Protists Dinoflagellates can be phytoplankton floating have two flagellae one for locomotion long one for feeding create water currents that draw prey to them mixotrophs floating and symbiotic zooxanthellae in coral live on or in coral many produce toxins fish kills Pfeisteria defense against predators and competitors red tides bloom when conditions are right temp food etc toxic bioluminescence Choanoflagellates predators feed on other protists phytoplankton and prokaryotes heterotrophic external organic carbon sources free living flagellum locomotion feeding Phytophthora infestans water molds oomycetes heterotrophs osmotrophs release enzymes into environment break down organic matter outside of orgs external digestion products of digestion are absorbed across cell membrane freshwater marine wet soil habitats Great Irish Potato Famine Algae floating phytoplankton green algae attached to some surface green red brown algae often critical component of food webs where they are found Green algae Chlorophyta and Charophyta attached forms are multicellular autotrophs Chara substrate habitat structure for many orgs freshwater Ulva marine Brown algae stramenopila seaweed marine and autotrophic dominant org food source and structure holdfast anchor attached NOT nutrient transport gas bladder provide buoyancy blade front where photosynthesis occurs some types always submerged nearshore some are sometimes dewatered intertidal forms both types provide much structure and food Kelp forest very much organismal diversity structure food source polar temperate oceans sea urchins consume massive quantities of kelp kelp disappeared sea otters love sea urchins disappeared due to overhunting keystone species if you remove them the whole food web collapses Red algae Rhodophyta red pigment harvests light energy at deeper depths can grow here with less competition for space deep coral reefs food structure nori used in sushi carageenan food additive agar plates Plasmodial Slime Mold terrestrial protist heterotrophic feed on fungi decaying organic matter huge unicellular multinucleate highly mobile sporangia reproductive structure of PSM each is loaded with thousands of spores launched when sporangium explodes spores spread by wind long lived once they sense food spore moves to food feeds as an osmotroph study of train logistics around Tokyo each piece of oatmeal represented a city slime mold represents Tokyo Cellular Slime Molds mobile terrestrial heterotrophs unicellular multinucleate osmotrophs release enzymes into environment break down matter into products of digestion that can be taken up more easily by the org dead organic matter model organism very well studied evolution of multicellularity sociality spores amoeboid spores aggregate some spores act as a base slug stage sporangiophore produces spores Amoeboid Protists Rhizopoda amoebas aquatic heterotrophs highly mobile using pseudopodia to move false feet can form anywhere on cell phagocytosis using pseudopodia to encase prey flood vacuole around prey with enzymes used to digest food products of digestion move into cytoplasm Actinopodia amoeboid protist Radiolarian marine heterotrophs amoeboid cell is encased in a calcium based shell secreted by the protist feed on bacteria fossil radiolarian shells are used to look at past ocean trends diff species have diff tolerances to T salinity nutrient conditions similar to diatoms Foraminifera amoeboid protist amoeboid body secrete a calcium carbonate shell feed on organisms that pass into shell heterotrophs fossils used for climate reconstruction Alveolata Ciliates common in all aquatic systems recently evolved separate physiological processes associated with individual organelles anterior posterior contractile vacuole excretion water ion balance macro micronucleus diff nuclei are associated with either reproduction or cell homeostasis cilia used for locomotion and feeding heterotrophs some have symbiotic cyanobacteria Health Related Protists Diplomonads Giardia cause giardiasis primarily aquatic untreated water fecal contamination etc line intestine block uptake of water and nutrients Parabasilids Trichomonas vaginitis reproductive tract infections Euglenozoa Euglena Trypanosoma autotrophic aquatic protist loaded with chloroplasts some heterotrophs many cause disease use flagellum for locomotion African sleeping sickness tsetse fly vector that pass parasites thru bites and feces treated by a 4 drug cocktail that is free to the world American trypanosomiasis Chagas disease more common in N A vector kissing bugs passed by saliva feces Plasmodium 5 species Malaria vector Anopheles mosquitos transfer parasites via saliva death occurs within 5 days if untreated about 250 million cases per year 1 1 5 million deaths Plants If plants had not colonized land most animals would have remained in the water Know flow chart for evolutionary organization of plants About 1 5 bya oldest definite fossils of eukaryotes were protists likely related to green algae Land plants originated about 500 mya What is a plant How do they gain carbon and energy autotrophs most relying on photosynthesis for carbon and energy photoautotroph sunlight Green chloroplasts to harvest sunlight for photosynthesis Carnivorous plants venus fly traps sundews pitcher plants True heterotrophs parasitic heterotrophs also capable of autotrophy mixotrophs living off of organic matter produced by living organisms beech drops plants that parasitize beech roots Complex life cycle alternation of generations all plants and some protists diploid haploid generations based upon chromosome number HUMANS 46 chromosomes diploid number diploid 2n n mom egg n dad sperm each parent provides a haploid number of chromosomes thru gametes gametes sex cells egg sperm haploid n 23 in humans in animals these stages cannot exist separately PLANTS independent haploid and diploid life stages diploid sporophyte haploid gametophyte all plants possess cell walls over evolutionary time become more rigid stable provides structure cellulose lignin multi cellular eukaryotic membrane bound nuclei and organelles chloroplasts mitochondria Land Water green algae Charophyta Chara likely origin of land plants genome level analysis finds them to be much closer to land plants Chlorophyta likely driven by competition for space and nutrients Challenges faced when moving from water land water free floating land gravity no need for structure in water ability to gain height in face of gravity
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