What is the Difference Between Darwinism and Neo-Darwinianism?

  1. I've heard both terms used and can't figure out what people are talking about when they discuss neo-Darwinianism. What's the difference/similarities between them? Thank you guys so very much!

    ...and if there is yet another type of Darwinianism I'm missing, then please feel free to add that too! :wink:
     
  2. jcsd
  3. Ryan_m_b

    Staff: Mentor

    Darwinism is simply the original set of ideas that Darwin proposed about evolution. After half a century of research and new discovery the modern synthesis (often refered to as neodarwinism) was formed that took into account many phenomenon that Darwin did not know about:

    http://en.wikipedia.org/wiki/Modern_evolutionary_synthesis
     
    1 person likes this.
  4. Gotcha. So, it's Darwinism + ____ ideas. It's basically adding onto Darwin's ideas rather than negating anything or proposing anything radically different. Just sort of an updated version of Darwinism, given new scientific discoveries?
     
  5. That is correct. After Darwin published On the Origin the concept of evolution was rapidly accepted by the scientific establishment, but debate continued over the cause. Natural selection, Darwin's hypothesis, fell out of favour.

    Then, at the turn of the century the work of Gregor Mendel on hereditary, was independently rediscovered by three researchers. This was associated with the concept of mutations and it was these that were seen as the source of new species, with no need for the intervention of natural selection.

    Next, in the 1920s Sewall Wright, J.B.S. Haldane and R.A.Fisher did brilliant work on population genetics that provided the foundation for the Modern Synthesis. This was formalised and wrapped into "everyday" biological thought by Theodosius Dhobzansky, Ernst Mayr and George Gaylord Simpson in the 1930s and 40s.

    Today, in the light of more recent discoveries, some researchers feel evolutionary theory has moved sufficiently far to justify a new name. My own view is that " a rose by any other name would smell as sweet".
     
  6. atyy

    atyy 10,834
    Science Advisor

    No. Natural selection is still considered a mechanism of evolution that is consistent with genetics.

    http://www.nature.com/scitable/topi...g-mechanisms-of-evolutionary-adaptation-34539
    http://www.nature.com/scitable/know...election-genetic-drift-and-gene-flow-15186648
     
  7. It seems that I have been unclear in my exposition. OF course natural selection is not only considered a mechanism of evolution, but along with mutations as one of the primary mechanisms.

    Clearly I should have explicitly stated that work of Haldane et al brought natural selection back into the theory as a central element. (There is the danger of being over familiar to the point one forgets to state what seems to be obvious.)

    Thank you for clarifying for any who may have been misled by my lack of explicit comments.
     
  8. atyy

    atyy 10,834
    Science Advisor

    Ha, ha! Great!
     
  9. The Neo-Classical Synthesis has proved to be problematic. It is occurring to some that just because something works, it is not necessary that this explains everything.

    A very convenient out for Biological Evolution has been

    "Thinking in terms of populations, rather than individuals, is primary: the genetic diversity existing in natural populations is a key factor in evolution. The strength of natural selection in the wild is greater than previously expected; the effect of ecological factors such as niche occupation and the significance of barriers to gene flow are all important."

    This works once the attribute has been introduced to the population.

    However, when one is considering a novel feature the mechanics do not work - well.

    Sexual reproduction injects a hurdle that is not found when one is experimenting with bacteria and such.
     
  10. I am not aware of any serious biologist who thinks that the current theory explains everything. (Please name names, if you think there are.) If anyone thought this they would discontinue their research. I'm no expert on logical fallacies, but your statement has the look and feel of a strawman. Perhaps I have misunderstood you, or you were using hyperbole.

    It would be nice to know who said this and where. i.e. citation.

    If it works, what is your problem with it?

    Please give an example, with proper citations.


    What is the nature of this hurdle? Please give examples, appropriately supported by detailed argument, or peer reviewed research.
     
    Last edited: Aug 29, 2014
  11. The so-called Modern Synthesis includes our knowledge of genetic inheritance and now also the nature of genetic information (DNA usually, RNA sometimes) and genetic variation. With molecular tools we can see examples of "evolution" in progress, such as novel gene duplications or losses (such as felines losing the sweet taste receptor gene by random mutation, and hummingbirds acquiring a new one by modification of a different gene).

    The specific issue about sexual reproduction, while posing a challenge for evolutionary biology, is not considered a serious argument "against evolution" by anyone I know. The problem is that sexually reproducing organisms by definition only transmit some of their genetic variation to their descendants, whereas asexual (i.e. cloning) organisms transmit all their variation. A simplistic interpretation therefore would be that sex cannot have "evolved". A more nuanced view is that there must be compensating factors, and many such have been proposed. Since it is difficult to do a true evolution experiment over a short time span, tests of these various hypotheses are simply difficult to test. But not implausible. Think about this though: random mutation of our genomes happens all the time (directly observed by DNA sequencing in families), and many such mutations are toxic (obvious by interpreting their effects on the genes in which they life). Sex provides a way to get rid of such toxic mutations, though it also risks losing rare beneficial new mutations. There must be a balance, such that sex is ultimately beneficial. Even organisms like bacteria also trade DNA, which suggests that pure asexual cloning is not the best way for species to survive over long evolutionary time spans and changing environments - although some apparently truly asexual ancient species are known, and of course are of great interest.
     
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