Changes

Jump to navigation Jump to search
m
Line 48: Line 48:  
::::I'll probably earn another 90/10 block for this, but when you continue to question Lenski's work while admitting that you've only skimmed the related paper, you accomplish nothing but setting a poor example of intellectual honesty for the students who use CP as a trustworthy resource.  With all respect, I would ask that instead, you retain the services of a qualified scientist who can engage in a proper review of Lenski's work, whose could then post an ongoing journal of the review process and its findings here on CP.  ''That'' would be an appropriate lesson for the students in the proper application of scientific scrutiny to findings that some find questionable.  Godspeed.  --[[User:DinsdaleP|DinsdaleP]] 20:20, 26 June 2008 (EDT)
 
::::I'll probably earn another 90/10 block for this, but when you continue to question Lenski's work while admitting that you've only skimmed the related paper, you accomplish nothing but setting a poor example of intellectual honesty for the students who use CP as a trustworthy resource.  With all respect, I would ask that instead, you retain the services of a qualified scientist who can engage in a proper review of Lenski's work, whose could then post an ongoing journal of the review process and its findings here on CP.  ''That'' would be an appropriate lesson for the students in the proper application of scientific scrutiny to findings that some find questionable.  Godspeed.  --[[User:DinsdaleP|DinsdaleP]] 20:20, 26 June 2008 (EDT)
   −
::::The development of citrate metabolizers wasn't the main intent (see Lenski's early papers) and it's actually irrelevant in the overall context. Zachary Blount describes the purpose of citrate in the media in his responses at Carl Zimmer's blog, The Loom. http://scienceblogs.com/loom/2008/06/02/a_new_step_in_evolution.php (see replies #115 & #270). Citrate was not added to be a carbon nutrient in the media but as a non-metabolizable chelator (the three carboxyl groups of citrate can bind certain cations in solution). The recipe for medium was taken from other microbiologists who developed the recipe as a general culture medium back in 1949. Lenski's description of the DM25 media is here: https://myxo.css.msu.edu/ecoli/dm25liquid.html. Glucose was the intended carbon source. If you read the Lenski article cited by Blount (Phenotypic and genomic evolution during a 20,000-generation experiment with the bacterium Escherichia coli. -- available here: https://www.msu.edu/~lenski/. An earlier article at generation 2000 is here: http://myxo.css.msu.edu/lenski/pdf/1991,%20AmNat,%20Lenski%20et%20al.pdf), you'll see the setup and reasons for performing the experiments. Basically, Lenksi wanted to see how mutations arise and move through populations over time. Even if the media and growth conditions remain pretty consistent over time, the populations continuously shift and change. That is because for a bacterium in the experiment the 'environment' is not just made up of the flask and media but also the *other cells in the flask* with which it must compete. This results in a continuously shifting competitive environment as mutations arise in lineages. Citrate utilization was just one of the many interesting variations acquired over the course of the experiment. Read his other papers for more details and a fuller understanding of the open-ended experiment's scope.--[[User:Argon|Argon]] 21:16, 26 June 2008 (EDT)
+
::::The development of citrate metabolizers wasn't the main intent (see Lenski's early papers) and it's actually tangential in the overall context of the long-term experiment. Zachary Blount describes the purpose of citrate in the media in his responses at Carl Zimmer's blog, The Loom. http://scienceblogs.com/loom/2008/06/02/a_new_step_in_evolution.php (see replies #115 & #270). Citrate was not added to be a carbon nutrient in the media but as a non-metabolizable chelator (the three carboxyl groups of citrate can bind certain cations in solution). The recipe for medium was taken from other microbiologists who developed the recipe as a general culture medium back in 1949. Lenski's description of the DM25 media is here: https://myxo.css.msu.edu/ecoli/dm25liquid.html. Glucose was the intended carbon source. If you read the Lenski article cited by Blount (Phenotypic and genomic evolution during a 20,000-generation experiment with the bacterium Escherichia coli. -- available here: https://www.msu.edu/~lenski/. An earlier article at generation 2000 is here: http://myxo.css.msu.edu/lenski/pdf/1991,%20AmNat,%20Lenski%20et%20al.pdf), you'll see the setup and reasons for performing the experiments. Basically, Lenksi wanted to see how mutations arise and move through populations over time. Even if the media and growth conditions remain pretty consistent over time, the populations continuously shift and change. That is because for a bacterium in the experiment the 'environment' is not just made up of the flask and media but also the *other cells in the flask* with which it must compete. This results in a continuously shifting competitive environment as mutations arise in lineages. Citrate utilization was just one of the many interesting variations acquired over the course of the experiment. Read his other papers for more details and a fuller understanding of the open-ended experiment's scope.--[[User:Argon|Argon]] 21:16, 26 June 2008 (EDT)
    
::::With regard to 'competent scientists' consider that Behe, in his discussions on this topic has not argued about the 'mechanics' and data presented in Lenski's paper. In his review that can be found on the amazon.com website, he calls Lenksi's work 'fascinating' (and means it in a good way).--[[User:Argon|Argon]] 21:29, 26 June 2008 (EDT)
 
::::With regard to 'competent scientists' consider that Behe, in his discussions on this topic has not argued about the 'mechanics' and data presented in Lenski's paper. In his review that can be found on the amazon.com website, he calls Lenksi's work 'fascinating' (and means it in a good way).--[[User:Argon|Argon]] 21:29, 26 June 2008 (EDT)
185

edits

Navigation menu