Question

Which one of the following shows isogamy with non-flagellated gametes?

• A. Ectocarpus
• B. Ulothrix
• C. Spirogyra
• D. Sargassum

Answer 1

The Correct Option is C

To determine the correct answer to the question about which organism shows isogamy with non-flagellated gametes, we need to understand the concepts of isogamy and non-flagellated gametes.

Isogamy refers to a type of sexual reproduction involving gametes of similar size and shape. In this process, the gametes are morphologically similar, although they may differ in terms of genetic mating types. Non-flagellated gametes mean that the gametes do not have flagella and, therefore, do not possess structures for motility.

Let's analyze each option provided:

1. Ectocarpus: Ectocarpus is a genus of brown algae, and it typically reproduces via anisogamy or oogamy, involving flagellated gametes (motile).
2. Ulothrix: This green alga reproduces through isogamy with flagellated gametes, hence not fulfilling the non-flagellated condition.
3. Spirogyra: Spirogyra is known for its isogamous reproduction where both gametes are of the same shape and size. Crucially, their gametes are non-flagellated, meaning they don't move on their own and meet via water currents.
4. Sargassum: Sargassum is another genus of brown algae, known for reproducing through oogamy, involving a large non-motile egg and smaller motile sperm, which does not apply here.

Given these considerations, the correct answer is clearly:

Spirogyra: It exhibits isogamy with non-flagellated gametes.

In conclusion, Spirogyra best fits the criteria specified in the question.