03_Protists - PROTISTS Reading Chapter 25 pp 516-517 Chapter 28 Groups we will NOT mention in lecture and that will NOT be on the final lecture

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PROTISTS Reading: Chapter 25, pp. 516-517; Chapter 28 Groups we will NOT mention in lecture, and that will NOT be on the final lecture exam: parabasalids (p. 580), euglenozoans (pp. 580-581), ciliates (pp. 584-585), golden algae (p. 586), rhizarians (pp. 589-590), red algae (pp. 590-591), and unikonts (pp. 593-596). A. WHAT ARE PROTISTS? 1. If it isn’t anything else, it’s a protist. Fig. 28.3 The phylogenetic tree of eukaryotes, with members of the former Kingdom Protista in yellow. According to this phylogeny, what are our nearest non-animal relations? Are land plants more closely related to brown algae or to dinoflagellates? Which of the lineages do you know to contain multicellular representatives? Do you think multicellularity is a homologous or an analogous trait among eukaryotes?
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Protists - 2 2. Most unicellular eukaryotes are protists, and most protists are unicellular. 3. There are several modes of nutrition among protists. § photosynthesis § ingestive heterotrophy § absorptive heterotrophy § mixotrophy 4. Most motility (if present) is by flagella, cilia, or amoeboid movement. 5. Most sexual life cycles are of the three major life cycle types. 6. Protists can reproduce asexually.
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Protists - 3 B. EUKARYOTIC ORIGINS 1. When? DIGRESSION: WHAT IS A SPORE? 1. A spore is neither a gamete nor a seed. § A spore is usually one cell, in contrast to a seed, which has many cells. § A spore does not contain an embryo, in contrast to a seed, which contains an embryo. § A spore contains almost no stored food reserves and must acquire nutrients as soon as it germinates, in contrast to a seed, which can live for awhile on its stored food after germinating. § A spore is developmentally self-sufficient; under good growing conditions, it can develop into a nutrient-acquiring vegetative cell or multicellular body. This contrasts with a gamete, which must find another gamete to fuse with if it is to develop any further. 2. A spore’s functions
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Protists - 4 2. Processes in the evolution of eukaryotes from prokaryotes § loss of the cell wall § infolding of the plasma membrane and elaboration of internal membrane structure § development of cytoskeleton § endosymbiosis of bacteria 3. Evidence for endosymbiosis a) plastids and mitochondria are approximately the same size as bacteria b) plastids and mitochondria have their own genes and gene expression systems c) plastids and mitochondria are surrounded by two (or more) membranes d) plastids and mitochondria have many molecular features in common with bacteria
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Protists - 5 e) there are living examples of more recent and less complete endosymbioses 4. Endosymbiosis can be primary, secondary or tertiary.
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This note was uploaded on 01/15/2011 for the course BIO General Bi taught by Professor Dr.gregorybeaulieu during the Fall '09 term at University of Victoria.

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03_Protists - PROTISTS Reading Chapter 25 pp 516-517 Chapter 28 Groups we will NOT mention in lecture and that will NOT be on the final lecture

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