Chlorophytes

Chlorophytes, commonly known as green algae, constitute a diverse group of photosynthetic eukaryotes within the phylum Chlorophyta. They occupy a range of habitats, including freshwater, marine, and damp terrestrial environments. In many classifications they are distinguished from the charophytes, which are more closely related to land plants, though both are green algae.

Chlorophytes share the hallmark pigments chlorophyll a and b, which give them their green color. They store energy as starch in plastids and typically have cellulose-rich cell walls. Their morphology spans unicellular flagellates, such as Chlamydomonas, to colonies (Volvox) and filamentous or thalloid forms (Spirogyra). Some lineages form complex multicellular tissues, including leafy sheets like Ulva.

Reproduction is varied. Chlorophytes can reproduce asexually by mitotic divisions or by producing propagules. Sexual reproduction ranges from isogamy to anisogamy and oogamy, and life cycles may be haplontic, diplontic, or alternation of generations.

Ecologically, chlorophytes are important primary producers in aquatic ecosystems, forming the base of many food webs. They contribute to nutrient cycling and can form large algal blooms under favorable conditions. The study of chlorophytes, including model organisms such as Chlamydomonas reinhardtii and Volvox carteri, has advanced understanding of photosynthesis, locomotion, and the evolution of multicellularity.