Plant-Like Protists (Algae)
 Autotrophs – photosynthetic, have chloroplasts, all






have chlorophyll a
Classified by pigment types / color group, food
storage, cell wall composition (7 phyla)
Produce most O2 on earth
No roots, stems, leaves – make gametes in singlecelled gametangia
Most aquatic, have flagella at some stage of life cycle
Store starch in pyrenoids
Unicellular (eg. Phytoplankton), multicellular (eg.
seaweeds) or colonial
Plant-Like Protists
Phylum Chlorophyta
– Green Algae
 Like plants, have chlorophyll a and b,
carotenoids, food stored as starch,
cellulose in cell walls  common
ancestor or plants evolved from green
algae
 Most aquatic, some terrestrial (moist
soil, tree trunks – Protococcus)
 some symbiotic with invertebrates
(corals) or fungi (lichens)
 Some motile, some sessile
Symbiosis w/
Fungi:
Lichens
Crustose &
Foliose
Symbiosis with
Cnidarians
Some anemones, corals, and
jellyfish have symbiotic algae
(zooxanthelae)
Unicellular
Colonial
Multicellular /
Filamentous
What type of life cycle is this?
What is the only step that uses
meiosis?
Plant-Like Protists
Phylum Phaeophyta –
Brown Algae
Giant kelp
 Multicellular
 Chlorophyll a and b,
plus fucoxanthin
brown accessory
pigment
 Most marine, include
seaweeds and kelp
 Sargassum –
floating seaweed
 Mycrocystis pyrifera
– giant kelp
 sessile
Kelp
Plant-Like Protists
Phylum Rhodophyta – Red Algae
 Chlorophyll a and phycobilins – red accessory
pigments that absorb light deep in water  can
live in deeper water than other algae
 Most are marine seaweeds, sessile
Plant-Like Protists
Phylum Bacillariophyta Diatoms
 Unicellular
 Cell walls = shells of silicon dioxide  two halves that
fit like a pill box  found in beach sand, used in
toothpaste, etc.
 Centric – round or triangular, mostly marine
 Pennate – rectangular, mostly freshwater
 Abundant in phytoplankton
Plant-Like Protists
Phylum Dinoflagellata - Dinoflagellates
 Usually unicellular, have two flagella perpendicular to each





other
Cell walls made of cellulose plates that resemble armour –
ex.: Cerratium
Most yellow to brown – carotenoids plus chlorophyll a and c
A few colorless heterotrophs
Some bioluminesce – genus Noctiluca
Some produce toxins & red pigment  “red tides”
Ceratium
Dinoflagellate “armour”
Red tide
Bioluminescence
Plant-Like Protists
Phylum Chrysophyta –
Golden Algae
 Unicellular, chlorophyll a and b, yellow due to




carotenoids
Two flagella on opposite ends of cell
Most live in freshwater
Form highly resistant cysts  survive in frozen or
dry lakes
Store energy as oils  formation of petroleum 
new biofuels?
Plant-Like Protists
Phylum Euglenophyta - Euglenoids
 Unicellular, plant-like and
animal-like:
 No cell walls, have protein
pellicle
 Chloroplasts (if raised in
presence of light)
 Eyespot sensitive to light
 Contractile vacuole
 Chlorophylls a and b,
carotenoids
 Most live in freshwater,
some in moist soil and
animal digestive tracts