BIOL101 Midterm: Bio 101 Midterm #2
Document Summary
Chemoheterotrophs absorb organic molecules or ingest larger food particles. Symbiont: an organism living in harmony (symbiosis) with another. Protist- the informal name for the group of mostly unicellular euks. Eukaryotic cells have organelles and are more complex than proks. They are found as unicellular organisms, and colonial and multicellular species. They are found in diverse aquatic environments such as: damp soil, leaf litter, oceans, ponds, and lakes (bottom dwellers) And protists often play the role of symbiont or producers. Some protist symbionts benefit their hosts such as dinoflagellates nourish coral polyps that build reefs and wood-digesting protists digest cellulose in the guts of termites. Some protists are parasitic such as plasmodium which causes malaria; Pfiesteria shumwayae is a dinoflagellate that causes fish kills. In aquatic environments, photosynthetic protists and prokaryotes are the main producers. They are limited by nutrients and sometimes populations can explode when limiting nutrients are added. Protists form the base of the ecological food web.
