That clever fellow John (Chris) Walken has proposed a useful idea—that we put together simple descriptions of basic concepts in our fields of interest for the edification of any newcomers to science. He picked the magic word Clade to write about first; I don’t know why he didn’t pick “Species”, since he could have just dumped his thesis into one short, simple blog post. Maybe he’ll do that next.

Larry Moran has joined in with a lovely lucid explanation of Evolution. This is very useful, because now whenever a creationist comes along here, we can just tell him or her to go to that post and argue with Larry. If they survive that, then they are worthy of further interaction.

All of my science posts are basic and simple, so I’m not sure what I could write to add to this collection. If anyone has any suggestions, chime in and let me know.


  1. #1 David Marjanovi?
    January 13, 2007

    I don’t know why he didn’t pick “Species”, since he could have just dumped his thesis into one short, simple blog post.

    You’re kidding. For anyone who doesn’t understand the joke: what “species” means depend on whom you ask. There are at least 25 species concepts out there. The differences are drastic: depending on which species concept you pick, there are between 141 and 200 (I forgot the number) endemic bird species in Mexico. No wonder that there are people who say “species” is just as arbitrary a Linnaean rank as any other (genus, family, order, class, etc.) and should be dropped like them; instead, the argument goes, only clades of all sizes should be named. “Clade” has exactly one definition.

  2. #2 David Marjanovi?
    January 13, 2007

    Wikipedia! Yes!!!

    What speciation is depends entirely on the species concept. For example, under the Hennigian Species Concept “cladogenesis” and “speciation” are synonyms, under the Biological Species Concept “speciation” means the evolution of a barrier to interbreeding (which makes cladogeneses permanent, but is otherwise completely unrelated to cladogenesis), under the Ecological Species Concept it means entering/creating a new ecological niche (which is mostly unrelated to either of the above), and so on.

  3. #3 Torbjörn Larsson
    January 13, 2007

    So, what is the beef between Mr Willikins/Walken/Wilkins and Mr Meyers/Mayers/Myers? Or is it an out in-joke?

    Anyway, my feeling was exactly that, the rest of SB will now try to catch up on PeZes/PeZeds/PZ’s type of science posts.

    If so, the laws of thermodynamics are basic to all!

    Well, chemistry seems to use it a lot. For most of physics statistical physics is probably used instead. And for example evolution, not really AFAIK.

  4. #4 David Marjanovi?
    January 15, 2007

    A gene is a segment of DNA that codes for a peptide chain.

    No, for an RNA, which may (mRNA) or may not (rRNA etc. etc. etc.) be translated later.

  5. #5 Torbjörn Larsson
    January 15, 2007

    A book (‘Time’s Arrow and Evolution’) by Blum about 40 years ago [snip] was on the subject

    The application of entropy to evolution doesn’t seem to have been successful. Of course energetics is important for chemistry, cells and life, but it doesn’t seem to have any bearing on evolution besides as constraints for development. (Sizes, mass vs area, et cetera.)

    Blum’s book seems to have been about cosmogony and abiogenesis.

    “[Blum] in his Time’s Arrow and Evolution (1951), argued that if life exists elsewhere in the Universe:

    [I]t probably has taken quite a different form. And so life as we know may be a very unique thing after all, perhaps a species of some inclusive genus, but nevertheless a quite distinct species.

    Pointing out the general tendency of the Universe to become more disorganized with time, in accordance with the second law of thermodynamics, he suggested that a system such as life which ran against this trend might be rare. Moreover, he adopted what would become the party line among evolutionary biologists in the era of space exploration, contrasting with the position of most astrobiologists, that (a) the appearance of life on Earth might have been due to a series of lucky accidents, and (b) that if it did evolve on other worlds it would be very unlikely to resemble any terrestrial variety.” ( )

    So he argued that abiogenesis was difficult, but not prohibitively so, and that humans are unique. Accordingly, he seems popular among creationists and theistic evolutionists. But I can’t find any modern texts on 2LOT and evolution or abiogenesis. The consensus seems to be that 2LOT doesn’t say anything on them.