"The World Until Yesterday" by Jared Diamond

This book is not as Enlightening as Jared Diamond's other books.  Still, it is interesting because you get to read personal stories of Jared Diamond's years in Papau New Guinea.  As always,  the interesting and thing worth noting is that our present state of society is has only existed for the past 5000-10000 years.  The norms that we have accepted as norms are not really "norms" in that sense.

I rather be a eunuch rather than to be dead

This NUS study shows how certain male spiders self- castrate rather to be eaten by the female spider.

In “ Why is sex fun”,  Jared Diamond covers why male spider is eaten by the female spider during copulation.

As he puts is,

” This cannibalism clearly involves the male's consent, because the male of these species approaches the female, makes no attempt to escape, and may even bend his head and thorax toward the female's mouth so that she may munch her way through most of his body while his abdomen remains to complete the job of injecting sperm into her.
.....

Suppose that opportunities to transmit genes arise unpre-dictably and infrequently, and that the number of offspring produced by such opportunities increases with the female's nutritional condition. That's the case for some species of spiders and mantises living at low population densities. A male is lucky to encounter a female at all, and such luck is unlikely to strike twice. (1) The male's best strategy is to produce as many offspring bearing his genes as possible out of his lucky find. (2) The larger a female's nutritional reserves, the more calories and protein she has available to transform into eggs. If the male departed after mating, he would probably not find another female and his continued survival would thus be useless. Instead, by encouraging the female to eat him, he enables her to produce more eggs bearing his genes. (3) In addition, a female spider whose mouth is distracted by munching a male's body allows copulation with the male's genitalia to proceed for a longer time, resulting in more sperm transferred and more eggs fertilized. "
.....

In Summary,

“Sexual cannibalism in spiders and mantises is favored by the ecological variables of low population densities and low encounter rates, and by the biological variables of a female's capacity to digest relatively large meals and to increase her egg output considerably when well nourished.”

So what do we make out of this case when the male spider actually chooses to make an escape.  Here are some questions:

• Does the male spider grows back his reproductive organ?  If yes, then this is simply an evolutionary development to have the best of both worlds - leave his reproductive organ to continue to transmit his sperm while growing a new one to impregnate another day.

• If the male spider does not grow back his reproductive organ, this is where everything breaks down and we have to relook the 3 clauses that I highlighted above.

By detaching his reproductive organ and leaving , the male spider continues to enjoy clause 3 of longer copulation time as his sperm continued pumping through the apparatus lodged in their reproductive organs.

But I think the article actually explains why such behaviour evolved:

•  “ the group found that the palps had delivered only a-third of their sperm after the females stopped copulation ...... and there is female-controlled short copulation, and ultimately the female's frequent cannibalism.

Therefore, from the male spider point of view, even if I am willing to be eaten, she copulates for such a short time that perhaps only a third of my sperm is used.

In addition, 

“ the detached palp can prevent other males from mating with the female, thus ensuring the paternity of the self-castrating spider. The eunuch also becomes more aggressive and guards the female from competitors while the sperm is being transferred.”

The Notes on Why is Sex Fun

Notes of “Why is Sex fun?” by Jared Diamond:

Chapter 1: The animal with the weirdest sex life

1. The funny characteristics of human sexuality (Pg 8):  
1. Long-term sexual partnerships
2. Co-parenting
3. Proximity to the sexual partnerships of others
4. Private sex – not public like other animals
5. Concealed ovulation
6. Extended female receptivity
7. Sex for fun
8. Female menopause

2. (Pg 14) Natural selection is not the maximization of survival but the transmission of genes and survival is just one of the strategy that provides repeated opportunities to transmit genes.
3. (pg 14) Sexual strategies that have evolved actually depend on both the ecological parameters and the species’ biology:
1. for eg, sexual cannibalism in spiders is common because of low population densities and low encounter rates, and the female’s biological abilities to digest large meals and increase her egg output’s when well nourished.
2. For humans, men can to copulate many times in a lifetime and women can’t eat an entire man at one go, neither will it significantly help the nutritional needs of the pregnancy.
3. However, Sexual evolution is a result of long period of adjustment by the species and we cannot expect the species to change it characteristics when is moved to a new environment overnight as in the recent thousands of years whereby we started living in cities.

Chap 2: The Battle of the sexes

1. When there is fertilized egg copulation, many ‘choices’ occur:
1. Should there be co-parenting?
2. Should the young be left for themselves?
3. Should the male take care of the young?
4. Should the female take care of the young?

However, which ever party that chooses to take care of the young, it means

2. Factors that decides the ‘choice’ of parent to be caretaker:
1. Relative size of investment in the young – usually the egg is a bigger investment as compared to one sperm.   Usually bigger for the females, especially for internal fertilization.
2. Foregone opportunity - giving up resources and time that could have been used in reproducing again.  Often, when a female is pregnant, there is not genetic good to copulate again, not the case for males.
3. Confidence of parenthood – Will spend more time and effort if you are sure that the young is yours.  More apparent for internally fertilized

females but not so for the males then.

Therefore, men are more interested than women in sexual variety, including casual sex and brief relationships because it maximizes transmission of a man’s genes.  However, women participating in extramarital sex is more due to marital dissatisfaction and they tend to be looking for a new lasting relationship.

3. The 3 exceptions to general pattern of male post-copulatory desertion:
1. Eggs are fertilized externally hence the male are confident that the young are his, eg some fishes.  
2. Sex-role –reversal polyandry where big females fight over males and males do most of the parenting work.  Examples included shorebirds like the Wilson’s Phalaropes.   Favourable factors include:  Relatively independent young that only need one parent’s care to survive; clutches of few but large eggs such that if the females are free from parenting, they can fatten up again to reproduce and  severe losses of eggs due to predation hence it is good if the female can produce another clutch of egg soon.
3. Co-parenting is needed for the young to survive.

Chapter 3:  Why don’t men breastfeed their babies?

Chapter 4:   Wrong time for love – the evolution of recreational sex

1. Trinity of bizarre human reproductive behaviours:
1. Concealed ovulation – why have sex when you don’t know whether it will result in fertilization or not?
2. Nearly constant female sexual receptivity – at the ‘wrong’ time of the cycle, during pregnancy and after menopause
3. Recreational sex – not efficient at all.

2. Hence we are not “efficient” when it comes to sex.  Why should all species try to be efficient in sex?
1. Sperm production is costly for males – worms with a mutation that reduces sperm production lives longer.
2. Sex occupies time that can be used to search for food.
3. Couples having sex risk being surprised by enemy or predator.
4. Fights between males for females lead to injury and death.
5. Extramarital sex is costly if caught for many animal species.

3. Two theories to explain the concealed ovulation in females:
1. “Daddy-at-home” – Man has no idea where females are fertile and they will stay at home and assiduously make love to her to fertilize her when she happens to be fertile.  It is also to guard her against other men since she may be fertile when he is away.  Basically, if the period which she is fertile is obvious, then he will only be around during that period to fertilze her.  
2. “Many-fathers” theory – concealed ovulation so that males cannot be sure if the child is his and will do his part to take care.   This is more relevant in traditional human societies where infanticide was common.  When a male wrestles over the control of the group and becomes the dominant male, he will kill the infants of the previous dominant male.  He knows that the infants do not have his genes and by so doing he terminates the mother’s lactation and allows her to be fertile again.  Females’ concealed ovulation makes the males unsure that the child is not his, and this ensures benevolent neutrality of almost all potentially murderous males in the immediate neighborhood.   

4. Hence “Daddy-at-home” views that woman’s conceal ovulations and constant receptivity evolved to promote monogamy, paternal care and fathers’ confidence in their paternity, while “Many-fathers” says conceal ovulation of females minimizes the threat of their offspring by adult males, confuses paternity and effectively undoes monogamy.

5.  Which is correct?  Also, why can’t females be aware of their ovulation period when actually only the males need to be unaware?   Could it be  because it is difficult for a female to fake interest in sex when she knows she is unfertile and turned off, hence it would be hard for her to deceive her husband unless she herself is deceived.

6.  From the following 3 studies among higher primates:

1. Signs of ovulation
2. Mating system
3. Any tendency for more or less conspicuous ovulations to be associated with a particular mating system?  
4. Study of family tree among primates using genes.

Conclusion – The evolution of concealed ovulation

Mating system	Harem	Harem	Monogamy
Ovulatory signals	Slight	Concealed	Concealed
Function of ovulatory signals, or lack of	Efficient sex	Confuse paternity, prevent infanticide	Keep daddy at home

Hence, concealed ovulation arose in a promiscuous or harem-holding species.  Then with concealed ovulation already present, the species switched to monogamy.

Chapter 5: What are men good for?

1. Anthropologies view that there is a job division among men and women, where men spend more time hunting big game while women spend more time gathering plant food and small animals and caring for children.  Hence, theoretically men should pursue the hunting strategy that yields the most meat and he should share it preferentially with his wife and kids then with non relatives.

2. However, it is found women through gathering collect more in terms of calories.  Though men may bring in a lot when they are successful in a big game, but the days that are unsuccessful greatly outnumber the days that they are.  Also, the men share most of their meat with non-relatives.  

3. Hence, it is suggested the reason for men’s interest in hunting is that it is serves him well in attracting more sex partners.  It is better to be a “show-off” who hunts and occasionally have lots of food to share with others but brings less food to his family than to be a “provider” who gathers/hunts food with a moderately high returns with high predictability.  In conclusion, men are not so noble in “bringing home the bacon”.

Chapter 6: Making more by making less

1. Women experience menopause which is a sharp decline in fertility around 40s, this is unique among animal world where many species either remain fertile till death or experience a gradual decline in fertility like men.  It appears to be self defeating cause if women are fertile till old age, they are then able to bear more children and hence propagate more of their genes.
2. Why do laboratory mice with abundant food and no risks, receiving better medical care than any wild turtle hardly live longer than 3 years, while wild turtles can live up to a century and their organs like eyes remain in very good condition till the end of their lives?
3. Answer:  Our genes face a trade-off between repairing the old body that contain the genes and making new containers (babies) for the genes.  Hence the evolutionary determinant of biological investment in repair (lifespan under the best possible conditions) is the risk of death from accidents and bad conditions.  Therefore, wild mice which are exposed to many predators to the wild are like less likely to live long as individual and rather invest resources in creating new bodies. Conversely, porcupines, protected by quills, age more slowly ( more resources into repair) than mammals of similar size.  
4. Therefore, we find that bodies of animals wears out at about the same time.  Wild animals which are subjected to predation, show few signs of age-related deterioration cause they die when the body is significantly impaired.  However, captive animals display gradual age-related deterioration like us humans, even for the male reproductive system.  The only glaring example is the female reproductive system which shuts down way before the rest of her organs shut down.
5. Thus, a woman’s apparently counterproductive evolutionary strategy of making fewer babies must actually result in her making more babies.  Reasons:
1. Human children have a long period of parental dependence.  The human child relies on the parents not only for food, but also not the parents to impart the use of tools which depends on language and can take up to a decade.  Tools are important cause humans acquire most of their food with tools (nets, spades) as well as to defend themselves (we lack sharp teeth).  Hence a mother must see her child goes into teenage years to be sure that her genes actually succeed.
2. Hunter-gather mothers suffers from high risk of child-birth deaths as well as delayed risk of death from exhaustion due to lactation, carrying a young child and working harder to feed more mouths.  Therefore the birth of a new child threatens the lives of her previous children whom are not independent yet.
3. Infants of older mothers suffer from more health defects.

6. In conclusion, the older a woman, she accumulates more children and have taken care of them longer.  With each successive pregnancy, she is putting a bigger investment at risk.  Also her risk of childbirth death and the risk of an unhealthy child increases with age.  In effect, the older mother is taking on more risk for less potential gains.
7. There is also another extended role of postmenopausal women. Without children to take care, therefore more hours at hand and with the experience, old women can gather an impressive amount of food that can go into feeding her children and grandchildren – all which bear her genes.

 

Skin Colour of Humans and some discrepancies by Jared Diamond.

 

In this article,Race without Colour dated November 1994, Jared Diamond wrote :

“ Among tropical peoples, anthropologists love to stress the dark skins of African blacks, people of the southern Indian peninsula, and New Guineans and love to forget the pale skins of Amazonian Indians and Southeast Asians living at the same latitudes. To wriggle out of those paradoxes, anthropologists then plead the excuse that Amazonian Indians and Southeast Asians may not have been living in their present locations long enough to evolve dark skins. However, the ancestors of fair-skinned Swedes arrived even more recently in Scandinavia, and aboriginal Tasmanians were black-skinned despite their ancestors' having lived for at least the last 10,000 years at the latitude of Vladivostok. “

He goes onto in the article to argue hence it is sexual selection is the reason for our skin colour difference.  It is covered here in a more succinct  article.

I just like to point out though in Chapter 17 of Guns, Germs and Steel, Jared Diamond points out  that the present residents of Southeast Asia, especially Indonesia and Malaysia had come from ancestors who arrived from  Taiwan.

This is the reason why present Indonesians and Filipinos have light skins although the presence of the famous Java Homo Erectus fossils proved that humans have occupied at least western Indonesia for a million years – long enough to evolved tropical adaptations like dark skin. Now only the Philippines  Negritos have dark skin like the New Guineans

Maybe it is just a case  of updated knowledge since Guns. Germs and Steel was wrote many years later.

To answer why the Tasmanians remained dark despite 10,000 years at a high latitude, this page has some answers:

“John suggests that the low genetic variation common among island peoples might be the factor behind why the folks of Oz remained dark. Certainly in the New World there is some variation in skin color among the indigenous peoples, but the tribes of the north remained far darker than equivalent Old World groups (and similarly those of the equatorial regions do not rival Africans, South Indians or Melanesians in complexion).”

Vengeance and government

Article:

Vengeance Is Ours

What can tribal societies tell us about our need to get even?

Read more http://www.newyorker.com/reporting/2008/04/21/080421fa_fact_diamond#ixzz1espXeR2T

In short, Jared Diamond tells the story from the tribal fighting in Papua New Guinea. From there, and by relating back to his own's father-law's experience in WWII, where he did not personally avenged his family; Jared Diamond learns about the importance of human vengeance as a human feeling - ranking as high as love, anger and grief.

It is interesting to note that the following 2 points:
1. "It’s true, of course, that twentieth-century state societies, having developed potent technologies of mass killing, have broken all historical records for violent deaths. But this is because they enjoy the advantage of having by far the largest populations of potential victims in human history; the actual percentage of the population that died violently was on the average higher in traditional pre-state societies than it was even in Poland during the Second World War or Cambodia under Pol Pot."
2. "This question of state government’s recent origins, and, conversely, of its long failure to originate throughout most of human history, is a fundamental concern for social scientists. Until fifty-five hundred years ago, there were no state governments anywhere in the world. Even as late as 1492, all of North America, sub-Saharan Africa, Australia, New Guinea, and the Pacific islands, and most of Central and South America didn’t have states and instead operated under simpler forms of societal organization (chiefdoms, tribes, and bands)."

Thereafter, Jared Diamond lists down the 2 reasons that cause societies of tribes to form into a state government, while noting that "No people has ever freely organized itself into a state in the absence of external pressure, and people have always been understandably reluctant to cede power over themselves to some other entity. "

1. " Sometimes external pressure from an encroaching state has placed a people under such duress that it ceded individual rights to a government of its own that would be capable of offering effective resistance."

2. "More frequently, chronic competition among warring non-state entities has ended when one gained a military advantage over the others by developing proto-state institutions"

To end:
" ethnographic studies of traditional human societies lying largely outside the control of state government have shown that war, murder, and demonization of neighbors have been the norm. Modern state societies rate as exceptional by the standards of human history, because we instead grow up learning a universal code of morality that is constantly hammered into us: promulgated every week in our churches and codified in our laws."


"Why, then, didn’t New Guineans give up a way of life that obviously made their lives miserable? A striking feature of New Guinea’s history is that New Guineans traditionally practiced unchecked violence against each other, yet they offered only limited resistance to the imposition of state government and the ending of that violence by European colonial powers. That wasn’t just because Europeans had guns and New Guineans didn’t; the number of armed Europeans involved in “pacification” was often absurdly few. Daniel’s view points to another reason: as more New Guineans were exposed to the benefits of state-administered justice, they saw that they were better off living without the constant fear of being killed, though, of course, no tribe could ever have followed that course of peaceful dispute adjudication unilaterally."

"My conversations with Daniel made me understand what we have given up by leaving justice to the state. In order to induce us to do so, state societies and their associated religions and moral codes teach us that seeking revenge is bad. But, while acting on vengeful feelings clearly needs to be discouraged, acknowledging them should be not merely permitted but encouraged."

The Worst Mistake In The History Of The Human Race

Is Agriculture. Or rather choosing to increase food production over limiting growth.

According to Jared Diamond, when our hunter gatherer society start to grow in population at the end of the ice ages, we chose agriculture to feed increasing number of people rather than limiting our population growth. This move has created problems that we still haven't learnt to solve, while the continued presence of hunter gatherer societies after tens of thousands of years proves the viability of the model.

So what are the problems that agriculture has caused for us for it to be the biggest mistake? - Lower nutrition level /less variety of food leading to more health problems/ smaller body builds. (according to archeological finds) - Risk of starvation as we depends on less and less variety of crops - Agriculture leads to crowding and vice versa which lead to the spread of spread of parasites and infectious disease

More importantly, agriculture allows the accumulation of food (impossible for hunter gatherers who have little or no stored food, and no concentrated food sources like farms), which then lead to class division: The appearance of a non food producing elite over the masses of disease-ridden people.

Also the inequality of sexes:

"Freed from the need to transport their babies during a nomadic existence, and under pressure to produce more hands to till the fields, farming women tended to have more frequent pregnancies than their hunter-gatherer counterparts-- with consequent drains on their health."

So why the heck did our ancestors choose agriculture over hunting gathering?

Because a hundred malnourished farmers can still outfight one healthy hunter.

Farming allows us to support more people, though with a lower quality of life. Our mistake was to choose farming over birth control. To most of us, the above argument seems ridiculous. However we belong to the elites: who are dependent on oil and minerals that must often be imported from countries with poorer health and nutrition.