Linda Glinds

Erica Civitate

 

Chapter 10 Dawkins Book

 

“You scratch my back, I’ll ride on yours”

 

Summary

            What do fish, birds, whales, and most insects have in common? These animals are all so different that it seems like they have nothing in common. The commonality is that they all live together in groups. According to evolutionary theory, the genes of these animals must benefit from this living situation in some way or it would not occur. Certainly, it makes sense that animals that hunt collectively can be much more successful than a single animal hunting by itself, even if it means sharing food. Yet, certain aspects of group living work against animals and may sometimes appear to threaten their survival.

            The selfish herd theory, formulated by W.D. Hamilton, states that animals that live in herds are looking out for their own selfish interests at the expense of other individuals. Common sense would tell you that the individuals on the outside edges of the herd are the most vulnerable to attack simply because they would be the easiest target for a predator. Individuals try to position themselves between two other individuals so that they will not be the chosen prey. So there is a constant migration of individuals toward the center of the herd. This model is a good example of how animals display selfish behavior in order to survive.

            However, not all animal behavior is so obviously selfish. For instance, take the case of bird alarm calls. Many bird species will give a warning call if they see a predator that the rest of the flock is unaware of. This act seems as if it is altruistic, because in the process of warning others that a predator is near, it turns the predator’s attention to the bird that called. There are two theories to explain why this act is in no way altruistic, and is, in fact, selfish.

The cave theory explains the action of birds that crouch into the undergrowth when danger is near. The bird that first sees the predator chirps a quick warning call to the rest of the flock so that they will all know to be very quiet and hide in the undergrowth as well. The bird that calls realizes that in order for him to be safe the entire flock must be aware of the predator’s presence.

The “never break ranks” theory explains the actions of birds that fly off when a predator approaches. If one of these birds sees a predator approaching he can fly off by himself, but he will ultimately be more vulnerable because he will be an “odd man out” and the predator will be more likely to go after him. Even if his companions were to follow him, he would be temporarily in danger because the first bird off the ground increases his domain of danger. The best thing to do would be to give an alarm call and fly for cover (to a tree) but also to make sure everyone else does the same. That way the bird has the advantages of being part of a crowd, and he does not become an odd man out. These theories show how these alarm calls are really nothing more than one bird trying to maintain his own survival.

A similar dilemma is the stotting behavior displayed by gazelles. If a particular gazelle sees a predator, he will deliberately try to get it’s attention by jumping as high he can. Again, this appears to be a purely altruistic action on the part of the gazelle. Surely he is inviting the predator to take chase. This, in fact, is not the case. The gazelle that begins stotting when a predator is near is actually trying to show-off for the predator. In effect, the gazelle is trying to show the predator what a healthy and vibrant animal he is that he can jump so high! This, he hopes, will convince the predator to go for someone else, perhaps one of his companions that do not jump nearly as high and will be easier to catch. It has been shown that predators do in fact look for prey that is easy to catch.

Similar selfish and manipulative behavior can be seen among social insect societies. The individuals in these societies are selfish in order to optimize their own genes. Within the Hymenopteran group of insects, individuals are divided into bearers and carers. The bearers are the reproductive males and females (called queens). The carers are the male and female workers. Workers seldom, or never reproduce and the queen never works at anything but reproduction. Workers provide food and protection to the queen and the brood (the young offspring of the queen). They each are responsible for a particular job. The obvious question becomes: what is in it for the workers? It seems that the queen is the selfish player in this situation, but that is not exactly the case.

When a female is born, one never knows if it will become a worker or a queen. This depends on how she is reared, not on what genes she has. Once she does become a queen, she goes on one mating flight and stores up all the sperm for the rest of her life. She then returns and begins reproducing by rationing the sperms out to her eggs as they pass through her tubes. But not all of the eggs are fertilized. Interestingly, the unfertilized eggs become male. So a male only has one set of chromosomes and obtains all of them from his mother. Every sperm of a single male is exactly the same. Explaining why this is would be quite exhaustive so please take my word for it.

            Things become very interesting when we are discussing the case of full sisters. Since all sperm in a single male are exactly the same, full sisters are equivalent to identical twins on their fathers side. Their father gave them both the exact same genes. Their mother, however, may have given them different genes. On the average, if a given female received a gene from her mother, the chance that her sister shares that gene is 50%. So, the relatedness of hymenopteran full sisters is three-fourths (3/4).

            Dawkins then makes the point that from the queen’s point of view, she is equally related to her sons and her daughters, so she wants to have children in equal ratios of male to female. The daughters want to manipulate their mother into having more sisters than brothers, so that they can further their own genes. How they do this is not worth discussing as Dawkins never backs up his claim with any evidence, accept to say that a given hemenopteran queen does seem to give birth to daughters and sons in the ratio of three-fourths.

            Many social insects have discovered, as man did much later, that settled cultivation of food can be more efficient than hunting and gathering.  Examples of this are several species of ant, as well as African termites.  What these insects cultivate are fungus gardens.  Their nests consist of huge underground galleries and tunnels which contain the fungus gardens.  The ants deliberately sow fungus of a particular species in special compost beds which they prepare by chewing leaves into fragments.  Instead of foraging directly for their own food, the workers forage for leaves to make the compost in which the fungus will develop.  The ants are also capable of weeding the fungus keeping it clean of any alien fungi.  The African termites evolved a very similar system of fungi farmers completely independent of the ants.

            Ants have a symbiotic relationship with Aphids which are bugs highly specialized for sucking the juice out of plants.  Symbiosis is a relationship of mutual benefit between members of different species.  Members of different species often have much to offer each other because they can bring different skills to the partnership.  In the relationship between the aphids and the ants, the aphids collect the juice from plants, and in this case honeydew.  Once digested the aphids pass the juice to the ants through their backside, the ants love the sweet juice.  The aphids do not have the ability to protect themselves from predators, so the ants in return for the sweet juices provides protection for the aphids.  This kind of favorable asymmetry can lead to evolutionary stable strategies of mutual cooperation.  Symbiotic relationships are common among animals and plants.

            There is one idea that is not scientifically proven, but rather a speculation that each one of our genes is a symbiotic unit.  We are gigantic colonies of symbiotic genes.  The other side of this is that viruses may be genes that have broken loose from colonies such as ourselves.

            When thinking about mutual benefits, problems may arise if there is a delay in repayment after giving a favor.  This is because the first recipient of a favor may be tempted to cheat and refuse to pay it back when his turn comes.  According to Darwin, delayed reciprocal altruism can only evolve in species that are capable of recognizing and remembering each other as individuals.  Dawkins used a theoretical model to prove this.  Imagine that there are Suckers, Cheaters and Grudgers.  Suckers always do favors regardless of anything.  Cheaters never do any favors for anyone.  Grudgers will do favors for people until a cheater does not return a favor then the Grudger will hold a grudge against that particular Cheater.  The Suckers would not last and die out very quickly.  The Cheaters would last for awhile, but once the Grudgers hold grudges against all of them, they can not survive.  The Grudger turns out to be an evolutionarily stable strategy against sucker and cheat, in the sense that, in a population consisting largely of grudgers, neither cheat nor sucker will invade.

            There is another category of subtle cheats who appear to be reciprocating, but who consistently pay back slightly less than they receive. It is even possible that mans brain evolved to reason mathematically so to produce more devious cheating, and ever more penetrating detection of cheating in others.

 

           

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Outline

 

I Geometry for the Selfish Herd by W.D. Hamilton

 

A.     Selfish behavior within the herd.

1.       Each individual tries to reduce his domain of danger.

2.       Domain of danger: the area of ground in which any point is nearer to that individual than it is to any other individual.

3.       No cooperation or apparent altruism present.

 

II Examples of seemingly altruistic behavior.

 

A.     Bird alarm calls

1.       Cave theory: the bird calls a quick warning to the rest of the flock only to keep them quiet so that he will not be discovered. He is acting upon his own selfish desires not to become prey.

2.       Never break ranks theory: the bird warns the rest of the flock so that they can all fly to cover together so that he will not become an odd man out. Again, the bird is acting for selfish reasons.

 

B.     Stotting of Gazelles

1.       Zahavi’s theory: the gazelles use stotting to convince the predator that      they are fit and healthy and that the predator should go after a member of the herd that does not jump as high and thus looks less healthy.

 

III Selfish behavior within the Hymenopteran species of insects.

           

A.     Males result from an unfertilized egg = 100% of male genes come their      mothers.

 

B.     All male sperm within the same individual is identical.

 

C.     Females: full sisters relatedness = ¾.

 

D.     Females manipulate queen to reproduce more females in order to further their own genes in the gene pool.


 

 

IV.       Cultivation of Food

 

A.     Parasol Ants & African Termites

 

1.       Fungus Gardens

 

V.        Symbiosis

 

A.     Aphids & Ants

 

1.  Mutual Benefits – Honeydew & Defense

           

B.     Symbionic Genes

 

1.       Viruses

 

C.     Repayment Problem

 

1.       Suckers

2.       Cheaters

3.       Grudgers

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Critical Review

 

            I (Linda) feel that Dawkins did not use anything to back up the fact that Hymenopteran insects use selfish behavior to further their own genes in the gene pool. He says that females refrain from breeding themselves and try to “farm their mother as a sister-producing machine”, but he does not explain how this is accomplished or that it is even possible. How can the female manipulate her mother into having more female children? I also would like to know if Dawkins is suggesting that bird alarm calls and stotting in gazelles is a conscious manipulative behavior on the part of the animal or if it is simply an unconscious behavior that has allowed animals to survive and pass the behavior on in their offspring and thus has become an adaption?  

 

I (Erica) thought that Dawkins did an excellent job in explaining the problem with the repayment factor of symbiosis.  Symbiosis only works if there is not a cheater in the compromise.  By explaining this with the suckers, cheaters, and grudgers it made it really comprehensible.  Dawkins spends many pages explaining the workings of an ant farm and their acquisition of slave ants…It was extremely difficult for me to follow this to even understand if how this made sense with his argument.

 

 

 

 

 

 

 

By Michael Mosbach.    Dawkins, Chap 10

 

The Evolution of Cooperation

If mankind is driven by natural selection, why is it that people sacrifice time money and energy and even safety for others every day?

A.      The Problem of Altruism

It has been explained in previous chapters that altruism benefits the family, however why would it benefit us to help friends?

1.        Because we receive something from the friends in return. I.e. hunter example of meat sharing.

2.        If efforts are not reciprocated, help ceases.

B.       Cooperation in Nature

1.        Vampire Bats – share blood with friends that were not successful in a hunt.

2.        Baboons – seek help from friends against whom is antagonizing them.  Usually for sexual partner problems.  The female will have sex with the one who requested help.

a.        Those who give help are much more likely to receive help.

3.        Chimpanzee Politics – A study has shown that chimpanzees not only reciprocate their shared endeavors, but they also recruit the aid of others in an attempt to keep control of group status and mating dominance.

C.       Social Contract Theory

1.        Reciprocal altruism benefits organisms, however, the reciprocal is not always now.  Organisms must remember, under a social contract, to aid the other or the deal is off!

2.        Cheaters benefit over cooperators for they benefit twofold.  Adaptation teaches us to avoid cheaters.

3.        Motivations to create social contacts and avoid cheaters.

a.        The ability to recognize many different individuals. (To have recollection of people.)

b.       The ability to remember some aspects of interactions with different individuals.  (To remember things about them.)

c.        The ability to communicate one’s values to others.  (To let friends know what you want.)

d.       The ability to model the value of others. (To understand what friends need.)

e.        The ability to represent costs and benefits, independent of the particular items exchanged.  (To understand a wide range of needed items.)

4.        Redefining the meaning of Altruism – should it redefined as an organism that gives and not just one that incurs cost?

D.      Becoming “Irreplaceable”

1.        The dilemma of helping friends who are more important.

a.        Making us more valuable to others both in status and economics.

E.       Fair weather friends, Deep Engagements, and the Dilemmas of Modern Living.

1.        A true friend is one who sticks around during hard times. 

2.        True friends are usually friends who one has a deep engagement with.

3.        Modern times take many of the needs of friend’s away, i.e. modern medicine, and cops, etc.

F.       Men and women benefit differently from friendships

1.        Men perceive short-term sexual access as a benefit of opposite-sex friendships.

2.        Women perceive protection as a benefit of opposite-sex friendships.


The Evolution of Cooperation

 

If mankind is driven by natural selection, why is it that people sacrifice time money and energy and even safety for others every day?  That is a problem of altruism. 

It has been explained in previous chapters that altruism benefits the family, however why would it benefit us to help friends?  We benefit from helping friends because we receive something from the friends in return.  A classic example of how friends helped each other is the hunter-gatherer theory.  When men killed an animal that had too much food for his family, and another man did not hunt as well that time, they would share it and later reciprocate the favor.

If efforts were not reciprocated, the hunter would no longer share with him.

                Many examples of cooperation are found in nature.  Vampire Bats share blood with friends that were not successful in a hunt by regurgitating extra blood from their stomachs.  Baboons seek help from friends in an effort to gain sexual partners, and higher status in the group.  Studies have found that when an ape helps another gain sexual favors, the female ape mates with the friend who received the help.  Apes who help another are much more likely to receive help in the future.  A study has shown that chimpanzees not only reciprocate their shared endeavors, but they also recruit the aid of others in an attempt to keep control of group status and mating dominance.

The concept of the social contract theory has many components.  Reciprocal altruism benefits organisms, however, the benefit is not always reciprocated immediately.  Organisms must remember, under “social contract,” to aid the other or the deal is off!  When social contract is broken, cheaters benefit over cooperators for they benefit twofold.  Adaptation teaches us to avoid cheaters.  Motivations to create social contacts and avoid cheaters include, the ability to recognize many different individuals so they can recollect other people, the ability to remember aspects of interactions with different individuals to remember things about them, the ability to communicate one’s values to others, so to let friends know what you want, the ability to model the value of others, to understand what friends need, the ability to represent costs and benefits, independent of the particular items exchanged, to understand a wide range of needed items.

Can we redefine the meaning of altruism?  Should it redefined as an organism that gives and not just one that incurs cost?  Organisms have a need to feel or become irreplaceable.  When faced with a difficult situation where two friends are in need of your help, the natural tendency is to help the friend whom we feel is, “more important.”  We ourselves therefore try to become more valuable to others both in status and economics. 

Fair weather friends, deep engagements, and the dilemmas of modern living shape the way we treat friends.  A true friend is one who sticks around during hard times.  This type of friend is usually one that has been around a long time.  Modern times take many of the needs of friend’s away, i.e. modern medicine, and cops, etc.

Men and women benefit differently from friendships.  Men perceive short-term sexual access as a benefit of opposite-sex friendships, while women perceive protection as a benefit of opposite-sex friendships.