Short Notes:

Algae is the collective name given to aquatic plants that lack specialized body parts (roots, stems, and leaves). They contain chlorophyll and undergo photosynthesis to make food. Algae's size range from microscopic diatoms to the giant kelp.

There are unicellular (one-cell) and multicellular (many cells) algae. Unicellular algae reproduces through simple cell division. Multicellular algae species propagate by spores and gametes in what is termed alternation of generations. This simple form of sexual reproduction is known as isomorphism. Some species, most notably kelp, have heteromorphism - there is a dramatic difference between the sporophyte and gametophyte generations.