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 earthNo roots, stems, leaves – make gametes in single-

celled gametangiaMost aquatic, have flagella at some stage of life cycleStore starch in pyrenoidsUnicellular (eg. Phytoplankton), multicellular (eg.

seaweeds) or colonial

Plant-Like ProtistsPhylum 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:

LichensCrustose &

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

MulticellularChlorophyll a and b,

plus fucoxanthin brown accessory pigment

Most marine, include seaweeds and kelpSargassum – floating

seaweedMycrocystis pyrifera

– giant kelpsessile

Giant kelp

Kelp

Plant-Like ProtistsPhylum Rhodophyta – Red AlgaeChlorophyll 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 ProtistsPhylum Bacillariophyta - Diatoms

UnicellularCell 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 marinePennate – rectangular, mostly freshwater

Abundant in phytoplankton

Plant-Like ProtistsPhylum Dinoflagellata - DinoflagellatesUsually unicellular, have two flagella perpendicular to each

otherCell walls made of cellulose plates that resemble armour –

ex.: CerratiumMost yellow to brown – carotenoids plus chlorophyll a and cA few colorless heterotrophsSome bioluminesce – genus NoctilucaSome produce toxins & red pigment “red tides”

Ceratium

Dinoflagellate “armour”

Red tide

Bioluminescence

Plant-Like ProtistsPhylum Chrysophyta – Golden Algae

Unicellular, chlorophyll a and b, yellow due to carotenoids

Two flagella on opposite ends of cellMost live in freshwater Form highly resistant cysts survive in frozen or dry

lakesStore energy as oils formation of petroleum new

biofuels?

Plant-Like ProtistsPhylum Euglenophyta - Euglenoids

Unicellular, plant-like and animal-like:No cell walls, have protein

pellicleChloroplasts (if raised in

presence of light) Eyespot sensitive to lightContractile vacuole

Chlorophylls a and b, carotenoids

Most live in freshwater, some in moist soil and animal digestive tracts