1. Welcome to Religious Forums, a friendly forum to discuss all religions in a friendly surrounding.

    Your voice is missing! You will need to register to get access to the following site features:
    • Reply to discussions and create your own threads.
    • Our modern chat room. No add-ons or extensions required, just login and start chatting!
    • Access to private conversations with other members.

    We hope to see you as a part of our community soon!

Questions about Evolution?

Discussion in 'Evolution Vs. Creationism' started by painted wolf, Apr 27, 2009.

  1. painted wolf

    painted wolf Grey Muzzle

    Messages:
    15,370
    Ok, so I can't promise I can answer every question... But I'm willing to give it a go.

    Is there some aspect of Evolution that you don't fully understand or want to know more about... Let me know and I'll see if I can't either explain it a bit or get you a resource to check out.

    I'm not an expert on the subject, but I'm learning and I find these sorts of discussions help me hone my knowledge and keep it from getting dusty. Also it comes in handy when I'm in an exam and have to answer a tricky question. :cool:

    Anyway, I am a senior student of Biology and I work as a Biologist when time and opportunity allows.

    So feel free to ask... even if you think you have a handle on Evolution, there is always something new to learn.

    wa:do
     
  2. 3.14

    3.14 New Member

    Messages:
    4,389
    what causes the flaws in the genetic code that lead to diffrent offspring
     
  3. painted wolf

    painted wolf Grey Muzzle

    Messages:
    15,370
    wow, that was quick! :D

    I assume you are talking about sexual reproduction? (don't start me off with an easy question by any means. :p )
    If so, then these aren't flaws per say... though flaws in the process can happen.

    I'll just touch on this briefly as I could easily write a whole essay on the subject... If you have any follow up questions feel free to add them.

    First you have to start with the process of Meiosis. During Meiosis parent cells (which have paired sets of chromosomes) divide in such a way to produce gametes (sex cells) that have only one copy of each chromosome.
    Problems in this phase produce what is called nondisjunction, when chromosomes fail to separate and you end up with one cell with too many copies (trisomy) and one without a copy (monosomy).

    Baring somthing that drastic you still have crossing over... in this process the two sister chromatids (half a chromosome) will litterally cross over one another and swap DNA. This process can lead to all kinds of fun... Indcluding deleting sections of DNA from one chromatid and doubling it in another... flipping sequences so they now run backwards and even translocating pieces to totally new areas of the chromosome.
    Many of these events can lead to the gamete being inviable... others end up producing new and novel alleles.

    Moving on from there two gametes come together from separate parents... Each chromosome matches up with its respective homolog... In this process you can also have issues crop up.
    Even though the chromosomes are the same, they are not identical copies of one another.
    This mean that when the chromosomes line up for recombination you can get copy errors.

    You can have the same nondisjuntion issues (often a cause of cancer in mature cells, fatal for zygotes) you can have the same crossing over events happen between the father and mother chromosomes... (sometimes this can even fix prior crossing over problems but that is quite rare)

    Inversions and deletions can cause the chromosomes to loop during matching up, effectively forcing the two parts to match up as if there wasn't a problem at all. So not all copy errors are perminant or fatal.

    However a great many of these are known as the cause of diseases... for example:
    Delietion on Chromosome 5 causes Cri du Chat: Cri du chat - Wikipedia, the free encyclopedia
    Duplication causes Charcot-Marie Tooth dissease: Charcot-Marie-Tooth disease - Wikipedia, the free encyclopedia
    Inversion causes Hemophillia A: Haemophilia A - Wikipedia, the free encyclopedia
    Translocation causes Chronic Myelogenous Leukemia (CML): Chronic myelogenous leukemia - Wikipedia, the free encyclopedia

    Hope this helps... If I missed anything you want me to cover a bit more let me know.

    wa:do
     
    3.14 likes this.
  4. Tolerant Believer

    Tolerant Believer New Member

    Messages:
    4
    How can evolution explain irreducible complexity? If there is a biological system in place that has several parts to it, the loss of any one preventing the system to work at all, how can it evolve? As an example, in order for blood to clot properly, there has to be a system in place to know where the cut is. There also has to be a mechanism to get the platelets there and, of course you have to have a clotting agent (platelets). If ever there was a person who didn't have any one of these mechanisms, he would have died from a paper cut. This, it seems, would prevent reproduction at all because no one would live long enough to reproduce.
     
  5. painted wolf

    painted wolf Grey Muzzle

    Messages:
    15,370
    Actually if you look closely at the blood of living creatures you find that there is no irreducible complexity to blood clotting.

    Dolphins do just fine without the Hagemann factor, a needed part of the human clotting mechanism.

    Lamprey for example do just fine with just six of the ten supposedly irreducibly complex proteins needed for mammal blood clotting. Indeed one can trace the evolution of those missing four proteins.

    Platelets are quite different between mammals and other vertebrates... ours have no nucleus and respond to different chemical signals than non-mammals platelets. Insects and other arthropods get along quite well without platelets at all.

    I'm afraid that irreducible complexity will have to do better than blood clotting as an example.

    wa:do
     
  6. eugenius

    eugenius The Truth Lies Within

    Messages:
    272

    You're good you! Glad to have you on the team.
     
  7. Tolerant Believer

    Tolerant Believer New Member

    Messages:
    4
    That may all be true, but the fact remains that in humans, it is an irreducibly complex system. I never meant to assert that all animals have the same systems, that is obviously not the case. But you and I have a system which is irreducibly complex. How can you explain that?
     
  8. Tristesse

    Tristesse New Member

    Messages:
    3,341
    Your making the assumption that humans are irreducibly complex, and your doing so by your own perception of complexity. You have to give an example of what it is you think is irreducibly complex.
     
  9. painted wolf

    painted wolf Grey Muzzle

    Messages:
    15,370
    Evolution doesn't happen in a single species. We inherited our clotting system from our ape ancestors who inherited it from their pro-simian ancestors and so on.
    You asked about the evolution of the clotting system... I demonstrated that the clotting system has changed significantly and in ways predicted by evolutionary theory.

    ie. the closer you get the last common ancestor you get the more 'simple' the clotting system becomes.

    The clotting system can not be both irreducibly complex and not irreducibly complex. Either it works with all its parts or it doesn't. Shuffling the goal posts to 'human only' isn't going to help.

    Yes, problems with clotting happen, but this doesn't make the whole system irreducibly complex and therefore not able to evolve. As I said, evolution isn't in single species, if you want an irreducibly complex system it can't have a simpler precursor in evolutionary history.

    We don't have an irreducibly complex clotting system, we have a highly evolved clotting system.

    wa:do
     
    fantôme profane likes this.
  10. Tolerant Believer

    Tolerant Believer New Member

    Messages:
    4
    I am sorry if I was unclear from the beginning, but I was only talking about the human clotting system, so I am not changing my argument at all. I have not studied all the blood clotting systems of the world, so I would not presume to speak about anything of which I know nothing. Sorry for the confusion.

    You say that you demonstrated the development of blood clotting, but I must disagree. You demonstrated that different species have different systems to deal with the issue, and with that I fully agree. I also agree with your definition of irreducible complexity, you restated my original premise very well, thank you.

    So I ask again. Specifically when talking about t he human blood clotting system, if you were to take away one part of it, it's effectiveness would not be diminished, it would cease to work at all. In order for this system to be in place, it had to appear fully intact, as it is, in our very first ancestor. How can evolution explain that?
     
  11. painted wolf

    painted wolf Grey Muzzle

    Messages:
    15,370
    *emphasis mine
    Simple...our very first ancestor wasn't human. We are the result of a long linage of living beings that stretches back into deep time.

    You are not arguing Irreducible complexity here... you are arguing special creation.

    wa:do
     
  12. themadhair

    themadhair New Member

    Messages:
    2,486
    You are also making the error of assuming the function of the current clotting system must have been the same as its ancestral form.

    That is how evolution works. A system is built up, piece by piece, with each step giving a greater advantage over each previous incarnation. This also provides a test for evolution – namely can we find simpler versions of the blood clotting system that have function? As painted wolf pointed out, the answer is yes with those simpler systems being present, and with function, in other creatures.

    If memory serves, the blood clotting system was one of the three examples of irreducible complexity that was used to argue for ID during Kitzmiller vs. Dover School District. The blood clotting system had its day in court and was demonstrated to be the product of the evolutionary process. Pretty much everything that was presented in favour of ID got routed in that trial.

    The biggest error you are making here Tolerant Believer is assuming that irreducibly complex means unevolvable. That isn’t so, and I think the best analogy to demonstrate this is the Roman arch. Imagine a builder who can add or subtract one brick at a time. Now imagine you have a Roman arch where to remove one single brick would collapse it – the Roman arch is irreducibly complex. The builder, who can add or subtract bricks one at a time, represents the gradualistic mechanism of evolution. The builder can, one brick at a time, build the irreducibly complex Roman arch. Think about how the builder can do this.

    In the same way evolution can also ‘build’ irreducibly complex structures. Various irreducibly complex enzyme and protein pathways have been evolved in laboratory experimentation. The bottom line is that irreducible complex does not mean unevolvable.
     
  13. themadhair

    themadhair New Member

    Messages:
    2,486
    And since you seem to be willing to answer questions regarding evolution painted wolf, what is the latest on the mechanism by which the molly doesn’t get ratched?
     
  14. painted wolf

    painted wolf Grey Muzzle

    Messages:
    15,370
    Well, the Amazon molly still uses males to trigger the reproductive response... occasionally their eggs do absorb genetic material from the male in question. Generally this genetic material doesn't go through recombination, so it doesn't contribute to the genetic make up of the offspring.

    It seems possible that every so often recombination does happen, infusing the next generation with a few more helpful alleles. (this makes sense giving the fact that sexual reproduction is so close in its evolutionary history.)
    Most asexual reproducers also have very effective means of pairing down harmful genetic mutations. Other forms of recombination can also reduce stress from Muller's ratchet.

    Muller's ratchet for those who don't know, is when an asexual species accumulates harmful mutations with no way of reversing them. It is part of the "Why have sex" question in evolution.
    Sex is a very effective way of reducing harmful mutations.

    wa:do
     
  15. fantome profane

    fantome profane quintessence of dust

    Messages:
    5,920
    Painted Wolf’s answer was about the human clotting system.

    The argument of irreducible complexity states that some biological systems could not possible have evolved as all parts must be in place for it to work. To use the irreducible complexity argument it is not enough simply to say that we don’t know how a particular system did in fact evolve, the claim of irreducible complexity is that there is no conceivable way that the system could evolve. And in the case of the human clotting system Painted Wolf has successfully refuted the claim by showing that there is in fact a possible way that the human clotting system could have evolved.
     
  16. Dezzie

    Dezzie New Member

    Messages:
    1,680
    I'll give a question a go... they say humans evolved from monkey's correct? What type of species was it exactly? I have always been confused with that because monkey's are still around today. I always felt that they would be extinct if we came from them...
     
  17. Tristesse

    Tristesse New Member

    Messages:
    3,341
    No, humans didn't evolve from monkey's. We evolved from a species that was closely related to monkies, and we both evolved in our own separate ways.
     
  18. Seyorni

    Seyorni Well-Known Member

    Messages:
    12,166
    Religion:
    Vedanta (reform)
    And didn't Americans evolve from Europeans? Why are there still Europeans? :shrug:
     
  19. Nepenthe

    Nepenthe Tu Stultus Es

    Messages:
    4,323
    Human/Chimpanzee divergence occurred about six million years ago, most likely due to geographic isolation which prevented the flow of genes between the populations (or allopatry). Sympatric speciation may have been the reason as well, as it likely did for early humans and neandertals. However the isolation occurred, it simply meant two populations went their seperate ways never to interbreed again, and both found their successful environmental niche and prospered. There's no reason for one species to supplant another when both are successfully breeding and passing those alleles along.
    [​IMG]
     
  20. Dezzie

    Dezzie New Member

    Messages:
    1,680
    I got ya... so... was that species closely related to monkeys those "cavemen" they always talk about in little childrens books? What did they evolve from?
     
Verification:
Draft saved Draft deleted