Lecture 10 28 2014 Review Ch 29 Protists A very diverse group Transduction horizontal gene transfer is associated with both the lytic and lysogenic cycle 2 billion year span between prokaryotes and eukaryotes first eukaryote found 1 5 billion years ago and prokaryotes are 2 billion years older 1st Eukaryote resembled green algae and had clear nuclear membranes enclosing the DNA Called the catch all group because if something has the characteristics of a plant but it s not a plant and an animal but it s not an animal then they throw it in with the protists Bizarre funky bunch phylogenetically have multiple independent lineages not clearly related to each other No characteristic UNIQUE to all protists Protist evolution contains critical evolutionary transitions 1 Prokaryotic Eukaryotic 2 Asexual binary fission Sexual allows for more diversification 3 Unicellular Multicellular allows for different roles among cells Theory of Endosymbiosis Prokaryotes Eukaryotes starts with membrane bound nucleus Based upon organisms living together in close association symbiosis This likely started with prokaryotes having other prokaryotes living in their cells mutualism then this relationship evolved into eukaryotic organisms Who are the Protists Aquatic Autotrophic Protists Amoeba ciliates paramecium diatoms euglena plasmodium malaria 1 killer in the world trypanosomes African sleeping sickness and chagas slime molds stentors kelp seaweed Very important to food webs make most of the oxygen in the world Phytoplankton phyto plants and plankton floating BUT they re not plants Found in all freshwater marine systems dominant organism in these systems Rely on photosynthesis CO2 H2O Light O2 most important Organic Carbon food Produce 80 85 of Earth s O2 Bloom Lots of phytoplankton River off coast of Argentina mostly diatom bloom nitrogen and phosphorus from river mouth make green bloom Dominated by green algae diatoms also include cyanobacteria but they aren t protists Figure 1 Gyory J Mariano A J and Ryan E H The Malvinas Current Ocean Surface Currents National Oceanographic Partnership Program Accessed October 30 2012 November 2 2014 http earthobservatory nasa gov NaturalHazards view php id 79567 Diatoms Largest most abundant group of phytoplankton Include floating forms and attached forms attached forms are not phytoplankton Floating form are not actively moving drifting passively with currents Can be single organism or colonial stacks of interacting cells Structure Living protest sandwiched between 2 shells frustules diatom secretes these shells made of a silica calcium matrix think of it like a petri dish with an organism living inside Diatoms are important to everyday life 1 Diatomaceous Earth mined used for toothpaste kitty litter pool filters 2 Used in paleontology based on the species of diatoms present in sediments geological 3 strata Indicate specific environment conditions due to differing species specific tolerances related to salinity acidity temperature They are truly found everywhere Green Algae chlorophyta Primarily unicellular colonial forms filamentous forms Strictly autotrophic phytoplankton floating forms and attached forms You can find these everywhere too Krill and Daphnia ingest diatoms green algae Phytoplanton Zooplankton Phytoplankton CRITICAL TO FOOD WEBS Marine Krill Anchovies Invertebrates Freshwater Daphnia Bluegill Invertebrates Predators Whales Basking Sharks Dinoflagellates can be phytoplankton Symbiotes with coral Zooxanthellae are the dinoflagellates that live in coral Defined based upon having 2 flagellae locomotion movement and foraging Primarily mixotrophs use both autotrophy and heterotrophy promoted by flagellum Extreme examples Pfeisteria massive fish death highly toxic dinoflagellate Blooms kill vertebrates and invertebrates Red tide typically toxic Bioluminescent
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