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Origin of Eukaryotic Diversity. AP Biology Crosby High School. Protist Diversity. Nutrition Aerobic with mitochondria Photoautotrophs Heterotrophs Mixotrophs Ecological Ingestive (Protozoa) Absorptive Photosynthetic (Algae). Motility and Life Cycles. Motility Flagella and Cillia
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Origin of Eukaryotic Diversity AP Biology Crosby High School
Protist Diversity • Nutrition • Aerobic with mitochondria • Photoautotrophs • Heterotrophs • Mixotrophs • Ecological • Ingestive (Protozoa) • Absorptive • Photosynthetic (Algae)
Motility and Life Cycles • Motility • Flagella and Cillia • 9 + 2 arrangement of microtubules • Life Cycles • All three life cycles • Haploid is main vegetative stage • Many form Cysts: resistant cells that survive harsh conditions
Habitats • Most Protists are Marine • The make a large portion of Plankton • Phytoplankton are the basis of most marine food webs
Eukaryotic Origins • Multicellular prokaryotes • Complex communities of prokaryotes • Compartmentalization • Infolding • Endosymbiosis
Mitochondria and Chloroplasts • Theory of Serial Endosymbiosis • Mitochondria: aerobic Heterotrophic bacteria • Chloroplasts: Photosynthetic bacteria • Both engulfed and became mutualistic • Heterotrophic host could have used photosynthetic symbionts • Anaerobe could have used aerobic endosymbionts • Mitochondria most likely first
Serial Endosymbiosis Support • Size • Enzymes and transport systems • Replication • Ribosomes
Eukaryotic Chimera • Ancestors • Mitochondria: α Proteobacteria • Plastid: Cyanobacteria • Compared the SSU-rRNA • Gene Transfer to Nucleus • Transformation resulted in nuclear DNA containing codes for part of mit. production
Secondary Endosymbiosis • Eu. Engulfs pro. Creating plastid • Eu. Enfulfs plastid containing eu. • Most parts of Primary symbiont dissappear • Cryptomonad algae contain nucleomorph • Traces of cytoplasm with different population of ribosomes • Probably happened in different stages with mitochondria and plastids
Diplomonadida and Parabasala • Diplomonads • Contains: Multiple flagella, simple cytoskeleton, no plastid or mit. • Giardia lamblia: causes sever diarrhea • Parabasalids • No mit. • Uses flagella and undulating membrane • Trichomonas vaginalis: infects vagina and urethra
Euglenozoa • Euglenoids (Euglenophyta) • Anterior pocket w/ one or two flagella • Paramylon • autotrophs • Kinetoplastids • Single large mit. Associated w/ kinetoplast • Some pathogenic • Trypanosoma: african sleeping sickness caused by tsetse fly • Escape artist
Alveolata • Unicellular protists w/ subsurface cavities • Dinoflagellates • Some colonial • Each char. Shape reinforced by internal cellulose plates • 2 flagella create spinning motion • Red tides (Xanthophylls) • Pfiesteria piscicida • Stuns fish and feeds off of them
Apicomplexa • Animal parasites • Infect through sporozoites • Plasmodium requires multiple hosts for life cycle • Causes malaria • Mostly found in liver and blood • Changes “face”
Ciliophora • Cilia groupings allow for env. Adaptation • Contain Macronucleus and several micronuclei • Macro has 50 copies of genome • Everyday functions and asexual reproduction • Paramecium has 180 micro • Sexual shuffling during conjugation • Meiosis and Syngamy separated from Reproduction
Stramenopila • Oomycota (“Egg Fungi”) • Water molds, white rusts, downy mildews • Reproduction • Grow on dead aquatic animals • Heterokont Algae • Hairy and Nonhairy flagella • Secondary Endosymbiosis of Red Algae
Types of Heterokont • Bacillariophyta (Diatoms) • Unique glasslike walls of Silica • Store food in Laminarin • Two fitted pieces of the cell wall • Chrysophyta (Golden Algae) • Color from Carotene and Xanthophyll • Phaeophyta (Brown Algae) • Largest and most complex • Seaweeds are mostly brown algae
Structural and Biochemical Adaptations • Thallus • Holdfast (“root”) • Stipe (“stem”) • Blades (“leaf”) • Biochemical Adaptations • Cell Wall: cellulose and gel-forming polysaccharide to cushion from tides • Uses • Laminaria: Soup “Kombu” • Porphyra: Sushi Wraps “Nori”
Alternation of Generations • Sporophyte: Produce diploid spores • Gametophyte: Produce haploid gametes • Heteromorphic: Different forms • Isomorphic: Same form
Other Algaes • Rhodophyta • Red Algae lack flagella • Different colors based on depth • Chlorophyta • Chlamydomonas: biflagellated unicellular • Large size and complexity evolved • Formation of colonies of individual cells • Repeated division of nuclei w/o cytoplasmic • Formation of multicellular by cell division and differentiation
Pseudopodia Protists • Rhizopoda (Amoebas) • Moves and feeds with pseudopodia • Extend pseudopod which anchors and allows cytoplasm to ooze into it • Actinopoda (Heliozoans and Radiolarians) • “Ray Foot” • Settle and accumulate as ooze at seafloor • Foraminifera (Forams): porous shells
Mycetozoa • “Fungus Animal” • Myxogastrida (Plasmodium Slime Molds) • Feeding stage is Plasmodium • Unicellular several cm in diameter • “Supercell results from nuclear division w/o cytokinesis • Dry habitat or scarce food and it becomes reproductive • Dictyostelida (Cellular Slime Molds)
