Chapter 28 sum - The Protists Protists(derived from the Greek word protos meaning"first the first eukaryotes to evolve and ancestors to all the

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1 The Protists Protists (derived from the Greek word protos, meaning "first")- the first eukaryotes to evolve and ancestors to all the other eukaryotes: fungi, plants, and animals. Protists are thought to have evolved by endosymbiosis. Explain the endosymbiotic theory. I. Characteristics Protists are so diverse that it is difficult to list general characteristics. For almost every characteristic there is an exception. Following is a "list" of characteristics that are most inclusive. A. morphology - Protists are predominantly unicellular though there are some colonial and some multicellular forms. colony - loose association of cells; may be semi-dependent, but each can take care of its own physiological needs Multicellular forms for the most part lack tissue differentiation. Note: protists are the most complex cells known B. feeding and nutrition Protists are metabolically diverse - the most nutritionally diverse of all eukaryotes. Most are aerobic. Where would cellular respiration take place in these protists? Some are photoautotrophs , some heterotrophs , and some are mixotrophs (combining photosynthesis and heterotrophic nutrition). Give an example of a protist that is a mixotroph. Euglena
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2 Protists are divided into three categories based on nutritional diversity: 1. protozoa (protozoan) : animal-like protists with ingestion as the mode of nutrition. Trypanosoma 2. algae (alga) : plant-like protists with photosynthesis as the mode of nutrition 3. fungal-like protists with absorption as the mode of nutrition C. movement Most protists are motile having cilia or flagella at some time in their life cycles. Describe the difference between prokaryotic and eukaryotic flagella. How do flagella and cilia differ? Some protists move by means other than cilia and flagella. Describe other type(s) of locomotion. D. reproduction Asexual reproduction is the most common (means of rapidly increasing population size); occurs by mitosis in most protists or by fragmentation (often observed in parasitic life cycles). Sexual reproduction is less common and has not been observed in many protists. Life cycles All three basic life cycle patterns found in eukaryotes are represented in protists. a. zygotic - most of life cycle is haploid; zygote only diploid stage Found in simpler algae, some protozoa, most fungi.
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3 b. gametic - most of life cycle is diploid; gamete only haploid stage Found in some protists and all animals. c.
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This note was uploaded on 11/29/2010 for the course BUSSINESS 221242 taught by Professor Michaeldouglas during the Spring '10 term at Georgia Perimeter.

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Chapter 28 sum - The Protists Protists(derived from the Greek word protos meaning"first the first eukaryotes to evolve and ancestors to all the

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