The alternation of generations, where plants alternate between haploid gametophyte and diploid sporophyte generations, describes the life cycles of plants. This gives plants the ability to reproduce both sexually and asexually. Generally, one generation is dominant in every plant. In nonvascular plants, gametophytes are dominant. Sporophytes are dominant in vascular plants. All plants follow the same general life cycle of diploid sporophytes producing haploid spores through meiosis, and haploid spores going through mitosis to produce gametes that combine to become diploids again.
Alternation of Generations: Change back and forth from one generation to the next between haploid and diploid stages in the life cycle of plants.
Haploid: Having only one chromosome of each type.
Gametophyte: Haploid generation in the life cycle of a plant that results from asexual reproduction.
Diploid: Having two of each type of chromosome (twice the amount of chromosomes in haploids).
Sporophyte: Diploid generation in the life cycle of a plant that results from sexual reproduction.
Sporangium (plural, sporangia): Structure inside diploid sporophytes that goes through meiosis to make spores.
Spore: Reproductive structure adapted for dispersal and surviving extended periods of time in unfavorable conditions.
Antheridium (plural, antheridia): Female reproductive organ that produces eggs.
Archegonium (plural, archegonia): Male reproductive organ that produces sperm with flagella.
Plants alternate between generations of haploid gametophytes and diploid sporophytes:
For every plant, one of the two generations is usually dominant.
Nonvascular plant: only type of plants with dominant gametophyte generation.
All vascular plants have dominant sporophytes.
Gymnosperms reproduce through cones
Angiosperm reproduction happens in flowers