Book Review for ‘The Human Superorganism’, by Rodney Dietert, Phd

Overall, I would give this book a rating of 4 out of 5 stars.  Although it contains truly revolutionary ideas that both have wide ranging scale, and can be easily understood with the proper background in DNA switches, it lacks a pure academic spirit in its writing style, method of citation, and common use of personal anecdotes.

To briefly sum up the book’s argument: Although a human being is currently understood as being one ‘species’ of animal, it is actually much more accurate to describe a human being as an entire ecosystem unto itself, with thousands of strains of bacteria, viruses, fungi, Archaea, etc. living and flourishing all throughout the body.  They live on our skin, inside our gut (making up the majority of our immune system, there), and in every organ of our body.  This set of thousands of different micro-organism species that make up the entire genome of a human being is christened, “The Bionome”, a combination of Micro-Biological and Genome.  It is, in other words, the real, and total, human genome.

More importantly, however, this Bionome is unique to each person, much like fingerprints.  It is inherited almost chiefly from the mother, as only one set of Bionomes can be safely passed from parents to child.  (This is one reason the egg is so large, while spermatozoa are so small, containing almost only the male’s chromosomes).  This Bionome grows with us as we do, changing as we change from children to adults.  Finally, not only does it act in an important way symbiotically with our own ‘bodies’, but its output can alter the genetic switches in our DNA, allowing for certain types of generation to generation evolution, as if by magic.

One example of such micro-switching controlling the expression of genes is known as ‘The Returning Soldier’ effect, where significantly more sons are born after a war, as if to replace the men who were lost.  According to the new theory of the Microbiome, this effect could be explained by the bacteria inside females reacting to the added stress of a war, secreting proteins that can alter our DNA switches, making certain change part of our internal programming.

Another important aspect of this book is its advocation of starting and maintaining a healthy Microbiome throughout our lifetimes.  This begins with breast feeding as a baby, passing important strains of bacteria from mother to child, as well as skin touching between mother and child, another essential part of the correct seeding of the Microbiome.  Today, we have probiotics to use to help correct imbalances in our microbiome, mostly through our gut, and these can be very useful in a large variety of health conditions, even obesity.  Because it is the correct balance of the useful strains of bacteria that is important, not the quantity of a single one.  It is surprising how much our living bodies are a product of the symbiosis of so many organisms, and the implications for future medicine are rife with such possibilities.

- This was a Book Review for The Human Superorganism (How the Microbiome is Revolutionizing the Pursuit of a Healthy Life), by Rodney Dietert, Phd, Dutton, 2016 (NY), 341 pages.

Guns, Violence, Anger, Human Beings, and Police. And Trump.

I had a bad day on Friday.  It’s not really important why – it was actually over a month of bad days that led up to this particular one.  So, I ended up coming home after teaching class and lost it, in my driveway.  Yelling, cussing, going on about all the crap I have to deal with.  I also misplaced my cell phone, which further exacerbated my bi-polar fueled rage.  Finally, I entered my house, tried to calm down, and relax.

The next thing I know, three female police officers are ringing my doorbell.  Some neighbor of mine had called the police because they felt I was a public threat of some kind.  Is this the culture of fear we want to live in?  Feeling the need to call the police on one of your own suburban neighbors, standing in their own driveway, doing nothing illegal?  Only after this incident did I hear about the shooting in Las Vegas, which was the largest national mass gun killing in history.  Could these two events possibly be connected?

Human beings are fragile.  We have emotions, nay passions, which can explode at the drop of a hat.  Anybody, given the right circumstance, is bound to ‘lose it’ and ‘go postal’ as long as guns are so incredibly available in a nation of about 300 million people.  Out of that number, at least SOMEONE is going to want to up the body count and make history, again.

Ergo, gun control.  Stalled for decades in this country – far behind any other country in the world.  Why?  Is the gun industry more important than our national liberty?  Our right to freedom?  Our right to pursue our own happiness?  How can this be accomplished in a gun state, gripped by fear, and controlled by police – who have almost unlimited power!  How many times has a police officer been acquitted of obvious brutality?  Too many to count.  Does every police officer even need to carry a gun?  I don’t recall mass shootings in England, and their cops lack firearms.  All lives matter.

I, for one, am tired of this constant violence and fear.  It is time for America to actually do something about fear, violence, and gun control.  I don’t think ‘President’ Trump is going to help, I think he is going to increase the amount of fear and division in this country, and the world – that is what his party feeds off of.  And how did he get elected?  Gerrymandering.  Russian interference.  All of these things are ridiculous.  We need to save this country from going to hell.  End of story.

Is American Football Ethical?

                Is American Football Ethical?  No.  A sport that is fundamentally based on physical and neural injury is not something that should be practiced, promoted, or allowed in a nation such as America.  The goal of any law abiding commonwealth is the overall common good of its citizens, and it is manifestly unfair for the good of some (or many) to come from the suffering of a few (or one).

                To think more about what it means for the state to exist for the common good of its citizens, we should ask the philosophical question, if we could make most people happy by having one person suffer constantly, would that be ethically right, i.e. morally just?  This question is framed in the mindset of human action and affairs, and not in any kind of divine framework.  Can we ask such of a person?  And what if the person volunteers, out of a genuine desire to help people and make their lives better?

                Again, the answer is no.  As a nation state, we must insure the most common good possible for each individual person.  That includes not allowing a person to legally injure themselves, for any reason, unless it be in the case of an emergency, when no forethought is allowed, as in the case of a fire, or a drowning person.

                So, what does that mean for the game of Football, its players, and fans?  Sadly, it means the end of an era for deliberately violent sports.  (This includes any and all contact sports including hockey, boxing, wrestling, etc.)  Competition, which is a natural state for mankind, including the ‘civilized’ members of American society, must begin to take a more intellectual form, with less risk for physical injury, over the complete course of a person’s athletic career, including training, diet, etc.  So, for example, Track and Field, which poses much less of a risk of severe head injury, should still be a sport where athletes are not encouraged to push themselves to their physical limit and beyond, posing the risk of possible injury.  However, looking at the wider view of sports in general, it seems that there exists no athletic activity that does not involve some risk of bodily harm over the course of a career.

                The honor and glory of playing organized sports, and the joy that comes from viewing and following such athletics, is a part of the human psyche, as expressed through competition.  This harkens back to the gladiator days of Rome and beyond – humans have always competed in games for the honor of victory (even at risk of certain death), and this natural desire will not disappear any time soon.  What we have to do, as intellectually evolving humans, is figure out a way to channel that aggression and desire for victory away from violent games and war to a more civilized and intellectual way of competing.

                In the end, we are going to have to phase out the most dangerous and violent sports from our arenas and schools, and shift towards a more intellectual field of play.  How, is a question I am in no position to answer.  But encouraging children to play Football, when they have no capability to understand the long term risks involved in it, is, and should be, a crime.  Children cannot make that decision, and therefore should not be allowed to play.  Older players have the choice of risking serious and traumatic permanent brain injury, but we as a society should not allow that possibility to be chosen.  It is our responsibly as a republic, based on liberty, to ensure that each citizen is free from the bonds of needing to achieve success through pain, injury, and suffering, athletically or otherwise.

The Philosophy of Sex, Part III: Human Nature, Monogamy, and Adultery

The Philosophy of Sex, Part III: Human Nature, Monogamy, and Adultery

Man is a highly complex and social animal, with strong cultural norms that help keep societies together, and yet these norms are sometimes violated, often in secret.  What we have left to examine in the philosophy of sex is its part in the formation of human nature; in evolution, culture, and divided duties.  What we will see, in the end, is that, like many animal species, human beings are ‘designed for a system of monogamy plagued by adultery’.  (Ridley, 176)

                In the first Part, we examined a theory of the metaphysics of sexual love, through Schopenhauer’s writings on the subject.  He hypothesized, c. 1860, that the sexual impulse in man, and in all of nature, is the will of the next generation, not yet existing, willing itself to be born.  That, in a sense, we (and all animals) are tricked by this impulse into begetting the next generation, raising them, all the while thinking it is our own will that we are following.

In Part II, we saw how sexual reproduction produces more complexity and diversity than asexual production, through the mixing of genes.  These genes not only get shuffled around during sex, but certain key ‘switches’ (known for short as ‘Hox’ genes), which control the major elements of body formation, can be moved around the genome to create new phylogenic forms, step by step, as organisms adapt to their respective environments.

Here, in Part III, we will take a look at some of the broader implications of sex, for life in general, and for human nature, specifically.  In order to hypothesize about the sexual behavior of humans, we will examine in general the sexual behavior and habits of the animal kingdom, and then compare them to humans to see if any insight can be gained.  For example, it will be easier in our study to examine the social and mating habits of birds who live in colonies, and have direct correlations to our own societies.  Birds living in colonies often have monogamous mates, but are also free to move about the colony in a semi-anonymous fashion, much like human beings.  We can also gather data from primitive hunter / gatherer societies still extant today, as well as archeological evidence from past hominid [pre-ancestors of humans] sites.

The very first question that must be asked in any exploration of the human condition through its evolutionary past is, how and why did the brains of our human ancestors get so big?  It is only through having such a large and complicated brain that modern civilization is possible; but what led to the evolution of such an organ?  It would be easy to say that big brains evolved in order to produce technology and culture, but such an explanation would be looking at human evolution through hindsight.  There must have been certain immediate advantages to having a larger brain, in order for it to evolve to so large a size, in so relatively short a span of evolutionary time (about 3 million years). 

After a period of about ten million years of relative stagnation, ‘The cerebrum of homo was expanded enormously during a relatively short span of evolutionary time .  (Wilson, 548)  In a period of about three million years, the adult cranial capacity of our ancestors went from about 500 cubic centimeters, to a height of 2,000 cubic centimeters in modern homo sapiens.  Again, we must ask, what kind of environmental and genetic pressures would lead to such a hypertrophy of the human brain? 

                The answer, I believe, is two-fold; first, early hominids moved, through environmental changes, from woodlands to a more open savannah, where their bipedal stance and modern anatomy could lead to further adaptations, and second, that sexual competition and selection between individuals of the same species led to there being a premium on intelligence, in order to outwit one’s fellow individuals, and reproduce more.  In the first case, the group of hominids that would eventually split off to form modern man had to adapt to a more grassland type of environment, more so than when they had been living in the dense trees of the forest.  (This was a result of natural climate and environmental change, as Africa became drier and more savannah-like.)  It has been hypothesized that the bipedal stance of hominids formed initially as an adaptation to pick seeds or fruit, as this would clearly be an advantage in such a living environment.  (Wilson, 569)  An easy example in support of such a theory is the human loss of the gene to create vitamin C.  It has been concluded that this gene was lost, as being unnecessary, since our ancestor hominids got enough from their diet that they did not ‘need’ the gene, anymore.  Perhaps rising on two feet and picking such seeds and fruit led to the eventually bipedal stance of the early hominids.

               

                Such would be an explanation of the hominid’s early ability to manipulate small objects, differentiate colors, etc.  But how would sexual selection lead to a second explosion in the enlargement of the human brain?  The answer, I believe, in this case, is that through the eventual addition of meat to the diet of hominids, and the competition among individual males for females to reproduce with, led to the enlargement of the brain.  First, the additional calories needed to create stronger embryos that would adapt faster and more effectually required the addition of meat, and its extra calories, to the hominid diet.  This raises the question of how a previously herbivorous species developed the ability to eat meat?  The archeological evidence tells us that early hominids, like the Australopithecus ,

“Were catholic in their choice of small animals.  Their sites contain the remains of tortoises, lizards, snakes, mice, rabbits, porcupines, and other small  vulnerable prey that must have abounded on the savanna.’ (Wilson, 567)

This would explain how, over time, the early hominids could have evolved the ability to digest small animals, even before the discovery of fire for cooking meat, which makes meat much more easily digestible by hominids.

                Next, with the caloric intake needed, came the next steps in sociality involving hunting, gathering, and the specialization of tasks for males and females.  This essentially involved outwitting one’s male competitors for the monopoly of females, and so required a greater amount of intelligence.  Human society became much more complex with the advent of organized hunting, specialized tasks, and ritualistic traditions around the group.  This meant that women were interested in not only a man’s hunting prowess, but also his ability to be a decent mate and father, as well as his genetic fitness for producing children.

                There is another facet of sexual selection that plays an important part in producing healthy and viable children; hereditary immunity against disease and parasites.  This is because as each generation comes into being, it will be attacked by many types of bacteria and other parasites,  and a key requirement is to keep such parasites guessing as to the immune defenses of the child in question.  Ridley explains it like so:

“Sexual species can call on a sort of library of locks that is unavailable to asexual species… There are different versions of the same gene at any one time… It transpires that many of the most notoriously polymorphic [multiple versions of genes] genes… Are the very genes that affect resistance to disease – the genes for locks.”  (Ridley, p. 72 – 73)

What Ridley is arguing here is that just as disease tries to invade an organism, that organism will try to defend itself with built in immunities.  As parasites evolve, they develop new ‘keys’ for the ‘locks’ of our genetically based immune system.  And so a sexual species has an advantage because they can also shuffle around the different immunities, or locks, every generation.  This keeps the parasites guessing, and gives the next generation a better chance for survival.

                So far we have covered the male motivation for having ‘more’ sexual partners; more offspring.  But what could be the motivation for a female to have multiple sexual partners, and what kind of defenses have evolved to combat such inter-species competition for the rights to reproduce?

                The answers to these questions are complex, indeed.  It will assist in understanding to compare humans to colonial birds, again, in order to address these issues.  Take female swallows, for example.  They are a colonial bird, and their reproductive strategy is as follows:

“A female swallow needs a husband who will help look after her young, but by the time she arrives at the breeding site, she might find all the best husbands taken.  Her best tactic is therefore to mate with a mediocre husband… and have an affair with a genetically superior neighbor… In short, the reason adultery is so common in colonial birds is that it enables a male bird to have more young and enables a female bird to have better young.”  (Ridley, 223 – 224)

Such an analogy may work in theory, but humans and birds are descended from much different lines; humans, or homo sapiens, are descended from the ape family, while birds are a part of the larger reptile family.  (One that descended from the dinosaurs, but that is outside our scope, here.)  So what then, are the special mechanisms hominid females developed to better their chances at having successful young?

“The answer may lie in our evolutionary past with the other members of the ape family.  Female primates seemed to be ‘Initiators of much promiscuity… A whole new light has been shed on the evolution of female behavior by a group of ideas known as ‘sperm competition theory’… In fact, as subsequent research revealed, infanticide is common in rodents, carnivores, and primates.”  (Ridley, 213)

The main goal of such behavior is to eliminate the genetic offspring of other males… And then, when the new ‘troop’ of males and females coalesces, it is of great advantage to the females to share her sexual favors with as many male members of the troop as possible, as this will prevent the knowledge of who is the male parent, and therefore prevent infanticide.  (Such is the basis of sperm competition theory.)  “An alpha male … has only a short time at the top, and infanticide helps these animals to father the maximum number of offspring during that time.”  (Ridley, 213) 

                And so groups of females found it a better investment to remain with one group of males, to prevent the murder of their offspring.  But, does this kind of evolved behavior belong to mankind?  The answer is no.  We are a social species, with a complex social hierarchy; infanticide goes against our most core social norms (although it still happens in more primitive cultures, to increase the number of males, for instance.)  But the question still remains: Why have a monogamous male mate to help care for the offspring, and then seek some other male’s better genes?

                Although a woman’s tendency is towards monogamy, and the monopoly of a man for life, it is still a fact that women are, ‘sometimes unfaithful.  Not all adultery is caused by men.”  (Ridley, 218)  Although there is evidence for sperm competition in humans in the past, it is now evident that different sexual strategies are at use.  This, in turn, led to a ‘bizarre and astonishing explanation of the female orgasm.’  (Ridley, 224)

It was, “discovered that the amount of sperm that is retained in a woman’s vagina after sex varies according to whether she had an orgasm, and when… In faithful women, about 55 percent of the orgasms were of the high retention type (that is, the most fertile type).  In unfaithful women, only 40 percent of the copulations were of this kind, but 70 percent of the copulations with the lover were of this fertile type… The unfaithful women were [also] having sex with their lovers at times of the month when they were most fertile.”

In other words, while seeking a decent husband for life, an unfaithful woman was still capable of orchestrating her sexual relations so that she was more fertile with her lover than her mate.  This would suggest a reason for the female ‘fake’ orgasm; she is trying to convince her mate that she had a fertile orgasm, when in fact she may have not.

                The male of the species can counter such cuckolding techniques through some genetic trickery of his own.  Perhaps the simplest method is to guard his mate until he is sure that no other male can have sex with her.  This is evidenced by the close guarding of other mammalian females during their estrous period.  Direct connections can be made to human history and society easily, such as the infamous chastity belt of the middle ages, or the strict laws against any female consorting with unmarried males, without an escort. 

However, by mating with a genetically superior male, a female’s offspring will share the qualities of that male, increasing their chances of survival, and of reproducing, themselves.  In other words, it is a better strategy for the female, in order to have a greater number of grandchildren, and of spreading her genes further.  Her sons will inherit the qualities of the genetically superior male, making it more likely that they themselves will mate and have descendants.  Ironically, it seems to be the fact across the animal kingdom that the more genetically attractive a male is, the less attentive a father he is.

But how can a female (or a male) know which individuals of their species have better genes?  This eventually revolves around to sexual ornaments and genetic fitness.  If a male is symmetrical, has superior ornaments that are attractive to the female (a longer tail in birds, for example) than it is more likely that his genes are all in order.  In such a way can genetic fitness be observed from physical characteristics.

And so we see, as descendants of the mammal and primate families, we will always be plagued with a society of monogamy mixed with adultery.  Such is the evolved sexual condition of human beings.  This is not to say, of course, that all people are unfaithful.  But, rather, that their strategies when they are unfaithful, aim for the best genetic fitness of their children.  Men may get around, but women have a whole bag of tricks of their own.  In such a way we can relate the first part of our philosophy of sex to our current part – the next generation, yearning to be born.  Whatever it may take.

Sources Cited:

Ridley, Matt. The Red Queen: Sex and the Evolution of Human Nature. Harper Perennial, London (2003).

            Wilson, E.O. Sociobiology: The New Synthesis. Harvard Press, Cambridge (1975).

The Philosophy of Sex, Part II: From Bacteria to Complex Life Forms

The Philosophy of Sex, Part II: From Bacteria to Complex Life Forms

By Josh Glazer

                It has been argued in the past, most notably by Richard Dawkins, et. al., that the most basic unit of selection, at the evolutionary level, is the gene.  In it, we hit a kind of biological bedrock, in which it is difficult to move beyond.  We know that certain genes contain the instructions (in DNA format) for creating specific proteins, the basic building blocks of life.  But we don’t know how DNA ‘evolved’.  We know how the properties of certain proteins emerge; from their specific makeup of amino acids, and their 3-dimensional structure, for example.  We also know that there are long stretches of so-called ‘junk’ DNA that do not code for any effective proteins .  Some of this junk DNA is the debris from genes that were lost in the evolutionary past.  Yet some junk DNA holds vitally important switches which control key components of embryonic development, such as the timing and activation of certain body parts in their growth cycle.  There are still large gaps in our knowledge of how DNA came about, and the earliest life, but we are beginning to make inroads towards an understanding of how both simple, and complex, life forms can develop, and even evolve, from certain sequences of genes.

We do have rich archeological and  geological records, among others, and along with modern genomics, we are able to extrapolate a great deal of data about the different lineages of animals, and also their lateral transfers of genes, which can happen at the bacterial level, as will be discussed below.  What we want to explore, here, however, is more basic question: how did complex body plans form from simple multi-cellular organisms? 

                In order to begin our inquiry, it will be helpful to briefly review, at this point, the first 4 billion years or so of earth’s history, and how life behaved during that time.  The earth formed as a fiery pit of asteroid collisions and volcanic eruptions about 4.5 million years ago, about the same age as the solar system as a whole.  After a period of cooling and a cessation of tectonic fireworks, the first vestiges of microbial life have been established as about 3.5 million years old.  These consist in faint impressions of the first living cells on this planet.  (Prothero, 164)

               

                These first cells, however, were simple in nature, lacking nuclei, and other complex components of life as we know it now.  These simple cells, or bacteria, would be the only life forms on the planet for about 3 billion years, until the formation of the first complex cell with a nucleus – the eukaryotic cell (Latin for ‘having a nucleus.  Prokaryotes are cells without a nucleus).  What brought about this transformation?  It is generally agreed upon now, although it was quite controversial when first published, that the eukaryotic cell was the result of two or more bacterium combining to live in symbiosis with one another.  In this way, the waste products of one bacteria could be used as the fuel for another type of bacterium, and vice versa.  Although prokaryotes far outnumber complex organisms on this planet, all plants and animals are made up of eukaryotic cells.

                The question now becomes; how did life make the jump from eukaryotic cells to complex life, with body plans that continued to evolve?  We can begin our inquiry with the first possible ‘version’ of sex, known as ‘bacterial conjugation’.  This, simply put, is when two bacteria link up via a cytoplasmic tube, and freely exchange genes.  Exactly why they do this, we do not know.  Another form of bacterial genetic exchange is the existence of ‘plasmids’, which are basically just floating chunks of bacterial DNA, ready to be taken up by any bacteria in the immediate area.  These methods are still in use today, as, for example, bacteria pass genes for resistance to modern antibiotics between one another, leading to an arms race between the bacteria’s ability to evolve counter-measures, and our ability to devise efficient anti-microbial medicines.

                But even these forms of ‘bacterial sex’, or, more literally, the exchange of DNA between two bacteria, are not representative of sexual reproduction, as it is known in more complex life.  A bacteria divides by asexual reproduction, making an exact copy of itself.  Rare mutations may occur through radiation, copying errors, or UV light, but these mutations are not nearly enough to produce the millions of species that exist on the planet today.

                In order for more complex body plans to exist, sexual reproduction had to evolve.  This came about around the beginning of the Cambrian Explosion, as it is known, about 650 million years ago, when radiations of new body plans and forms began to proliferate.  Why did this new form of reproduction lead to such a vast new number of organisms?  As opposed to asexual reproduction, sexual reproduction is a complex procedure which thoroughly mixes the genes of the two parents.  To summarize:

“Meiosis is simply the procedure by the which the male selects the genes that will go into a sperm or the female selects the genes that will go into an egg… During meiosis something peculiar happens.  Each of the 23 pairs of chromosomes is laid alongside its opposite number.  Chunks of one set are swapped with chunks of the other in a procedure called ‘recombination’.  One whole set is then passed on to the offspring, to be married with a set from the other parents – a procedure known as ‘outcrossing’...

“Sex is recombination plus outcrossing; this mixing of genes is its principal feature.  The baby gets a thorough mixture of its four grandparents’ genes (through recombination) and its 2 parents genes (through outcrossing).”  (Ridley, 29-30)

                This blending of genes eventually leads to the creation of an embryo, which then develops into a more fully grown young, ready to be exposed to the world.  One question that may still be asked at this point is, how does all of this ‘genetic mixing’ lead to the incredible proliferation of life forms in the Cambrian period, and afterwards?

                The answer may lie in a relatively new biological field call ‘Evolutionary Developmental Theory’, or just ‘Evo / Devo’ for short.  This new field lies at the crossroads of embryology and evolutionary biology; hence the name.  (Carroll, 9)  Essentially, it compares an embryo’s development across several related species, and tries to figure out what controls the formation of the body, limbs, etc.  Being that 98% of our DNA is the same as chimpanzees, that 2% is rather important in the understanding of our human species.  Evo / Devo seeks to understand how embryos both develop and evolve by creating genetic maps, which indicate where certain body parts begin to emerge from the once single celled embryo.

                The first studies of Evo / Devo were done using simple laboratory animals like fruit flies, and provided almost miraculous results.  They revealed, after years of studies on the fruit fly’s third chromosome, that there sat 8 genes, in order, which formed the entire body of the fruit fly.  More so, all animals, from fruit flies to mice to humans, shared a similar set of these form making genes.  They controlled modular formation of the organism, such as you might see in a millipede; the same structure repeated a thousand times.  Or, a new appendage grown where there had been only a bud before.  Through careful manipulation, scientists were able to show that these genes existed across major species lines; growing weird mutants with legs in strange places, all to demonstrate the ubiquity of these genes.  These genes were somehow controlling the growth of the embryo, telling it what to do and when to do it, in order to create a specific organism.

                Since the form of these genes was similar across protein domains (existing spaces of possible DNA coded proteins), ‘The shared DNA sequence was dubbed the homebox and the corresponding domain it encoded, the homeodomain… Hox genes for short.’  (Carroll, 65)  The discovery of these Hox genes opened a whole new window into the way that body plans were organized through genetic mixing; simple switches could enable a particular body part to either multiply or appear at a different place.  Over evolutionary time, this was enough evidence to explain the immense diversity of organisms on this planet, and also their basic similarities at the same time, like DNA and other formations, such as Mitochondria and other organelles.  One incredible revelation is that all the instructions for most animals are contained in the DNA of similar animals; it is the genetic switches (or Hox genes) which controlled what life form would develop from the initial blastula. 

               

                (Above Picture, from Carroll, 62.  Illustrates Hox genes expressed in a fruit fly.)

And so, we can see that the genetic mixing of sexual reproduction greatly increases the chances of new adaptations, which, over evolutionary time, can create entirely different forms, based on an organism’s adaptation to its environment.  Additionally, when we use all of our most advanced scientific techniques to look backward in time towards our most universal common ancestor, it appears that many of the key elements of life already existed almost 1 billion years ago; it was merely a matter of arranging them in the correct format.

                Here, we will end Part II.  In Part III, we will finally see how sexual selection in human beings has helped shaped human nature, our species, our history, and even our different cultures.

Sources Cited:

Carroll, Sean B. Endless Forms Most Beautiful: The New Science of Evo Devo. Norton, New York (2005).

Jastrow, Robert & Rampino, Michael. Origins of Life in the Universe. Cambridge, London (2008).

Ridley, Matt. The Red Queen: Sex and the Evolution of Human Nature. Harper Perennial, London (2003).