Question

What is the fern life cycle?

Answer 1

Hint: Ferns are vascular plants with leaves. While they, like conifers and flowering plants, have veins that allow water and nutrients to flow, their life cycle is extremely different. Conifers and blooming plants have adapted to withstand harsh, arid environments. Ferns need water to reproduce sexually. In the absence of water the ferns can also reproduce asexually through various means.

Complete answer:
The fern has two phases in its life cycle: sporophyte, which produces spores, and gametophyte, which produces gametes. Sporophyte plants are diploid, while gametophyte plants are haploid. Alternation of generations is the term for this sort of life cycle.
The various steps in the fern life cycle are as follows:
1. Meiosis, the same mechanism that creates eggs and sperm in mammals and flowering plants, produces haploid spores in the diploid sporophyte.
2. Mitosis transforms each spore into a photosynthetic prothallus (gametophyte). Each cell in the prothallus is haploid because mitosis preserves the number of chromosomes. This plantlet is a fraction of the size of a sporophyte fern.
3. Mitosis generates gametes in each prothallus. Because the cells are already haploid, meiosis is not required. A prothallus will frequently generate both sperm and eggs on the same plantlet. The gametophyte has leaflets and rhizomes, whereas the sporophyte has fronds and rhizomes. Sperm is generated within the gametophyte in a structure called an antheridium. In a similar way, the egg is formed from an archegonium.
4. Sperms utilise their flagella to swim to an egg and fertilise it when there is water present.
5. The fertilised egg is still connected to the prothallus after fertilisation. The egg is a diploid zygote made up of DNA from both the egg and the sperm. The life cycle is completed when the zygote develops into a diploid sporophyte by mitosis.

Note:
Ferns can also reproduce asexually. A sporophyte transforms into a gametophyte without fertilisation in apogamy. When the circumstances are too dry for fertilisation, ferns adopt this technique of reproduction. At proliferous frond tips, ferns can generate baby ferns. The weight of the young fern leads the frond to droop toward the earth as it grows. The baby fern may survive without the parent plant after it has established roots.