Alternation Of Generations Life Cycle

The multicellular diploid plant structure is called the sporophyte which produces spores through meiotic asexual division.

Alternation of generations life cycle. The multicellular haploid plant structure is called the gametophyte which is formed from the spore and give rise to the haploid gametes. It is a phenomenon of the succession of two or more generations in the life cycle of an organism where there is a generation that reproduces sexually with one generation or more that reproduce asexually There are some plant and animal species can breed both asexually and sexually during their life cycle to gain the adventure of both methods together. In Plants there are 2 phases of the life-cycle.

Useful notes on alternation of generations in the life-cycle of a bryophyte. Alternation of Generations is also known as metagenesis. Since mitosis occurs only in the haploid phase the life cycle is called the haplontic life cycle wherein the gametophyte is the dominant phase.

The term alternation of generations refers only to the sexual cycle. Alternation of generations is a common factor in plants algae and fungi. Alternation of Generations Sexual reproduction involves the two alternating processes of meiosis and fertilization.

Alternation of generations is defined as the alternation of multicellular diploid and haploid forms in the organisms life cycle regardless of whether or not these forms are free-living. The sexual generation in plants produces gametes or sex cells and is called the gametophyte generation. This is in contrast to animals in which the only multicellular phase is the diploid organism such as the human man or woman whereas the haploid phase is a single egg or sperm cell.

Organisms may have asexual reproduction as well. Alternation of generations is a type of life cycle found in terrestrial plants and some algae in which subsequent generations of individuals alternate between haploid and diploid organisms. This process of alternation of generations was demonstrated for the first time in 1851 by Hofmeister.

The zygote2n divides to form the sporophyte2n and sporesn divide to form the gametophyten. In some species such as the alga Ulva lactuca the diploid and haploid forms are indeed both free-living independent organisms essentially identical in appearance and therefore said to be isomorphic. There is a rotation between these generations.