Question

Write an essay on reproduction in algae.

Answer 1

Reproduction in algae occurs in various methods:

1. Vegetative reproduction - This type of reproduction occurs when a part of the thallus detaches from the body and develop into a new plant.

• Binary fission - This process involves the division of cells by mitosis. E.g. Chlamydomonas reproduces by this process.
• Fragmentation - In this type of reproduction, the thallus splits into many fragments. Each fragment then develops into a new plant.E.g. Spirogyra

2. Asexual reproduction - This type of reproduction occurs where the algae produce spores. The spore produces male and female gametes. These gametes fuse together to form new algae. There are various types of spores that can be formed. Zoospores are motile spores as they can be bi-, quadri- or multiflagellated. Alplanospores are not motile and can be transported only by water currents.
3. Sexual reproduction - This type of reproduction involves the fusion of male and female gametes. The gametes are haploid and undergo meiosis cell division to form diploid cells called a zygote. Sexual reproduction occurs when there is a change in the environment like an increase in temperature, inorganic nutrients like nitrogen, phosphorous, etc.

• Anisogamy or heterogamy is the fusion of gametes that are dissimilar in sizes.

Isogamy is the fusion of gametes of similar sizes.

• Oogamy is the fusion of a large immotile female gamete with a motile male gamete.