Details of algae

• Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic plants.
• They occur in moist stones, soils, and wood or in association with fungi and animals.

Example-1. Lichen is the association of algae with fungi.

1. Algae grow on the body of sloth bear.

• Some algae are unicellular, some exist in colonial or filamentous forms, and a few marine plants form massive plant bodies.
• The algae reproduce by vegetative, asexual, and sexual methods.
• Vegetative reproduction is by fragmentation, where each fragment develops into a thallus.
• Asexual reproduction is by the production of flagellated zoospores which on germination give rise to new plants.
• Sexual reproduction takes place through fusion of two gametes, if the gametes with or without flagella are similar in size they are isogamous, if dissimilar in size they are anisogamous , and if female gamete is large, non-motile and male gamete is smaller, motile, the gametes are termed as
• Isogamous gametes with flagella are seen in Chlamydomonas and without flagella are seen in Spirogyra , anisogamous gametes are seen in in some species of Chlamydomonas, and oogamous gametes are seen in Volvox, Fucus.