What is the life cycle of Obelia?
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.
What stage of the life cycle is Obelia a cnidarian?
Structure of Obelia Obelia belongs to the phylum Cnidaria. It takes two forms throughout its life cycle — polyp and medusa.
What is Obelia biology?
Obelia refers to a genus of invertebrate marine animals which are available throughout the Earth’s oceans. It involves mainly marine and some freshwater animal species.
What is the reproduction of Obelia?
The Obelia life cycle begins as immobile polyp colonies that contain digestive hydranth and reproductive gonangium units. The gonangium reproduce asexually, releasing medusa by budding. The medusa, or jellyfish, swim freely and reproduce sexually, releasing eggs and sperm into the water.
What is metagenesis explain with life cycle of 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 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 are the characteristics of Obelia?
- 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.
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 the habitat of Obelia?
What is Metagenesis explain with life cycle of Obelia?
What is the function of Obelia?
Food enters the body of an obelia through the mouth and enters the manubrium. Food is distributed all through the body of an obelia through a canal system that comprises 4 radial canals and an outer ring. In the end, the food is expelled through the mouth. Obelias have an incomplete digestive tract.
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.
What is alternation of generation explain it with reference to the life cycle of Obelia?
LIFE CYCLE OF OBELIA – THE METAGENESIS Medusae produce eggs which after fertilization develop into hydroids. The hydroids produce medusae by asexual budding. This phenomenon was formerly called as “alternation of generations.” Thus, in fact, there is no true alternation of generations in Obelia.
What does Obelia feed on?
The medusae of most Obelia species do not grow well on a diet of Artemia salina nauplii, the usual food for laboratory-reared hydrozoans, and their rearing is often difficult. Previous observations reported that Obelia medusae might eat phytoplankton, driven to the mouth by movements of both the bell and the tentacles.
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.
Is Obelia a plant or animal?
What is metagenesis in Obelia?
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.
What is Metagenesis in obelia?
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.