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