Table of Contents
What is the structure of Obelia?
Structure. 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.
Is Obelia a plant or an animal?
Obelia, genus of invertebrate marine animals of the class Hydrozoa (phylum Cnidaria). The genus, widely distributed in all the oceans, is represented by many species. The animal begins life as a polyp—a tentacled, stalklike form resembling a small sea anemone attached to the ocean bottom or some other solid surface.
What is Obelia and characteristics?
Obelia is a very tiny marine hydroid with a height of 2 cm or a little more. The obelia’s body has two kinds of filaments which are vertical hydrocaulus and horizontal hydrorhiza. Obelia’s life cycle begins as hydroid polyps. Hydroid polyps are small, immobile animals that have tentacles and stalks.
What is Obelia life cycle?
Obelia’s life cycle includes both asexual and sexual generations, which alternate to complete the life cycle. Obelia’s life cycle alternates between hydroid and medusoid phases on a regular occasion. Medusae lay eggs, which develop into hydroids following fertilisation. Asexual budding is how hydroids produce medusae.
What is the scientific name of Obelia?
ObeliaObelia / Scientific name
Why Obelia is called sea fur?
Obelia is sedentary, marine colonial form found attached on the surface of sea weeds, molluscan shells, rocks and wooden piles in shallow water up to 80 metres in depth. Obelia is cosmopolitan in distribution, forming a whitish or light-brown plant-like fur in the sea; hence, the common name sea-fur is assigned to it.
How does Obelia eat?
Contrary to other Hydromedusae that are macrophagous, Obelia is a microphagous and filter-feeding medusa, at least at the onset of its medusan life. As Cnidaria evolved before their current metazoan prey, their ancestral diet was probably microphagous.
What is the habit and habitat of Obelia?
Habit and Habitat: Obelia is typically marine, colonial and sedentary. It is found attached on piles, rocks and sea weeds in shallow water. The polyp represents the asexual phase which is a prominent branched hydroid colony found attached to rocks, stones, shells of animals, wooden pilings etc.
What classification is Obelia?
HydrozoansObelia / Class
How do Obelia reproduce?
Through filaments, Obelia attach to various surfaces, most often the ocean floor, but sometimes seaweed, shells or wharves. Reproduction of Obelia in this life stage occurs by budding, new polyps growing and breaking away to become members of the increasingly larger colony.
Does Obelia have cell walls?
They have a single- layered core of vacuolated endoderm cells with thick walls inside a layer of ectoderm. Ectoderm: It consists of long, conical columnar epitheliomuscular cells, their inner ends are produced into muscular processes which run longitudinally.
What is polyp and medusa in Obelia?
In organisms that exhibit both forms, such as members of the cosmopolitan genus Obelia, the polyp is the asexual stage and the medusa the sexual stage. In such organisms the polyp, by budding, gives rise to medusae, which either detach themselves and swim away or remain permanently attached to the polyp.
What is the mouth of Obelia?
The mouth is at the tip of a process, the manubrium that elevates it above the oral surface. The opposite pole is the aboral end. The imaginary line connecting the oral and aboral poles is the axis of symmetry around which the radial symmetry of the body is organized.
What’s the difference between polyp and medusa?
Polyp are sessile while medusa are mobile. Polyp present a tubular shape with the mouth facing the water upwards,while medusa present a bell shape with the mouth facing the water downwards. Polyp do not have a manubrium, while medusa of the class Hydrozoa present a tube hanging down from the bell known as manubrium.
What is polyp of Obelia?
The polyp members of Obelia are asexual, stalk-like, and usually attached to the ocean floor, rocks, shells, or other surfaces. The polyps generate additional polyps by budding, creating a branching colony of the organisms that has a structure similar to that of a tree.
What is medusa and polyp?
Introduction. polyp and medusa, names for the two body forms, one nonmotile and one typically free swimming, found in the aquatic invertebrate phylum Cnidaria (the coelenterates). Some animals of this group are always polyps, some are always medusae, and some exhibit both a polyp and a medusa stage in their life cycle.
What is medusa form?
medusa, in zoology, one of two principal body types occurring in members of the invertebrate animal phylum Cnidaria. It is the typical form of the jellyfish. The medusoid body is bell- or umbrella-shaped. Hanging downward from the centre is a stalklike structure, the manubrium, bearing the mouth at its tip.
What is difference between jellyfish and obelia?
Obelia refers to a genus of sedentary colonial coelenterates with upright branching stems bearing minute cups in which the polyps sit while jellyfish refers to a free-swimming marine coelenterate with a gelatinous bell- or saucer-shaped body that is typically transparent and has stinging tentacles around the edge.
In this article we will discuss about the structure of obelia. This will also help you to draw the structure and diagram of obelia. 1. It is the slide of obelia, which is a marine, colonial and arborescent animal. 2. It is found attached to submerged objects like rocks and weeds etc.
What is the life cycle of an Obelia?
The common term for obelia happens to be sea fur. Also, a very unique aspect of this animal is that their reproduction strategy takes place two distinct stages. Furthermore, it takes two generations to complete. Obelia throughout its life cycle takes two forms: polyp and medusa.
What is Obelia slide?
It is the slide of obelia, which is a marine, colonial and arborescent animal. 2. It is found attached to submerged objects like rocks and weeds etc. 3.
How are hydrula and Obelia formed?
The free end forms a manubrium with a mouth and a circlet of tentacles. Thus, a simple polyp or hydrula is formed which grows a hydrorhiza from its base, from which an Obelia colony is formed by budding.