protozoans
Microscopic one-celled organisms
Protozoans are single-celled organisms that were traditionally classified as the simplest animals.
The term covers a vast range of microscopic life—amoebas, paramecia, and the parasites that cause malaria and dysentery.
Modern biology has largely abandoned protozoa as a formal category, recognizing these organisms as only distantly related, but the word persists in casual and medical contexts: The water tested positive for protozoans.
Shape-shifting single-celled organism
- parameciumCiliated slipper-shaped protozoan
- euglenaPlant-animal hybrid microbe
- giardiaWaterborne intestinal parasite
- plasmodiumMultinucleate protoplasmic mass
vorticella · entamoeba · toxoplasma · cryptosporidium · babesia
Drifting marine microlife
- zooplanktonDrifting aquatic microorganisms
- microfaunaMinute soil animals
- freshwaterNon-saline aquatic environment
- marineRelating to the sea
sediment · biofilm · symbiosis · decomposers · food chain · benthos · pond water · soil
Hairlike cellular projections
- flagellaWhiplike locomotion appendages
- cytoplasmGel surrounding the nucleus
- nucleusCentral controlling part
- vacuoleCell's storage compartment
pellicle · contractile · phagocytosis · binary fission · conjugation · cyst · organelles · mitochondria
Mosquito-borne parasitic infection
- dysenteryBloody intestinal infection
- toxoplasmosisParasitic infection from cats
- giardiasisProtozoan intestinal infection
- leishmaniasisSandfly-transmitted parasitic disease
trichomoniasis · pathogen · parasite · infection · vector · host · transmission · waterborne
Whips harshly, often ritually
- apicomplexaParasitic protozoan phylum
- excavatesDigs out from ground
Mineralized organic remains
- microfossilsMinute preserved organism remains
- PrecambrianEarliest geological eon
- CambrianEarliest Paleozoic period
- stromatolitesLayered sedimentary bacterial structures
paleontology · sedimentary · limestone · chalk · Proterozoic · siliceous · calcareous
amoeba
Shape-shifting single-celled organism
- parameciumCiliated slipper-shaped protozoan
- euglenaPlant-animal hybrid microbe
- giardiaWaterborne intestinal parasite
plasmodium · vorticella · entamoeba · toxoplasma · cryptosporidium · babesia
plankton
Drifting marine microlife
- zooplanktonDrifting aquatic microorganisms
- microfaunaMinute soil animals
- freshwaterNon-saline aquatic environment
marine · sediment · biofilm · symbiosis · decomposers · food chain · benthos · pond water · soil · aquatic
cilia
Hairlike cellular projections
- flagellaWhiplike locomotion appendages
- cytoplasmGel surrounding the nucleus
- nucleusCentral controlling part
vacuole · pellicle · contractile · phagocytosis · binary fission · conjugation · cyst · organelles · mitochondria · endoplasm
malaria
Mosquito-borne parasitic infection
- dysenteryBloody intestinal infection
- toxoplasmosisParasitic infection from cats
- giardiasisProtozoan intestinal infection
leishmaniasis · trichomoniasis · pathogen · parasite · infection · vector · host · transmission · waterborne · mosquito-borne
flagellates
Whips harshly, often ritually
- apicomplexaParasitic protozoan phylum
- excavatesDigs out from ground
fossilized
Mineralized organic remains
- microfossilsMinute preserved organism remains
- PrecambrianEarliest geological eon
- CambrianEarliest Paleozoic period
stromatolites · paleontology · sedimentary · limestone · chalk · Proterozoic · siliceous · calcareous
- protistsamoeba, amoebas, ciliate, dinoflagellate, Paramecium
- tiny invertebratesmites, tardigrades, nematodes, water bears, springtails
- aquatic parasitessea lice, white spot, flukes
- biofoulingbarnacles, mussels, biofilm, tube worms, blue mussels
protozoansanimals
Multicellular mobile organisms
vertebrates · mammals · plants · fungi · humans
protozoansprokaryotes
Organisms without membrane-bound nuclei
bacteria · archaea · eubacteria · cyanobacteria · viruses