Kingdom Protista

Heterotrophs with flagella or cilia -
Phylum Sarcomastigophora - Zoomastigotes
Unicellular, heterotrophic, highly variable in form
Possess one to thousands of flagella
Some free-living, some parasitic
Some reproduce asexually only
One group alternates between amoeboid and
flagellated stages
Some trypanosomes are human pathogens
cause sleeping sickness, East Coast fever,
Chagas' disease
many spread by insects, such as tsetse flies
Some inhabit guts of wood-eating insects
have enzymes capable of digesting cellulose
Choanoflagellates are similar to feeding cells of
sponges and are likely ancestors of all animals