Life Cycle Terms

Oospore

A thick-walled sexual spore

Megaspore

A large spore in land plants which germinates into a female gametophyte, which produces egg cells.

Haplodiplontic life cycle

A life cycle where the haploid gametophyte is photosynthetic and independent, and it alternates with a short lived, multicellular sporophyte phase, which lives and is dependent on the gametophyte.

Diplontic life cycle

A life cycle where the independent, photosynthesizing phase is the sporophyte, alternating with a short-lived haploid gamete.

Haplontic life cycle

A life cycle where the sporophytic generation is the zygote, there are no free living sporophytes. Meiosis in the zygote results in haploid spores. The spores divide mitotically and form the free-living gametophyte, the dominant photosynthesizing phase.

Ploidy

The number of each type of chromosome

Meiosis

The type of cell division that results in a reduction of chromosome number. Involves two rounds of cell division, the ploidy is cut in half.

Mitosis

The type of cell division where the ploidy remains the same. A parent cell replicates its DNA, which then splits to form two daughter cells with the same ploidy as the parent cell.

Gametic meiosis

The type of cell division which occurs during gamete formation, resulting in the formation of haploid gametes.

Sporic meiosis

The type of division which occurs during sporogenesis, resulting in haploid spores.

Sporophyte

What does the zygote forms in the female moss plant in order to reproduce

Zygospore

A diploid reproductive stage, created by the nuclear fusion of haploid cells. When the environment is favorable, it germinates, meiosis occurs, and haploid vegetative cells are released.

Microspore

A land plant spore that develops into male gametophytes

Archegonia

Female reproductive structures (gametangia), produce egg cells and are the sites for fertilization.

Zygote

First (diploid) cell that is a result of fertilization

Protonema

First growth of a spore that leads to a patch of haploid gametophytes.

Spores

Haploid reproductive cells used in asexual reproduction.

Gametes

Haploid reproductive cells, used in sexual reproduction.

Antheridia

Male reproductive structures (gametangia), producing sperm cells that they release for fertilization. Produces non-motile sperm (spermatia), called spermatangia.

Zoospores

Motile asexual spores that use a flagellum for locomotion

Fertlilization

Process of reproduction between gametes and zygote

Mitosis

Process of reproduction between gametophytes and gametes

Mitosis

Process of reproduction between spores and gametophytes

Meiosis

Process of reproduction between sporophytes and spores

Mitosis

Process of reproduction between zygote and sporophytes

Metagenesis

The alternation of generations

Haploid

The condition where a cell has only one copy of every chromosome (n)

Diploid

The condition where a cell has two copies of every chromosome (2n)

Sporophyte

The diploid generation that gives rise to spores

Oogamy

The female gamete (e.g. egg cell) is significantly larger than the male gamete and is non-motile. The male gametes are typically highly motile spermatozoa competing for the fertilization of the immotile egg.

Isogamy

The gametes look alike and cannot be classified into "male" or "female."

Sporangium

The growth which holds spores

Gametophyte

The haploid generation that gives rise to gametes