Kingdom Protista

General Information

1. Diverse group (not a plant, animal, fungus, or bacterium)

2. All eukaryotes3. Most are unicellular4. Can be photoautotrophic or heterotrophic5. If motile, usually use flagella (but

sometimes only in part of the life cycle like reproductive cells)

6. 3 major groups

What are Plankton?

• Unicellular aquatic organisms– Usually protists– Can include animal larvae or small

crustaceans– Important in aquatic food chains– 2 types:

• Phytoplankton- photoautrophic• Zooplankton- heterotrophic

The Plant-Like Protists (ALGAE)

1. Phylum Euglenophyta (Euglenoids)– Ex. Euglena– ~900 species– Unicellular– Motile with flagella– Photosynthetic– No cell wall (pellicle instead)– Mostly freshwater– Reproduce via simple cell division

The Plant-Like Protists (ALGAE)

2. Phylum Bacillariophyta (Golden Algae)– Diatoms– ~100000 extant species– Mostly unicellular– 2-part outer shell (frustule)– Cell wall of silica (glass-like)– Diatomaceous earth– Photosynthetic– Abrasive- used in toothpastes, scouring pads,

cosmetics, silver polish– Major component of aquatic ecosystems

The Plant-Like Protists (ALGAE)

3. Phylum Chlorophyta (Green Algae)– Ex. Volvox– ~1700 species (very diverse)– Unicellular and multicellular– With chlorophyll for photosynthesis– Mostly freshwater– Believed to have given rise to modern-day

plants

The Plant-Like Protists (ALGAE)

4. Phylum Phaeophyta (Brown Algae)– Ex. Seaweed, kelp– ~1500 species– Multicellular– “roots” and “leaves”– Source of iodine– Used in fertilizers– Photosynthetic– Almost entirely marine

The Plant-Like Protists (ALGAE)

5. Phylum Rhodophyta (Red Algae)– Ex. Coralline algae, nori– ~5000 species– Autotrophs– Multicellular and very complex– Carageenan and/or agar in cells used in

making agar for petri dishes, ice cream, pudding, gel caps for pills, makeup

– Food items

The Plant-Like Protists (ALGAE)

6. Phylum Dinophyta (Dinoflagellates)– Ex. – Unicellular– Autotrophs, heterotrophs, few parasites – Motile with flagella– Some bioluminescent when disturbed– Algal blooms/ red tide (up to 20 million cells/ liter;

neurotoxin)– Many are zooxanthellae (symbiosis in hosts such as

coral reefs)

The Plant-Like Protists (ALGAE)

The Plant-Like Protists (ALGAE)

The Animal-Like Protists (PROTOZOANS)

1. Phylum Sarcodina (Rhizoids)– Ex. Amoeba, foraminiferans, Entamoeba hystolytica– ~12000 extant species– Pseudopodia (false feet) for moving and engulfing

prey– Use cytoplasm and pseudopodia to move– Some chalk-like, some glass-like– When forams die, their tests (protective shell-like

covering) sink and accumulate in large batches• Great Pyramids of Egypt are built from sandstone

composed largely of fossilized giant Nummulites, an ancient kind of foram

• The famous White Cliffs of Dover are limestone cliffs formed from the skeletal remains of forams

The Animal-Like Protists (PROTOZOANS)

2. Phylum Ciliophora (Cilates)– Ex. Paramecium– Motile with cilia– Cilia beat in synchronized waves and

thereby propel the organism through water – Macronucleus for metabolism and

micronucleus for reproduction

The Animal-Like Protists (PROTOZOANS)

3. Phylum Mastigophora (Flagellates)– Ex.

• Trypanosoma gambiense (African sleeping sickness via tsetse fly)

• Trichonympha and Trichomonas (termites’ digestive tracts)

• Trypanosoma cruzi (Chagas’ disease)• Giardia lamblia (abdominal pain and diarrhea)

– Motile with flagella

The Animal-Like Protists (PROTOZOANS)

4. Phylum Apicomplexa (Sporozoans)– Ex.

• Plasmodium (malaria)• Cryptosporidium (chronic diarrhea)• Toxoplasma (cats/ fecal contamination- exposure

to humans)

– Sessile– Parasites

The Animal-Like Protists (PROTOZOANS)

The Fungus-Like Protists (SLIME MOLDS)

– Sometimes unicellular, sometimes multicellular– Recycle organic matter (decomposers)– Phyla– Phyla

• Myxomycota- Plasmodial slime molds – formed when individual flagellated cells swarm together and

fuse – Amoeboid movement, phagocytosis

• Oomycota– Water molds and downy mildews

• Acrasiomycota- cellular slime molds– These spend most of their lives as separate amoeboid cells;

however, upon the release of a chemical signal, the individual cells aggregate into a great swarm.

The Fungus-Like Protists (SLIME MOLDS)

The Fungus-Like Protists (SLIME MOLDS)In 2000, a team of Japanese and Hungarian researchers, writing in the journal Nature,1 claimed to have found the slime mold Physarum polycephalum is capable of finding the shortest way through a maze. Pieces of the slime mould were enticed through a 30-square-centimeter (five-square-inch) maze by the prospect of food at the end of the puzzle. The researchers concluded that the creature was exhibiting a kind of primitive intelligence.

The Fungus-Like Protists (SLIME MOLDS)

•http://video.google.com/videosearch?hl=en&q=slime%20molds&um=1&ie=UTF-8&sa=N&tab=wv#

Physarum polycephalum also serves as the brain of a six-legged robot developed at the University of Southampton, England. The slime-mold, which naturally shies away from light, controls the robot's movement so that it too keeps out of light and seeks out dark places in which to hide itself.