Plant Biology: Kingdom Protista

Introduction

Protists are in the Domain Eukarya

Protists may be unicellular or multicellular

Protists obtain nutrition in varied ways, including photosynthesis, ingestion of food, and absorption of food

Reproduction in protists occurs sexually and by cell division

Algae

Examples include seaweed, pond scums, films in fish tanks, and colored patches in swimming pools.

Algae are in Kingdom Protista

Algae are grouped into several phyla based on form of reproductive cells and combinations of pigments and food reserves.

Phylum Chlorophyta - The Green Algae

Chlorophyta are unicellular

Chlorophyta form platelike colonies, netlike tubes, hollow spheres, and lettuce-like leaves

The greatest variety of Chlorophyta occur in freshwater lakes, ponds, and streams, but other occur on tree bark, in animal fur, in snowbanks, in flatworms or sponges, on rocks, and in lichen partnerships

Chlorophyta have chlorophylls a and b, store food as starch, and reproduce both sexually and asexually.

Diatoms (Bacillariophyceae)

Diatoms are unicellular

Diatoms are found in fresh and salt water and are particularly abundant in cold marine habitats

Diatoms are the dominant algal flora on damp cliffs, tree bark, and buildings

Diatoms look like ornate glass boxes with lids, and as much as 95% of the walls are silica

Diatoms may have 1, 2, or many chloroplasts

Phylum Rhodophyta - the Red Algae

A red algae known as Gelidium produces agar, which is used in bakery products, cosmetics, and as a solidifier in nutrient culture media

Phylum Dinophyta - the Dinoflagellates

Red tides are sudden multiplications of dinoflagellates, including some that produce neurotoxins that accumulate in shellfish

Phylum Myxomycota - the Plasmodial Slime Molds

Plasmodial slime molds do not have chlorophyll

Slime molds feed on bacteria and other particles

Phylum Oomycota - the Water Molds

Water molds caused the Irish Potato Famine