Life cycle of Ectocarpus and Fucus respectivley are

Options

A. haplontic,diplontic
B. diplontic,haplodiplontic
C. haplodiplontic,diplontic
D. haplodiplontic,haplontic

Answer

To understand the life cycles of Ectocarpus and Fucus, we need to break down their respective life cycles step by step.

### Step-by-Step Solution:

1. **Understanding Life Cycle Types**:
- There are three main types of life cycles in plants and algae: Haplontic, Diplontic, and Haplodeplontic.
- Haplontic: The dominant stage is haploid (n), and the diploid (2n) stage is represented only by the zygote.
- Diplontic: The dominant stage is diploid (2n), with haploid (n) gametes forming the diploid zygote.
- Haplodeplontic: This is a combination of both haploid and diploid stages, where both are prominent.

2. **Life Cycle of Ectocarpus**:
- Ectocarpus is an example of an organism with a **Haplodeplontic** life cycle.
- In this cycle, both haploid and diploid phases are present and multicellular.
- The haploid phase produces gametes, which fuse to form a diploid zygote.
- The zygote then develops into a diploid sporophyte, which produces haploid spores through meiosis.

3. **Life Cycle of Fucus**:
- Fucus exhibits a **Diplontic** life cycle.
- In this cycle, the diploid phase is the dominant stage.
- Fucus produces gametes that are haploid, which fuse to form a diploid zygote.
- The zygote develops into a multicellular diploid organism (sporophyte), which does not have a free-living haploid stage.

4. **Conclusion**:
- To summarize, Ectocarpus has a haplodeplontic life cycle, while Fucus has a diplontic life cycle.

### Final Answer:
- Ectocarpus: Haplodeplontic life cycle
- Fucus: Diplontic life cycle