not only of other children, but also of nephews, nieces, herself, etc.
There is no genetic reason why the mother would prefer one offspring over another, if the two offspring were rather the same. However, if one is younger for example, the mother would give more food to the younger, simply because the older has a better shot at finding food for himself. Seeing as how one individual self is twice more related to himself than to his brother or sister, it would make sense that an individual would want to hog the mother's resources for himself and leave less for his brother or sister. He then gives on examples of this, on how baby birds, in an ideal world, scream in proportion to how hungry they are. However, screaming louder can get you more food, and if everyone is screaming as loud as they can, not screaming as loudly will get you penalized by getting you less food, which means less chances of survival. It is noted of course, that the volume of the screaming is only up to a certain decibel, as screaming too loudly can lure in predators.
___________________________________________________________________________________
Chapter 9: Battle of the Sexes
The reasons mate, who have virtually no genetic relation to each other, cooperate with each other is because their commonality stems from the genes in their offspring. However, it is important to note that females can only have a certain amount of children, while males can virtually have an infinite amount. This is why male gametes tend to be smaller in size and faster in speed. They're essentially contributing less resources to the offspring, while the mother contributes more. This type of favored outcome in natural selection stems as a result of female exploitation from ideally same-sized isogametes. In other words, male gametes tend to become smaller and faster, eradicating the bigger sized and average sized ones to take advantage of this exploitation.
Is there a way that the female can get some compensation for this sex exploitation strategy? The answer is yes, because the female is in demand in a seller's market. Two possibilities are brought up that try to explain how this 'negotiation' can arise through natural selection, namely the domestic-bliss strategy, and the he-man strategy.
The domestic-bliss strategy describes the strategy that a female takes, that includes looking the male over to try and spot signs of fidelity and domesticity in advance. One way for a female to do this is to play hard to get for a long time, to be coy. Any male who is not patient enough to wait until the female eventually consents to copulate is not likely to be a good bet as a faithful husband. This feminine coyness is in fact very common among animals. If you work out the game theory, using the arbitrary values, it comes out that a population in which 5/6 of the females are coy, and 5/8 of the males are faithful, is evolutionarily stable.
For water-dwelling animals, mating and fertilization does not happen in the female womb. It is for this reason that for water-dwelling animals, males are the ones that have to put in a higher P.I., because the female has to secrete her eggs first, so that the male can consequently release his sperm to allow for fertilization. This gives the female a few precious seconds to swim away after she releases her eggs, forcing the male to take care of the offspring, while the female goes somewhere else, perhaps to another male to do the same thing. So in essence, for water-dwelling animals, these gender roles are reversed.
The he-man strategy involves a female choosing males with sexually attractive characteristics. However, it is important to note that characteristics that give a higher chance of producing successful offspring are not inherently sexually attractive, but become sexually attractive for that reason.
___________________________________________________________________________________
Chapter 10: You Scratch My Back, I'll Ride On Yours
The chapter commits itself in talking about intra and inter-species mutualism, or symbiosis. "A fish who swims obliquely behind another fish may gain a hydrodynamic advantage from the turbulence produced by the fish in front. This may be a reason as to why fish school. A related trick concerned with air turbulence is known to racing cyclist, and it may account for the V-formation of flying birds. There is probably competition to avoid the disadvantageous position at the head of the flock. Possibly the birds take turns as unwilling leader - a form of the delayed reciprocal-altruism discussed at the end of the chapter."
Ultimately, he refers to the altruistic behavior seen in a insects, some of which was mentioned before. This includes worker bees and the hierarchy in ant colonies.
___________________________________________________________________________________
Chapter 11: Memes: The New Replicators
This chapter introduces the concept of a 'meme'.
- Meme - An idea, behavior, or style that spreads from person to person within a culture
Memes, like genes, are replicators that propagate through human minds in the form if imitation.
Interestingly, this concept details how memes, like genes, are in competition with each other to survive and replicate. This can explain certain cultural norms that are perpetuated among a plethora societies, and can also explain behaviors and ideas such as religious ones.
"To take a particular example, an aspect of doctrine that has been very effective in enforcing religious observance is the threat of hell fire. Many children and even some adults believe that they will suffer ghastly torments after death if they do not obey the priestly rules. This is a peculiarly nasty technique of persuasion, causing great psychological anguish throughout the middle ages and even today. But it is highly effective. It might almost have been planned deliberately by a Machiavellian priesthood trained in deep psychological indoctrination techniques. However, I doubt if the priests were that clever. Much more probably, unconscious memes have ensured their own survival by virtue of those same qualities of pseudo-ruthlessness that successful genes display. The idea of hell fire is, quite simply, self perpetuating, because of its own deep psychological impact. It has become linked with the god meme because the two reinforce each other, and assist each other's survival in the meme pool."
"Another member of the religious meme complex is called faith. It means blind trust, in the absence of evidence, even in the teeth of evidence. The story of Doubting Thomas is told, not so that we should admire Thomas, but so that we can admire the other apostles in comparison. Thomas demanded evidence. Nothing is more lethal for certain kinds of meme than a tendency to look for evidence. The other apostles, whose faith was so strong that they did not need evidence, are held up to us as worthy of imitation. The meme for blind faith secures its own perpetuation by the simple unconscious expedient of discouraging rational inquiry."
___________________________________________________________________________________
Chapter 12: Nice Guys Finish First
In the most succinct of language, this chapter is dedicated to talking about the prisoner's dilemma. It's so blatantly simple, yet so complex, that there are whole library shelves dedicated to the subject, and even attempts at creating laws to ban dilemma's like this in other discourses. Dawkins essentially, makes the case that "nice guys" can finish first, by taking the dilemma and realizing that one can get a very good yield if there is a perpetual cooperation between both parties. He cites experiments done by Robert Axelrod to make this case.
Below, is the classic example of the prisoner's dilemma.
___________________________________________________________________________________
Chapter 13: The Long Reach of the Gene
The last chapter of the book commits itself to talking about Dawkins' book, The Extended Phenotype. This book is aimed to be the sequel to The Selfish Gene.
- The Central Theorem of the Extended Phenotype - An animal's behavior tends to maximize the survival of the gene 'for' that behavior, whether or not those genes happen to be in the body of the particular animal performing it.
In other words, this is the notion that phenotype should not be limited to biological processes such as energy expenditure or tissue growth, but also extended to include all of the effects that a gene has other than its biological processes, such as the effects it has on its environment, inside or outside the body of the organism.
___________________________________________________________________________________
No comments:
Post a Comment