09 AUG 2014 by ideonexus
Brain Differences Between Sciences and Humanities
The areas of academic interest (sciences or humanities) and area of study have been known to be associated with a number of factors associated with autistic traits. However, despite the vast amount of literature on the psychological and physiological characteristics associated with faculty membership, brain structural characteristics associated with faculty membership have never been investigated directly. In this study, we used voxel-based morphometry to investigate differences in regional g... 1 
notes
notes30 JUL 2013 by ideonexus
Why Marriage is Not Like Prostitution
What's more, most males could not possibly afford to buy a
woman's reproductive potential if courtship were a simple economic exchange. What would be an appropriate market price for a nine-month pregnancy, the pain of childbirth, the exhaustion of breast-feeding, and twenty years of maternal care? At least half a million dollars at a basic salary of $25,000, one would think. How much do men spend on courtship in the first few months? Perhaps a tenth of 1 percent of the proper market price. Th... 1 notes
notesNo amount of gifts and showy displays can pay for the investment a female would have to make in offspring.
26 JUN 2013 by ideonexus
Evidence of Sexual Selection in Humans
By primate standards, humans look strange, even after we step out of our sport utility vehicles. Compared with other apes, we have less hair on our bodies, more on our heads, whiter eyes, longer noses, fuller lips, more expressive faces, and more dextrous hands. In most species, sexual ornaments like long head hair, hairless skin, and full lips would have evolved only in males, because females would have been the choosy sex. Males have few incentives to reject any female mates. The fact that ... 1 notes
notesMany characteristics of our bodies which differentiate us from other primates, are probably the result of mating preferences of our ancestors.
23 JUN 2013 by ideonexus
Hamilton's Model
Hamilton's rule is rb - c > 0. Here c is the cost to the giver's fitness (c fewer offspring
because of helping), and b is the benefit to the recipient's fitness (offspring gained by the recipient from the help). Here again, "r" is a measure of the relatedness between giver and the receiver
[...]
Hamilton’s rule says that for unrelated individuals (r = 0) no benefit can overcome the cost of loss of the altruist's fitness (0 - c can't be greater than 0) and aid giving is selected against... 1 notes
notesExplains why members of a species will sacrifice themselves for offspring that are not their own.
20 SEP 2011 by ideonexus
Mating Strategies of Males and Females
A vivid demonstration of this difference can be seen by looking up the
record number of children sired by a human female versus a male. If you
were to guess the maximum number of children that a woman could
produce in a lifetime, you’d probably say around fifteen. Guess again.
The Guinness Book of World Records gives the “official” record number
of children for a woman as sixty-nine, produced by an eighteenth century
Russian peasant. In twenty-seven pregnancies between 1725 and
1745, sh... 1 notes
notesA Great summary of the differences between them evolutionarily.
20 SEP 2011 by ideonexus
Postmating Competition
Sexual selection doesn’t end with the sex act itself: males can continue
to compete even after mating. In many species, females mate with more
than one male over a short period of time. After a male inseminates a
female, how can he prevent other males from fertilizing her and stealing
his paternity? This postmating competition has produced some of the
most intriguing features built by sexual selection. Sometimes a male
hangs around after mating, guarding his female against other suitors.
Wh... 1 notes
notesVarious evolutionary strategies males of different species keep a female from mating with other males after sex.
08 JUN 2011 by ideonexus
Circumcision Increases an Infant's Sensitivity to Pain
Glover’s findings are supported by research on the effects of pain experienced by infants after birth. Anna Taddio, a pain specialist at the Hospital for Sick Children in Toronto, noticed more than a decade ago that the male infants she treated seemed more sensitive to pain than their female counterparts. This discrepancy, she reasoned, could be due to sex hormones, to anatomical differences—or to a painful event experienced in this part of the world by many boys and no girls: circumcisio... 1 notes
notesCompared to males who are uncircumcised.
08 JUN 2011 by ideonexus
China and India Aborting Millions of Fetuses
Williamson’s wise advice went unheeded. In the years after her study was published in 1978, ultrasound became increasingly available in Singapore and other countries in South and East Asia. The introduction of this technology enabled a new and brutal form of sex selection: if the sonogram shows it’s a girl, abort. Researchers’ estimates of the number of female fetuses aborted over the past twenty years are mind-boggling: ten million in India, twenty million in China. Because of this pra... 1 notes
notesBecause they are girls and the numbers are mind-boggling.
19 MAY 2011 by ideonexus
Guppies Evolve Their Spots in Experimentation
Guppies are popular freshwater aquarium fish. As with the pheasants we met in Chapter 3,
the males are more brightly coloured than the females, and aquarists have bred them to become
even brighter. Endler studied wild guppies (Poecilia reticulata) living in mountain streams in
Trinidad, Tobago and Venezuela. He noticed that local populations were strikingly different from
each other. In some populations the adult males were rainbow-coloured, almost as bright as those
bred in aquarium tanks. H...Folksonomies: evolution experimentation
Folksonomies: evolution experimentation
1 Spots are attractive to females, but also attractive to predators.
04 MAY 2011 by ideonexus
The Waist-to-Hip Ratio
Why does the waist-to-hip ratio matter? Singh observes that a "gynoid" fat distribution—more fat on the hips, less on the torso—is necessary for the hormonal changes associated with female fertility. An "android" fat distribution-—fat on the belly, thin hips—is associated with the symptoms of male disabilities such as heart disease, even in women. But which is cause and which effect? It seems to me more likely that both the shape and the hormonal effects of it are sexually selected by...
1 Men are unconsciously directing the evolution of women.
