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What is alternation of generation in plant?

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Asked By: Severo Mikhaleiko | Last Updated: 23rd March, 2020
Alternation of generations describes a plant’s life cycle as it alternates between a sexual phase, or generation and an asexual phase. The sexual generation in plants produces gametes, or sex cells and is called the gametophyte generation. The asexual phase produces spores and is called the sporophyte generation.


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Keeping this in consideration, what does alternation of generation mean?

Alternation of generations (also known as metagenesis) is the type of life cycle that occurs in those plants and algae in the Archaeplastida and the Heterokontophyta that have distinct haploid sexual and diploid asexual stages. The haploid spores germinate and grow into a haploid gametophyte.

Subsequently, question is, what is alternation of generation in fungi? Alternation of generations is a reproductive cycle of certain vascular plants, fungi, and protists. Two gametes (originating from different organisms of the same species or from the same organism) combine to produce a zygote, which develops into a diploid plant of the sporophyte generation.

Likewise, people ask, why is a plant’s life cycle called an alternation of generations?

The multicellular haploid plant structure is called the gametophyte, which is formed from the spore and give rise to the haploid gametes. The fluctuation between these diploid and haploid stages that occurs in plants is called the alternation of generations.

What is alternation of generation in Pteridophytes?

There is a regular feature of alternation of generations. The gametophyte of sexual generation intervenes between meiosis and syngamy while the sporophyte or asexual generation intervenes between syngamy and meiosis. The haploid phase (n) is the gametophyte and the diploid phase (2n) is the sporophyte.

Why is alternation of generation important?

The alternation of generations allows for both the dynamic and volatile act of sexual reproduction and the steady and consistent act of asexual reproduction. When the sporophyte creates spores, the cells undergo meiosis, which allows the gametophyte generation to recombine the genetics present.

What is alternation of generation with example?

The haploid spores germinate and grow into a gametophyte which produces gametes by mitosis. Two gametes fuse to form a zygote, which develops into a sporophyte. The classic example is the mosses, where the green plant is a haploid gametophyte and the reproductive phase is the brown diploid sporophyte.

What are the two stages of alternation of generation?

In most plants meiosis and fertilization divide the life of the organism into two distinct phases or “generations”. The gametophyte generation begins with a spore produced by meiosis. The spore is haploid, and all the cells derived from it (by mitosis) are also haploid.

What is Sporophytic generation?

A sporophyte is a multicellular diploid generation found in plants and algae that undergo alternation of generations. It produces haploid spores that develop into a gametophyte. The gametophyte then makes gametes that fuse and grow into a sporophyte.

What are the two types of Gametophytes?

These spores develop into two distinct types of gametophytes; one type produces sperm and the other produces eggs. The male gametophyte develops reproductive organs called antheridia (produce sperm) and the female gametophyte develops archegonia (produce eggs).

Which best describes the alternation of generations?

A gametophyte is a haploid phase best describes the alternation of generations.

What is the advantage of alternation of generations?

Theoretical advantages of alternation of generations

One benefit of this is that a mutation that causes a lethal, or harmful, trait expression will cause the gametophyte to die; thus, the trait cannot be passed on to future generations, preserving the strength of the gene pool.

Is a spore haploid or diploid?

Spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes.

What is the plant life cycle?

The plant life cycle starts when a seed falls on the ground. The major stages of the flower life cycle are the seed, germination, growth, reproduction, pollination, and seed spreading stages. Seed Stage. The plant life cycle starts with a seed; every seed holds a miniature plant called the embryo.

Is alternation of generations unique to plants?

Is the alternation of generations unique to plants? Explain. Yes. There are 2 different multicellular stages unlike animals and it has one DIPLOID and one HAPLOID stage.

What happens during alternation of generations in plants?

Alternation of generations is a common element of all land plants. A haploid plant of the gametophyte generation makes gametes by mitosis. The zygote develops into a diploid plant of the sporophyte generation. This sporophyte makes spores through meiosis.

Do gymnosperms have alternation of generations?

Gymnosperms are unique plants because they produce naked seeds. This alternation of generations in gymnosperms, such as pine trees, means that there are multicellular stages that are haploid and diploid.

What is the life cycle of bryophytes?

As do all plants, bryophytes alternate a gametophytic generation with a sporophytic one (a sporic meiosis, a life cycle in which meiosis gives rise to spores, not gametes). Each of the haploid (1 n) spores is capable of developing into a multicellular, haploid individual, the gametophyte.

What is the difference between Sporophyte and Gametophyte?

Gametophytes are haploid (n) and have a single set of chromosomes, whereas Sporophytes are diploid (2n), i.e., they have two sets of chromosomes. A sporophyte reproduces asexually and a gametophyte sexually. Significance: For a diploid (2n) sporophyte to produce haploid (n) spores, the cells have to undergo meiosis.

What is the main function of the mature gametophyte?

What is the main function of the mature gametophyte? The main function of the gametophyte, once mature, is to produce the gametes, the reproductive sex cells which will fuse to form a zygote.

Which parts of the life cycle are haploid?

Majorly, the stages categorized into haploid and diploid, which undergo alternation of generations for every life cycle. Haploid stage consists of gametes that with a single set of chromosomes (n) to fertilize and produce zygote. This stage is termed as gametophyte stage.