Page 2 of 2 FirstFirst 12
Results 16 to 20 of 20

Thread: On Darwin and his influence

  1. #16
    Maybe YesNo's Avatar
    Join Date
    Oct 2010
    Location
    Near Chicago, Illinois USA
    Posts
    9,420
    Blog Entries
    2
    Quote Originally Posted by Dark Star View Post
    I think you misunderstood his statement about controversy. The matter is a lot like global warming; there is no controversy about the matter among scientists. Among the general public and evolution "opponents", that is a different issue. Once in a while scientists will write a paper aimed at giving a demonstration of "debated" principles for non-scientists to help them understand, but generally Behe et. al.'s views (and papers) produce little more than an eye roll among most scientists.
    The people I am reading, Eldredge and Foster, are scientists and there are controversies, like it or not.

    I have yet to read Behe, but I have read Nagel who is an atheist philosophy who has this to say about the way neo-Darwinists treat people like Behe:

    Even if one is not drawn to the alternative of an explanation by the actions of a designer , the problems that these iconoclasts pose for the orthodox scientific consensus should be taken seriously. They do not deserve the scorn with which they are commonly met. It is manifestly unfair.

    Nagel, Thomas (2012-08-29). Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False (pp. 10-11). Oxford University Press. Kindle Edition.

    I agree with Nagel.

  2. #17
    Registered User 108 fountains's Avatar
    Join Date
    Apr 2013
    Location
    Falls Church, Virginia
    Posts
    602
    Let me put in my two cents to try to clarify a couple of the sub-topics here.

    On direction in evolution: Mutations at the molecular level take place all the time. Most mutations are a random change in one of the base-pairs (a single point mutation) of a DNA (or RNA) molecule that codes for a specific protein. The mutation can be caused by exposure to ultra-violet light, by radiation, exposure to certain chemicals, and other causes, not all of which are fully understood.

    The effect of the mutation is usually a very minor change to a particular protein produced by the organism. The larger and more complex the organism is, the more unlikely that a single mutation affecting a single protein will have any effect at all on the organism’s ability to survive or to reproduce. Indeed, whether we are talking about a bacterium or a mammal, the vast majority of genetic mutations have no noticeable effect. Among the very few percent of mutations that do affect the organism as a whole, the effect will be adverse or harmful most of the time. If the effect is such that the organism does not survive before it reproduces, the mutation is deleted from the species’ gene pool. Some adverse mutations can be harmful, but not lethal and can be passed on to future generations. A well-known example of this kind of adverse, non-lethal single point mutation in humans is found in sickle-cell anemia.

    There can be very rare occasions when a mutation causes a change to a protein that affects the organism in a beneficial way. Examples would be a mutation that would allow a plant to be more resistant to herbicides or a mutation that would allow a bacterium to be resistant to penicillin. Under normal environmental conditions, neither one of these mutations would have any noticeable effect on the organism. However, if the environmental conditions changed - if herbicides were introduced into the plant’s environment or if penicillin was introduced into the bacterium’s environment, then the individuals with the genetic mutations would have a better chance to survive and reproduce than other individuals of their species which do not share the mutation. The changes in the environment I describe here do not cause the genetic mutations to take place; the genetic mutations take place independently of the environment, but the new, changed environmental conditions allow for the genetic mutations to be expressed and to be passed on to future generations.

    So even though mutations occur in a random fashion that usually result in either no noticeable effects or adverse effects, a combination of the occurrence of random mutations and environmental change can eventually lead to genetic changes that are beneficial, resulting in individuals more fit to survive and reproduce under the changed environmental conditions. This was Darwin’s notion of “natural selection” (or Herbert Spencer’s “survival of the fittest”), and this is the reason that, while on the microscopic level, genetic mutations occur randomly, on the macroscopic level, evolution shows “direction.”

    On evolutionary timeframe: When I got my BS in Microbiology nearly three decades ago, there were many scientists who, while adhering to the concept of natural selection, were at a loss to explain the wide variety of species of life on earth that had evolved in the relatively short timeframe of life on earth. There were possible explanations - the possibility of more intense ultraviolet rays in the atmosphere during the earliest periods of life on earth, the possibility of increased levels of mutagenic chemicals in water or soils, and these, coupled with environmental changes could account for an accelerated pace of evolution in earth’s early history - but this was indeed a controversial topic back in the day.

    Some religious types seized on the controversy about the evolutionary timeframe to try to de-bunk Darwinism, and in fact the whole concept of Intelligent Design was born from this controversy. I was very interested to hear OrphanPip assert that scientists now agree that there was plenty of time for life to evolve on earth as it has. I’m not sure if there really is the scientific consensus that OrphanPip asserts, but I have been out of touch with genetic science for many years now, so I have not kept up with the latest thinking, and OrphanPip seems to have a good understanding of the topic. (Thanks for the links, OrphanPip; I’ll have a look at them when I have time.) I know there is a lot of mathematical work being done with algorithms and fractals as they relate to biological systems, including genetics, but I just have not kept up with the latest thinking on the issues.
    A just conception of life is too large a thing to grasp during the short interval of passing through it.
    Thomas Hardy

  3. #18
    Maybe YesNo's Avatar
    Join Date
    Oct 2010
    Location
    Near Chicago, Illinois USA
    Posts
    9,420
    Blog Entries
    2
    Quote Originally Posted by 108 fountains View Post
    Some religious types seized on the controversy about the evolutionary timeframe to try to de-bunk Darwinism, and in fact the whole concept of Intelligent Design was born from this controversy. I was very interested to hear OrphanPip assert that scientists now agree that there was plenty of time for life to evolve on earth as it has. I’m not sure if there really is the scientific consensus that OrphanPip asserts, but I have been out of touch with genetic science for many years now, so I have not kept up with the latest thinking, and OrphanPip seems to have a good understanding of the topic. (Thanks for the links, OrphanPip; I’ll have a look at them when I have time.) I know there is a lot of mathematical work being done with algorithms and fractals as they relate to biological systems, including genetics, but I just have not kept up with the latest thinking on the issues.
    I don't have a conclusion yet about OrphanPip's references primarily because I don't understand the issues well enough, but I am hoping to remedy that misunderstanding.

    Let's forget the religion issue. Characterizing opponents as "religious types" sounds like the scorn that Nagel justly objects to.

    The time frame is not the only controversy.

    There is also the controversy with Eldredge and Gould's punctuated equilibrium. How do you view that? My reference is Eldredge's Reinventing Darwin. The fossil data does not support the smooth, random change that neo-Darwinist theory requires.

    There is also the research on hypermutation that Foster presented. That is lab data that does not support the smooth, random change that neo-Darwinist theory requires. It also shows what looks like cooperative behavior since only a few of the organisms engaged in the individually dangerous process of hypermutation when stressed by a lack of an expected food source. How do you view this?

  4. #19
    Registered User 108 fountains's Avatar
    Join Date
    Apr 2013
    Location
    Falls Church, Virginia
    Posts
    602
    Quote Originally Posted by YesNo View Post
    I don't have a conclusion yet about OrphanPip's references primarily because I don't understand the issues well enough, but I am hoping to remedy that misunderstanding.

    Let's forget the religion issue. Characterizing opponents as "religious types" sounds like the scorn that Nagel justly objects to.

    The time frame is not the only controversy.

    There is also the controversy with Eldredge and Gould's punctuated equilibrium. How do you view that? My reference is Eldredge's Reinventing Darwin. The fossil data does not support the smooth, random change that neo-Darwinist theory requires.

    There is also the research on hypermutation that Foster presented. That is lab data that does not support the smooth, random change that neo-Darwinist theory requires. It also shows what looks like cooperative behavior since only a few of the organisms engaged in the individually dangerous process of hypermutation when stressed by a lack of an expected food source. How do you view this?
    These are all valid and well-considered points. My earlier post referred specifically to point mutations, but there are other types of genetic mutations that can affect more than just a single point in the in the DNA base-pairing sequence - insertion of viral DNA into a chromosome, other types of frame-shift mutations, heritable epigenetic changes, multiple point mutations caused by ultraviolet or other radiation or mutagenic chemicals, or even damage to the physical structure of the chromosome during meiosis. Theoretically, I suppose, such mutations could account for some instances of punctuated equilibrium, but I think that is unlikely since these types of mutations are (almost) always harmful. It seems more likely to me that evolutionary “jumps” are/were caused by point mutations that affect proteins involved in processes having to do with cell differentiation and embryonic development. -- This type of discussion can go very technical very quickly, and I don’t have the technical knowledge to go much further, but I know that research is ongoing, and I’ll trust to the scientific method that we will eventually find the answers.

    I don’t believe that evolution proceeded uniformly. It seems logical, and likely, to me that evolution proceeded in the “fits and starts” suggested by punctuated equilibrium or “quantum” evolution. But I have not read about or heard of a completely satisfactory explanation of the mechanisms that would cause evolution to proceed that way. It seems logical to me that extreme environmental change, which has occurred at various times in earth’s history, is part of the answer, but not the complete answer.

    I’ll be the first to admit that, like the gaps between observed species, there are gaps in our knowledge of the evolutionary process. Personally, I would even be willing to give up on the theory of evolution entirely, if an alternative was available based on evidence, logic and objectivity. But as yet, there is no such alternative available. It seems likely to me that evolution, despite imperfections in our knowledge of it, is in fact the process of how life has developed on earth, and that our understanding of that process will proceed as we learn more.
    A just conception of life is too large a thing to grasp during the short interval of passing through it.
    Thomas Hardy

  5. #20
    Maybe YesNo's Avatar
    Join Date
    Oct 2010
    Location
    Near Chicago, Illinois USA
    Posts
    9,420
    Blog Entries
    2
    I wouldn't want to give up on evolution either. There does seem to be structural similarities between different species justifying something that could be called evolution. There is something connecting us.

    Although I don't have the technical knowledge, but I do like puzzles.
    Last edited by YesNo; 08-02-2014 at 09:52 AM.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •