What are nematocysts and its functions?
Nematocysts are organelles that have stinging cells. They are present in Cnidarians. Nematocyst paralyses the preys by injecting poison and helps Cnidarians to catch their prey.
What are nematocysts class 11?
Hint: A nematocyst or a cnidocyte is a type of an explosive cell which contains an enormous organelle known as a cnidocyst. The nematocyst is a minute, elongated, and spherical capsule which is present exclusively in the members of the phylum Coelenterata which contains jellyfish, corals, and sea anemones.
What are nematocysts Class 5?
A capsule within specialized cells in the tentacles of cnidarians, such as jellyfish and corals, containing a barbed, threadlike tube that delivers a toxic sting to predators and prey.
What is the definition of Nematocyst?
Nematocyst, minute, elongated, or spherical capsule produced exclusively by members of the phylum Cnidaria (e.g., jellyfish, corals, sea anemones). Several such capsules occur on the body surface.
What does Metagenesis mean?
alternation of generations
What is Metagenesis give example?
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. (biology) The production of sexual and asexual organisms in alternate generations.
What is Coelenterate Metagenesis?
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 Metagenesis Class 11 example?
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) where polyp form alternates with medusa in its life cycle.
What is Metamerism Class 11?
Metamers are the isomers having the same molecular formula but different alkyl groups on two sides of functional groups. This phenomenon of isomerism is called metamerism. You can give an example of diethyl ether and methyl propyl ether.
What is the role of feathers Class 11?
It means that they prevent the loss of heat from the body. Therefore, feathers help in thermoregulation or control the temperature of the organism’s body. The other functions of feathers are that they help in making the bodies of birds streamlined. Streamlined bodies cut easily through the air and aid birds in flying.
What animals show Metagenesis?
Answer. Obelia animal exhibits Metagenesis.
Does Aurelia show Metagenesis?
Option C: Aurelia or commonly moon jellies is a cluster of 13 different species and is widely distributed across marine environments. No metagenesis is observed in the case of Aurelia.
Where is Metagenesis found?
Metagenesis can be seen in physalia. Metagenesis is a process which takes place in algae and primitive plants. Here the plant is able to perform both sexual and asexual reproduction.
What do you mean by Metagenesis give an example of an animal that shows Metagenesis?
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 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.
Which generation is dominant in fungi?
In bryophytes, such as mosses and liverworts, the gametophyte is the dominant life phase, whereas in angiosperms and gymnosperms the sporophyte is dominant. The haploid phase is also dominant among fungi.
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.
What is meant by Metamerism?
1 : the condition of having or the stage of evolutionary development characterized by a body made up of metameres The basic principle of arthropod design is metamerism, the construction of the body from an extended series of repeated segments.—
What is the life cycle of obelia?
Through its life cycle, Obelia take two forms: polyp and medusa. They are diploblastic, with two true tissue layers—an epidermis (ectodermis) and a gastrodermis (endodermis)—with a jelly-like mesoglea filling the area between the two true tissue layers. They carry a nerve net with no brain or ganglia.