Evolution Of Humans In The Last Hundred Years.

Discussion in 'Human Science' started by Anarcho Union, Feb 10, 2011.

  1. Ronaldo01 Registered Member

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    The question arises here that why there is so changed in the present and the people of past. I think the time is totally changed and absolutely there are many changes come into see. And technology has changed many things in this present time.
     
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  3. Honeyb35 Registered Member

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    humans are still evolving. the rate of human evolution may have changed but we are still in the slow process of evolving. natural selection, even if offset in part by artificial selection, is still present.

    btw: 10 000 years is nothing in terms of evolution. in a million years will we be humans be exactly the same?
     
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  5. Fraggle Rocker Staff Member

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    Yes, in fact there have been two genetic bottlenecks in our species's past. One was Mitochondrial Eve, who lived very roughly 120,000 years ago. The other was Y-Chromosome Adam, who lived about 60,000KYA. All humans have her mitochondrial DNA and all male humans have his Y chromosome (women have only two X's).

    This is why we have such low genetic diversity compared to many other species.
    Well good, since I haven't checked in lately.
    As someone already explained, in Iceland it was customary for boys to be called "Bill, John's son," while girls were called "Suzan, Margaret's daughter." (With the appropriate unpronounceable umlaut-laden Norse names substituted for my English versions, with a few thorn (Þ) and eth (ð) tossed in for good measure. Back in the days before the Sexual Revolution, Icelandic tourists had a heck of a time renting rooms in American hotels because they appeared to be unmarried.

    It was unusual, but not unknown, for a boy to be called his mother's son, especially if his mother was famous and/or beloved. In these days of women's liberation, which started about a generation earlier in Iceland, it's even more common although still not standard. But I have never heard of a man calling himself anyone's dottir. That's grammatically incorrect. No more so than "Ladybird Johnson" of course, but we no longer spell it "John's son" so its easier to overlook. In Icelandic the genitive ending is still there and eliminating the space is the standard grammatical technique for building a compound word, so it's still, literally, "Jorgen's son" or "Aegir's daughter."

    Just as in England, these patronymics (and less often matronymics) eventually became fossilized and were passed down to grandsons and granddaughters. It still doesn't explain the bad grammar. Perhaps the daughter of Icelandic immigrants to another country grew up without learning the language of the Old Country and lost track of the literal meaning of her name. Then when she got divorced (or in some other circumstance of single motherhood), she gave her own surname to her son and neither of them realized the inherent joke.
    That depends on the species. It's only a few hundred generations for us, but about 20,000 for dogs, with their much faster pubescence. With natural selection helped along by selective breeding, in the 12,000 years since dogs first came to live with us they have evolved:
    • Smaller brains than wolves, to compensate for the diet of a scavenger having less protein than a predator.
    • Teeth that are not quite as good for ripping the meat off of a carcass before the larger carnivores come along to steal it, but much better for chewing carrots.
    • A broadened social instinct that accepts other species as comrades.
    • A muted alpha instinct, allowing them to live in harmony within a much larger community than a wolf pack, and even accepting a member of another species as the alpha--the one who singlehandedly brings home a dead cow every month.

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    Even a million years isn't an extremely long time. Speciation does occur on that time scale, but the differences are modest, such as the polar bear evolving from the brown bear or the American eagle evolving from the white-tailed eagle. Obviously we are in that same category, having evolved (along with our sister species the Neanderthals) from Homo erectus roughly a quarter-million years ago. It could be argued that in our case the differences are more than modest, but I wonder how it would look from the perspective of someone from another solar system. Are we just slightly taller, slightly more clever variations on H. erectus?
     
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  7. Skeptical Registered Senior Member

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    Fraggle

    With the greatest of respect (since you generally post excellent science), I must continue to point out your error on dog evolution. You insist on a natural evolution. Yet the research work by the Russian geneticist, Dr. Belyaev, done on the silver fox, shows that the basic changes that wolf to dog gave are easily obtained by simply breeding for tameness.

    It is highly unlikely that wolves evolved into dogs by any 'natural' process. Since we have seen solver foxes undergo very similar changes by breeding, only for tameness, it seems very probable that wolves were also bred for tameness and became dogs.
    http://www.suite101.com/content/domesticating-the-silver-fox-a68305

    I quote :

    "Only the tamest animals from each generation were allowed to breed. Inbreeding was intentionally kept at a minimum within the population, just to make sure that it was selection for tameness alone that was being tested. By the tenth generation, nearly twenty percent of all foxes were friendly and quite tame.


    As the experiment continued, something else began to happen. By generations eight and ten, the foxes started developing spots. Some of them were even marked like border collies. Some foxes developed shorter legs and tails than the wild type, while others had tails that curled over their backs. Even more unusually, a few vixens had estrus cycles longer than normal, and a few also had estrus cycles twice a year. All of these traits are traits of domestic animals."


    Dr. Belyaev began his breeding for tameness as an attempt to make a breed of silver fox that would be more docile for fur ranching. It kind of backfired, since the result changed the fur, making it less saleable!

    My own hypothesis is that wolf cubs were adopted by the women of ancient human tribes, "because they were so cute". After all, we see the same behaviour in our womenfolk today in pet shops. However, the menfolk in those tribes would be more aggressive and less sentimental. While they might indulge the women in their need for something to nurture, they would have no patience with a growing wolf that turned nasty. Thus the more aggressive wolf pets would be bopped on the head. This inadvertently would breed a tamer wolf, with the qualities we associate with dogs.

    Wolves and dogs differ by 1 to 2% genetically, which would imply a separation due to evolution of about 130,000 years ago. However, the sub-fossil record shows dog bones with human sites for only about 12,000 years. The simplest explanation for this discrepancy, in my view, is accelerated genetic change, such as we would see with breeding.
     
    Last edited: Apr 8, 2011
  8. sump oil recycling Registered Member

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    4
    I've become much more intelligent.
     
  9. Ophiolite Valued Senior Member

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    9,232
    Judging by that post you must have come from a low starting level.

    Welcome to the forum.
     
  10. charles brough Registered Senior Member

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    To me, there is no reason to think that "Creation" is the only alternative explanation of how we gained our present emmense cultural heritage and manage to rule the world other than biological evolution! The biological change we have undergone in the last 40,000 years is insignificant. It does not in any way account for the rise of civilization.

    Evolution is going on, however. Just as the cells in our bodies mostly stopped evolving, so we have also stopped when our societies began to compete and suffer the natural selection process, one that began those some forty milleniums ago. There is a reason why our culture evolved so slowly---as slowly as that of the Neanderthal---until the 4 millenium marker. Since then, societies have evolved and are responsible for our continued growth in culture and numbers since then.

    I define a "mainstream society" as "the mass of people bonded together by a common ideology and covering a definite territory." We are small group primates who evolved as hunter/gatherers and, like most social animals, we are territorial. Our groups compete for space and resources and ideology "religions" bind us into these immense "groups" or societies.

    Our secular belief system is also an ideology and functions to federate the four mainstream societies of the present day so we can minimize conflict between us and set up the global economy.

    brough,
    civilization-overview dot com
     
  11. spidergoat Liddle' Dick Tater Valued Senior Member

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    Evolution is usually a slow process, it's unlikely that we would see very many obvious changes in a primate like humans in only 10 or 40 thousand years. The rise of certain key inventions led to civilization in some places. Those were domestication of animals and the cultivation of grains.
     
  12. RJBeery Natural Philosopher Valued Senior Member

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    4,222
    Immunity to the Black Plague and general tolerance to dairy products are two recent "evolutionary achievements" of the human species. We are also many inches taller than we were 2000 years ago. When people think of evolution they think in terms of something strange or exotic like growing a third eye, when in reality our gene pool typically adapts to the world gradually, almost without notice, one dead Black Plague victim at a time...
     
  13. charles brough Registered Senior Member

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    476
    Yes, you are right and I am glad you posted it . . .

    It is possible that a minute change in our genetic structure could take place in a single century but it would be so minute and insignificant as to be of no importance. What change we experience is epigenetic instead.

    Anyway, biological evolution does not in any way explain the growth of the human technological/cultural heritage and, hence, our number here on Earth during the last 40,000 years.

    The age of 16 is a good age to begin to learn and understand, not to propose grandiose theories based upon little knowledge.

    brough,
    civilization-overview.com
     
  14. Fraggle Rocker Staff Member

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    24,690
    But there are exceptions. The polar bear speciated from the brown bear in 100,000 years. The American eagle speciated from the white-tailed eagle in less than 20,000.
    There was a whole series of Paradigm Shifts. (Dates are approximate and in any case shifts did not occur in all locations at the same time.)
    • The Agricultural Revolution 9500BCE, cultivation of plants (actually figs and peppers came before grains) and domestication of animals, resulting in the first food surplus, rival clans learning to live together, and the use of animal musclepower.
    • The Dawn of Civilization 9000BCE, towns so large that people had to learn to live among anonymous strangers, linked in trading networks, resulting in non-food-related occupations.
    • The Bronze Age 3000BCE, the first metallurgy, resulting in massive increase in productivity and the first "weapons of mass destruction," requiring formal governments which waged war on each other, and recordkeeping which evolved into writing.
    • The Iron Age 1500BCE, metallurgy so easy that "barbarian" tribes could do it, increasing prosperity and population, resulting in scarcity of farmland and a shift from meat-based to grain-based diet, which in turn resulted in malnutrition and reduced life expectancy.
    • The Industrial Revolution 1800CE, increasing the portion of the population in non-food-related occupations from <1% to 97%, resulting in discretionary income, universal literacy and education, leisure time, ease of long-distance travel, the advance of science and democracy, and an explosion of cultural and recreational pursuits.
    • The Electronic Revolution, 1925CE, resulting in global communication, better-informed populace, transnational communities, and new occupations, cultural and recreational activities that are just beginning to appear.
     
  15. RJBeery Natural Philosopher Valued Senior Member

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    This one made me raise my eyebrows. Is this well established? I mean, we don't even have a scarcity of farmland today(!), and the idea that eating grains, fruits and veggies would shorten lifespan is contrary to conventional wisdom.
     
  16. Me-Ki-Gal Banned Banned

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    4,634
    I heard Onions are the oldest crop ? Funny there are Doctors that say onions are bad for you now . Every 20,000 years for a single mutations is what I learned . Discovery Channel !! eat your garlic like a good little boy . You can't live on candy alone . Well maybe since you are still here you can in the beginning.
     
  17. Skeptical Registered Senior Member

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    1,449
    RJ

    What shortens the lifespan is not eating meat and fruit. In other words, intensive agriculture of grains like wheat, and eating too little else.

    Fraggle
    How sure are you, though, of the shortened life span? What documentation or other empirical evidence exists? Human appetite being what it is, I suspect that early farmers grew fruit trees and crops other than wheat also. If a person eats too much grain, and too little anything else, they develop a craving for other foods.
     
  18. Me-Ki-Gal Banned Banned

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    4,634
    Fruit was a luxury item during the mini ice age. You think about how Sinter Claus with his Black mambo side kick left nuts and fruit in your stocking at Christmas back in the day . They were lucky and glad to get it too . The best thing I ever ate in my life was an apple after eating only fish for five days . I didn't even like apples for the most part before that fish trip into the black hills of the Yellowstone , but after that experience apples taste like food of the gods
     
  19. sump oil recycling Registered Member

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    4
  20. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Yes, exactly so.

    Also, however, I do believe that overall there is a 'selection pressure' for beauty in all cultures. That is, I believe 'beautiful people' tend to have more children than 'ordinary' people. Each culture, of course, has its own standard of beauty, so we see beautiful-looking people in each culture, which has formerly been primarily associated with racial groups. There are actually quite a few studies on what constitutes 'beauty', with average composites producing images of great beauty.

    But that is not evolution, but rather raciation, as I've mentioned in another thread. For it to be evolution, the traits have to become present in all humans.
     
  21. Fraggle Rocker Staff Member

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    24,690
    Yes. It's easy for archeologists to estimate the ages at which people die, from the condition of their skeletons. At the end of the Paleolithic Era (nomadic hunter-gatherers) the life expectancy of an adult who had the good fortune to survive childhood was in the 50s. By the Roman era, it had fallen to the low-to-mid 20s. Only the aristocrats could afford meat. Everybody else was eating a grain-intensive diet.
    Of course... not when taking the entire planet into account. The Western Hemisphere is so sparsely populated that we could feed three or four Earths all by ourselves. The United States is a net food exporter; most of the land in California, our most populous state, is farm, forest and desert.

    But we have trucks, trains and airplanes that can carry food to any part of the planet while it's still reasonably fresh. (And refrigeration technology to supply people with frozen food.) Our ancestors didn't have that. Everything had to be hauled at the speed of an oxcart, before it spoiled. That made food grown very far from a population center terribly expensive. They couldn't devote all the land around a city to livestock herds, which wouldn't be enough to feed the whole population of a big city anyway, and besides, the average person didn't have enough income to eat three meals a day of meat. If they did that, they'd be importing all of their grain and other plant-tissue food from so far away that they wouldn't be able to afford that either. Only the aristocrats could afford to eat meat on a regular basis, and their life expectancy reflects that.

    The Industrial Revolution had a colossal impact on the way we eat, and our entire relationship with food. Until very recently, more than 99% of the human race were doomed to "careers" working 80-100 hour weeks in the "food production and distribution industry." Mechanized farming made possible the work that the majority of us do, with something like three percent of the population feeding us.
    Fruits and vegetables have a lot of vitamins and minerals and are a great addition to a diet, especially a meatless diet. But grains don't provide much more than protein and calories. Grain is a more efficient use of farmland so the Roman citizens ate a lot of bread and not many fruits and vegetables. It's only recently that we've even learned of the existence of vitamins and minerals, much less the role they play in nutrition.

    Meat is a complete balanced diet, because all those animals have approximately the same nutritional requirements that we have, so their tissue contains approximately the right proportion of vitamins and minerals for our survival. If you stray from your nature (Homo sapiens is the only predatory species of ape) and attempt to survive by eating only plant tissue, you have a lot of counting and balancing to do.
    Yes. A quick Google search will give you a dozen sources. This is no surprise after all. Right up into the late 19th century the life expectancy of an adult who had survived the perils of childhood was still only in the 30s. This is well documented in United States government records. And it was higher here than most other places because America was built on land that had never before hosted a civilization, so its soil, forests, minerals and other natural resources had not already been plundered. On top of that, our population density was very low compared to the Old World, so there was lots of land for livestock and their feed. Heck, the early Americans actually grazed their cattle on public land. Today they keep them in pens and feed them grains from factory farms.
    Well sure. Grains weren't even the first cultivated plants. It was figs in Mesopotamia and peppers in Central America: nice, rich high-calorie fruits with strong flavors. But as population increased and land became more valuable, they had to start growing grains to provide all those people with protein, because the per capita GDP became too low to provide everyone with meat.
    They also come down with all kinds of vitamin and mineral deficiencies. Their teeth will start falling out within a few months. Ricketts, scurvy, kwashiorkor, there are dozens of conditions.
     
  22. Skeptical Registered Senior Member

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    1,449
    Fraggle

    I have no doubt that people over most of the past 10,000 years had shortened lifespans. My query was about paleolithic peoples. Not so much about diet, but lifespan as it results from all causes. I am aware that recent hunter/gatherer societies in the Amazon had high levels of male on male conflict, leading to death of males at up to 60% of the male population. Such fatalities must bring the average lifespan down substantially.
     
  23. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    2,555
    I have to correct you here. I missed reading that earlier. There is no evidence that I am aware of that a genetic bottleneck occurred during the time frame of either Mitochondrial Eve or Y-Chromosome Adam. This appears to be a misunderstanding on your part of what those signify.

    Mitochondrial Eve would have lived in a large clan of people, who would have contributed their DNA in subsequent generations. While it is conceivable that there was also a genetic bottleneck at that time, there is no evidence for that then. Same with Y-Chromosome Adam; no evidence for a bottleneck, and his descendants would have received DNA contributions from the surrounding clan members as well.

    We don't yet know which person lived first, though it appears that Y-chromosome Adam came tens of thousands of years after Mitochondrial Eve. Mitochondrial Eve's mother would have had a single man who impregnated her, giving birth to Mitochondrial Eve. That couple would have been the 'Adam and Eve' of religion, if Mitochondrial Eve came before Y-Chromosome Adam. (We don't know how many men Mitochondrial Eve was impregnated by, so we step back one generation to a single couple.) If it was Y-Chromosome Adam who came first, then his mother and father would have been the 'Adam and Eve', because we don't know how many women he might have impregnated.
     

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