PLANT HISTORY

NEC95ISA09 at mecn.mass.edu NEC95ISA09 at mecn.mass.edu
Mon Oct 17 10:48:14 EST 1994


I am curious, primative plants, i.e., Liverworts, Hornworts, and moss are
considered to be ancestors to blue green algae.  We note that they are
nonvascular plants which mean they live in moist, shady areas.  In the
reproductive stage, we are told that gemetophytes are produced which produce
sporophytes.  From the sporophytes, we note a spore is formed.  When things
get a little better, the spores turn into gametophytes.

My question:  In the early stages of plante groups, was there a lack of
oxygen more than now.  Has the time of the planet earth's existence
permitted the 20% oxygen to exist???

bill poulin NEC95ISA09 at MECN.MASS.EDU



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