Can You Explain The Significance Of Alternation Of Generation?

Alternation of generation is very significant because:It promotes the chances of survival of organisms.The populations become increasingly better adapted to environment.

Better chance for survival:

During the formation of spores from spore mother cells by meiotic division reshuffling of genes occurs. As consequences, a great variety of spores with different genetic make up are produced. These spores in turn produce gametophytes with different genetic combinations. The gametophytes with better genetic make up will have a better chance for survival in the environment. On the other hand, the gametophytes with less advantages characteristics will be eliminated. There is no reshuffling of genes during gametogensis in gametophyte as gametes are produced after mitosis.

Better adapted to environment:

The oospore developing after fertilization now has a new genetic make up as compared to the parent. This genetic variation passes to the new sporophytes which on maturity once again produces further genetic recombination which is transferred to the gametophytes. In the long run, this will allow the populations to become increasingly better adapted to their environment.

Definition:

It is the phenomenon in the life cycle of many plants in which haploid gametophytes and diploid sporophyte regularly alternates with each other.

Explanation:
In the life history of liverworts, mosses and hornworts there are two distinct phases or generations.

Gametophyte:
The gametophytes is the dominate generation because it is more conspicuous. It produces gametes called spermatozoids and eggs, therefore called gametes producing generation. A haploid spermatozoid fuses with a haploid egg to produce diploid oospore.The oospore produces a totally different plant called sporophyte (also called sporogonium).

Sporophytes:
The sporophyte is a less conspicuous generation, which is usually differentiated into foot, seta and capsule. Spores develop with in the capsule by meiosis from spore mother cells. The sporophyte produces spores and is, therefore, called spore producing generation. Each spore on germination gives rise to the gametophyte.

Thus in the life history of a bryophytic plant, the two generations, the gametophyte and the sporophyte, regularly alternate with each other. The phenomenon of alternation of gametophte and sporophyte in the life history of plant is called alternation of generations.