What is metagenesis class 11?
Matthew Wilson Answer: Metagenesis is the phenomenon in which one generation of certain plants and animals reproduce asexually, followed by the sexually reproducing generation. ... Coelenterates exhibits metagenesis (e.g., Obelia - Wikipedia
What is metagenesis explain?
The definition of metagenesis is the reproduction cycle of an organism that alternates between sexual and asexual generations. An example of metagenesis is the reproduction cycle of a cnidarian. ... Reproduction in which there is alternation of an asexual with a sexual generation, as in many cnidarians.
What is metagenesis mention one example?
Answer : The phenomenon of alteration of generations between sexual and asexual mode of reproduction is called metagenesis. This phenomenon is exhibited by Obelia in which polyps produce medusae asexually while medusa produces polyp sexually.
What is metagenesis in which phylum?
This cycle is known as the alternation of generations or metagenesis. Metagenesis is shown by organisms belonging to the phylum Cnidaria and some algae, fungi, mosses, ferns, and seed plants.
What is metagenesis BYJU's?
Metagenesis refers to the alternation between sexual and asexual stages. E.g. Cnidarians such as Obelia exist in both polyp and medusa forms and show metagenesis. Polyps develop from medusae sexually and medusae develop from polyps asexually.
What is metagenesis ? Mention an example which exhibits this phenomenon.
28 related questions foundWhere is metagenesis found?
These species are characterised by their ability to exhibit both the stages of polyp and medusa as a part of their life cycle. As polyp represents the asexual form while the medulla represents the sexual form, it is quite evident that the metagenesis is common in Obelia.
What is polymorphism in biology class 11?
The phenomenon when an organism have different kinds of zooids for different functions is called polymorphism e.g., cnidarians.
What is metagenesis in cnidaria?
Some cnidarians exist in polyp and medusa forms. Such cnidarians show metagenesis. It is the phenomenon of alternation of generations in which polyps produce medusae asexually and medusae produce polyps sexually. Metagenesis is observed in Obelia.
What is polyp and medusa?
There are two basic cnidarian body shapes: a polyp form, which is attached to a surface; and an upside-down free-floating form called a medusa. Some cnidarians change form at different phases of their life cycle, while others remain in one form for their entire life.
What is difference between polyp and medusa?
Sessile structures are called polyps while the swimming forms are called medusa. The key difference between polyp and medusa is that polyp is a fixed, cylindrical structure, representing the asexual stage and medusa is a free swimming, umbrella-like structure, representing the sexual stage.
What is bioluminescence class 11th?
- Bioluminescence is the production and emission of the light by the living organisms. - Bioluminescence is a form of chemiluminescence (production of light from a chemical reaction).
What is metagenesis in Obelia?
METAGENESIS The life cycle of Obelia represents a remarkable example of alternation of generation where the asexual and sessile phase of Obelia reproduces asexually by budding and gives rise to sexual and free-swimming medusa. ... This phenomenon of alternation between two diploid phases is termed as metagenesis.
What is the role of feathers Class 11?
Answer: Feathers are the epidermal growth that forms distinctive outer covering or plumage in birds. Feathers play a variety of roles like (i) They help in creating airfoil shape for wings so, as to provide lift and help in flight. (ii) Feathers helps in maintaining body temperature.
What is metagenesis short note?
Metagenesis Introduction
Alternation of generation is also known as metagenesis. It is a phenomenon whereby, in the life history of an organism, a diploid asexual phase and a haploid sexual phase regularly alternate with each other. This type of true alternation of generation is present in plants like mosses and ferns.
What is Flame cell Class 11?
Flame cells is a specialised excretory cell found in the simplest freshwater invertebrates, including flatworms. They function like a kidney, removing waste material. It is a hollow cup shaped cell containing a bunch of cilia, whose movement draws in waste products and wafts them out through a tubule.
What is polymorphism in cnidaria?
Polymorphism refers to the occurrence of structurally and functionally more than two different types of individuals within the same organism. It is a characteristic feature of Cnidarians, particularly the polyp and medusa forms, or of zooids within colonial organisms like those in Hydrozoa.
What is polip?
A polyp is a projecting growth of tissue from a surface in the body, usually a mucous membrane. Polyps can develop in the: colon and rectum. ear canal. cervix.
What is planula in zoology?
Planula, plural planulae, free-swimming or crawling larval type common in many species of the phylum Cnidaria (e.g., jellyfish, corals, and sea anemones). The planula body is more or less cylindrical or egg-shaped and bears numerous cilia (tiny hairlike projections), which are used for locomotion.
Is Coral medusa or polyp?
Classes. In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species undergoing a life cycle with both a polyp stage and a medusa stage.
What is metagenesis in zoology?
metagenesis The occurrence, during the life cycle of an organism, of two types of individual, both diploid, both of which reproduce, one sexually and the other asexually. The term is sometimes used loosely (but incorrectly) as a synonym for the alternation of generations. A Dictionary of Zoology MICHAEL ALLABY.
Which organisms exhibit metagenesis among cnidarians?
The alteration of generation between the sexual and and asexual phase within the same species is called as mutagenesis. It generally shown by cnidarians which exhibits both forms, polyps and medusa.
What is metagenesis explain how Cnidaria shows metagenesis with example?
Metagenesis is referred to the phenomenon of alternation of generation shown by cnidarians which exhibit both forms- polyps and medusae . Polyps produce medusae asexually and medusae form the polyps sexually (e.g., Obelia).
What is meant by an allele?
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. ... Genotypes are described as homozygous if there are two identical alleles at a particular locus and as heterozygous if the two alleles differ.
What is Morphism in biology?
noun. 1Biology. The state or condition of being a morph; variance of form in an animal or plant species; polymorphism.
What causes polymorphisms?
polymorphism can be maintained by a balance between variation created by new mutations and natural selection (see mutational load). genetic variation may be caused by frequency-dependent selection. multiple niche polymorphism exists when different genotypes should have different fitnesses in different niches.
