EukaryotesUnicellular or multicellular
Very varied group
Origin and Diversity
• Probably formed by cells taking in prokaryotic cells and keeping them
as organelles
– Ex – mitochondria andchloroplasts were probably monerans that were captured
Colonies formed before multicellular Protists
• Once cells were growing together, they eventually developed specialized functions. – These eventually became attached
and relied on each other for those functions. (Kind of like people who live in groups – they become specialized and begin to rely on each other.
Protists are conveniently divided into three groups1. Animal-Like Protists
• heterotrophs
2. Plant-Like Protists• autotrophs
3. Fungus-Like Protists• Decomposers (heterotrophs that eat
dead organic matter)
Animal-like protists
• Often called protozoans
• Unicellular and don’t have specialized tissues, organs or organ systems.
Animal-like protists - Sarcodines
• Amoebas – move using pseudopods
Amoeba
Animal-like protists-Zooflagellates
• Move using flagella
Animal-like protists - ciliophorans
• Move using cilia
• These are paramecia
These are cilia
This is its oral groove
Here is a paramecium dividing by binary fission
Paramecium structure
Oral groove
Animal-like protists – sporozoans –always parasites and
no way to move on their own
• Plasmodium is a parasite that you get from a mosquito bite. The disease it causes is malaria, which kills about 3 million people a year around the world. It lives in your red blood cells and
destroys them.
Plant-Like protists - algae
• Autotrophic – by photosynthesis
• Commonly called algae or seaweed
• Unicellular or multicellular
Unicellular algae
• Food for other organisms• Dinoflagellates cause red tides and
some other harmful algae blooms in the oceans.
diatoms
Diatoms – live in glass cases
Diatoms – in fresh and salt water
Bottom of food
chain
Case made of silica
(glass-like)
Used for abrasives
and filters
euglenoidseuglenoids
euglena
Multicellular algaeVolvox – colony of
Flagellated single cells
• almost multicellular
Green algaePredominant pigment is chlorophyll
Found in all types of water
Red algae• Grow in warm salt water• Some grow very deep in the ocean or
on ice
Brown algae
• Mostly saltwater
• Grow in cool salt water
• Includes largest Protists
Fungus-like protists
• Slime molds – creep along in an amoeba-like fashion
Protists in the Biosphere
• Some cause disease – Red tide– African sleeping sickness– Giardia– Potato blight– Malaria
Good uses of protistsPlankton – bottom of the food chain
Food – carageenan, agar, algin – thickeners and flavor enhancers
Seaweed as food
Diatoms for filters and as abrasives
Indicators of the general health of the environment
The end
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