1	PROTISTA Small eukaryotic organisms. A collection of eukaryotes that are NOT animals, plants or fungi. Most live in water.
2	Reading Assignment Reading Assignment is Chapter 28 up to section 28.4. Box 28.1 emphasizes how little molecular diversity there is among plants, animals and fungi compared to that within protists. Mating types are defined on page 680 and in the glossary. Pages 104-05 cover electron microscopes.
3	PROTISTA Includes some algae, e. g., kelp, that grow to huge size as well as many species that are small. Includes both free-living and parasitic forms. Most are only found in water, i.e., aquatic.
4	PROTISTA DIVERSITY Protista do not have the metabolic diversity of Archaea and bacteria, but they do have: Great structural diversity, Highly complex life cycles, Alternate metabolic pathways, including some with a different genetic code.
5	Diseases caused by Protists Super Phylum Genus Disease Alveolata Plasmodium Malaria Discicristata Trypanosoma Sleeping sickness
6	MALARIA One of most important human diseases. Complex life cycle, two hosts. Mosquito is the “vector” that transmits the Plasmodium to humans. Different stages live in liver and red blood cells. Fertilization in Plasmodium takes place in Anopheles mosquito. Alternate forms of hemoglobin can protect against malaria.
7	Uses of protozoa (non-green protista) Ciliates are major eaters of bacteria. Wastewater treatment oxidizes organic matter into CO₂. The process involves aerobic growth of a lot of bacteria and consumption of the bacteria by ciliates and other protista. Clarity of the water improves as the smaller cells are converted into larger cells.
8	Classification of Protista Studies with the light microscope can only resolve structures larger than 0.5 um. Electron microscopes resolve structures much smaller and have lead to discoveries of similarities that were not seen using light. Phylogenies are most unambiguously determined using molecular data.
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11	Electron Microscopy
12	Protista is a Paraphyletic Group Eukarya are divided into 17 groups on the basis of SSU RNA sequences (Fig 28.7). Most protista groups have relatively few species. Because the collection labeled Protista does not include ALL the branches of a node (place where branches meet) Protista is called paraphyletic (biologists prefer monophyletic groups and Protista as a name is unlikely to persist as a name).
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14	Mitochondria & Chloroplasts Mitochondria are present in all eukaryotic cells. They are the ‘powerhouse’ of cells –the place where ATP is generated by transfer of electrons to oxygen. Chloroplasts are present in plant cells. They also generate ATP by electron transport. Mitochondria and Chloroplasts are the only organelles with their own DNA. Both make their own ribosomes.
15	Origin of mitochondria and chloroplasts by endosymbiosis The endosymbiosis theory suggests these organelles arose by capture of bacteria by eukaryotes. Similar size and similar ribosomes Double membrane which suggests membranes from engulfer and engulfee remain present. Both organelles have own DNA Alternative: The organelles arose by selection on nuclear genome of eukaryotes.
16	Multicellular organisms have specialized cells.
17	Ciliates Paramecium Tetrahymena Stentor The fish disease, “ich”, is caused by a ciliate.
18	Stentor
19	Different species concepts Traditionally, species have been defined by morphological characteristics. Higher taxonomy needs to be organized by molecular phylogeny. (see slide 13) Individuals that mate are clearly members of the same species. The biological species concept arose when it was discovered that individuals with similar morphology could often be divided into more than one reproductively isolated groups as revealed by mating.
20	Identifying Biological Species
21	A pair of Tetrahymena cells mating
22	Biological species & Mating types Cells can often be divided into 2 (or more) reproductively isolated groups according to mating patterns. If there are no morphological differences between the cells that mate, the types are called mating types, often designated by roman numerals. The terms male and female are reserved for cases with only 2 types and morphological differences between the two types.
23	Problem Mating types within a biological species define who mates with whom. A type can mating with every other type (and not with other cells of the same type). Five lines of a species have the mating types shown by roman numerals; A = I, B = II, C= I, D = III, & E = III. Draw the results expected if you made mixes of all possible pairs of lines.
24	Vocabulary Paraphyletic Aquatic Biological species Mating Mating type Endosymbiosis Vector Malaria