protozoanotes

protozoanotes - Kingdom Protoctista: Protozoa Biological...

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Kingdom Protoctista: Protozoa 1 Biological Sciences 102 – Animal Biology – Notes & Vocabulary ¾ Kingdom Protoctista versus Kingdom Protista General classification has seen marked changes since the mid-70s to the present. The term protista is still used in many schemes for classification. Protozoa was once considered a single phylum in the Kingdom Protista. Now considered to consist of at least 29 to 45 phyla within what used to be 3 different kingdoms (now the Kingdom Protoctista by some authors). Many taxonomists consider it best to group the different groups as different phyla. Margulis and Schwartz promote the term protoctista because protista denotes only organisms which are unicellular. The protoctista scheme contains many multi-cellular organisms with tissue specialization. The protista system places several of the protoctistan phyla into the plant and fungi kingdoms. According to the system used for classification by Lynn Margulis and Karlene Schwartz, members of the protoctista are identified primarily by exclusion from all the other kingdoms. Animals develop from a blastula. Plants develop from an embryo. Fungi develop from spores, and lack flagella and cilia Monerans (prokaryotes) lack a membrane bound nucleus. All remaining organisms are placed into the kingdom protoctista. They are aquatic, living in saltwater, freshwater, and of the watery tissues of other organisms. There are many protozoan parasites of both invertebrates and vertebrates. Depending on the source the Kingdom Protoctista is now considered to consist of at least 29 to 45 phyla within what used to be 3 different kingdoms. ¾ General Characteristics of Protoctistans 1. unicellular eukaryotes (some multinucleate, a few loosely multicellular), not all have mitochondria (microspores, many flagellates). 2. up to about 400 micrometer in size (some larger) 3. all have at least one nucleus 4. most are free living, but many parasitic forms including entire phyla 5. motile by a variety of mechanisms but also several non-motile taxa 6. Many have cyst stages secreted by trophic or spore stages Cysts/spores have four basic functions: protect against unfavorable conditions serve as sites for multiplication assist in attachment to surfaces such as hosts transmission stage from host to host 7. all types of nutrition are exhibited by the Kingdom. autotrophs : photosynthesis heterotrophs (holozoic vs. saprozoic) phagocytosis : ingestion of solid particles (e.g., bacteria) pinocytosis : same as phagocytosis but intake of liquid saprozoic or saprotrophy: diffusion or active transport across membrane
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Kingdom Protoctista: Protozoa 2 Biological Sciences 102 – Animal Biology – Notes & Vocabulary ¾ Characteristics of Protozoa The protozoa are a diverse assemblage of unicellular eukaryotic organisms in the Kingdom Protoctista having at least two animal-like properties: (1) absence of a cell wall and (2) presence of at least one motile stage in the life cycle. All functions of life are performed within the limits
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protozoanotes - Kingdom Protoctista: Protozoa Biological...

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