Lecture 10 30 2014 Choanoflagellates Remember Zooplankton are floating animals but they are protists Characterized as zooplankton Strictly marine Unicellular colonial organisms Heterotrophs rely on organic carbon that they take in Feed on protists phytoplankton and prokaryotes Oomycetes water mold lack chitin so not fungi Common in aquatic wet soil Heterotrophs osmotrophy release enzymes into environment when they encounter organic matter food enzymes then break down organic matter external digestion Products of digestion absorbed by water molecules Forage on crops Ex Phytophthora infestans Caused great Irish potato famine Fed on potato plants which destroyed the main crop of Ireland 1 million deaths and 1 2 million people left Ireland Protisits are organized by their structure and function Attached Protists Attached to some substrate rocks soil sand etc Often critical components of food webs provide food habitat structure 1 Ex Green Algae chlorophyta Multicellular subdivision of labor among cells Autotrophs Found in freshwater chara and marine systems Ulva or sea lettuce 2 Brown Algae Stramenopila 99 are marine multicellular and autotrophs Often dominant organism in ecosystems Have gas bladders act as buoys holding up kelp in H2O column Holdfast the anchors that keep kelp in place NOT roots Period of Kelp Forests disappearing sea urchins love to eat kelp and sea otters love to eat sea urchins sea otters were killed off and urchins were able to multiply and destroy large portions of kelp forests Sea otters keystone species when you pull species out everything collapses Kelp forests increased bio diversity Shark dolphins whales etc can all live in kelp forests Healthy kelp forests increase food structure 3 Red Algae Rhodophyta Red pigments allow them to live at deeper ocean depths than other algae Autotrophs still need light Red pigments allow them to use the few light wavelengths hitting these depths Found in deep water coral reefs provide food structure Used in sushi nori seaweed Agar used as growth medium for microbes Carrageenan food additive used to gel solidify foods Plasmodial Slime Molds Terrestrial found on forest environment grasslands Heterotrophs osmotrophs Huge unicellular organism also multinucleate Feed on decaying organic matter plants animals anything really fungi Shares a common cytoplasm which makes it efficient in moving inner material Mobile Reproduce through sporangia loaded with spores then pops and spores are spread by wind to a new location very long lived Once condition temperature moisture food source is right They move like amoeboid towards food source Once they get there the whole organism begins to grow through energy nutrients carbon nitrogen phosphorous taken in through osmotrophy and whatever they dissolve on one side goes to the other Because they are so efficient at finding and moving organic matter they are used in research on logistics transportation Ex Shinkansen train system Simulate Japan s topography and use food as stops on train route Then the slime mold was put into the simulated Japan and they observed how it moved The slime mold showed them the most effective routes look like vein structures Video for this experiment can be viewed here https www youtube com watch v BZUQQmcR5 g
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