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Introduction to Eukaryotes. http:// www.ucmp.berkeley.edu/alllife/eukaryota.gif. Evolution of Eukaryotes: ENDOSYMBIOTIC THEORY. proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. Origin of mitochondria & chloroplasts internal parasite
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Introduction to Eukaryotes http://www.ucmp.berkeley.edu/alllife/eukaryota.gif
Evolution of Eukaryotes:ENDOSYMBIOTIC THEORY proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms • Origin of mitochondria & chloroplasts • internal parasite • ingested but not digested • Benefits: source of molecules for biochemical activities (e.g., ATP, organic molecules) • Evidence/support • Mode of reproduction: splitting • W/ own circular DNA & ribosomes • Surrounding membranes: inner, outer • Modern-day symbiosis: Cyanophoraparadoxa Lynn MargulisBoston University, 1960 http://www.isepp.org/Media/Speaker%20Images/04-05%20SJ%20Images/MargulisCheadR.jpg, http://www.biol.tsukuba.ac.jp/~inouye/ino/gl/Cyanophora2.GIF, http://www.univie.ac.at/ibmz/groups/loeffelIm/cyafig1.jpg
Classification of Protists:ACCORDING TO MODE OF NUTRITION Artificial classification! Because of their diversity, biologists cannot agree on how to best classify the protists; best approach for now is the traditional single kingdom
Kingdom Protista:EVOLUTIONARY SIGNIFICANCE • Protists occupy a pivotal position in the history of life • The first ones arose from prokaryotes, and their descendants gave rise to all plants, fungi, and animals, as well as modern protists.