Protists

Protist Characteristics

An extremely diverse group

Eukaryotes Mostly unicellular

some colonial some multicellular

Some heterotrophic, some autotrophic, some both

Some have cell walls

3 Major Types

Animal-like protozoa

Fungus-like

Plant- like algae

“Animal-Like” Protists

Protozoans Are heterotrophs (some are parasites!)

Types of protozoans: 1. sarcodines2. ciliaphore3. flagellates4. sporozoans

Protist Phyla

1. Sarcodines – use pseudopodia (“false feet”) to move and get food

EX: Amoebas, foraminifera. radiolarians

http://www.funsci.com/fun3_en/protists/exhibition.htm

Amoeba change forms continuously

2. Ciliophores – use cillia to move

EX: paramecium

http://www.funsci.com/fun3_en/protists/exhibition.htm

Paramecia

http://ebiomedia.com/gall/ciliates/index.html - more ciliates

3. Flagellates- have whip-like flagella

             This flagellate lives in termite gut – digests cellulose.

This one is a pathogen – causes diarrheaEX: Giardia

Dinoflagellates have 2 flagella

A related protist, Leishmania, causes the disease leishmaniasis.

These protists are transmitted by biting flies, and are a serious public health problem in much of the world.

Leishamanasis

4. Sporozoans – no method of movement

form spores, many are parasitesEX:

- Toxoplasma- carried by rodents, birds, and domestic cats (can be harmful to unborn babies if mom changes the kitty litter box)

- Plasmodium- causes Malaria (carried by mosquitoes)

Life Cycle of Malaria

“Plant-like” protists

Are autotrophs

Mostly algae

Are classified by their pigments (their color) – red, green or brown

Many are multicelled

Do not have stems, leaves and roots like plants

Make up phytoplankton (bottom of ocean food chain)

Plant like protists

1. Green Algae

Are green in color Ex –

Spirogyra

Spirogyra

http://www.funsci.com/fun3_en/protists/exhibition.htm

Desmid- unicellular green algae

Green algae - Volvox

             

Green algae - Haematococcus Turns birdbath red

2. Red Algae

Multicellular Commonly called sea weed Live in deep salt water Are used by humans to help make ice cream

and hair conditioner Are eaten in some Asian cultures

3. Brown Algae

Multicellular Commonly called sea weed Thallus- plant-like seaweed

body Holdfast- root-like; anchors to

surface Stipe- stem-like Blades- leaf-like

Have air-filled sacs called air bladders

Used in many foods and beauty products

Diatoms

Photosynthetic protists Mostly marine Have silica (glass-like)

shell Used to make

reflective paint, toothpaste, and abrasives

“Fungus-Like” Protists

Slime & water molds

Some of these can move

Many are decomposers or parasites

Slime molds