Diversity

Acritarchs are the oldest known fossils of any protist, being 2.1 billion years old.
Plankton are colonies of protists.
Most protists are aerobic.  Non aerobes may or may not have aerobic symbionts.
Classifications include protozoans, algae, and fungus-like molds.
Eukaryotic flagella are extensions of the cytoplasm with microtubules (surrounded by the plasma membrane).
     Bacterial flagella are protein rods attached to the cell surface.
Protists have many variations of reproduction and life cycles.
All protists are capable of asexual reproduction but not all can sexually reproduce.
Protists can form cysts.  Cysts are special cells resistant to harsh conditions.

Motility and Feeding

Rhizopoda
     These are naked and shelled amoebas; pseudopods are used for both motility and feeding.

Actinopoda (heliozoans/radiozoans)
     These have slender pseudopods called axopods radiating from the central area of the cell.  These axopodia help the cell increase its surface area for prey to stick to its axopodia.  Cytoplasmic streaming carries the food to the main cell.  Heliozoans are fresh water protists and radiozoans are marine protists having silica dioxide shells.

Foraminifera (forams)
     These are always marine creatures.  Most are attached to a surface, some form plankton.  Forams are multi-chambered cells with a hardened calcium carbonate shell.  To swim, feed, and expand (grow) forams extend their cytoplasm through pores in their shell.  Some of these protists have algae symbionts inside of them.

Apicomplexa (sporozoans)
     These are parasites, such as Plasmodium.  The mosquito Anopheles bites you, transferring sporozoites (infectious cells) that after several cell divisions become merozoites.  These merozoites are different physiologically from sporozites and tend to diverge in the liver.  The merozoites develop into gametocysts (cysts that produce male or female gametes) which in turn fertilize each other and create new sporozites.

Zoomastigophora (zooflagellates)
     These are mostly solitary organisms, rarely colonial.  Zooflagellates often for symbiotic relationships with more complex organisms (like Trichanympha and termites, and Trypanosoma - or African Sleeping Sickness - and humans).  The euglena-type algae are closely related to zooflagellates.

Ciliophora (ciliates)

Most are solitary, fresh-water organisms.  They are among the most complex cells today.  The rhythmic beating of a ciliates cilia (tiny hairs used in locomotion and feeding) is controlled by a submembrane system of microtubules.  Taxis in ciliates is coordinated by the polarity of this outer cytoplasm layer.  Cilia organization can range from clumps (Stylonychia), to one edge of the cell (the circle of cilia in Stentor), to evenly spaced across the entire cell membrane (Paramecium). [Diagrams:  Blue refers to the presence of cilia.  Top is an example of clumps.  Bottom is an example of the top end of a stentor.]

The Paramecium has a two nuclei types:  the macronuclus and the micronucleus.  The macronucleus has 50+ copies of the entire genome of the cell with 100s of copies of a few genes, and runs the day-to-day operations.  The macronucleus replicates by binary fission; no mitosis, it just elongates and splits.  There can be 1 to 80 micronuclei.  The micronucleus performs sexual reproduction by replicating "big-time" then giving, swapping, or receiving micronuclei from another Paramecium.

Next:  "Molds."