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As scientists continue to explore our evolutionary history, new facts appear explaining how the past forms modern people, from the size of our brain to the length of our lives. Yet more intriguing is the role that chance played in shaping brain and bodies that modern people have.
1. Human faces have formed to withstand hit
Until recently, it was widely believed that strong human faces formed around four to five million years back to help our ancestors Australopithecus chew hard food such as nuts. But now this opinion is destroyed by direct a blow to the face.
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According to a study by the University of Utah, our distant the past was not as peaceful as we once thought. Probably, violence played a much larger role in the development of human physiology than we suspected before. Researchers believe that male faces are designed to minimize injuries from strikes during fights for women, food and territory.
The bones of the face became stronger so as not to break during melee battlefield. These bones represent the difference between male and female the skull. Obviously, male faces needed to evolve this way because bones breaking in battles in men larger.
If this theory is true, people were not noble savages, become aggressive because of civilization. Instead our physical abilities developed to enhance our combat force.
2. Human hands evolved to strike
While human faces formed to withstand blow, our hands formed to apply it. In an earlier a study by the same University of Utah, scientists found that human hands are formed in a paradoxical way.
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Compared to monkeys, the same features that allow us clench your fists – short four fingers and a palm with more long, strong and flexible thumb – also give us dexterity, to make and use subtle tools. But while chimpanzees can make tools, they cannot clench their fists.
It is also possible that our hands evolved from the same genes that gave us short toes and an extended toe when we started walking and running upright.
Scientists believe that our aggressive and cruel nature made our bodies turn into war machines. Human, striking with a clenched fist, can strike harder without harming to myself. Fists can also be used for bullying. IN ultimately, our hands – with their ability to both kill and create – can share good and evil in human nature.
3. We had herpes before we became human
Some of our physical characteristics have not just evolved into over time. Some diseases, such as herpes, came to us from chimpanzees.
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About 67% of modern people have at least one herpes simplex virus (HSV). In fact, people are the only ones primates that have two HSVs, usually manifesting as cold sores on the lips or blisters on the genitals.
Herpes of the first type affected people before they separated from chimpanzees about six million years ago. HSV of the second type transmitted to us from chimpanzees about 1.6 million years ago. Scientists from University of California consider studying the origin of these viruses help prevent the passage to people of others diseases.
Another group of scientists from Oxford and Plymouth universities discovered ancient neanderthal viruses in modern human DNA These viruses come from the HML2 family and may be associated with cancer and HIV of modern man. This information may in the future come in handy for developing therapy.
4. Man is the only primate whose tooth size decreases with increasing brain size
Over the past 2.5 million years, two trends have been linked. human development – the size of the human brain increased, and tooth size decreased. We are the only primates that can boast of it.
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Usually, when the brain grows, the teeth grow, because the body needs more energy from products nutrition. Therefore, scientists call what happened to people, evolutionary paradox. They believe that it happened because that people began to eat more meat that feeds our brain.
Also, humans are the only primates who have developed a thick tooth enamel. In herbivorous primates, tooth enamel is thin, in higher primates and monkeys that feed on both plants and animals, enamel of medium thickness. People’s enamel is even thicker probably to crush hard foods. Scientists human enamel also allows you to determine the age and diet of ancient people by human fossils.
And Neanderthals are the oldest hominids who used toothpicks to relieve pain from dental diseases such as gum soreness.
5. Our common male and female ancestors lived in about the same the same time
Researchers often use the name “Y-chromosome Adam” to our closest common ancestor. Men usually have one X-chromosome and one Y-chromosome, women – two X-chromosomes.
According to a study published in the European Journal human genetics, “” Adam “probably lived about 209 thousand years back.
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This model contradicts a previous study by the University. Arizona, suggesting that the Y chromosome existed before of humanity. Scientists from Arizona believed that Y-chromosomes modern men were created by crossing species of more than 500 thousand years ago.
But the authors of a new study argue that Arizona research, if interpreted correctly, creates “spatio-temporal paradox, according to which the most an ancient individual belonging to the species Homo sapiens has not yet born. ”
A new study also puts the Y-chromosome “Adam” in times of “Eve”, the closest female common ancestor of modern people. However, scientists say that there wasn’t one “Adam” and one “Eve” – instead of them there were groups of “Adam” and “Eve” wandering around to the world.
6. Grandmothers help us live longer
Grandmothers made us who we are. This conclusion was made by scientists from the University of Utah who launched a computer simulation to test the famous “grandmother’s hypothesis.”
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According to this evolutionary theory, in humans, the duration longer than monkeys because grandmothers helped feed your grandchildren. Other primates themselves seek food after excommunication from the mother.
When human grandmothers began to help feed their grandchildren, mothers were given the opportunity to give birth to more children. Modeling showed that on evolution from women dying immediately after of childbearing pre-living decades after menopause it took 60 thousand years.
Many anthropologists believe that increasing the size of our brain contributed to an increase in the duration of our lives. However Utah researchers controlled brain size, hunting and pairing in computer simulation. When they introduced minimal effect from the presence of a grandmother, duration human life has increased dramatically. Scientists have concluded that grandmothers contributed – or even caused – such important changes in human evolution, as the development of a larger brain, social dependence and our tendency to work together.
7. Protein could contribute to the development of a larger brain the size
Researchers at the University of Colorado have another theory about why the human brain has evolved so quickly to such a size and complex system. These scientists found that the protein domain, which is a specific unit of protein structure, in a larger found in humans than in animals.
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This is the DUF1220 protein domain, and the larger it is, the larger your brain. People in the genome have 270 copies of it, followed by chimpanzees with 125 and gorillas with 99 copies. Mice have only one copy. it means that brain size can be highly dependent on the amount protein domain.
Also contributed to the development of large brain difficulty finding rare insects for food for which development of skills for problem solving and application was required tools. But a larger brain size was not the only factor. human evolution from primacy – in humans is also more complex genetic activity that helps in learning.
8. Throwing made us human
The throwing skills of modern baseball players come from ours extinct human ancestors. Early people learned how to throw stones and sharpened wooden spears during the hunt for almost two million years back.
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According to scientists from George Washington University and Harvard University, even chimpanzees can’t compare with people in these skills. At best, chimpanzees can only throw a third as fast as a 12-year-old Minor League pitcher.
Researchers wanted to find out why people quit so well. While watching a record of a baseball game, scientists realized that the human shoulder works like a slingshot, preserving and releasing energy during the throw. Some features of the human torso, shoulders and arms have been specially developed to help us keep this energy.
Throwing skills allowed our ancestors to kill and eat big game. Eating meat stimulated the development of human body and brain to large sizes. So the unique ability of our throwing ancestors helped us become human beings.
9. The life span of a person may be associated with extremely slow metabolism
Humans and other primates burn 50% less calories than others. mammals. This means that to burn as many calories, how many other mammals of the same size burn per day, a person will have to run a marathon.
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According to a new study, explain why we are so grow slowly, so rarely give birth to children and live for so long, maybe our slow metabolism. He can also explain why we have so many different weight loss programs have been developed.
But if you exercise and you have problems with loss weight, research may also indicate the cause. There was also found that primates in cages at the zoo spent as much energy, how much their counterparts in the wild, and this in turn means that physical activity probably affects the amount less calories burned per day than we thought.
In comparison, most mammals such as ours domestic dogs or hamsters, quickly go through all stages of life and die early – often after ten years or less. Scientists consider environmental conditions to influence development slow metabolism, which gives us a long life.
10. The irony of fate that influenced the human evolution
Scientists from the University of Chicago are engaged in “molecular time travel “to see how human evolution could go differently. They started with an important protein in the body. man since he existed hundreds of millions of years ago. This protein eventually became a cellular receptor for the hormone stress cortisol.
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Biologists wanted to know how this ancient protein became sensitive to cortisol. After exploring thousands of alternatives versions, they found only one answer – it came out by chance. Must there were two extremely rare mutations so that the protein could develop sensitivity to cortisol. In other words, the modern form of protein was due to chance in our distant the past.
Researchers believe a series of unlikely random events – the irony of fate – influenced the proteins that made us those who we are. If proteins develop new functions, you can will explain the diversity and genetic diversity of life. it also means that with a slightly different set of circumstances people could turn into something completely different.
Viruses DNA Time Life Evolution
