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Thread: Biology HEREDITY AND EVOLUTION, CLASS X

  1. Join Date
    Feb 2008
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    5

    Biology HEREDITY AND EVOLUTION, CLASS X

    Hello,

    I want to be clear about these questions from HEREDITY AND EVOLUTION, CLASS X.

    Firstly, Is Geographical isolation a major factor in speciation of a***ually reproducing and self-pollinating species? Please explain in detail. If NO, how come we have such a wide ranging species of unicellular species most of which reproduce a***ually? Also, if not, what is the major cause of speciation in a***ually reproducing and self-pollinatign species?

    Also, The NCERT question that "A trait 'A' exists in 60% of an a***ually reproducing species. If a trait 'B' exists in 10% of the population, which of them is like le to arise earlier? The common answer will be 'A', but what if trait 'B' is unfavourable to adaptation and have died out , with only 10% remaining? Trait 'A', arising later, may exist in 60% of the population because it is favourale to adaptation. Please explain this. ALso, what is the significance of the species reproducing a***ually?

    Lastly, the question that" Mother has blood grp A, Father has O. Child has O. Can we conclude that O is dominant trait? If yes, please explain this: Consider the situation that O is recessive, A is dominant. Mother has alleles AO. Father has OO. Offspring CAN POSSIBLY have OO [O from both parents]. Then, O being recessive, we can have an offspring with blood grp O.

    PLZ PLZ PLZ REPLY AS QUICK AS YOU CAN. PLEEEEASE!!!!!!!!!!!!

    :?:
    Yasin

  2. Join Date
    Apr 2007
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    105

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    Anyone here knows biology???

    Please help yasin
    We are either part of the problem or part of the solution.

  3. Join Date
    Feb 2008
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    2

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    No, because a***ually reproducing organism do not have any major variation as they copy their own DNA.So in whatever place they will go even if there will be any kind of barriers, since dna is copied so speciation will not occur.

    and in case of Self pollinating plants since reproduction occurs in same flower and thus flowers do not have to look for any other flower that is why speciation will not occur

    I hadn't understood ur second qns. but i can answer 3rd qns
    answer is no because universaly A is dominnt gene while o is expressed in the daughter because being recessive it expressed in the form of IoIo(o will be in super script)

  4. Join Date
    Feb 2008
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    5

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    Thanks you, whoever u r. But then, what causes speciation in a***ually reproducing and self-pollinating species? Only mutation? But then how come we have sooo many different kinds of unicellular organisms that reproduce mainly a***ually? There should not have been that many types. Plz reply this fast.
    Yasin

  5. Join Date
    Feb 2008
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    147

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    do you have to go to such great depths? i guess u r soooo much interested!
    i dont know much about the first question but i think i can agree wit the second one.

    for a detailed explanation best ask your teachers!!

  6. Join Date
    Feb 2008
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    5

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    Well my teacher says what Aayush has said. But I haven't seen ANYTHING that contradicts the condition I asked for. One source even said that the definition os a species is blurred since it is something we humans have defined for our convenience!!
    Anyway, PLZ reply whatever you know, anyone. I want the EXACT answer.
    Yasin

  7. Join Date
    Mar 2008
    Posts
    27

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    I do agree with you all but Dna copying is a biochemical process no biochemical process give back exact copies.so even though the dna copied may look similar they may not be exactly identical.I have heard this cause variation.And we have learned that accumilation of variation can cause speciation
    Or
    it can be due to natural selection or genetic drift too.
    i am not sure about the answer ok.

  8. Join Date
    Feb 2008
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    5

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    Well I weighed those factors, but you see, still those are fairly slow, much slower than ***ual reproduction. So, even if they act, we would have accumulated variation fairly slower than ***ual reproduction. But we do not have any dearth of organisms that reproduce only a***ually. However, the possibility is not zero, and we MIGHT have so many species of a***ually reproducing organisms just by accumulation of variation.
    Now what I asked in the beginning is again coming back. You (Teena) said there could be natural selection or genetic drift, both of which are based on accumulation of variation, one favourable to adaptation and one random. But the answer to the question then would be "YES." But doesn't solve it all because whatever Ayush said is also true. It's all locked up and I can't find a convenient answer. (Look - Ayush and Teena both said contradictory answers and both are well reasoned. That's what confuses!)PLZ PLZ HELP.
    U-R-G-E-N-T.
    Yasin

  9. Join Date
    Feb 2008
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    147

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    ok...........you are right yasin............this is all really really confusing.

  10. Join Date
    Feb 2008
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    5

    Re: Biology HEREDITY AND EVOLUTION, CLASS X

    Well its all over anyway, and none of this stuff came. Anyway, thanx - everybody of this forum for commenting. I'm still eager to know the answer though, so anyone comes across it, please post it here or send a private message to me. PLZ!.
    So bye, and hope 2 meet u sometime
    Yasin

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