Encyclopedia Britannica, the Volvox
genus contains about 20 different species (2015). These autotrophic algae live
in fresh water where they form “spherical or oval hollow colonies” by using
cytoplasmic filaments to unite “500 to 60,000 cells” (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).