Alternation of generation in pteridophytes. Why seed is not formed in pteridophytes? 2022-10-25

Alternation of generation in pteridophytes Rating: 5,8/10 408 reviews

Animal testing is the use of animals in scientific and medical research to develop new products or to test the safety and effectiveness of existing ones. It is a controversial practice that has been the subject of much debate and controversy for many years. While proponents of animal testing argue that it is necessary for the advancement of medical science and the development of new treatments and therapies, opponents argue that it is unethical, unnecessary, and inhumane.

One of the main arguments against animal testing is that it is unethical. Many people believe that animals have the same rights as humans and that it is wrong to use them for experimentation. They argue that animals are sentient beings with the ability to feel pain and suffering, and that it is therefore wrong to subject them to procedures that may cause them harm.

Another argument against animal testing is that it is unnecessary. Many opponents of animal testing argue that there are alternative methods of testing that are just as effective and more humane. For example, researchers can use cell cultures, computer models, and human volunteers to test the safety and effectiveness of new products. These methods are not only more humane, but they also offer more accurate and reliable results, since they more closely mimic human biology and behavior.

Finally, opponents of animal testing argue that it is inhumane. Many animals used in research are subjected to harsh conditions, including confinement, deprivation, and physical and psychological stress. They may also be subjected to painful and invasive procedures, such as surgery and injection. These conditions can cause animals to suffer, and many people believe that it is wrong to subject animals to such treatment.

In conclusion, animal testing is wrong because it is unethical, unnecessary, and inhumane. While it may be tempting to use animals in scientific research to advance medical science and develop new treatments and therapies, there are more humane and effective alternatives available. We should strive to find ways to test new products and treatments that do not rely on animal suffering, and instead focus on methods that are more ethical, accurate, and reliable.

Life Cycle of a Plant and Alteration of Generations: Examples and Videos

alternation of generation in pteridophytes

Whittier 1962 and Whittier and Steeves 1960,1962 could induce the apogamous production of sporophytes from a number of othwerwise normal fern gametophytes by the incorporation of suitable sugar concentrations in the culture medium. The capsule is composed of a single layer of thin walled cells stomium and highly thickened cells annulus. Filicophyta Flow chart of Pteridophyta: 1. ADVERTISEMENTS: The spores are of two kinds-the smaller spores are known as microspores or male spores and are developed in microsporangia, while the larger spores are called megaspores or female spores and are formed in megasporangia. In general, clubmosses are slender, herbaceous plants that have leaves called microphylls. The sporophytes are being differentiated into stems, leaves and roots. Which plant does not produce seeds? Life Cycle of Pteridophyta Pteridophytes show alternation of generations.


Next

Pteridophytes: Useful Notes on Alternation of Generations of Pteridophytes

alternation of generation in pteridophytes

The female prothallus is well developed and larger in size. He observed two types of morphologically distinct individual in the life cycle of mosses and fern in the vascular plants the sporophyte individual is a complicated, independent and a dominant generation, whereas the gametophyte is comparatively much reduced. Bryophytes have the plant body as haploid gametophyte. They do not produce flowers and seeds, hence they are also called Cryptogams. On separation of these buds grow into new plant. Both sporophytes and gametophytes have an independent existence.

Next

Pteridophytes (Spore Producing Plants: Ferns and More)

alternation of generation in pteridophytes

What are the characteristics of pteridophyte? Some genera evolved the formation of two types of spores, i. Two hypotheses have been advanced to explain these difference. Stems The majority of the branches are herbaceous, but some are woody. Gametophyte The gametophyte, sometimes referred to as a prothallus, is multicellular, microscopic, and generally short-lived. The tropics have the largest diversity of Pteridophytes, with just around 600 species adaptable to temperate conditions.

Next

Alternation of generation in Pteridophytes

alternation of generation in pteridophytes

Speaking of benefits: A. These are also known as club mosses. In Bryophytes, the dominant phase in the life-cycle is the gametophyte, for the sporophyte is retained upon it throughout its life and is either partially or completely dependent on it for nutrition. These individuals may be identical or dissimilar in appearance. The leaves are arranged spirally.

Next

PTERIDOPHYTA

alternation of generation in pteridophytes

ADVERTISEMENTS: Pteridophytes: Useful notes on Alternation of Generations of Pteridophytes! Contrary to it in pteridophytes the sporophyte is the dominant generation, for it very soon becomes independent of the gametophyte prothallus and grows to a much greater size. These are present in all kinds of habitats. The sporophytic or asexual generation is diploid 2n , while the gametophytic or sexual generation is haploid n. They grow in terrestrial habitats. Dry fronds of many ferns are used as a cattle feed.

Next

Why seed is not formed in pteridophytes?

alternation of generation in pteridophytes

Pteridophytes include ferns like this. The older embryos, however, produced normal sporophytes. Vascular Tissues The vascular tissues have a good amount of development. The plant body has roots, stems, and leaves. This theory postulates that a change in the genetic system in the early progenitors of land plants brought into being two distinct and independent individuals in the life cycle of the land plants. Homosporous individual produce only one type of spores, whereas heterosporous individuals produce two types of morphologically distinct spores i. The prothallus reproduces sexually by fusion of male and female gametes and gives rise to sporophytic structure zygote.

Next

ALTERNATION OF GENERATIONS IN PTERIDOPHYTES

alternation of generation in pteridophytes

Tmesipteris, on the other hand, grows mainly in Australia, New Zealand, and Ophioglossales Ophioglossales contains one family, Ophioglossaceae, otherwise known as tongue ferns. Bell 1970 opined that the totality of evidence leads us to perceive the life cycle as an integrated sequence of events, each key event coded by a specific set of the genome. If you're trying to lose weight then you certainly need to start using this brand new custom keto diet. Pteridophyta, on the other hand, is a primitive terrestrial plant that has evolved. Apogamy is the formation of new sporophyte directly from vegetative tissue of prothallus gametophyte. Bower discussed it in detail in 1935. Their life cycle is similar to seed-bearing plants, however, the pteridophytes differ from mosses and seed plants as both haploid gametophyte and diploid sporophyte generations are independent and free-living.

Next

Pteridophytes

alternation of generation in pteridophytes

They presumed that these early land plants migrated from amphibious situations; where water was available in plenty for effecting sexual reproduction , to terrestrial habitats where waster was available only during rainy seasons and extensive dew. Leaves Leaves come in three varieties: scale, small sessile, and huge petiolate compound. The main genus, Equisetum, contains horsetails and scouring rushes. As they produce neither flowers nor seeds, they are referred to as Cryptogams. In conclusion, it can be said that we have learnt about the different classifications of Pteridophytes, we have also learnt about the life cycle of a Pteridophyte.

Next

Pteridophyta

alternation of generation in pteridophytes

They germinate to give rise to the gametophyte, known as prothallus. The dominant sporophyte uses meiosis to produce spores. Homosporous plants produce only one type of spore that contains both male and female parts. In Bryophytes which stage is dominant? Modern evidence provides more support from the homologous origin of alternation of generations Stebbins, 1960 but even if we accept this theory we have still to account for the morphological differences between the sporophyte and the gametophyte. Sporophylls can also form cones or strobili, which are compact structures.

Next