The costa rican moth caterpillar

Discussion in 'Biology & Genetics' started by Dr Lou Natic, Apr 9, 2003.

  1. Dr Lou Natic Unnecessary Surgeon Registered Senior Member

    Messages:
    5,574
    No
    that is not where it started.
    Why is it so hard to understand that I was never questioning evolution at all? I KNOW evolution is a fact, if edgar really thought about the breeding process he would too.
    What I was questioning was random mutations producing perfect mimmicries.
    That is all.
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. ElectricFetus Sanity going, going, gone Valued Senior Member

    Messages:
    18,140
    ok ok ANd some of use saw no problem in that and others did now where do we go?
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Dr Lou Natic Unnecessary Surgeon Registered Senior Member

    Messages:
    5,574
    I don't know if I really have a problem with it anymore, when I first saw it I was like "wtf?!" because it seemed like it would require knowledge of snakes to evolve that perfectly but you guys have explained it fairly well I suppose.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Robert Jameson Registered Senior Member

    Messages:
    75
    Quote from Canute

    How do you know the peacocks' tail is beyond its optimum size? Is there some evidence? Is the human brain past its optimum size?

    If we assume that running and flying are important for the survival of birds then the peacock’s tail is too big. And Darwinism holds that species best able to survive and pass on their genes will drive the evolution of body parts.

    The following quote from Chapter 13 of God Gametes addresses both the peacock’s tail and the human brain.

    Is Braininess Sexy?

    In The Blind Watchmaker Dawkins discusses the evolution of human intelligence in terms of ‘sexual selection’ and ‘explosive evolution’. This concept is discussed in more detail in the ‘Arms Race’ in Chapter 15 but the basic concept is that there may arise in any population a sexual preference for a long tail on a bird, long antlers on deer, or in the case of humans, more intelligence. His argument is that there may not be a significant advantage in a particular trait but if it is selected, genes for selecting trait (and having trait) will compound and be expressed in increasingly exaggerated ways as each generation refines these features. Once a peacock’s long tail is selected, male offspring will have long tails and female progeny a sexual preference for long tails. For example, it is thought that the combined selective pressure of peacocks needing longer tails and peahens preferring them pushes the length of tails a long way beyond the optimum length for the species:

    “Setting wrens on one side, peacock fans, and widow bird and bird of paradise tails, in their gaudy extravagance, are very plausibly seen as end?products of explosive, spiralling evolution by positive feedback. Fisher and his modern successors have shown us how this might have come about. Is this idea essentially tied to sexual selection, or can we find convincing analogies in other kinds of evolution? It is worth asking this question, if only because there are aspects of our own evolution that have more than a suggestion of the explosive about them, notably the extremely rapid swelling of our brains during the last few million years. It has been suggested that this is due to sexual selection itself, braininess being a sexually desirable character (or some manifestation of braininess, such as ability to remember the steps of a long and complicated ritual dance).” 8

    Even if it were possible to evolve these traits by way of cumulative selection we are as well asked to believe that species are programmed to select for characteristics that impact in such a negative way, on their chance of survival. There is little doubt that the tail of a peacock is beautiful so it is possible that the peahen may decide to mate with the male with the most impressive display purely on aesthetic grounds. But if survival of the fittest is driving the evolution of species, there is no escaping the conclusion that genes for growing a long tail and also for preferring a long tail would soon be lost because of the unjustifiably high costs they impose.
    It is also difficult to believe that human intelligence evolved because our ancestors needed to remember the steps of a dance. This overlooks the fact that greater brain volume could never outweigh the numerous other physical and social costs this evolutionary course has imposed on our species.
    More importantly though, it makes the completely false assumption that dance is related to intelligence. Dance is an expression of emotion and an artistic display of body movements that has little to do with remembering steps. It is possible that academics who spend the bulk of their lives closeted on university campuses may come to think that braininess is sexy but it is doubtful if this view is shared by the outside world. The music industry makes billions of dollars promoting sex and dance and there is little evidence to suggest they are interested in presenting popular ‘body movers’ as intelligent. If the promoter of some future rock star were to later discover that his ‘body shaker’ was not just sexy but also intelligent, it would likely be regarded as an unfortunate oversight to destroy his career if made public.
    There seems little evidence to suggest that society has ever regarded intelligence as sexy. If being able to dance were driving our evolution, emotional expression and a good sense of rhythm might well have been caught up in a spiral of explosive evolution, not intelligence. Mastering the theory of relativity or designing microchips is not sexy. Darwinists need to come up with a far better explanation than ‘remembering steps of a dance’ to explain the rapid evolution of our human brain.
     
  8. spuriousmonkey Banned Banned

    Messages:
    24,066
    there are plenty of brids that can't fly.
    there are birds that can fly but prefer walking (roadrunner).

    you got confused because you heard 'survival of the fittest' a few times too often, without realizing that Darwin never said this, but someone else as a subsitute term for natural selection.

    let me repeat myself:
    'survival of the fittest' was never a term used by Darwin, but rather coined by Herbert Spencer. Not only is the term highly tautological, spencer was also the spokesperson for the social theory based on a brtutal struggle for existence, misleadingly termed social Darwinism.

    See Ernst Mayr 'The growth of Biological thought'

    Your focus on the term survival has therefore caused an error in your perspective on evolution. Forget survival and think natural selection.
     
  9. Robert Jameson Registered Senior Member

    Messages:
    75
    Quote by Spuriousmonkey

    'survival of the fittest' was never a term used by Darwin, but rather coined by Herbert Spencer.

    Does it matter that the term was not coined by Darwin himself. This is like saying that Darwinism is an invalid theory because Darwin himself (allegedly) repented and said he believed in a God when on his death bed. Supporters of Darwinism correctly argue that it would not matter because his theory would stand or fall on its merits. Same with the term “survival of the fittest”. Darwinists for many generations have embraced this term because it accurately sums up the Darwinian concept in a short and very catchy little phrase.


    Quote from Canute

    Is the human brain past its optimum size?

    From Chapter 13 of God Gametes that can be down loaded free from www.e-publishingaustralia.com

    The Human Brain:

    When addressing the issue of the rapid evolution of the human brain Dawkins points out that in 3 million years the cranial capacity of homo sapiens’ brains has nearly trebled. Figures provided in The Blind Watchmaker for our Australopithecus ancestor is a brain volume of about 500 cubic centimetres. The average modern human brain has a volume of about 1,400cc, an increase of 900. Dawkins points out that if it took 3 million years for Australopithecus to evolve into modern homo sapiens, and assuming an average of 4 cycles per century, the increase in brain volume has been less than 0.01cc per generation. 6 The suggestion here of course is that such a small increase in cranial capacity can easily be explained by cumulative selection.
    Let us however examine more closely what is involved in this seemingly insignificant increase in brain volume.
    Modern homo sapiens’ brains have an estimated 100 billion nerve cells interconnected by an incredible 100 million, million pathways.7 This means that in 3 million years our species has evolved an additional 64.3 billion nerve cells (i.e. 500cc divided by 1,400cc multiplied by 100 over 1, equals 35.7% - or Australopithecus had about 35.7 billion nerve cells. 100 billion homo sapiens’ nerve cells less 35.7 billion Australopithecus nerve cells gives a 64.3 billion increase.) If it took 3 million years for our species to evolve 64.3 billion new nerve cells, this is an increase of 21,430 per year but Dawkins has allowed for 4 generations per century so on average a son or daughter will have 535,830 more nerve cells than parents (i.e. 64.3 billion new nerve cells divided by 3 million years multiplied by the generational time of 25 years, equals 535,830).
    This increase cannot be explained by selective pressure on a particular group that for some reason needed a larger cranial capacity to facilitate adaptation to unusual geographical conditions or a changing environment. It is the average increase for our entire species common to all geographical regions and climatic conditions to which our species has had to adapt. So if greater cranial capacity were being driven by natural selection it is extremely unlikely increases in brain volume would be common to all areas when environmental conditions have varied so much.
    Given that our intelligence has presumably improved as the size of our brains increased, it would not seem unreasonable to conclude that each incremental increase conferred a related upgrading of intelligence. It would in fact be an understatement to simply argue that human intelligence has increased threefold over a period of 3 million years in line with the trebling in brain volume. Increase in human intelligence has been explosive and the Darwinian theory of natural selection cannot dismiss it by reference to the number of cubic centimetres by which our brain has grown. Homo sapiens’ brains have evolved on average 535,830 new brain cells for every generation for the last 3 million years. This happened in an extremely short time and cannot be explained by cumulative selection. An average increase of 535,830 new brain cells in every generation for 120,000 generations with the complex wiring up and the increased intelligence they confer, is not what Dawkins previously referred to as the minimal X.
    The Darwinian theory of evolution needs to explain why our species, regardless of climatic conditions or geographical locations have evolved such significant increases in brain size.
    Even if cumulative selection and mutation could find a way to evolve 535,830 new brain cells in every generation there still needs to be a reason why. It is not as if we were competing with another intelligent species for the same environmental niche. Some will argue that our increased intelligence might have provided a benefit in developing hunting and gathering skills yet our more primitive relatives do not appear to have had problems acquiring the necessary skills for making a living gathering food or hunting prey.
    Natural selection cannot explain why the size of our brain has continued to increase when it would have imposed a significant survival liability on our species. A larger head would no doubt have caused many premature deaths of mothers giving birth. If young mothers, their death would not only mean their own loss to the population, but the child they were carrying and also any future children they might bear. And if the mother already had children, the infants in her care would most likely not survive. Our increased brain size made it necessary for much of our cranial development to happen after birth and this meant that newborn members of our species have been far more dependent on parental care and for a far greater period than our close primate relatives. Again this would have placed enormous hardships on our species. For most of the 3 million years our ancestors were evolving greater brain volume they would have found it conferred no survival advantages but numerous disadvantages.
     
  10. Dr Lou Natic Unnecessary Surgeon Registered Senior Member

    Messages:
    5,574
    The human brain

    I like the aquatic ape theory for the evolution of humans, mainly because of our brains.
    In fact I might make a thread about it

    Please Register or Log in to view the hidden image!

     
  11. spuriousmonkey Banned Banned

    Messages:
    24,066
    As I pointed out, not darwinists have embrace this term, but people with a misplaced social agenda.

    People have embraced survival of the fittest because they are idiots and lazy thinkers. Survival of the fittest is, was and always will be a lousy replacement for 'natural selection' and the urge to embrace this term is a clear indication of misunderstanding evolution.
     
  12. Dr Lou Natic Unnecessary Surgeon Registered Senior Member

    Messages:
    5,574
    I don't think trying to understand with either phrase is a good idea.
    The best thing to do IMO is to have no preconcieved ideas of what you think evolution is and to learn about each species, their breeding habits, their ancestry and their relatives.
    Then, rather than struggling to figure out how someone else thinks evolution works, you "realise" it for yourself.
    Its common sense if you spend enough thought on it.
     
  13. Canute Registered Senior Member

    Messages:
    1,923

    So if we assume that attracting mates are important for the survival of a peacock's genes then it isn't too big (and some may be too small) The size of the tail is a compromise between evolutionary benefits and disbenefits. There is no way any human being can work out whether it is at its optimum size or not, a fact that seems too obvious to have to mention.
     
  14. ElectricFetus Sanity going, going, gone Valued Senior Member

    Messages:
    18,140
    I agree with you on what Darwin believed or said has no effect on the validity of modern evolutionary theory (it an Ad hom. class fallacy) but evolution does not invalidate god (just the accuracy of biblical history is affected) so belief in god and evolution is not interdependent and you can believe in both without contradictions.

    Also yes survival of the fittest is a very general but still can be interpreted accurately, phase. If I said “survival of the most successful reproducibility in a specific environment” that would not be as “catchy”

    Actually human brain size increase at uneven rate and to say roughly every generation ~500,000 new brains cell increase per generation is not correct. Also that’s the same amount of brains cells lost by 1 night’s binge drinking. The variance per person is far more then 500,000 brain cells so it would not be hard to continually breed people together that have a genetically higher amount of brain cells. Your statement in general says nothing about why this is not possible it just say so (Smoke screen fallacy). Also Evolutionary theory only needs to say that there was an evolutionary advantage in having bigger brains. So far the development of the human brain has match well with evolutionary theory and fossil records. The exact reason why our brains are larger is debated but that has no effect on the fact that we evolved bigger brains.

    Yes Robert I actually read one of your self advertising book promotion quotes.
     
  15. river-wind Valued Senior Member

    Messages:
    2,671
    a couple points:

    one_raven:
    "and vivid color (someone help me out with this one, please) ..." vivid color in nature often means "I'm poisonous, I don't need to hide, cause if you eat me, you're screwed"


    Robert:
    There are different types of selection which you seem to be mixing together. Evolution is the final product of all the type of selection. In this thread, the main two types of selection are reproductive and survival.
    A peacock tail is a detrament to the individual's survival. It is a benefit to the reproductive success, though. The benefit profided by reproductive success is greater than the detrament of having a large tail, so the tails stays.
    Why do Peahens like large tails? Why do human women find men who can't touch their own sides sexually attractive? The lack of mobility due to sheer muscule size is surely a detriment, as my scrawny ass can pummel a much larger guy in a fight because of my speed. Sexual select, like everything else in the world, can (and often does) go over board. It's a self-regulating system. A larger tail, some millions of years ago, helped a few peacocks reproduce. As sign of virillity, perhaps. so the offspring got bigger tails, which allowed them to reproduce better (again, a sign of virrillity). over generations and years, the purpose of the tail was lost, as females who were attracked to large tail displays were more likely to reproduce with strong males (weak males couldn't overcome the burden placed on them by a genetically large tail). So not only is there a benefit to producing a large tail display in males, there is a selection benefit to a female choosing a male with a grand tail display. Now we are at today, then the basis for the message the a tail display provides has been largely lost, the peahens just like the look of the big tail.
    White-tailed deer have forked antlers to looks like tree branches. ok, maybe. however, if you watch 2 male deer fight for mates, then do not ram each other, like water buffalo. they lock antlers gently, and then twist back and forth. forked antlers are more helpful in this arm-wrestling style of fighting than bull horns would be.



    I'm not sure who said it, but I think it was Canute: " Viruses and bacteria adapt to their environment faster than multi-cellular organisms."

    Given the short life span of single-celled organisms, the population is able to adapt faster to environmental change. however, the individual orangism is not. Same goes for viruses, though the faster mutation Rate in RNA than in DNA also helps them adapt faster (again, as a population).

    In a multi-cellular organism, you have an additional thing to consider- survival of the multicellular organism. This is apart from the survival of the individual cell. The cells, due to specialization, are more able to adapt to an environment change than bacteria. As individual cells, mind you.

    so:
    1)single-celled organisms can adapt somewhat to environmental change on an individual level
    2)cells in a multi-cellular organism can often alter their function slightly, allowing for the multi-cellular organism to survive greater environmental changes
    without resorting to evolutionary tachtics and reproduction.
    3)bacteria, though massive numbers, a high reproductive rate, and fast mutation, can evolve faster than a multi-cellular organism.
    4)because of #3, bacterial populations can deal with environmental changes faster then multi-cellular organisms.
    conclusion.
    on a cell-to cell comparisom, multi-cellular organims can adapt to environmental changes at a slightly better than can single-cell organisms, due to specialisation.
    on an organismal level, single-celled organisms adapt to external environmental changes much less effectively than multi-celluar organisms
    on a population level, single-celled organisms can adapt to environmental changes faster, due to their less complex nature; mutaion can take hold faster.
    Humans can, while naked, survive temp variations from ~40F to ~110F; this is a huge range in comperison to an individual bacterial cell, who's functional range is usually around 30 degrees F (ie 40F to 70F). Bacteria as a population, however, has individuals who have evolved to survive below freezing, and all the way up to above boiling.
     

Share This Page