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2021-05-15

What is the relationship between the Sporophyte and gametophyte generations?

What is the relationship between the Sporophyte and gametophyte generations?

Diploid sporophyte cells undergo meiosis to produce haploid spores. Each spore goes through mitotic divisions to yield a multicellular, haploid gametophyte. Mitotic divisions within the gametophyte are required to produce the gametes. The diploid sporophyte results from the fusion of two gametes.

What is produced by the gametophyte and Sporophyte stage?

Plants have two distinct stages in their lifecycle: the gametophyte stage and the sporophyte stage. After reaching maturity, the diploid sporophyte produces spores by meiosis, which in turn divide by mitosis to produce the haploid gametophyte. The new gametophyte produces gametes, and the cycle continues.

What is Haplobiontic life cycle?

This is the life cycle in which the diploid phase is followed by two dissimilar haploid generations. In plants like Nemalion, Batrochospermum the gametophyte haploid plant produces the zygote during sexual fusion. This kind of life cycle is called haplobiontic type. …

What is triphasic life cycle?

The triphasic life cycle includes an alternation of two diploid or sporophyte generations. There are two diploid phases and one haploid phase. Red algae show a triphasic life cycle. Red algae also called rhodophyta is one of the oldest groups of eukaryotic algae.

What is Heteromorphic life cycle?

Species with heteromorphic life cycle have a large multicellular body in one generation but have a microscopic body in the other generation of a year. In contrast, isomorphic species have both diploid and haploid life forms with very similar morphology, having more than two generations in a year.

What are the two types of life cycles of algae?

There are five different types of life cycles in algae based on the number of haploid and diploid generations.

  • Haplontic Life Cycle.
  • Diplontic Life Cycle.
  • Haplo-diplontic Life Cycle.

What type of life cycle is present in algae?

The haplontic life forms produce the gametes through mitosis. After fertilization a zygote is formed: this cell is the only diploid cell in the entire life cycle. It is thus that same zygotic cell that later undergoes meiosis. A haploid life cycle is found in most fungi and in some green algae like Chlamydomonas./span>

Which type of life cycle is found in Fucus?

diplontic life-cylic

What is the life cycle of Laminaria?

Laminaria exhibits a diplohaplontic life cycle, with macroscopic sporophytes followed by a microscopic gametophyte with an oogamous mode of sexual reproduction (Fig. 3.11).

What is the ploidy of Fucus?

Fucus (rockweed), a brown alga, displays a diploid life history. The zygote (2n) becomes an embryo (very young sporophyte) and developes into the mature Fucus with receptacles at the tip of the algae.

What is the life cycle of Volvox?

Haploid life cycle occurs in green algae. Volvox, for example is a colonial green algae in which both male gametes and egg are produced in the 1n stage, which then fuse together to form a zygospore, an encysted zygote that is protected from the harsh conditions of the environment.

What is Plakea stage?

This stage is called plakea stage or cruciate plate (Fig. 3.53D). The 4th division forms 16 celled stage (Fig. 3.53E) and at that time it becomes a hollow sphere with an opening towards the outer side, called phialopore. The division of cells continues up to the number specific for a particular species.

What is the range of cells in a Coenobium of Volvox?

500 to 50,000

How does Volvox reproduce asexually?

Sexual reproduction is common, with gametes that have two or four flagella. Asexual reproduction is by cell division (Protococcus), motile or nonmotile spores (Ulothrix, Oedogonium), and fragmentation.

Is Volvox motile or nonmotile?

All Gametes Motile in some (not all) Algae In some related species, sexual fusion is between larger and smaller motile cells, which may be called male and female; the female gametes may, as in the colonial genus Volvox, lose their flagella and become nonmotile, so becoming more like eggs.

Why is thallus of Vaucheria called Siphonaceous?

The filaments are non-septate, the protoplasm with many nuclei is continuous along the entire length of thallus thus the coenocytic Vaucheria thallus makes siphonaceous structure (Fig. 1A, B).

Are cross walls present in Vaucheria?

Hoshaw/Encyclopædia Britannica, Inc. Vaucheria species are characterized by multinucleate tubular branches that lack cross walls except when associated with reproductive organs or when injured. Sexual reproduction also occurs.

What is Gongrosira stage short answer?

Each part develops cysts or hypnospores. This stage of Vaucheria is called Gongrosira stage as it resembles the alga Gongrosira. The cyst ruptures in favourable conditions and protoplast comes out by amoeboid movement. This protoplast become spherical and secretes new wall./span>

In which class of algae Vaucheria is included?

Xanthophyceae

What is Synzoospores?

The zoospore of vaucheria is a compound structure which is formed by the failure of the protoplast within the zoosporangium to divide into uninucleate, biflagellate zoospore. It is also known as Synzoospore or conidiospores and these spores generally develop in aquatic forms of vaucheria.