Notices
Results 1 to 17 of 17

Thread: Question about evolution

  1. #1 Question about evolution 
    Forum Professor WVBIG's Avatar
    Join Date
    Jan 2008
    Location
    West Virginia
    Posts
    1,046
    http://www.dictionary.com defines evolution as any process of formation or growth; development: the evolution of a language; the evolution of the airplane. So if we evolved from apes, why did we lose one chromosome?


    Steven
    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Professor
    Join Date
    Sep 2007
    Posts
    1,079
    Biological ecvolution and cultural evolution are two different processes. The term evolution needs to be used carefully, it has been eroded in a sense, much like the word organic.

    Naturally, biological evolution says nothing about a need to gain chromosomes, as that would be at odds with the process which is basically random changes, allowing some percentage (of offspring) to survive a changing environment.


    Reply With Quote  
     

  4. #3 Re: Question about evolution 
    Forum Ph.D.
    Join Date
    Dec 2006
    Posts
    894
    Quote Originally Posted by WVBIG
    http://www.dictionary.com defines evolution as any process of formation or growth; development: the evolution of a language; the evolution of the airplane. So if we evolved from apes, why did we lose one chromosome?
    I don't have the technical knowledge to answer, or even confirm the factual accuracy of, the above question, but I have enough general knowledge to remember it is a basic error to state that we "evolved from apes" when one should say that humans and apes have a common ancestor.
    Reply With Quote  
     

  5. #4  
    Forum Cosmic Wizard paralith's Avatar
    Join Date
    Jun 2007
    Posts
    2,190
    WVBIG, the technical definition of biological evolution is a change in gene frequencies over time. Any change of any kind by any mechanism. As long as the offspring are not 100% identical to the parents, evolution is happening.

    Natural selection is one of several mechanisms by which evolution can happen, and it is natural selection that leads to adaptations to the environment. Losing traits can be just as adaptive as gaining them. For example, animals that live deep in caves often lose skin pigmentation and their eyes. Why? Generating eyes and generating skin pigment isn't free, it takes up energy. But these animals now live in an environment where there is no benefit to eyes or skin pigment, and that energy could be better spent elsewhere.

    Naturally, biological evolution says nothing about a need to gain chromosomes, as that would be at odds with the process which is basically random changes, allowing some percentage (of offspring) to survive a changing environment.
    Sorry to nitpick, free radical, but we are talking about definitions here. Evolution is not in itself a random process. Some of the mechanisms of evolution, the mechanisms of change, are random (mutation, drift, etc), but some of them are not, some of them are directional (natural selection).
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
    Reply With Quote  
     

  6. #5  
    Forum Freshman Incoming Dessert's Avatar
    Join Date
    Aug 2009
    Location
    North Yorkshire, England
    Posts
    81
    It's like what Halliday said, apes and humans evolved from a common ancestor (most likely with the same amount of chromosomes as us), which means that they could have gained a chromosome. Humans could have lost a chromosome along the way, but the apes gaining seems more likely, since ancient species like ferns apparently have dozens.

    Of course, technically speaking, humans are apes, but that's not really relevant
    The wise man believes half of what he reads. If he knew which half to believe, he'd be a much wiser man.
    Reply With Quote  
     

  7. #6  
    Forum Cosmic Wizard paralith's Avatar
    Join Date
    Jun 2007
    Posts
    2,190
    Humans have one less chromosome because two of our ancestral chromosomes fused together into one. Thus we didn't actually lose one, two just joined together.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
    Reply With Quote  
     

  8. #7 answer 
    Forum Freshman
    Join Date
    Aug 2009
    Posts
    6
    1. Losing something is not necessarily regression.
    2. Evolution can happen in multitude of directions. You don't always go from less complicated to more complicated.
    Use computer programming to do science!
    www.scienceprogramming.com
    Reply With Quote  
     

  9. #8 Re: Question about evolution 
    Moderator Moderator TheBiologista's Avatar
    Join Date
    Aug 2008
    Posts
    2,569
    Quote Originally Posted by WVBIG
    http://www.dictionary.com defines evolution as any process of formation or growth; development: the evolution of a language; the evolution of the airplane.
    The dictionary definition refers to the original and very general meaning of the word. There are various mechanisms colloquially referred to as "evolution" in which the word simply means "change over time", not necessarily meaning growth. Stellar evolution refers to the changes that a star undergoes over its lifetime, which may include growth or catastrophic loss of mass. Similarly, biological evolution just refers to the changes we have seen in organisms over time.

    Quote Originally Posted by WVBIG
    So if we evolved from apes, why did we lose one chromosome?
    The chromosome was not lost, two chromosomes fused to form one longer chromosome. Even if it had been lost, this would not contradict our understanding of evolution as change.
    Reply With Quote  
     

  10. #9  
    Forum Bachelors Degree
    Join Date
    Mar 2008
    Location
    Canada
    Posts
    414
    Here is a great video from one of Ken Millers presentations that explains exactly what occurred.

    http://www.youtube.com/watch?v=zi8FfMBYCkk
    "The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt" - Bertrand Russell
    Reply With Quote  
     

  11. #10 Re: Question about evolution 
    Forum Masters Degree Golkarian's Avatar
    Join Date
    Nov 2008
    Posts
    510
    Quote Originally Posted by WVBIG
    http://www.dictionary.com defines evolution as any process of formation or growth; development: the evolution of a language; the evolution of the airplane. So if we evolved from apes, why did we lose one chromosome?
    Now that I reas the posts I realize this might be a bit redundent.

    We didn't lose it (that would be fatal), two chromosomes fused together, this is shown by finding two centromeres on our chromosome 2 (there usually is only one) and finding telomeres (usually found on the ends of a chromosome) at the center of our chromosome 2.

    Also reversion is possible in evolution, as shown by the loss of function of many genes involved in scent, which work in mice but are in inactive form in us.

    http://www.evolutionpages.com/chromo...htm#References
    Reply With Quote  
     

  12. #11  
    Forum Freshman
    Join Date
    Aug 2009
    Posts
    16
    Are humans the optimal species on the planet? Darwinian idea is controversial for me not because it opposes creationism, but because it underestimates the chance. For example, creatures with two pairs of arms should become more intelligent than creatures with just one pair. They would be forced to process and use tools faster in order to stay in competition against each other, and their brains would have to adapt accordingly. No such creatures materialized at the stage where the transition to primates occurred, but if they did, everything else being equal, this additional pair of hands would give them an edge to defeat other species and increase their intelligence competing among themselves.
    Reply With Quote  
     

  13. #12  
    Forum Cosmic Wizard paralith's Avatar
    Join Date
    Jun 2007
    Posts
    2,190
    Quote Originally Posted by bongobay
    Are humans the optimal species on the planet?
    Optimal according to what standard? We are among the most widespread species and one of the most numerous mammals. We do have the most general intelligence of any known animals. But when it comes to specific tasks and traits, other organisms could be considered more optimal.

    Darwinian idea is controversial for me not because it opposes creationism, but because it underestimates the chance.
    It may have started out as Darwin's idea but modern evolutionary theory has changed considerably since Darwin's time. It is not a controversial idea in science as evolution is one of the most robustly supported explanatory frameworks in the history of science. But what do you mean, underestimates the chance? Chance of what?

    For example, creatures with two pairs of arms should become more intelligent than creatures with just one pair.
    Why should they? Insects have six pairs of limbs total and no one insect is smarter than a single human. Octopi have four pairs of limbs and though they are among the smartest invertebrates they are not smarter than humans either.

    They would be forced to process and use tools faster in order to stay in competition against each other, and their brains would have to adapt accordingly.
    That's assuming they use tools at all. Most animals don't. And speedier use does not necessarily mean better competitor. Speed only helps you as long as you can still do the job well, and sometimes those two do not go hand in hand. Sometimes you have to choose one or the other, speed (quantity) or quality.

    No such creatures materialized at the stage where the transition to primates occurred, but if they did, everything else being equal, this additional pair of hands would give them an edge to defeat other species and increase their intelligence competing among themselves.
    Not necessarily. Just because you have more motor control doesn't necessarily mean you have more general intelligence, as evidenced by my examples of animals with more limbs than humans but that are certainly not as smart.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
    ~Jean-Paul Sartre
    Reply With Quote  
     

  14. #13  
    Forum Freshman
    Join Date
    Aug 2009
    Posts
    16
    I said “everything being equal.” I know that some creatures have more than a pair of functional extensions, some have dozens. And this was only an example of one set of characteristics that may have helped humanoid, but not necessary humanoid, creatures to outcompete humans. Because humans rule the planet does not mean that humans are the absolute, final complex organism that could have ever evolved. When primates evolved from mammals, there was only one branch of primates, one individual at the initial stage. Then, with time, hundreds, already different from each other creatures materialized. And one of them became human, because it did so only by chance, unless you want to say that humans evolved from the fittest of them. If so, there is no proof of that.
    Reply With Quote  
     

  15. #14  
    Forum Professor WVBIG's Avatar
    Join Date
    Jan 2008
    Location
    West Virginia
    Posts
    1,046
    paralith said "Optimal according to what standard? We are among the most widespread species and one of the most numerous mammals. We do have the most general intelligence of any known animals. But when it comes to specific tasks and traits, other organisms could be considered more optimal"

    I agree. Supposedly, cockroaches would survive nuclear war. Does that mean they are optimal to humans?
    Steven
    Reply With Quote  
     

  16. #15  
    Forum Isotope
    Join Date
    Feb 2009
    Location
    Transient
    Posts
    2,914
    In the event of a world-wide nuclear holocaust, yes.
    Wise men speak because they have something to say; Fools, because they have to say something.
    -Plato

    Reply With Quote  
     

  17. #16 Re: Question about evolution 
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,046
    Quote Originally Posted by WVBIG
    http://www.dictionary.com defines evolution as any process of formation or growth; development: the evolution of a language; the evolution of the airplane. So if we evolved from apes, why did we lose one chromosome?
    You could similarly ask why the biplane evolved into a plane with a single pair of wings. Equally valid question.
    Reply With Quote  
     

  18. #17  
    Forum Cosmic Wizard spuriousmonkey's Avatar
    Join Date
    May 2005
    Posts
    2,193
    Drosophila lost a lot more than a chromosome. It streamlined its genome.

    It evolved.
    "Kill them all and let God sort them out."

    - Arnaud Amalric

    http://spuriousforums.com/index.php
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •