BIO153H5 Lecture Notes - Lecture 7: Red Algae, Archaea, Amoebiasis
Document Summary
Rhizarians (diverse assemblage: radiolarians, foraminiferans, cercozoans. Uniknots: amoebozoans (slime molds and cellular slime molds) One of the most important stories in the diversification of protists was the evolution of novel methods for finding food. Protists feed by one of three methods: ingesting packets of food, absorbing organic molecules directly from the environment; or, performing photosynthesis. Ingestion process is possible in protists that lack a cell wall. Many protists are large enough to surround and ingest bacteria and archaea; some protists are large enough to ingest other protists or microscopic animals. A flexible membrane and dynamic cytoskeleton give these species the ability to surround and swallow prey with long, fingerlike projections called pseudopodia some protists also feed by sweeping food particles into their mouth with cilia. Absorptive feeding occurs when nutrients are taken up directly from the environment, across the plasma membrane. Some protists that live by absorptive feeding are decomposers, feeding on dead organic matter, or detritus.
