PROTISTS: THE UNICELLULAR EUKARYOTES

PROTISTS

Eukaryotic

Usually unicellular

Diversely shaped

Not a fungus, plant or animal

Three types:

- Animal-like

- Fungus-like

- Plant-like

** Refer to the table on page 72 **

ANIMAL-LIKE PROTISTS

Also known as Protozoans

Heterotrophs

Some are parasitic

ANIMAL-LIKE PROTISTS

THE CERCOZOANS: PHYLUM CERCOZOA

Ex: Amoebas

- Cell membrane without a cell wall: change shape using

their cytoskeleton

- Pseudopods: temporary extensions of cytoplasm (false

feet), used for feeding and locomotion

- Live in salt water, fresh water and mud; few are

parasites in an animal

ANIMAL-LIKE PROTISTS

THE CERCOZOANS: PHYLUM CERCOZOA

Ex: Amoebas

- Ex: Entamoeba hystolitica- Feeds on lining of small intestine causing

amoebic dysentery- Spread by contaminated water or produce

ANIMAL-LIKE PROTISTS

THE CILIATES: PHYLUM CILIOPHORA

Ex: Paramecia

- Large and complex

- Have many cilia covering their surface for

locomotion and sweeping food into

themselves

- Free-living; other types are parasites

ANIMAL-LIKE PROTISTS

THE CILIATES: PHYLUM CILIOPHORA

Ex: Paramecia

- Ex: Balantidium coli- Lives in large intestine and causes diarrhea

ANIMAL-LIKE PROTISTS

THE FLAGELLATES: PHYLUM ZOOMASTIGINA

Ex: Flagellates

- Have one or more flagella with protective

coverings

- Some are free-living, some are parasites, some are

in mutualistic relationships

ANIMAL-LIKE PROTISTS

THE FLAGELLATES: PHYLUM ZOOMASTIGINA

Ex: Flagellates

- Ex: Flagellates living in termite intestines- Convert cellulose to sugar in return for food and

habitat

ANIMAL-LIKE PROTISTS

THE SPOROZOANS: PHYLUM SPOROZOA

Ex: Sporozoans

- Parasites of animals

- Most with alternating sexual and

asexual reproduction, even alterning

between two hosts

ANIMAL-LIKE PROTISTS

THE SPOROZOANS: PHYLUM SPOROZOA

Ex: Sporozoans

- Ex: Plasmodium

- Cause malaria in humans

FUNGUS-LIKE PROTISTS

Heterotrophs

Absorb nutrients from living organisms, dead

organisms, and wastes

Produce spores

Different from fungi at the cellular level

FUNGUS-LIKE PROTISTS

PLASMODIAL SLIME MOULDS: PHYLUM MYXOMYCOTA

Ex: Plasmodium

- Many nuclei

- Tiny slug-like organisms

- Creep over damp, decaying plant material in forests and fields

- Engulf small particles of food into their cytoplasm

- Part of cytoplasm is concentrated to form a skeleton-like

structure

FUNGUS-LIKE PROTISTS

CELLULAR SLIME MOULDS: PHYLUM

ACRASIOMYCOTA

- Individual amoeboid cells with one nucleus each

- Feeds by ingesting tiny bacteria or yeast

- Can also feed by releasing a chemical that causes

them to gather together to form a

pseudoplasmodium (only when food is scarce)

FUNGUS-LIKE PROTISTS

WATER MOULDS: PHYLUM OOMYCOTA

- Filamentous (resembles fungi)

- Can extend fungus-like threads into their host’s

tissues where they release digestive enzymes and

absorb resulting nutrients

- Live on dead organic matter

- Some are parasites on fish, insects, and plants

PLANT-LIKE PROTISTS

Contain pigments in their chloroplasts (Ex:

chlorophyll) to carry out photosynthesis

PLANT-LIKE PROTISTS

DIATOMS: PHYLUM CHRYSOPHYTA

Ex: Diatoms (type of phytoplankton)

- Single celled aquatic organisms

- Free floating

- Rigid cell walls with an outer layer of silica

- Two unequal parts to cell wall

- Reproduce asexually by mitosis or sexually when conditions are

unfavourable

- Important food source for larger marine organisms

PLANT-LIKE PROTISTS

DINOFLAGELLATES: PHYLUM PYRROPHYTA

- Type of phytoplankton

- 2 flagella at right angles to one another

- Flagella allow organisms to spin

- Reproduce quickly (causing an algal bloom)

- Some living inside other organisms

PLANT-LIKE PROTISTS

DINOFLAGELLATES: PHYLUM PYRROPHYTA

- Ex: Red Tide - Dinoflagellates with red photosynthetic pigments- Red bloom- Produce a toxin that can accumulate in plankton-

eating-shellfish which can be fatal to humans

PLANT-LIKE PROTISTS

DINOFLAGELLATES: PHYLUM PYRROPHYTA

- Ex: Symbiodinium- Reef building corals- Use nitrogen and carbon dioxide from corals in

return for photosynthetic products- In high termperatures: coral bleaching occurs

which breaks the coral-protist partnership

PLANT-LIKE PROTISTS

EUGLENOIDS

Ex: Euglena

- Found in shallow fresh water

- Have chloroplasts which allow for photosynthesis

(in sunlight)

- Have flagella and can absorb nutrients (in

darkness)

- Have an eyespot for light detection