Protists
Three Groups of Protists:
Animal-like Protists
Plant-like Protists
Fungus-like Protists
Protist Diversity
 200,000
species: different
shapes, sizes, and colors
 All eukaryotes – have a nucleus
and membrane-bound organelles
 Not bacteria, animals, plants,
fungi (the organism junk
drawer)
 Reproduce asexually or sexually
Protists are the most diverse of all eukaryotes.
Asexual reproduction
Binary
 fission

Sexual reproduction

Conjucation
Animal-like Protists
“Protozoa”
Protozoans
 Unicellular
–one cell
 Heterotrophs – they eat
other organisms or dead
organic matter
 Classified by how they move
Phyla of Protozoans
Phylum Zoomastigina “Zooflagellates”
(giardia)
Phylum Sarcodina“Sarcodines”
(amoeba)
Phylum Ciliophora “Ciliates”
(paramecium)
Phylum Sporozoa “Sporazoans”
(plasmodidium)

Sarcodines – move by extensions of
their cytoplasm.

Ciliates – move by means of cilia.

Sporozoans – do not move on their own.
Amoebas: the blobs
 No
cell wall
 Move using pseudopods –
plasma extensions
 Engulf bits of food by
flowing around and over them
Amoeba
Pseudopods
Found in
freshwater
Moves using pseudopods- “false feet”cytoplasmic projections
They also use pseudopods for feeding
Amoeba
Pseudopod
Paramecium
Pseudopod
Food
Vacuole
More amoebas

Amoebic dysentery
Entamoeba histolytica
 Amoebas feed on intestinal lining, causing
bloody diarrhea.
 Contaminated food or water.

Flagellates: the motorboats
 Use
a whip-like extension
called a flagella to move
 Some cause diseases

Giardiasis – Giardia lamblia
Cramps, nausea, diarrhea,
and vomiting
 Contaminated water

Leishmaniasis – Trypanosoma
Skin sores and deep, eroding lesions.
Bites from sand flies.
 Trichomonas
foetus : cow disease
 Trichomonas
vaginalis: an STD
Ciliates: the hairy ones
 Move
beating tiny hairs
called cilia
Paramecium- move using cilia (tiny hairlike projections)
Paramecium reproduction
Sporazoans: the parasite
 Non-motile
- Do not move
 Live inside a host
 One type causes malaria
 Malaria
in red blood cells

MALARIA – Plasmodium
Causes severe chills, fever, sweating,
confusion, and great thirst.
 Spread from person to person by the
anopheles mosquito.

Plant-like Protists
“Algae”
The Unicellular
Plant-Like Protists
What are Algae?
 Unicellular
– made of one cell
 Multicellular – made of more than
one cell
 Photosynthetic – make their own
food
 No roots, stems, or leaves
 Each has chlorophyll and other
photosynthetic pigments
Red algeal bloom
Brown Algea:
Giant Kelp Forest
Volvox: a green colonial algae
Phyla of Unicellular Algae
Phylum Euglenophyta (euglena)
Phylum Chrysophyta (golden algae)
Phylum Bacillariophyta (diatoms)
Phylum Pyrrophyta (dinoflagellates)
Euglenoids:
 Aquatic
 Move
around like animals
 Can ingest food from
surroundings when light is
not available
Euglena


Euglena contain:
chloroplasts, a
flagella, and an
eyespot to sense
where light is.
Unique because
they are both
heterotrophic and
autotrophic.
Diatoms: The Golden
Ones
 Have
shells made of silica
(glass)
 Photosynthetic pigment
called carotenoids – give
them a golden color
Dinoflagellates: The
Spinning Ones
 Spin
around using two
flagella
 Responsible for Red Tides
 Create toxins that can kill
animals and sometimes people
Algal Blooms
High temps and increase in
nutrients (nitrates and
phosphates) lead to increased
algae populations
 Harmful to fish and humans (red
tide)

Swimming with Bioluminescent
Dinoflagellates
Plant-like Protists
“Algae”
The Multicellular
Plant-like Protists


All are autotrophic-meaning they can
make their own food
Examples:
Euglena
Algae
Phyla of Multicellular Algae
Phylum Rhodophyta (Red Algae)
Phylum Phaeophyta (Brown Algae)
Phylum Chlorohyta (Green Algae)
Red Algae:
 Seaweeds
 Multicellular,
marine
organisms
 Have red and blue pigments
Brown Algae:
 They
have air bladders to help
them float at the surface –
where the light is.
Green Algae:
 Most
live in fresh water
 Can be unicellular or
multicellular
 Live alone or in groups called
colonies
Green Algae:
 Unicellular
 Colonial
– Chalamydomonas
Algae – spyrogyra, volvox
 Multicelluar
- Ulva
Conjugation of Spyrogyra
The life cycle of Chlamydomonas
“cloning” –
plants
identical to
each other
Isogamy =
male and
female gamete
identical in
size
Sexual
reproductioncreate
variation
Fungus-like Protists
Fungus-Like Protists
Fungus-like Protists
 All
form delicate, netlike
structures on the surface of
their food source
 Obtain energy by
decomposing organic material
Phyla of Fungus-like Protists
Phylum Acrasiomycota - Cellular
Slime Molds
Phylum Myxomycota - Plasmodium
Slime Molds
Phylum Oomycota - Water Molds
& Downy Mildews
Slime Molds
 Live
in cool moist, shady
places where they grow on
damp, organic matter
Plasmodium Slime Molds
 Form
plasmodium: a mass of
cytoplasm that contains many
diploid nuclei but no cell walls
or membranes – its feeding
stage
 Creeps by amoeboid
movement – 2.5 cm/hour
Plasmodium continued…
 May
reach more than a meter in
diameter
 Form reproductive structures
when surroundings dry up
 Spores are dispersed by the
wind and grow into new
plasmodium
Cellular Slime Molds
 In
feeding mode, they exist
as individual amoebic cells
 When food becomes scarce,
they come together with
thousands of their own kind
to reproduce
 May look like a plasmodium
Slime molds upclose
Water and Slime molds are not in the Kingdom
Fungi because their cell walls are made up of
cellulose not chitin.
Figure 27.32 A Cellular Slime Mold
Figure 27.14 Alternation of Generations
The standard or
beginning model
Water Molds and Downy
Mildews
 Live
in water or moist places
 Feed on dead organisms or
parasitize plants
 Fuzzy white growths
Water molds:

Water molds:



Completely aquatic
Often
decomposers
Sometimes
parasitic
Water mold attacking a fish