Life cycle terminology in green algae: Chlamydomonas exhibits a life cycle that alternates between haploid and diploid phases with distinct stages. What is the correct term for this pattern?

Introduction / Context:
Life cycles vary widely among algae, and correct terminology is essential. Many green algae demonstrate shifts between haploid and diploid phases, each with its own morphology and timing. Recognizing the correct term ensures clarity when comparing algae to plant life cycles.

Given Data / Assumptions:

• We consider a cycle with both haploid and diploid stages.
• Chlamydomonas is the model organism in the question.
• We choose the standard biological term used in textbooks.

Concept / Approach:
Alternation of generations refers to life cycles with alternating haploid (gametophyte) and diploid (sporophyte) stages. In many green algae, the haploid stage dominates, and the diploid zygote may undergo meiosis to return to the haploid state. The precise details vary by species, but the overarching concept is the alternation between ploidy levels.

Step-by-Step Solution:
Identify haploid and diploid phases within Chlamydomonas life cycle diagrams.Note that sexual reproduction produces a diploid zygote which can undergo meiosis.Recognize the alternation between ploidy levels as the defining feature.Select the term alternation of generations.

Verification / Alternative check:
Laboratory observations of mating types, zygote formation, and subsequent meiosis confirm alternating ploidy stages in Chlamydomonas.

Why Other Options Are Wrong:

• Sexual-asexual exchange: vague and not a standard term.
• Transposition cycle: unrelated genetic term.
• Algal transformation: refers to genetic uptake, not life cycles.

Common Pitfalls:
Assuming alternation of generations always implies equal or isomorphic stages; in many algae one phase is reduced.

Final Answer:
an alternation of generations