Kingdom Protista: Algae and Heterotrophic Protists

Chapter 15

Heterotrophic Phyla• Oomycota- water molds.• Myxomycota- plasmodial slime molds.• Dictyosteliomycota- cellular slime molds.

Oomycota- water molds

• Characteristics– Unicellular, coenocytic and filamentous.– Saprophytic and parasitic.– Food reserve- glycogen.– Eukaryotic nucleus.– Zoospores- 1 tinsel and 1 whiplash.– Cell wall cellulose/cellulose-like.

• Habitat- marine, freshwater, terrestrial.• 700 species.• Examples- Saprolegnia and Phytophthora.

Phytophthora- sudden oak disease, Ireland potato famine, crop destruction.

Myxomycota- plasmodial slime molds

• Characteristics– Streaming protoplasm.– Saprophytic and engulf bacteria,

yeast, fungal spores.– Food reserve- glycogen.– Eukaryotic nucleus.– Gametes- 2 unequal, apical, whiplash.– No cell wall.

• Habitat- terrestrial.• 700 species.• Example- Physarum.

Dictyosteliomycota- cellular slime molds

• Characteristics– Amoeba-like cells that form slugs.– Engulf bacteria.– Food reserve- glycogen.– Eukaryotic nucleus.– Flagella- none.– Cell wall cellulose.

• Habitat- terrestrial.• 50 species.• Examples- Dictyostelium.

Dictyostelium- cellular slime mold

Dictyostelium

Photosynthetic Phyla (the algae)

• Myzozoa- dinoflagellates.• Euglenozoa- euglenoids.• Cryptophyta- cryptomonads.• Haptophyta- haptophytes.• Chlorophyta- green algae.• Rhodophyta- red algae.• Heterokontophyta- heterokont algae.

– Phaeophyceae- brown algae.– Chrysophyceae- golden-brown algae.– Bacillariophyceae- diatoms.

Myzozoa- dinoflagellates

• Characteristics– Unicellular, colonal.– Chlorophylls A and C, peridinin.– Food reserve- starch in cytoplasm.– Thylakoids in 3.– Mesokaryotic nucleus.– Flagella- 1 transverse and 1 longitudinal.– Cell wall with cellulose in thecal plates.

• Habitat- marine and freshwater.• 4,000 species.• Examples- Ceratium, Peridinium, Dinophysis,

Alexandrium, Pfiesteria.

Pfiesteria piscicida

Euglenozoa

Euglenozoa- euglenoids• Characteristics

– Unicellular.– Chlorophylls A and B, carotenoids.– Food reserve- paramylon in cytoplasm.– Thylakoids 2-3.– Mesokaryotic nucleus.– 2 unequal flagella, long one with hairs.– No cell wall, proteinaceous pellicle.– Eyespot.

• Habitat- marine and freshwater; puddles, ditches, ponds, streams, lakes, rivers.

• 1,000 species.• Example- Euglena.