To determine the life cycle pattern in pteridophytes and gymnosperms, we need to analyze the characteristics of their life cycles step by step.
### Step-by-Step Solution:
1. **Understanding Pteridophytes:**
- Pteridophytes, which include ferns and horsetails, exhibit a life cycle known as **haplodiplontic**. This means that both the haploid (gametophyte) and diploid (sporophyte) phases are multicellular and prominent in their life cycle.
2. **Life Cycle of Pteridophytes:**
- In the haplodiplontic life cycle, the **sporophyte** is the dominant phase. It is a multicellular diploid organism that undergoes **meiosis** to produce **haploid spores**.
- These spores germinate to form **gametophytes**, which are haploid and can produce gametes through mitosis.
- The fusion of gametes (syngamy) leads to the formation of a **zygote**, which develops into a new sporophyte, thus completing the cycle.
3. **Understanding Gymnosperms:**
- Gymnosperms, which are naked-seeded plants, also follow a life cycle pattern that is primarily **diplontic**. In this case, the sporophyte is the dominant phase, and the haploid phase is represented only by the gametophytes.
4. **Life Cycle of Gymnosperms:**
- In gymnosperms, the sporophyte undergoes meiosis to produce **haploid spores**. These spores develop into gametophytes, which are typically reduced and dependent on the sporophyte.
- The gametophytes produce gametes, and upon fertilization, a **zygote** is formed, which develops into a new sporophyte.
5. **Conclusion:**
- Therefore, the life cycle pattern in pteridophytes is **haplodiplontic**, while in gymnosperms, it is **diplontic**. Thus, the correct answer is that the life cycle pattern in pteridophytes and gymnosperms is **haplodiplontic and diplontic respectively**.
### Final Answer:
The life cycle pattern in pteridophytes and gymnosperms is **haplodiplontic and diplontic respectively**.
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