Chlorophyta Study Notes

Chlorophyta Overview

• Division of green algae containing chlorophylls a and b.

• Store food as starch in plastids.

• Habitat: Freshwater, marine, terrestrial (mostly aquatic).

General Characteristics

• Growth: Optimal in summer, high light, nutrients, temperature.

• Variability: Species include unicellular and multicellular forms.

• Structural traits: Biflagellated gametes; filamentous forms can be inedible.

Cell Structure and Metabolism

• Unicellular, colonial, and coenocytic types exist.

• Cell walls: Composed of cellulose; chloroplasts are double-membrane bounded.

• Key pigments: Major pigment is chlorophyll b; some species have siphonoxanthin.

Reproduction and Life Cycle

• Asexual: Fission, fragmentation, or production of zoospores.

• Sexual: Isogamous, anisogamous, or oogamous forms.

• Example: Ulva lobata exhibits alternation of generations.

Ecology

• Adaptation: Mainly freshwater; some species on rocks/trees; some form symbiotic relationships (e.g., lichens).

• Notable species: Caulerpa racemosa (Mediterranean spread); Spirogyra insignis (adaptation through mutation).

Classifications of Chlorophyta

Class Chlorophyceae

• Largest species group; reproductive methods include zygospore formation.

• Includes unicellular (e.g., Chlamydomonas) and colonial (e.g., Volvox) genera.

Class Ulvophyceae

• Marine, with varied morphology; meiosis in spores.

Class Charophyceae

• Ancestors of land plants; unique mitotic processes; includes Spirogyra and desmids.

References

• Include relevant textbooks and articles for detailed reading on algae and their classifications.