Encyclopedia Britannica, the Volvox
genus contains about 20 different species (2015). These autotrophic algae live
in fresh water where they unite “500 to 60,000 cells” with cytoplasmic
filaments to create “spherical or oval hollow colonies” (2015). Each somatic
cell has a pair of flagella and one chloroplast (2015). These microorganisms engage
in “phototaxis” by grouping the colony members with larger “light reception”
areas together to form an area specifically targeted for photosynthesis (2015).
Most Volvox species reproduce
asexually and sexually with some switching “primary modes of reproduction” (2015).