Bio1b Summer 2008 Plants Lecture 2 Eric Harris Page 1 of 2 Updated on 07/20/08 PLANTS LECTURE 2: ALGAE & BRYOPHYTES Reading: 7th ed., 523–524, 553–562, 567–583; 8th ed., 516–517, 580–589, 590–592, 600–610. A. Algae i) The origins of the chloroplast: endosymbiosis ii) Like the “protists,” the traditional group of algae is a polyphyletic assemblage of evolutionarily disparate things, including both unicellular (plankton) and multicellular (seaweed) organisms. Main groups: Unicellular 1 - Bluegreen algae – cyanobacteria (a prokaryote!) 2 - Dinoflagellates – responsible for toxic red tides 3 - Euglenoids – flagellated single celled organisms 4 – Diatoms – important component of freshwater and marine plankton 5 – Golden algae – carotenoid pigments; some colonial species Multicellular 6 - Brown algae – e.g., kelp 7 - Red algae – why is red algae red? proximate (phycoerythrin pigments) and ultimate (evolution in deep sea) explanation 8 - Green algae – e.g., Ulva. Introduction to the Alternation of Generations life cycle (isomorphic alternation of generations) iii) Economic importance of AlgaeBio1b Summer 2008 Plants Lecture 2 Eric Harris Page 2 of 2 Updated on 07/20/08 B. Bryophytes i) Move onto land ~ 430 million years ago (recall: Paleozoic era) ii) Challenges of living on land: dessication, increased UV irradiation & sunlight, gravity/wind iii) Mechanisms for coping to living on land: protection, internal transport, support iv) The first land plants = complex algae. v) The Bryophytes include: mosses, liverworts, hornworts. These are contemporary land plants that probably are the most similar to the first land plants. vi) Bryophyte life cycle – main plant body is haploid gametophyte, water is required for flagellated sperm cells to swim to the archegonium (7th ed. p. 581, 8th ed. p. 607) vii) Economic importance of
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