20 MAR 2018 by ideonexus
Human Females Menstruate to Eliminate Unviable Fetuses
From a female perspective, pregnancy is always a huge investment. Even more so if her species has a hemochorial placenta. Once that placenta is in place, she not only loses full control of her own hormones, she also risks hemorrhage when it comes out. So it makes sense that females want to screen embryos very, very carefully. Going through pregnancy with a weak, inviable or even sub-par fetus isn't worth it.
That's where the endometrium comes in. You've probably read about how the endometriu...Folksonomies: human evolution pregnancy
Folksonomies: human evolution pregnancy
1 20 MAR 2018 by ideonexus
Human Pregnancy is Adversarial Between Mother and Fetus
Inside the uterus we have a thick layer of endometrial tissue, which contains only tiny blood vessels. The endometrium seals off our main blood supply from the newly implanted embryo. The growing placenta literally burrows through this layer, rips into arterial walls and re-wires them to channel blood straight to the hungry embryo. It delves deep into the surrounding tissues, razes them and pumps the arteries full of hormones so they expand into the space created. It paralyzes these arteries ...Folksonomies: human evolution pregnancy
Folksonomies: human evolution pregnancy
12 DEC 2017 by ideonexus
The Fraud of Agriculture
Scholars once proclaimed that the agricultural revolution was a great leap forward for humanity. They told a tale of progress fuelled by human brain power.Evolution gradually produced ever more intelligent people. Eventually, people were so smart that they were able to decipher nature’s secrets, enabling them to tame sheep and cultivate wheat. As soon as this happened, they cheerfully abandoned the gruelling, dangerous, and often spartan life of hunter-gatherers, settling down to enjoy the ... 1 
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notes12 NOV 2015 by ideonexus
Humans as Self-Domesticating Animals
at the end of the Pleistocene, certain human
groups and their animal associates began progressively
to show parallel reductions in size and stature,
cranial gracilization, changes in post-cranial robusticity,
shortening of the face and jaws, tooth crowding and malocclusion,
and tooth-size reduction and simplification.
There has been no recent attempt to explain the parallelism,
although numerous explanations exist for the
changes as they affect one or other of the parties. Some
of the explana... 1 notes
notesRestrictive environments, artificially constructed give us many of the traits shared with the animals we domesticate.
18 FEB 2015 by ideonexus
Human Self-Domestication
...the hypothesis of human self-domestication has recently been revived as a possible explanation of changes of human physical traits since the late Pleistocene. These changes include the reduction of body size and decrease in skeletal robusticity, modifications in cranial and dental features including reduction in cranial capacity, shortening of the facial region of the skull and maleruption of teeth, and reduction in sexual dimorphism. In contrast to earlier biological writings, other domes...09 AUG 2014 by ideonexus
Did Lower Testosterone Help Civilize Humanity?
A new study appearing Aug. 1 in the journal Current Anthropology finds that human skulls changed in ways that indicate a lowering of testosterone levels at around the same time that culture was blossoming.
“The modern human behaviors of technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament,” said lead author Robert Cieri, a biology graduate student at the University of Utah who began this work as a...Folksonomies: human evolution anthropology
Folksonomies: human evolution anthropology
1 notes
notes26 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.
28 MAY 2013 by ideonexus
Beginnings of Speciation in Romantic Paintings
She wandered on her own, looking at the portraits. The big crowd scenes were too much for her, like epic movies all jammed into a single frame. The subjects of the portraits, on the other hand, looked at her with expressions she recognized immediately. “I am always me, I am always new, I am always me”—for eight centuries they had been saying it. Nothing but women and men. One woman had her left nipple exposed, just under the curve of a necklace; in most periods that would have been tran... 1 notes
notesCharacter walking around an art museum.
03 MAY 2011 by ideonexus
A lot happens in 100k Years of Evolution
Inside my skull is a brain that was designed to exploit the conditions of an African savanna between 3 million and 100,000 years ago. When my ancestors moved into Europe (I am a white European by descent) about 100,000 years ago, they quickly evolved a set of physiological features to suit the sunless climate of northern latitudes: pale skin to prevent rickets, male beards, and a circulation relatively resistant to frostbite. But little else changed: Skull size, body proportions, and teeth ar...Folksonomies: evolution human evolution
Folksonomies: evolution human evolution
A brief descriptions of the characteristics acquired in 100,000 years of human history.
03 MAY 2011 by ideonexus
Genetic Similarity Among All Humans
Every human being has two parents, four grandparents, eight great-grandparents, sixteen great-great-grandparents, and so on. A mere thirty generations back—in, roughly, A.D. 1066—you had more than a billion direct ancestors in the same generation (2 to the power of 30), Since there were fewer than a billion people alive at that time in the whole world, many of them were your ancestors two or three times over. If, like me, you are of British descent, the chances are that most all of the fe...Folksonomies: human evolution genetics
Folksonomies: human evolution genetics
1 notes
notesThe genetic differences between those with the same geographic background exceeds the difference between those of different "races."
