Protists

Some Basics: 200 000 species difficult to classify no “typical” protist most aquatic, some terrestrial only characteristic that all protists share is that they are not animals, plants or fungi most single-celled

Some Characteristics of single-celled protists: 1) eukaryotes – membranes around their organelles (nucleus), > 2m 2)   unicellular – one celled 3)   reproduce asexually by binary fission 4)   must live in moist surroundings

Method of Reproduction Phylum (Group) - energy source Species Name Sketch Method of Movement Method of Reproduction Mastigophoria   (euglenoids) - autotrophs - photosynthetic Euglena gracillis   flagellum Binary fission Sarcondina   (amoebas) - heterotrophs Amoeba proteus   pseudopods Binary fission Ciliata   (ciliates) - heterotrophs Paramecium caudatum   Stentor coeruleus   cilia Binary fission (asexual)   Conjugation (sexual)

Life Cycles Single-celled protists        reproduce asexually (binary fission) and sexually (conjugation)   Multi-cellular protists        more complex        may involve the formation of sex cells (haploid sperm and egg), when sex cells fuse, diploid zygote is formed        some alternate between a diploid and haploid stage (alternation of generations) Examples: Brown algae (Fig. 13 page 65) Plasmodium – malaria protist (Fig. 14 page 66)

Metabolism PROTISTS Heterotrophic Autotrophic Animal-like Fungus-like Plant-like - can be parasitic/pathogenic - parasites * sleeping sickness * malaria Examples: - Amoeba - Sporozoans - ciliates like Paramecium - most are decomposers - prefer cool, damp habitats Examples: - Molds (water, slime) - single-celled (vs. multicellular fungi kingdom) - contains chlorophyll - photosynthesize Examples: - Euglena – unicellular, flagellates, heterotrophic at night - Algae – single-celled, colonies, multicellular (Note: responsible for 50-75% of all photosynthesis on Earth)