Natasha Saltz

Cat Rotunno

Ivy Featherstone

 

 Ridley, Matt. The Red Queen

Chapter 3: The Power of Parasites

 

            Sexual reproduction is something that has puzzled scientists for many decades. With sexual reproduction, each of the offspring is slightly different than its parent which is unlike species that reproduce asexually and have identical offspring. Matt Ridley calls this “The art of being slightly different” (56) and says that most ecologists agree that it is this difference that is the purpose of sex.

           

In 1966, George Williams noticed something peculiar about sexual reproduction. He noticed that sexual reproduction requires animals to focus on the survival of the species in a way that also requires them to ignore their short-term interests. He also felt that this “form of self-restraint...could have evolved only under very peculiar circumstances” (56). Williams noticed a connection between sex and dispersal and decided that if a species wants its young to travel then the young should be varied  through sex so that they have a better chance of survival away from home.

           

John Maynard Smith, in 1971, elaborates on the problem that Williams noticed. Maynard Smith’s idea “suggested that sex was needed for those cases in which two different creatures migrate into a new habitat in which it helps to combine both their characters” (57). Williams returns and says that if the young are going to travel then it will be only the fittest that will survive and it would be better to have a few exceptional young rather than many average young. This means that “sex is useful to the individual rather than the species when the offspring are likely to face changed or unusual conditions” (57). Williams was intrigued by creatures that were able to reproduce both sexually and asexually ( like aphids and rotifers) because he felt that they further proved his theory;

                        While conditions were favorable and predictable, it paid to

reproduce as fast as possible-asexually. When the little world

came to an end and the next generation of aphid or rotifer faced

the uncertainty of finding a new home or waited for the old one to reappear, then it paid to produce a variety of different young in

the hope that one would prove ideal (57).

 

            William’s theory was criticized because it only works if the rewards are high; “only if a very few of the dispersers survive and do spectacularly well does sex pay its way” (58). Graham Bell from Montreal decided to catalog species according to their ecology and sexuality. The results of his finding were different than from what was expected as a result of William’s theory. Bell found that asexual species were living in harsh environments where, according to Williams, they should be producing sexually. Also, William’s example of the aphids and rotifers turned out to be a myth because it is not the winter or a drought that made them turn sexual, but overcrowding which affects the food supply. Graham Bell calls this the “tangled bank” theory. Basically, the “tangled bank” theory states that “sexual organisms in saturated environments, rather than churning out more of the same offspring, would be better off varying them a bit in the hope of producing offspring that could avoid the competition by adapting to a new niche” (60).

           

            A student of Bell’s, Austin Burt, looked at the recombination that occurs in the genes of mammals to see if the tangled bank theory fit the facts. He found that the tangled bank theory did not fit because “the amount of recombination bears no relation to the number of young, little relation to body size, and close relation to age at maturity. The tangled-bank theory would predict the opposite” (62).

           

            Next came Leigh Van Valen, the person who started a theory called the Red Queen Theory. He came upon this theory when he was studying marine fossils. He discovered that “the probability a family of animals would become extinct does not depend on how long that family has already existed. Their chances of extinction are random” (64). A species cannot afford to relax and stop adapting to its environment because the enemies which the adaptation is trying to protect the species from is also adapting. This theory is called the Red Queen theory after the character in Alice in Wonderland  who ran and ran, but got nowhere. In the world, and in evolution, there is change, but not necessarily progress. Therefore, “sex, according to the Red Queen theory, has nothing to do with adapting to the inanimate world – becoming bigger or better camouflaged or more tolerant of cold or better at flying – but is all about combating the enemy that fights back” (65).

 

            The biggest enemy that fights back are parasites, predators, and competitors. In the past most of the deaths were caused by Smallpox, tuberculosis, influenza, pneumonia, diarrhea, etc.  Recently Richard Dawkins said that “Parasites are touted as the prime movers in the evolution of sex, promising a final solution to that problem of problems” (66). In fact, parasites are more deadly than predators for two reasons. The first reason is that there are more of them which makes them a huge threat. The second reason is that parasites are smaller than their host which means that their life spans are shorter. The shorter life span allows for a parasite to go through many generations in one host which then allows them to multiply and adapt faster than the host can. In fact, “the more successful the parasite’s attack, the more the host’s chances of survival will depend on whether it can invent a defense. The better the host defends, the more natural selection will promote the parasites that can overcome the defense” (66).  It is the parasites that provide the genes incentive to change. This has even been proven with the use of artificial viruses in computers.

 

            Animals have only three ways of defending themselves against parasites. The first way, usually used by plants, is to grow and divide faster than the parasites. The second defense is sex and the third defense is the immune system which is only used by the descendants of reptiles. Other species, like plants and amphibians, use a chemical defense like antibiotics.

 

            As it turns out, “Austin Burt’s discovery of a correlation between generation length and amount of recombination is evidence of the Red Queen at work” (71) and Bell and Burt discovered that “the mere presence of a rogue parasitic chromosome...is enough to induce extra recombination in a species” (71). These things show that sex is necessary for combating parasites. The job of parasites such as viruses, fungi, and bacteria is to break into cells and either eat them or use their genes to make new cells. In order to break into the cells the parasites have to bind to them first. They do this by employing protein molecules that fit into the molecules on the surface of the cell. It is easier to think of the hosts having a lock that the parasites are the key to. When a parasite has the correct key to the lock, then the host changes the lock.

 

            It is in this key & lock analogy where the advantages to sexual reproduction become apparent. Sexual reproduction creates a species to have lots of different locks, whereas species that reproduce asexually all have the same lock. If a parasite comes along with a key that works then the sexual species will be fine, but the asexual species will be completely wiped out. The idea of the Red Queen running and not going anywhere comes into play again because when a lock becomes rare, the parasite’s key becomes rare, so that lock is once again useful to the host. The host is right back where is started.

 

            The Red Queen’s method of defense and the immune system are actually interconnected. Hans Bremermann of the University of California at Berkeley says that the immune system would not work without sex. Author or The Red Queen, Matt Ridley, explains it in the following way:

                        The immune system consists of white blood cells that

come in about 10 million different types. Each type has

a protein lock on it called an “antibody,” which corresponds

to a key carried by a bacterium called an “antigen.” If a key

enters that lock, the white cell starts multiplying ferociously

in order to produce an army of white cells to gobble up the

key-carrying invader (74).

There are a few things that the parasite can do to defend itself against the immune system. It can try to infect somebody else before it is killed by the immune system, it can hide inside host cells, it can keep changing its own keys, or it can try to imitate the password that the host’s cells have in an attempt to not be noticed. According to Bremermann, the parasites that imitate the host’s password put a pressure on the host to change the password which is where sex comes in; “sex keeps parasites guessing” (83). It is the Red Queen theory that expresses how sex helps organisms to be one step ahead of the parasites to better their chances of survival. 

 



 

 

                                Chapter 4: Genetic Mutiny and Gender


Chapter four takes on the theory of the Red Queen in a completely different light. It presents all the strangeness that is associates with the theory and it is quite interesting. It is about “harmony and selfishness, about conflicts of interest between genes inside bodies, and about free-rider genes and outlaw genes.” (Page 2) The lifestyle of genes can easily be related to an everyday community. For the most part everyone works together, but there are times when you have to turn your back on someone who may be on your “team” for the sake of yourself.
A town would not be a community without cooperation. This is the same for genes, without cooperation between them their inhibited body would never become built and their genes would never be able to be passed on to future generations. Cooperation is made possible by the assumption by Williams, Hamilton, and many others who say a gene does anything to enhance its own survival. “Cooperating to build a body is a great survival strategy.” (Page 2)
Along with cooperation also comes specialization in which genes form together to make groups called chromosomes. These chromosomes then merge together to make a supercell, which is the beginning of the modern cell. These cells then team together to make plants, animals, and fungi. This is how genes work together to build a body and pass their genes on generation after generation.
Cooperation among genes may be harmonious in on sense, but a gene is also just as much selfish as it is a team player. “A society is not all cooperation, a measure of competitive free enterprise is inevitable.” (Page 2) This sense of selfishness can be illustrated through the idea of the “tragedy of commons”. The “tragedy of commons” is basically a matter of ownership, “the free-rider wins at the expense of the good citizen”. (Page 1) An example of this selfishness is called bacterial “sex” which wasn’t invented for the bacteria but rather for the genes. It is a case of self-fulfillment at the expense of the other genes, “abandoning them for another team.” It suggests an “origin for sex”. (Page 3) If a gene were able to make its “owner-vehicle” have sex, they would do it even at the expense of the individual. An example of this would be rabies. The virus makes the dog act wild in order to make it bite another dog and pass on the virus to another host.
Cooperation may be a major part of a gene society but it is competition and the selfishness of a gene that leads to reproduction. In fact competition is what led to the invention of gender and why boys are different from girls. It explains why not all creatures are hermaphrodites and why we have sex sexes.
“The genes of animals and plants turn out to be full half-suppresses mutinies against the social harmony.” (Page 4) Some flour beetles carry a gene called Medea in which chromosomes selfishly do nothing but invade every egg the insect makes to insure they will continue generation after generation. Another interesting situation is the parasite of what is called the scale insect, which has more than one sperm penetrating the egg when fertilized. The extra sperm divides as the egg does, and then eats out the gonads of the maturing creature. The parasite sperm cells then replace the gonads with its own to ensure their spot in the next generation.
However, it is during sex that the best opportunity for selfish genes occurs. The fact that most plant and animals are diploids, (their genes come in pairs) the partnership between two sets of genes is sometimes uneasy. A gene will thrive and its partner does not if monopolizing the egg or sperm is capable.
This process has interested many biologists whom have made logic out of it through using the process of when a woman conceives as an example. Since we only get half of our chromosomes from our mother and half from our father, the genes have to fight to become one of the twenty-three “lucky ones” in order to guarantee themselves in the next generation. A selfish gene would simply kill off the one that comes from the other grandparent of the embryo. “Crossing-over” is the process in which the genes are mixed together or shuffled, and it happens in pretty much all pairs of chromosomes of animals and plants. David Haig and Alan Grafen believe this process is merely a sense of “law enforcement”, in order to keep the division of chromosomes fair.
A female’s purpose is to produce eggs and the male’s purpose is to produce sperm or pollen. There are few genes that actually come from the mother, and when a sperm fertilizes an egg, all it donates is a bunch of genes (which is called a nucleus). Evolution has done many things to try and keep the father’s organelles out. However there is one exception, Chlamydonas which is an alga that has two genders. Because of these two genders this species performs in what is called fusion sex, which is when sex consists of the fusing of two cells. Most animals and plants practice this type of sex and have two genders.
Bacteria and viruses are just as much rebels as organelles are in the genetic world. “When cells fuse, the rival bacteria in each engage in a struggle to death.” If a bacterium living happily inside an egg suddenly finds its path invaded by a rival carried by a sperm, it will have to compete, and that might as well mean abandoning its latency and manifesting itself as disease. An example of this is AIDS, which remains dormant until another virus enters the body and triggers what was then only called HIV to full blown AIDS.
Gender was invented to resolve the constant battle between two parents and the cytoplasmic genes. Although there are few people who are actually hermaphrodites, most plants are. Hermaphrodites are constantly in a state of battle against genes that are trying to get rid of their male parts. Male sterile genes are then made and when at work, plants have two types, hermaphrodites and females. In a hermaphrodite plant, if the male is killed, the female part grows stronger and produces more seed.
Therefore separation into two genders by animals “ended the first mutiny of the organelles”. (Page 9) However, they may have ended mutiny, but now they have a different focus, to get rid of all males and to have only females. There are two reasons this does not phase the organelles. First they are able to give the species virgin birth to try and get rid of sex. Second even if it leads to long-term suicide, short-term competition is always sought.
It is the sex chromosome that determines the gender of their owner’s children. The mother gives an X and either an X or a Y is given from the father. If a child is XX, they are female and if they are XY they are thus male. But sex chromosomes themselves began to have interest in which gender would be of their owner’s children, as strange as this may be. Bill Hamilton who saw this phenomenon as potentially a great danger to extinction, studied this. This case of lemmings illustrates how even sex chromosomes, which were supposed to be invented to control gender ratio, they can actually alter it as well.
There are three basic ways of determining gender. The first is when gender is chosen based on what may be appropriate for a species sexual opportunity. An example of a secondary creature that would do this is what is called a Slipper Limpet. This creature begins life as a male and changes into female when it settles upon a rock. When another male Limpet sits upon it, it too becomes females, and so on and son on. The second way of determining gender depends completely on the environment in which the creature lives. For some fish, shrimp, and reptiles, temperature plays the determining factor in the gender that the creature in the egg will become. For example, turtles that eggs are warm will hatch into females, and alligators whose eggs are warm will hatch into males. The third is based on the mothers right to choose. This is particular in species such as monogonont rotifers, bees, and wasps. Their eggs become female only if the mother fertilizes them, otherwise they will be male.
The idea of choosing gender leads into the basic Red Queen Theory itself. Higher-class people want to have males and parents of lower social or economical status “should” prefer to have a female. This is because females tend to marry up in class and males tend to marry downward. It is also said that there is more abuse among males in lower class family and among females in an upper class family. This leads to the very interesting statistic that the children of presidents of the United States leads 60 to 40, males. Chelsea Clinton is an exception to this curious ration, but it has been shown that royalty has produced slightly more sons than daughters over time.
This concept of the Trivers Willard theory can be illustrated through using apes as an example since humans, or mankind is in a sense is an ape. Studies show that when senior females give birth to young males, they rise to the top much quicker than do junior females. Therefore according to Trivers Willard logic, females with high social status should rather have male young. High social status males tend to have more children than lower status males (and social status is inherited). Just like apes, human males tend to inherit their fathers (or mothers) social status more than daughters inherit that of either parent. The fact that royals and aristocrats are more likely to give birth to male children brings about the question once again, why is there such a male-biased sex ration at birth? How are people “unconsciously achieving something they consciously have been striving to achieve for generations unnumbered?”
In past history there have been some strange methods on how to influence the sex of a child. Books have been written, theories have been made, and “gender kits” have been sold. All these ancient methods have been faults but with the science we have today, more convincing methods have been brought into consideration. Invented by Roland Ericson a method where X and Y sperm are separated to ensure proper choice of a gender swears to his method but has not yet published any data to back him up. Larry Johnson has developed a more convincing method in which he first dyes the sperm DNA with fluorescent dye and then allows the sperm to swim Indian file past a detector. When under light, some of the sperm glow brighter than others, and are sorted accordingly. The sperm are then fertilized using in-vitro fertilization. Then again, not many humans would submit their sperm to such dies or in-vitro fertilization to have a boy. There are however, some people in some parts of the world who decide to do a more do a more serous and time consuming method.  This would referring to the act of selective spontaneous abortion.  As early as possible the sex of the fetus is found out, but if it is not the particular sex that the parents want, the child will be aborted.  This process will be done over and over until the desired sex is finally obtained.
The Trivers Willard Theory suggests that there seems to be no genetic control of the sex ration. They also say “evolution will build in an unconscious mechanism for altering the sex ration of an individual’s progeny.” People like to think they are rational or have the control, but really evolution arrives at the conclusions all on its own.

 

 


 

 

OUTLINES:

                                         

                                         Ridley, Matt.  The Red Queen

                                       Chapter 3:  The Power of Parasites

 

I.  Sexual Reproduction

         A.  Offspring is slightly different from parent

         1.  Focused on the survival of the species, not the individual.

  2.  Fittest will survive dispersal into new environments.

                    3.  A few exceptional young is better than many average young.

II.  “Tangled Bank” Theory

A.    Graham Bell basically says that sexual organisms in saturated environments, are better of to produce different offspring to avoid the competition by taking on a new environment.

B.    Austin Burt found that this theory proved the opposite, since varying offspring  has nothing to do with body size, age at maturity, and number of young.

III.  Red Queen Theory

A.    Leigh Van Valen named this theory after the character in Alice in Wonderland who ran as fast as they could but stayed in the same place.

1.     Thus, sex is about shuffling genes and keeping pathogens unable to

      adapt, not about adapting to an environment.

IV.  Parasites, Predators, and Competitors

A.    Richard Dawkins found that parasites are the most deadly and are “the prime                 

      movers in the evolution of sex” (66).

    1.  The number of parasites alone poses a huge threat.

2.     The short life span of a parasite allows them to multiply and adapt

quicker.

B.    Computer programs and viruses, or artificial intelligence, has helped prove this theory.

C.    Different ways animals defend themselves.

1.     Grow and divide fast enough to leave the parasites behind.

    a.  Plants and plant breeders use this method usually.

2.     Sex.

    a.  This method of defense has been practiced by many.

3.     An immune system.

          a.  Practices only by the descendants of reptiles

   4.  The use of antibiotics.

a.      Fungi originally produced this chemical to kill bacteria.

V.    Austin Burt and Graham Bell Show the Red Queen at Work.

A.  Burt discovers more genetic mixing is needed the longer the generation time, in

                order to stay ahead of the parasites.

B.    Both discover that the presence of “B chromosome”, or rogue parasitic

      chromosome, causes more genetic recombination.

VI. Virus, Bacteria, and Fungi, the Causes of Most Diseases

    A.  They brake into cells for two reasons.

              1.  Bacteria and fungi eat cells.

  2.  Viruses use them to make new viruses.

B.    How they bind themselves on cell surfaces.

                     1.  They “employ  protein molecules that fit into other molecules on cell

     surfaces” (70).

VII. The Key and Lock Analogy

A.    Parasites carry different keys to the locks of the host.

1.  Sex shuffles genes, therefore creating new locks.

2.  Asexual offspring are the same, all carrying the same locks.

3.  When locks become rare, so do the parasites keys, making that rare lock

     useful to host again, and so it repeats itself.

                               a.  Hence the Red Queen runs as fast as she can, but never gets

     anywhere.

VIII.  What the Parasite Must Do to Win

A.    Infect someone else before the immune response.

B.    Conceal itself inside the host cells.

C.    Change its own keys frequently.

D.    Try to imitate the password that the host’s own cells use to escape attention.

 

 

 

                                Chapter 4: Genetic Mutiny and Gender

 

I.  Intragenomic Conflict

A.  Conflicts of interest between genes inside a body.

          1.  If genes could not cooperate, the body they inhibit would never get built,

                       never passing any genes to the future generations.

II.    Cooperation and Competition

          A.  A  gene is defined as, “the descendant of a gene that was good at getting into           

                future generations” (95).

                    1.  Therefore, the genes have used cooperating to build a body as their                                                    

                         survival strategy.

B.  Competition led to the invention of gender.

III.  Molecules

A.  Replicated molecules became numerous and began to assemble as chromosomes.

B.    Chromosomes use cells to replicate chromosomes efficiently.

C.    Chromosomes then merged several kinds of cells to form a supercell.

1.     Thus, the invention of a modern cell from different bacteria.

D.    These cells then grouped together, forming animals, plants, and fungi.

IV. Viruses and Bacteria

A.    Disposable vehicles for simple teams of genes.

                     1.  Each team is extremely competitive.

                     2.  Team members are harmonious.

         a.  This harmony, however, breaks down when bacteria merge to

                                   become cells.

3.  On rare occasions, some bacteria abandon their team for a better team,

     Conjugation.

1.  The bacteria shunts some copies of genes across a narrow pipe to

     another bacteria.

V.    Selfish Genes

A.    Segregation disorder in a certain fruit fly.

                    1.  This Cain gene kills all sperm with the other copy of chromosome two.

B.    Meiotic-drive genes in flies, mice, and a few other creatures are rare.

    1.  Crossing over swaps certain chromosomes to keep chromosome division

                fair.

2.     The “mask” that protects Cain is swapped to Abel’s chromosomes.

C.    This Cain gene on the sex chromosome of an X, can safely kill the Y

      chromosome.

VI. The Invention of Two Genders

A.  The alga called Chlamydomas has a plus and minus gender, they go to war

      leaving 95% of the cell destroyed, plus gender left with the 5%.

1.     The docile suicidal organelles, or minus gender, would proliferate.

a.  Thus, two genders are invented: killer which provides the

     organelles, and the victim, which does not.

B.  The two genders are a consequence of sex by fusion.

          1.  Sperm only passes the nucleus into the egg to avoid introducing bacteria  

                               or viruses.

C.  Genders were, “invented as a means of resolving the conflict between the

       cytoplasmic genes of the two parents” (104).

1.     So an agreement was made, instead of destroying the offspring.

D.    “Hermaphrodites are in a state of constant battle against rebellious organelle

      genes trying to destroy their male parts” (105).

VII. Deciding Gender

A.    The X and Y chromosome of a man’s sperm decides gender, the first on to the

      egg wins.

B.    Three different and better ways to determine gender.

               1.  Choose the gender appropriate to your sexual opportunities, for sedentary

                    creatures.

                              a.  Lots of female shoal fish mate with the single large male, and

    when he dies, the largest female changes gender.

2.  Leave it to the environment.

a.  For alligators and crocodiles warm eggs hatch as larger babies than           

     the cool ones.  Male size and competition for females.

3.  Mother to choose the sex of her child.

a.  Female bee and wasp eggs are the fertilized ones, and the

     unfertilized are male.

C.  “Lower down the social scale, daughters are preferred even today.  A poor son

      is often forced to remain single, but a poor daughter can marry a rich man”

                  (126).

 

 

Critical Review

 

A.)  Three Interesting Points

           1.  Genes that kept one generation of a species protected from a parasite, can be

      harmful to the next generation when the parasite adapts to them.  Also that

      parasites adapt so quickly.

 

2.  How diseases like HIV lay dormant until they are reawakened by “rival”  

     infections.  Then the HIV virus multiplies rapidly.

 

3.  The idea that genes have formed a system of cooperation and competition, in

     order survive natural selection and pass to future generations.

 

B.)  Weak/ Confusing Cases

1.  In the beginning he talks about species going from asexual to sexual.  He  

     does not explain how that happened.  Also, I do not understand if he means 

      two sexes appear or if one sex trades genetic material.

 

2.  Chapter four seemed to jump around in strange directions without a clear

      explanation.  His writing style, thought process, and organization were not

                   as enjoyable as I had hoped.  After about the fifth time I read chapter four it  

                   started to make some sense.

 

3.  His writing style in both chapter three and four were sometimes irritating!

      In chapter three he ends one sentence, “…by vaccination or whatever” (74).

      Also, in chapter four he ends another statement, “-whatever that may mean”

     (120).

 

 

C.)  Needed to Explain Further/ We had Questions About

           

1.  In the beginning of chapter three the author states that sex is useful to the

      individual and not the species.  But if an individual is able to survive because      

                  they were created sexually, then they will most likely be able to reproduce as             

                  well.  That seems to be for the good of the species.

 

2.  In chapter three, the “B chromosome”, or rogue chromosome, was not fully

     explained.  It was also mentioned in chapter four, and I am still not sure

     what its role is, other than cause more genetic recombination.  Also, how does

     it cause more?

 

3.  In chapter four, segregation disorder and Meiotic-drive genes got rather

     confusing, especially when he brought in the Cain and Abel metaphor.