What determines the traits we acquire, and the traits we lose?

Discussion in 'Biology & Genetics' started by Unconcept, Mar 2, 2012.

  1. Unconcept Registered Senior Member

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    I haven't read anything that answers this question, What determines the traits we acquire, and the traits we lose?
    If the species gain new traits and lose ones solely based on the adaptability to the environment, I could dream up all kinds of traits off the top of my head that we could acquire. Why didn't any species develop a way to fall asleep fast since they've been used to sleep for a long time

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  3. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    Unconcept

    Survival to pass on those traits, mostly. Some traits(like blue eyes)have little effect on survival, but don't hurt it either, so some people have blue eyes, but not all. Upright walking, however, has great survival value, so every human has that trait.

    Grumpy

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  5. scheherazade Northern Horse Whisperer Valued Senior Member

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    LOL....are you finding it difficult to sleep?

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    For the record, I have developed that trait, mostly in response to my strange job hours.

    I can lay down, turn off my mind and literally be asleep before the covers have settled on my person.

    It's a rather necessary skill set but I would observe that it has been acquired through experience although I do think the ability to tolerate extended graveyard work may be an inherited trait and I also note from seven years of 'field research' that in these parts, those who seem the most successful on this schedule are of predominantly European origin.
     
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  7. Xotica Everyday I’m Shufflin Registered Senior Member

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    It’s all a bit odd. I have no set hourly work schedule. I have 24/7 physical access to the research facility, or I can connect with my colleague’s electronically via various avenues... cell phone, e-mail, dedicated chat, instant messaging, video conferencing, etc. For the most part, I’m a natural night owl.

    Does anyone have a clue why some people - like me - are nocturnal oriented?
     
  8. Aqueous Id flat Earth skeptic Valued Senior Member

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    The traits you acquire replace the traits you lose. The egg and sperm have each already sacrificed half of their family traits by the time they merge to form a new double set. The determination is strictly random. Let's talk abut your maternal grandparents. Their DNA was in every cell in your mother's body when she produced the egg of you. At the formation of the egg, a single strand from her mother and a single strand from her father twisted together like rope, and split longitudinally, creating two mixed sets. One of those became the nucleus of the egg. This process is called crossover, and it is strictly random. The same thing happened on your father's side. So when the single egg set merged with the single sperm set, a new hybrid (you) was formed by random combinations for each of the four grandparents, equally weighted between mother and father. However, for each pair of codes that describe the trait, there is also a randomizing that determines which one of the two will dominate. So it possible to receive more apparent traits from one ancestor than another, and then pass down the recessive genes, which may later crop up in one or more of your descendants.
    Above I thought you were talking about individuals. Here you are asking about evolution, which is what happens when certain traits in a population are so adverse to survival that those traits get replaced by mutations.

    In order to survive some changing stress in the environment, or to fill an environmental niche, that is, to exploit some open opportunity for surviving in a different way, a favorable mutation will provide an advantage for the individuals that carry it, namely, they will tend to survive in that niche. The ancestral line may remain stuck in the older niche, either on the verge of extinction, or else in maintaining the population, in which case the two species might branch and coexist. There are other variations on this idea, for example, the species might not evolve at all, but it might drift, such as the polar mammals who established a white coat.
    But they can only crop up from crossover and mutation, which do no tend to invent large functional changes, since traits are not stored in the DNA in a linear one-to-one correspondence. Mutations normally will only persist in the species as a whole if they are useful toward survival of the species as a whole. They will also normally tend to involve changes that amount to acquiring more efficiency for a given set of characteristics needed to survive the pressures of the particular niche.
    Birds seem to fall asleep as soon as the sun sets. Other animals may not sleep at all. Others may need to sleep lightly, to listen for intruders and run from danger. It all depends on what the requirements of their niche calls for.

    Also, as a passing comment to what Grumpy mentioned:

    The blue eyes came with the skin color change, because somewhere in the past those became genetically connected. The skin color needed to change to increase UV absorption, to increase Vitamin D production (from sunlight), which diminished at northern latitudes.

    The point here is that some traits may stick because of an underlying cause, and many are tied into a long sequence of cause and effect that is woven over all of evolutionary history.

    That's a good place to be. I have periods when I can do that, and then other times when it just doesn't work. In those cases it seems to have a lot to do with an urge to stay awake, like a feeling that I didn't finish something, and I don't want to put it off.
    I was just reading something that mentioned circadian rhythms in plants, so your comment made me wonder if something genetic like this could be at play, and if it might not show up in one lineage more than another, for some reason having to do with who knows what kind of stresses one ancestral group was dealing with, versus another.

    Here you speak of work, so maybe it's on your mind a lot? I also tend to set my own hours, so I can relate to what you are saying. I can just as easily be made sleepy by wrangling over something tedious as to be amped up and wide awake over something interesting or unfinished.
     
    Last edited: Mar 2, 2012
  9. C C Consular Corps - "the backbone of diplomacy" Valued Senior Member

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    Advanced human culture/society has apparently even introduced the wrinkle of allowing weakening or "undesirable" characteristics to be retained in its populations longer than what they might otherwise have been. Or enabling some to get a foothold at all, if they were of the sort that would otherwise result in a child's death well before adolescence. Of course, we can contend that as long as a community has the available resources and time to cope with genetic-based birth defects and extend the longevity and quality of life of those concerned, then "undesirable" is only a relativistic classification. There's also the potential of technology being able to repair detrimentally stray mutations at their source, before reproduction or after conception (surely already tentatively the case).
     
  10. Xotica Everyday I’m Shufflin Registered Senior Member

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    I can choose to work anytime. I can choose to play anytime. Despite such unfettered scheduling freedom, I almost always elect to be active at night. Don't know why. It just feels more natural to me.
     
  11. Unconcept Registered Senior Member

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    Yes, I am! lend me your gene man!

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  12. aaqucnaona This sentence is a lie Valued Senior Member

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    Traits are determined as expressions of genes which control the development of features and pre-determined behaviours [like reflexes and instincts]. These genes are inherited from our parents. Lets say all our great grandparents form the first generation of a population that has a new gene introduced into the genepool - say a gene for faster falling asleep. Now what that gene must be capable of to become prevalent in the population of the fourth generation [ours] is that it must make the persons who have that gene benefitted in such a way that it improves their chances of having a larger number of offspring. This is the only goal of evolution - not complexity, betterment, survival, food or well-being. So, the prevelance of a gene and hence the determinant of the acquirance or loss of a trait is a such -

    0. New traits are limited by the specifics of previous genes - eg. A bird is almost certainly never going to have a new trait which gives its hands with opposable thumbs.
    1. A new trait is introduced - eg. longer beaks.
    2. This trait has a cost - the beaks require more material in development, hence a larger toll on the mother.
    3. As a result, the trail can only hope to compete if it can give its holder an advantage greater than its cost - the longer beak allows the bird to eat harder nuts, dig out insects from deeper crevaces, etc in larger amount than used by the mother to help develop the longer beak.
    4. The gene now has to compete with other genes [eg. shorter beaks]. If the environmental pressure is not high enough, the longer beak will not be enough of an advantage so that brid will have just a little more offspring than others in its population.

    At this point, two paths are possible.

    5a. There is a new pressure [drought, new predator species, etc] which makes the difference important.
    6a. Now, the previous trait starts to lose is hold eg. the shorter beaked ones start to die off and the longer beaked birds survive.
    7a. If the pressure remains the whole popluation remains as only long beaked and if this population is so different from the previous one that the two could not mate, a new species emerges. If the pressure subsides, the long beaked ones may either become a subspecies or die off to their previous level - either way, this trait would be diluted and lost unless the pressure remains long enough to replace most of the short beaked birds.

    5b. There is no new pressure, but the long beaked birds can survive where there are different or scarcer resouces, like more drier areas.
    6b. This birds can now spread to a larger or different area than the ancestral population, thereby increasing the range of that genus.
    7b. They become adapted to the new environment and become differentiated so much that they cannot mate with the ancestral population and 2 species emerge, modern short beaked and modern long beaked - out of the previous generations of archaic short beaked and archaic long beaks, which themselves emerge out of the single species of ancestral short beaked.

    At this point, new pressures can lead to the exitinction of one or both of the species and this entire process would be captured as snapshots - fossils in the rocks of those time preiods.

    So you see, the traits are limited by a very ruthless process of adversity to survival and reproduction [the natural world] which means only some traits can be formed - elephants are not human-smart and humans not have claws and massive canines and we are also muscularly weak compared to chimps or bears.
     
  13. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    Not necessarily discounting anything that’s been said up until now, I think the answer to this question is very simple: selective pressure.

    That sums it all up, doesn’t it?


    If there’s no selection pressure resulting in reproductive advantage then there’s not much chance of developing those traits.
     

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