A life cycle is a period involving one generation of an organism through means of reproduction, whether through asexual reproduction or sexual reproduction.

In regard to its ploidy, there are three types of cycles; haplontic life cycle, diplontic life cycle, diplobiontic life cycle.

These three types of cycles feature alternating haploid and diploid phases (n and 2n).

The haploid organism becomes diploid through fertilization, which joins of gametes.

This results in a zygote which then germinates.

To return to a haploid stage, meiosis must occur.

The cycles differ in the product of meiosis, and whether mitosis (growth) occurs.

Zygotic and gametic meioses have one mitotic stage and form: during the n phase in zygotic meiosis and during the 2n phase in gametic meiosis.

Therefore, zygotic and gametic meiosis are collectively term haplobiontic (single mitosis per phase).

Sporic meiosis, on the other hand, has two mitosis events (diplobiontic): one in each phase..

For more information about the topic Biological life cycle, read the full article at Wikipedia.org, or see the following related articles:

Meiosis — In biology, meiosis is the process by which one diploid eukaryotic cell divides to generate four haploid cells often called gametes. Meiosis is ...  > read more

Spore — In biology, a spore is a reproductive structure that is adapted for dispersion and surviving for extended periods of time in unfavorable conditions. ...  > read more

Somatic cell — A somatic cell is generally taken to mean any cell forming the body of an organism. Somatic cells, by definition, are not germline cells. In mammals, ...  > read more

Fertilisation — Fertilisation, also spelt fertilization (also known as conception, fecundation and syngamy), is fusion of gametes to form a new organism of the same ...  > read more

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