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Does Time Equals Complexity?

  1. Mar 26, 2005 #1
    Do you think that given time, organisms become more and more complex no matter how slow the evolution of complexity is, organisms do get more complex over time?
  2. jcsd
  3. Mar 26, 2005 #2
    I don't believe that.. but I could be wrong. It really depends on the environment and how chance shapes that environment, simultaneously shaping how the organism accumulates mutations.
  4. Mar 26, 2005 #3
    How about, an ever-changing environment plus time equals increased complexity?
  5. Mar 26, 2005 #4
    Its not really chance, its more like whichever species becomes more adaptable to that environment live on
  6. Mar 26, 2005 #5


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    Evolution shapes the organisms to fit their environment, but that does not necessarily mean more complexity. The greatest mass of living organisms is still today in the bacteria; from that point of view, the whole mammalian evolution, including us, is just a minor fluctuation!
  7. Mar 26, 2005 #6
    But dont you think that given time creatures like animals would arise?
  8. Mar 26, 2005 #7
    When all the niches for the "simple" organisms are filled there would still be possible niches for more "complex" organisms. If you believe that it is possible for more complex organisms to evolve from more simple organisms, its seems inevitable that at some point more complex organisms would arise that fit in to one of the unexplored niches and would therefore flourish. A major step from simpler to more complex organisms seems to have taken place during the so-called "cambrian explosion".

  9. Mar 26, 2005 #8
    So given time do you think these simple-life "niches" would eventually be filled and that would pave the way for more complex life?
  10. Mar 26, 2005 #9
    just replication with small errors (this would lead to offspring different from its progeny that could fill an unfilled niche)
  11. Mar 26, 2005 #10
    So does this mean that "explosion" was caused by the filled niches of the more simpler organisms?
  12. Mar 27, 2005 #11
    It is a huge debate what was the cause of the enormous increase ("explosion") of many complex multicellular organisms in the cambrian period. I just meant to say that there seems to have been "room" for multicellular organisms so once they arose they had ample "room" to stay. I did not mean to say that multicellular organisms are caused by the fact that niches for unicellular organisms were filled, but just that there were many unoccupied niches that could be filled by multicellular organisms.

    (It is a palaeontological finding that many multicellular species first appeared during a short period about 550 million years ago which is called the cambrian period, that is why that period is sometimes referred to as the "cambrian explosion")
  13. Mar 27, 2005 #12
    So do you think over time complexity will eventually arise, somewhere? I am talking about one planet.
  14. Mar 27, 2005 #13
    yes if the condition are right, but I would not know what the conditions would have to be exactly...

    I know it is not a very satisfying answer, but I do not a better answer.
  15. Mar 27, 2005 #14
    Like if the environment is complex?
  16. Mar 27, 2005 #15
    Yes, I guess so.
    The planet should be chemically complex enough to offer a possibility of any from of life to arise. I guess there should be water and lots of reactive/interacting chemicals.
  17. Mar 27, 2005 #16
    In another thread I asked if single-cell to multi-cell was an inevitability, you responded with:

    Could you elaborate me please

    Thanks a bunch.
  18. Mar 27, 2005 #17


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    There is not always a path from the state of the organism to the possible niches in the environment. It is not inevitable that the descendents of worms will learn to fly, or to read!

    Gould, in the last section of his book Wonderful Life! paints a picture of a sort of air mattress organism that could have come to dominate earth's biosphere and given the slowness of any developments from a single organism, the sun would have gone red giant before anything interesting evolved.
  19. Mar 27, 2005 #18
    You guys sure do look at the bright side of things huh?

    But yeah complexity might sometimes not be assured, but in our case (the only case we know of) it was/is.
  20. Mar 28, 2005 #19
    I was just describing a few ways in which unicellular organisms could give rise to multicellular ones. Since I can think of ways in which this could occur and can also imagine that the multicellular organisms have ample opportunity to flourish when they are formed, this lead me to guess that given enough time it was inevitable that they would arise.

    I guess the most important path is the path in which a single cell organism divides and the descendants stay together, and divide again and again. They all stay together forming a colony. Living in such a colony provides opportunities for functioning in different ways than when living alone, so some may specialize and be only able to perform a specific function and rely on the work of other cells in the colony for other things that are important for their survival. They may acquire capabilities of influencing neighboring cells in the colony (by releasing chemicals). After time these specialized cells may not be able survive on their own anymore. Now and then cells are released from the colony but these cells have now such a make-up that whenever they are alone they start dividing and dividing until they have formed a colony and then the individual cells within the colony start releasing chemicals influencing the others in their surrounding to specialize.

    At this stage the colony looks like a multicellular organism. It starts with one cell that through many divisions provides all the cells for the colony (organism) and then each cell specializes to perform one specific function. All these cells will have the same DNA so they all possess the tendency to form a colony and influence their neighbors in the colony in specific ways. So the whole “behavior” of the cell (the forming of a colony etc.) will aid in the replication of this DNA in new colonies. So you now have a system that is guided by its DNA to produce more copies of itself, which also have this DNA and thus will also make more copies etc. so you now have a multicellular organism.

    It is interesting to note that still nowadays the life cycle of multicellular organisms go through a unicellular stage. It starts with it. It is a bit more complicated because most species have developed two sexes, but anyway most organisms start as one cell that keeps dividing and specializing until the body of the organism is formed. In some “simpler species like for example sponges small pieces of the sponge can break of to form a new sponge or even single cells can be released by the sponge that from a new sponges.
  21. Apr 5, 2005 #20
    An interesting case is where a complex organism evolves into a seemingly more simple organism. For example, in the plant knigdom, for hundreds of millions of years there were no flowering plants. All plants that had seeds grew them in cones or conelike structures (the conifers and related groups). Cones are always pollinated by the wind. Wind pollination is not very efficient because the plant has to send out huge amounts of pollen that will randomly float around on the wind and maybe happen to land on a cone of the same species.
    Then one group developed a new adaptation, flowers. These allowed pollen to be carried by specific pollinators (often insects), which greatly improved a plant's chances of getting its pollen to the seed of another plant of the same species. This adaptation was so successful that nowadays the vast majority of plant species have flowers. Scientists consider flowering plants more complex and advanced than others.
    But later after the development of flowers, a new group of plants emerged called the monocots. These plants usually have greatly reduced flowers which are not meant to attract pollinators. In fact most monocots are pollinated by the wind. (There are still other monocots that are insect pollinated) They are simpler in other ways too, and their entire body plan is simpler than other flowering plants. Still, they are considered the most advanced of all plants. It seems strange to me that they would be called advanced because they have lost "unnecessary" complex parts, when other plants that never developed these things are considered primitive just because they evolved long before.
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