Compare and contrast slime molds and water molds.

Both the slime molds and the water molds are saprobes, and neither of them are fungi, as the names would suggest. In spite of the similarity of names, however, these organisms are more different than they are similar.
Slime molds are classified among the protozoa (Amoebozoa). They are phagocytic saprobes without cell walls and occur in two forms: plasmodial and cellular.
The plasmodial coenocytic slime molds are diploid under normal conditions, but under adverse conditions they produce haploid spores that can germinate to produce a unicellular form (myxamoeba) that uses flagella or pseudopodia for motility, depending on conditions. Two compatible myxamoebae fuse to form a new diploid, which, in turn, becomes a new coenocytic plasmodium.
The cellular slime molds are haploid. Under ideal conditions, the cellular slime molds live as single-celled organisms (myxamoebae). When food becomes scarce, the myxamoebae congregate and cooperate to form a sporangium, and some individuals then become spores. No diploidy or meiosis is involved.
The water molds are classified with the algae (Stramenophila), but they do not carry out photosynthesis. They are diploid saprobes with cell walls of cellulose. Their spores are motile by means of two flagella, which are structurally different. Some water molds are plant pathogens.