Here's a breakdown:

* Diploid stage: The organism has two sets of chromosomes (one from each parent). This stage is often called the sporophyte generation.

* Haploid stage: The organism has one set of chromosomes. This stage is often called the gametophyte generation.

In many algae, the life cycle alternates between these two stages. The sporophyte produces spores through meiosis, which develop into haploid gametophytes. The gametophyte produces gametes (sperm and egg) through mitosis, which fuse to form a diploid zygote, and the cycle starts anew.

This alternation of generations allows for genetic diversity and provides advantages in different environmental conditions.