What is the biological importance of Obelia?
O. dichotoma uses asexual and sexual reproduction and feeds on mainly zooplankton and fecal pellets. Obelia dichotoma has a complex relationship with the ecosystem and many economic systems….
| Obelia dichotoma | |
|---|---|
| Class: | Hydrozoa |
| Order: | Leptothecata |
| Family: | Campanulariidae |
| Genus: | Obelia |
What is a Obelia in biology?
Obelia is a sedentary, marine colonial life form that attaches to seaweeds, rocks, timber piles, and molluscan shells in shallow water. Obelia starts out as small, motionless animals with stalks and tentacles that resemble sea anemones. Hydroid polyps are another name for these little invertebrates.
What is the life cycle of Obelia?
Structure of Obelia Obelia throughout its life cycle takes two forms: polyp and medusa. The first form is diploblastic, two true tissue layers – an epidermis (ectodermis). In contrast, the second form is gastrodermis (endodermis), with a mesoglia which is jelly-like filling the area between the two tissue layers.
What is the classification of Obelia?
HydrozoansObelia / ClassHydrozoa are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. Wikipedia
What are the characteristics 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 is the scientific name of Obelia?
ObeliaObelia / Scientific name
Binomial name. Obelia longissima. (Pallas, 1766) Synonyms. Campanularia flabellata Hincks, 1866.
How does 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.
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. It exists in two principal form— I. The polyp.
How does Obelia reproduce asexually?
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 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 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.
What is the alternation of generation explain with the reference of 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 structures are used for reproduction in Obelia?
Reproductive organs: The medusae are dioecious, they have either four testes or four ovaries in the sub-umbrella just below the radial canals. A gonad has an outer ectoderm and inner endoderm with mesogloea between the two layers. The gonad has a small diverticulum of the radial canal.
What is alternation of generation in Obelia?
Obelia shows an alternation of generation between asexual and sexual forms. Polyps produce medusae asexually and medusae produce polyps sexually. Further reading: Coelom.
What type of reproduction does Obelia have?
Reproduction of Obelia medusae occurs sexually, eggs and sperm uniting to become small larvae surrounded by cilia. Although, beginning as a free moving individual, the larvae eventually settle, each one becoming the founding member of a new polyp colony.
What does the alternation of generations in ferns show?
The life cycle of the fern has two different stages; sporophyte, which releases spores, and gametophyte, which releases gametes. Gametophyte plants are haploid, sporophyte plants diploid. This type of life cycle is called alternation of generations. To follow the life cycle of the fern, begin at number one below.
What is cleavage in Obelia?
Cleavage: The fertilized egg undergoes cleavage which is equal and holoblastic (complete). The blastula is a hollow boll consisting of single layer of cells enclosing the blastocoel. This cavity gets completely filled up with cells budded from the wall of the blastula.
What is medulla and polyp stage in Obelia?
During the polyp stage, the mouth is situated at the top of the body, surrounded by tentacles, whereas during the medusa stage, the mouth is situated at the distal end of the main body structure. Four gonads lie in this main body structure, or manubrium. When food is taken in through the mouth, it enters the manubrium.