Maria Abenes
Shane Davis
Selena Yribe
Panel Presentation
Dawkins, Chapters 6 & 7
Dawkins, Chapter 6-Genemanship
The whole purpose of a selfish gene is to become abundant in the gene pool by showing the body how to survive and reproduce. This particular bit of DNA can exist in many individuals at once. The main point of chapter six is that if this gene can assist other replicated genes in other bodies, does this mean that this gene selfishness leads to individual altruism.
Dawkins provides the example of the albino gene to support this idea of altruism. In order for someone to be albino, that person must have two doses of the albino gene, which occurs in about 1 in 20, 000 cases. However, 1 in 70 individuals have single doses of the albino gene that are not albinos. He states that, "Since it is distributed in many individuals, a gene such as the albino gene could, in theory, assist its own survival in the gene pool by programming its bodies to behave altruistically towards other albino bodies, since these are known to contain the same gene."(Pg. 88) In other words, theoretically albinos would be especially nice to each other. Dawkins points out that this isn't the case and those albino genes do not want to help other albino gene or survive. If by chance an albino gene does act altruistically toward another albino gene they would become more abundant in the gene pool. Dawkins states that, "In order for this to happen, the gene would have to have two independent effects on bodies. Not only must it confer its usual effect of a very pale complexion. It must also confer a tendency to be selectively altruistic towards individuals with very pale complexion."(Pg. 89) This double-effect gene would theoretically be successful in the population, but is very unlikely.
Arbitrary labels such as albinism enables genes to recognize copies of it in other individuals. For example, in families there are many genes being shared and it is common for parents to behave altruistically toward their children. This applies to other relations, "If an individual dies in order to save ten close relatives, one copy of the kin-altruism gene may be lost, but a larger number of copies of the same gene is saved."(pg.90) Even a gene that is rare in the population is common among a family. Between a parent and child, the chances that you have received a particular gene from either parent is 50 percent since half of your genes are from your father and the other half are from your father, the relatedness between parent and child is always 1/2. This relatedness shows the chance of a gene being shared between two relatives.
Dawkins provides a calculation for figuring out relatedness:
1. Identify all common ancestor of A and B
2. Count the generation distance (climb up the family tree until you hit a common ancestor and sum up total steps for A and B)
3. Calculate that part of their relatedness for which that ancestor is responsible (multiply 1/2 by itself once for each step of the generation distance)
4. If there are more than one common ancestor, add on the equivalent figure for each ancestor.
5. Multiply by the number of ancestors to get the relatedness between A and B
In terms of the altruistic gene, full brothers and sisters, and parents and children are 1/2. Identical twins' relatedness is 1. Uncles and aunts, nephews and nieces, grandparents and grandchildren, and half brothers and half sisters, have a relatedness of 1/4. So altruistically speaking, it would be more common in a population to have a gene for saving five brothers or ten first cousins, instead of a gene simply saving five cousins. Dawkins states, "the minimum requirement for a suicidal altruistic gene to be successful is that it should save more than two siblings (or children or parents), or more than four half- siblings (or uncles, aunts, nephews, nieces, grandparents, grandchildren), or more than eight first cousins, etc."(Pg. 93) In other words, the individuals that the altruist gave up its life for must be worth it.
This explanation of relatedness can show why twins are so concerned about each other. Both twins carry the gene for twin altruism if one died; the gene would still survive. We can also look at parenting as an example of altruism. Dawkins points out that; "there is nothing special genetically speaking about the parent/child relationship as against the brother/sister relationship. The fact that parents actually hand on genes to children, but sister do not hand on genes to children, but sisters do not hand on genes to each other is irrelevant, since the sisters both receive identical replicas of the same genes from the same parents."(Pg. 94)
Kin selection is altruism within a family and the stronger relationships derive from closer relationships. There are many that oppose to this term and say that there are no definite lines between family and non-family. Dawkins states that, "We do not have to decide whether, say, second cousins should count as inside the family group or outside it; we simply expect that second cousins should be 1/16 likely to receive altruism as offspring or siblings."(Pg. 94) In other words, kin selection isn't a case of group selection but rather a result of gene selection.
These calculations of relatedness can be applied to life situations such as life insurance. An individual is expected to invest some of his assets in the life of another person. The individual takes into account their relatedness and other person's future expectancy. Dawkins states that, "In order for altruistic behavior to evolve, the net risk to the altruist must be less than the net benefit to the recipient multiplied by the relatedness."(Pg. 96) In other words, risk and benefits need to be weighed out before any altruistic behavior.
Simplifying these relatedness calculations and applying them to animal behaviors would show that individual animals do what is best for their genes. These calculations are already done by these genes and influence the bodies into doing certain behaviors. In real life animals to not take into account every detail when coming to a decision. Their genes give animals a rule for action, such as being nice to a member of their species since they could be kin. Dawkins provides the example of whales rescuing baby or injured whales, "it is not known whether whales have ways of knowing who their close relatives are, but it is possible that the overall probability that a random member of the school is a relation is so high that the altruism is worth the cost."(Pg. 100)
There is an example of a mistake that is so extreme that it provides evidence against the selfish genes theory. It is the case of bereaved monkey mothers who have been seen to steal a baby from another female and looking after it as if it were their own. Dawkins sees it as a double mistake, since the adopter not only wastes her time; she also releases a rival female from the burden of child-rearing, and frees her to have another child more quickly. Dawkins speculates that these mothers may be deliberately trying to deceive naïve young females into adopting their children.
Another example of an abnormality of the maternal instinct is when cuckoos lay their eggs in another nest. By doing this the break the rule that restrict altruism to only their own kin. By laying eggs in other nests the cuckoos, since many birds re unable to recognize their own eggs would make other birds sit on their eggs for them. Many birds soon realized they were being cheated and learned to use certain marking or other feature to detect what was really their eggs. The cuckoos retaliated by making their eggs look more like the eggs of host species. The cuckoos that hatch and survive to lay more eggs as a result of this host hatching allow this deception to be spread more through the cuckoo gene pool.
Brian Bertram made a comparison between an animal's estimate of its kinship with other members of its group. He estimates the average relatedness between individuals in a lion pride. A pride consists of 7 females who are permanent and two males who's role is unsettled. The females give birth to batches of cubs and care for them in a group. The fathering of these cubs is shared between the males. The young females remain in the pride to replace the old one and the males are driven out when they reach adolescence and roam from pride to pride. Under these circumstances it would be impossible to compute relatedness, "we may expect that the natural selection will have favored a degree of relatedness in a typical pride."(pg.105) This shows that the kinship estimates of animals and of good naturalist might end up rather the same.
Dawkins conclude that, "the true relatedness may be less important in the evolution of altruism than the best estimate of relatedness that animals get."(pg.05) This supports the fact that parental care is more common and devoted than brother and sister altruism. In other words, even though genetically there is no difference in terms of relatedness, individuals are more certain about who their children are than whom their siblings are. This difference in certainty results in a difference in devotion and altruism.
In many species mothers will be more certain that their offspring are theirs than the fathers are. This causes the fathers to be less involved in the caring of their children. For example, because of marital infidelity, uncles from the mother side should be more altruistic than the fathers. The uncles know that at the very least the mother is his half sister but the father knows nothing.
It is also shown that parents care for their children more than children care for their parents even though the genetic relationship and certainty of relatedness is equal. This can be explained by the fact that parents are older and more competent and are able to care for their kids. Also, since children are younger they know they have a longer life expectancy than their parents do. Dawkins states that, "Expectation of life is an important variable which, in the best of all possible worlds, should enter into an animal's calculation when it is deciding whether to behave altruistically or not."(Pg.107) In other words, it would not be advantageous to be altruistic toward an individual that may die soon.
The main point Dawkins was trying to make in chapter 6 is that child protection and parental care are examples of kin-selection principle. He is trying to defend his stand against critics that fail to understand that parental care is no less and example of kin selection than brother/sister altruism. This error is common because when Hamilton talked about this he stressed other relationships. Dawkins believes that the natural selection that predicts parental altruism also predict collateral kin altruism.
In the beginning of the chapter, Dawkins makes a distinction between bringing a child into this world also known as childbearing and caring for existing individuals also known as child caring. An individual has to decisions to one being caring and the other being bearing decisions. According to Dawkins, a decision means an unconscious strategic move. “The caring decisions are of this form: ‘This is a child; its degree of relatedness to me is so and so; its chances of dying if I do not feed it are such and such; shall I feed it?’” (Dawkins, pg. 109). Dawkins goes on to state that bearing decisions “are like this: ‘Shall I take whatever steps are necessary in order to bring a new individual into the world; shall I reproduce?’”(Dawkins, pg. 109). Finally, Dawkins states that if caring exist then some kind of bearing needs to go on. For example, a mammal will make a decision to bear a new child usually followed by a decision to care for it.
The chapter focuses on how an individual should decide whether to bring new individuals into the world. According to Wynne-Edward’s, he brings up the point that animals do regulate their birth rates. Adherents of the selfish gene theory would agree that animals do regulate their birth rates. It appears that “any given species tends to have a rather fixed clutch-size or litter-size: no animal has infinite number of children”(Dawkins, pg. 112).
“The main disagreement is over whether animal birth-control is altruistic, practiced for the good of the group as a whole; or selfish, practiced for the good of the individual doing the reproducing”(Dawkins, pg.112).
The first theory is Wynne-Edwards on how individuals have fewer children than what they are capable of, for the benefit of the group as a whole. Wynne-Edwards claims that group whose individual members restrain their own birth rates are more likely to exist longer than if a rival group reproduces so fast that they endanger the food supply. The restrain by an individual is considered a form of birth control but he comes up with a conception in which the whole of social life is seen as a mechanism of population regulation. “For instance, two major features of social life in many species of animals are territoriality and dominance hierarchies” (Dawkins, pg. 113). According to Wynne-Edwars animals fight for territory in order to gain a token prize instead of an actual prize. Many females refuse to mate with a male that does not claim a territory. If an animal wins a territory than it gives them a ticket to breed. If a male does not have an official ticket to breed then they voluntarily refrain from breeding and leave the winners to breed and get on with propagating the species.
Furthermore, the hierarchies system is similar to the territory explanation. Animals know who they can beat in a fight and who can beat them because animals create a ranking system. The interpretation is that he high ranking individual are more likely to breed than the low ranking individuals because they are preferred by females or because they physically prevent low ranking individuals from getting near females. Therefore, high social rank is considered another ticket to breed. “But, as in the case of territorial behavior, the result of this ‘voluntary acceptance’ of the rule that only high-status males should breed is, according to Wynne-Edwards, that populations do not grow fast” (Dawkins, pg. 114).
Dawkins introduces a word that Wynne-Edwards coined, which is epidemic behavior. Dawkins explains it by using the example of the huge flock of starlings. What happens is the huge flock of starlings mass together over a gatepost to perform a census of their population. “Since he is supposing that individuals restrain their birth-rates in the interests of the group as a whole, and have fewer babies when the population density is high, it is reasonable that they should have some way of measuring the population density” (Dawkins, pg. 115). Wynne-Edwards is not suggesting that we make population estimate consciously but rather an automatic or hormonal mechanism linking the individuals’ sensory perception of the density of their population with their reproductive systems (Dawkins,pg. 115).
Dawkins claims that Wynne-Edwards’s theory is convincing to a certain point but the evidence is not good enough. The next theory he examines is the selfish gene theory. Dawkins claims that Wynne-Edwards’s theory is convincing to a certain point but the evidence is not good enough. The next theory he examines is the selfish gene theory. Dawkins brings in Lack’s perspective of the theory. In the selfish gene theory, an individual wants to have their genes become more numerous in the gene pool. One would think an individual would have a bunch of children so the genes will eventually be replicated. The opposite occurs meaning an individual will choose the amount of children they have in order to maximize the number of children she rears. For example, an animal whose clutch size is three is due to the fact that there is enough food supply in order for the children to reach adulthood. The animal that has four children are jeopardizing the chance of their children reaching adulthood due to the food so thinly spread between the four babies. “They are practicing birth control in order to maximize the number of surviving children they actually have, an aim which is the very opposite of that which we normally associate birth-control” (Dawkins, pg. 116). Furthermore, the total amount of food and other resources an individual female or male can collect is the limiting factor determining the number of children they can rear. Natural selection adjusts initial clutch size so as to take maximum advantage of these limited resources.
The another topic Dawkins touches upon is the issue of individuals having too many children due to unnatural support such as welfare. In the modernized world, the amount of children an individual has is no longer limited due to the limited amount of resources that parents can provide. Instead, if a mother and father have too many children the state will step in and provide assistance rather than penalize the family. The state in a sense keeps the surplus children a sense keeps the surplus children alive and healthy. The point is humans do want the large families to be penalized so they leave them to starve and the state takes on the responsibility. The support should not be taken for granted.
The final topic mentioned in the chapter deals with the fact that overcrowding sometimes reduces birth rates. For example, mice in a cage were given ample amount of food and the population grew. As soon as the cage became over-crowded, the females became less fertile even though there was enough food as a consequence of over-crowding. Animals are programmed for life in the, and it is likely that in natural conditions over-crowding is a reliable indicator of future famine. Adherents of the social gene theory claim animals will tend to have the optimum number of children from their own selfish point of view. “Now, ‘just the right number’ is likely to be smaller number in a year when the population is over-crowded than in the year when the population is sparse” (Dawkins. Pg. 120).
In conclusion, parents practice family planning but in the sense that they optimize their birth rates rather than keeps them from public services such as welfare. Individuals maximize the amount of children they have which means having the right amount of children. “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” (Dawkins, pg. 122)
Outline of Chapter 6
1. The Selfish Gene
A. Trying to get more numerous in the gene pool. Assisting replicas of itself in other bodies aids this process. What appears as individual altruism is brought about by gene selfishness.
2. Kin selection: different than group selection, not simply a special case of it.
A. How genes recognize copies of themselves in other individuals. Individuals that are related have a greater than average chance of sharing genes. Even genes that are rare in the population as a whole are common within a family. We are more likely to assist those who physically resemble us because this indicates that they may have the same genes. The higher the degree of relatedness, the more likely we are to aid an individual.
3. Mathematical calculations can produce the degree of relatedness: # of common ancestors x (1/2)^; where ^ =the generation distance.
A. Animals can not perform such complex calculations in their head: at some subconscious level, something equivalent to the mathematical calculations is going on. The net risk to the altruist must be less than the net benefit to the recipient multiplied by the relatedness.
B. Other factors affecting Kin Selection:
1. Life (Reproductive) expectancy: genetically advantageous to save young, distant relative over old, close one. This can be extended to the parent/child relationship to explain why parents care more for their children than children care for their parents even though the genetic relationship is symmetrical and certainty of relatedness is the same.
2. Certainty: parent and child share same amount of genetic material as brother and sister, yet parental altruism much more prominent than fraternal altruism. One reason is because one can be more certain of their children than of their brothers and sisters. Also, fathers are less likely to invest in offspring than mothers are because they are more susceptible to deception; he can not be 100% sure the child is his.
4. Examples of Kin Selection
1. Baby chicks: use one chirp to attract the mother, which is ignored by the other chicks, and another to call the other chicks to a source of food. This appears altruistic, but, in actuality, it is aiding in the survival of genes shared by all the chicks.
2. All instances of child protection and parental care, and all associated bodily organs, milk secreting glands, kangaroo pouches, and so on, are examples of the kin-selection principle working in nature.
I. Distinction between caring and bearing decisions
A. Caring decisions
a. Decide if you should feed the child according to the relatedness and if the child can survive without you
B. Bearing decisions
a. Can I take the steps needed to bring a child in this world and reproduce
C. Caring needs some kind of bearing needs to go on
II. Wynne-Edwards’ theory about birth regulation
a. Restrain births equals longer existence and prevent endangering the food supply
b. Mechanism of population regulation
a. Fight for territory to gain right to breed
b. Females mate with males with territory
a. High ranking individuals are likely to breed
b. Population does not grow fast due to hierarchy
a. Perform a census of population
1. Example of the starlings
b. Automatic or hormonal mechanism aids in estimation
III. Selfish Gene Theory
A. Have genes become numerous in the gene pool
B. Adjust clutch size to maximize survival of gene
a. Example: three vs. four clutch size
C. Goal is for children to reach adulthood
IV. Overcrowding reduces the birth rates
A. Females become less fertile in overcrowding
a. Example of the mice in the cage
B. Resources will eventually reduce so limit births
C. Selfish gene theory
a. Right number is smaller in overcrowding
§ We found it very interesting that the reasons that parental care is much more devoted than brother/sister altruism, even though they are no closer genetically related, is because its certainty is better. In other words, individuals are more certain about who their children are thean who your siblings are. Another reason is that children are always younger than their parents and their longer expectation to live makes it an advantageous for the parents to behave altruistically.
§ One confusing part of Chapter 6 was the mathematical equation Dawkins gave to determine relatedness. It was the only item in this whole chapter that was hard to follow. Other than that this chapter was easy to read and comprehend.
§ We found it very interesting that even animals use a method of birth control. Dawkins mentions that, “animals deliberately reduce their birth rates for the good of the whole group.” Another interesting point we get from the reading is that if you space the generation out more, populations would grow at a slower rate. So having kids at thirty would aid in the overpopulation problem.
§ Chapter 7 was very self-explanatory. Nothing was really difficult to understand. One part that we had a problem with was the debate about whether mothers should treat all her children equally or have favorites. This was tough to swallow simply because it goes against what has been instilled in us growing up. Theoretically it makes sense, but personally it seems outrageous.