Title: gametophyte | Definition & Examples | Britannica
Headings: Gametophyte
Gametophyte
biology

Content: Emerging from the spore at the time of germination...
In the gametophyte phase, which is haploid (having a single set of chromosomes ), male and female organs (gametangia) develop and produce eggs and sperm ( gametes) through simple mitosis for sexual reproduction. When these unite in fertilization, the zygote then develops into the diploid (having two sets of chromosomes) sporophyte phase, which produces unicellular spores through meiosis. These, in turn, develop into a new gametophyte phase. moss life cycle
Life cycle of moss. Encyclopædia Britannica, Inc.
The character and relative extent of the two phases vary greatly among different groups of plants and algae. Over the course of evolution, the gametophyte stage has become progressively reduced. Thus, the gametophyte stage is dominant in the more primitive (nonvascular) plants ( bryophytes ), whereas the sporophyte is the dominant phase in the life cycle of higher (i.e., vascular) plants. In algae, the dominant phase often depends on environmental conditions, though some species have determinant life cycles. This article was most recently revised and updated by Melissa Petruzzello, Assistant Editor. History at your fingertips
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