Thursday, April 21, 2011

Blog #11

http://www.learner.org/courses/essential/life/images/show4.alternation.jpg
Alternation of generations  is a term primarily used in describing the life cycle of plants A mature sporophyte produces spores by meiosis, a process which results in a reduction of the number of chromosomes by a half. Spores germinate and grow into a gametophyte. At maturity, the gametophyte produces gametes by mitosis. Two gametes (originating from different organisms of the same species or from the same organism) fuse to produce a zygote, which develops into a diploid sporophyte. This cycle, from sporophyte to sporophyte (or equally from gametophyte to gametophyte), is the way in which all land plants and many algae undergo sexual reproduction.

http://www.bio.miami.edu/dana/pix/fern_altgen.jpg

http://www.world-builders.org/lessons/less/les8/les8gifs/altgen.gif

http://schools-wikipedia.org/images/294/29410.png

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