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Human evolution: when male and female fully developed into separate and distinct ?

  1. Jun 13, 2010 #1
    I'm finding it hard to describe what I mean, but here it goes. According to the evolution theory monkeys, apes among others, and humans have a common ancestor - their hereditary line of ascent leads to a common forefather(s). As evolution predicts, let's say, male nipples is a proof that human species is a product of evolution. Where did that male and female beings got separated - became fully developed into separate and distinct entities? What I'm trying to say is: there would be times when, perhaps, male being also had nipples which somewhat looked more like female mammary glands which would simply mean male hadn't become a full male yet, on the other side, maybe female vestigial organ looked more of a male sex organ. Also, before they fully developed how did they reproduce? Were they able to reproduce before the sex organs fully developed? What about all those enzymes, chemicals - without the proper chemicals sexual reproduction is impossible, at least that's what I can possibly think?

    It's possible I'm thinking along the wrong lines. I'm not a biology student neither am I very knowledgeable about the evolutionary theory. So, please, try to keep your reply as simple as possible so that I and many others like me can understand what you say and appreciate your effort to the fullest. Thank you.
     
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  3. Jun 13, 2010 #2

    arildno

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    Re: human evolution: when male and female fully developed into separate and distinct

    Definitely. Otherwise, we wouldn't be here. Thus, whatever sex organs they had were fully functional then, whatever degree of similarity they might have with our own.

    As for when sexual distinction arose, I'd hazard for an extremely early age in mammalian history, long before there were any apes, let alone humans, around.

    I'll leave to others more qualified than me to answer some of your other questions
     
  4. Jun 13, 2010 #3
    Re: human evolution: when male and female fully developed into separate and distinct

    The sex differentiation of animals go far beyond you imagine on evolutionary line. Apes still have full sexual differentiation from their ancestral. Fishes already have full sexual separation.
    If you study molecular evolution you will see that some proteins are very well the same in their folded forms from bacteria to humans.
     
    Last edited: Jun 13, 2010
  5. Jun 13, 2010 #4
    Re: human evolution: when male and female fully developed into separate and distinct

    Probably the best place to learn about this is through the study of amphibians which can and do change their gender according to environment. It is not the beginning of the story, but it's a good place to start.
     
  6. Jun 13, 2010 #5
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  7. Jun 13, 2010 #6
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  8. Jun 13, 2010 #7
    Re: human evolution: when male and female fully developed into separate and distinct

    i was always excited to find them on a piece of live rock in my old aquarium
     
  9. Jun 13, 2010 #8
    Re: human evolution: when male and female fully developed into separate and distinct

    You had sea squirts in your aquarium? That's... actually pretty cool. Beats the hell out of brine shrimp in a bag!
     
  10. Jun 13, 2010 #9
    Re: human evolution: when male and female fully developed into separate and distinct

    i had those once, too. Sea Monkeys!
     
  11. Jun 13, 2010 #10
    Re: human evolution: when male and female fully developed into separate and distinct

    re: The sex differentiation of animals go far beyond you imagine on evolutionary line

    I'm sorry for this off-topic question. I'm also an English learner, so it'd be nice if you could help with the language so that I can get the point.

    I would have written: The sex differentiation of animals go far beyond you can imagine on the evolutionary line.Or, rather better: The sex differentiation of animals happened far long ago on the evolutionary line. Does my way match what you had in my mind?

    re: Apes still have full sexual differentiation from their ancestral. Fishes already have full sexual separation

    Here, by apes , you mean monkeys, gorillas, etc? Yes, I have no doubt about it - there are a lot of male and female monkeys around! But I don't think this is what you exactly meant. You used two different words, 'sexual differentiation' and 'sexual separation', to refer to what appears the same feature to me. Did you do that on purpose, or, just for the sake of variety?

    Thank you for all the help.
     
  12. Jun 13, 2010 #11

    russ_watters

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    Re: human evolution: when male and female fully developed into separate and distinct

    Not a biologist either, but I wonder if the OP's question isn't looking in the wrong direction: things like nipples and sex organs need not be completely separate sexual "parts". Thinking as someone who'se done a little computer programming, it strikes me that the genetic code could be simplified by making related functions or having certain parts of a program activated in different ways. Hence, you could differentiate male and female before nipples and breasts even evolve at all.

    Just speculating though - I'm curious to know from a biologist how that actually works.
     
  13. Jun 13, 2010 #12

    russ_watters

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    Re: human evolution: when male and female fully developed into separate and distinct

    Yours is better.
     
  14. Jun 13, 2010 #13
    Re: human evolution: when male and female fully developed into separate and distinct

    Can you give me an example, please?
     
  15. Jun 13, 2010 #14
    Re: human evolution: when male and female fully developed into separate and distinct

    Unfortunately, I am Brazilian and English isn’t my native tongue, I am just struggling to be understood and trying to improve my English like you. Maybe a native speaker can correct me too.
     
  16. Jun 13, 2010 #15
    Re: human evolution: when male and female fully developed into separate and distinct

    Sex has a stronger selection factor than just sexual mechanics. The generation of genetic diversity is the reason sex separated individuals are so successful. Sex mechanics, or how individuals exchange genetic material is a know cause of speciation.
     
  17. Jun 14, 2010 #16
    Re: human evolution: when male and female fully developed into separate and distinct

    Of course, I'm sorry I should have done that in my original post. Here is one very odd example, where the frog in question has some funky chromosomes.

    http://www.genetics.org/cgi/content/full/164/2/613

    Here is a less rigorous, but broader bit to read: http://www.thefreelibrary.com/Jumping+gender:+frogs+change+from+she+to+he.-a08784789

    and from the gov:

    http://newton.dep.anl.gov/askasci/bio99/bio99128.htm

    Some fish do this to an astonishing degree, where there are all females, save for one male. If the male dies, another female undergoes major morphological changes and rapidly grows, and becomes male!
     
  18. Jun 14, 2010 #17
    Re: human evolution: when male and female fully developed into separate and distinct

    It is also possible for different sexes to arise independently in different types of organisms. There are clearly male and female plants in some species. There are lizards that are essentially all female... So having differentiation of sexes can be thought of just like any other trait that might help, or sometimes not, in the continuing evolutionary success of a certain population of organisms. There are some protist species with about 13 different sexes I believe.
     
  19. Jun 14, 2010 #18
    Re: human evolution: when male and female fully developed into separate and distinct

    13 sexes, that must be one fun orgy, but the cleanup! Yuck. :)
     
  20. Jun 14, 2010 #19
    Re: human evolution: when male and female fully developed into separate and distinct

    Biology is a very messy science. Thats why most people who like a tidy world choose Physics:)
     
    Last edited: Jun 15, 2010
  21. Jun 14, 2010 #20
    Re: human evolution: when male and female fully developed into separate and distinct

    You mean, several (discrete) types of individual, which can pair (binary coupling) and exchange genetic material readily (or at least far more readily than with individuals not classed as types of this species)? Not that several individuals, one from every type, all combine (each contributing less than half their individual genome) in the process of creating a complete offspring?
     
    Last edited: Jun 14, 2010
  22. Jun 15, 2010 #21
    Re: human evolution: when male and female fully developed into separate and distinct

    I have not been at this for a while. But the rules for exchanging genetic material was quite complex and not at all worked out. At the time I looked at it they had assigned the protists mating types. The rules of which type exchanges with which type and how exchange was taking place was still being explored. They may have figured out more about this. Molecular genetics and such is absolutley exploding. Its mind boggling compared to what I learned. Im sure its somewhere out there in all its glory now explained in more detail. I just dont want to make my head hurt trying to understand it. So if you want to explain further about mating types v. true sexes (however that is defined now) be my guest.

    The major point I was trying to bring is that sexual reproduction has advantages and disadvantages from an evolutionary point of view. So sexual reproduction, just like any other mechanism that is under selective pressure, has arisen independently more than once. And in some species sexual reproduction has "dissappeared". We tend to look at the world from our point of view, boy meets girl, and its just so much richer than this. I remember reading a Steven J. Gould article about the life of the male in a species of deep sea Angler Fish and feeling completely humbled, being a male myself. My wife has continued the humbling process...
     
  23. Jun 15, 2010 #22
    Re: human evolution: when male and female fully developed into separate and distinct

    That is a very keen observation, and one I am not prepared to refute. I myself, enjoy a wide variety of worlds to play in.
     
  24. Jun 15, 2010 #23
    Re: human evolution: when male and female fully developed into separate and distinct

    The sex differentiation of animals goes farther down the evolutionary line than you might have imagined.

    On a related note, there was an article here on physorg a few months back about a breed of flower in north america, i think, that is in the process of evolving into a two-sex reproductive pattern, that is the mutation occurred at some point in the past but across the entire population, many of these flowers are still asexual. It was, supposedly, proof that not all animals inheretid sex from the same ancestor but that it could've arisen at different times among different species.

    I would still agree, though, that our line acquired sex long before we crawled out of the sea.
     
  25. Jun 15, 2010 #24
    Re: human evolution: when male and female fully developed into separate and distinct

    Given how useful sexual reproduction seems to be, I find the possibility of parallel evolution of that trait believable. Not proven, but not absurd either. Asexual reproduction may well leave a species open to extinction, but a little mutation that nudges the species from asexual to some kind genetic swap-meet could save it. It makes sense that if this is the case, we find ourselves with the survivors, and asexual organisms will have to evolve or die as changes occur in their environment, and now at a high rate with the aid of humans.
     
  26. Jun 15, 2010 #25
    Re: human evolution: when male and female fully developed into separate and distinct

    Thank you very much, everybody. I will need some time to assimilate the information, and make some sense out of it because I'm not a biology student - just a stupid lazy person! Shamsael, thanks for better version of the sentence.
     
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