Evolution of monocots vs dicots

Dave Haas dhaas at uncfsu.campus.mci.net
Sun Nov 17 15:32:23 EST 1996


> >Biolabbers
> >We have just finished our week on plant diversity in which we looked at
> >evolutionary advances in reproductive structures from mosses to ferns to
> >gymnosperms to angiosperms. While discussing the structure of monocot
> >(corn) and dicot (kidney bean) seeds, one student asked what the
> >evolutionary significance of these differences might be. While I could
> >supply information on different lineages within the angiosperms and
> >developmental and morphological differences between monocots and dicots, I
> >was hard pressed to account for the evolutionary forces that may have lead
> >to the development of these lines.
> >
> >Am I overlooking the obvious? Is there a simple answer that escaped me
> >since we are buried under four feet of snow, it is not even Thanksgiving,
> >and we are nearing the end of the semester with our tails between our legs?
> >
> >James M. Bader
> >Manager of Graduate and Undergraduate Biology Teaching Laboratories


My humble ideas are as follows:

Evolution is a kind of controlled chaos.  The rules are more or less
understood but the specific environments in which the rules were applied
in the past are not.  It is therefore, difficult to say with certainty
why or how specific characteristics evolved.  
Evolution of course acts on all of the organisms traits simultaneously,
at the same time.  Some traits especially those involved directly with
reproduction appear to be more evolutionary significant but many simply
go along for the ride so to speak.  

In the case of dicots vrs monocots the monocot seed structure is
probably related to the overall morphology which is considerably
different than most dicots.  The characters of the seed although
different than those of dicots are just as good at doing what seeds do. 
There are many ways in nature to solve the same problems.  Evolution
doesn't care how you stay alive to reproduce, therefore, many weird and
wonderful organisms have evolved since the race began 3.7+ bya. 

What is snow? .....  Oh yes. I remember. Cold wet stuff.  I hope we get
some this winter in NC.  


D. Haas



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