What is planula stage?

What is planula stage?

The planula is the first larval stage of Aurelia, and is formed soon after the egg and sperm combine to form a zygote. The planula is lined with cilia and eventually settles, forming a scyphistoma. Planula larval stages are common to many Cnidarians.

How is a planula formed?

Fertilization of an egg within the body of a coral polyp is achieved from sperm that is released through the mouth of another polyp. The sperm and egg merge and form a planula larva, which matures inside the body of its mother. When the larva is ready, it gets spit out into the water through the mouth of its mother.

What is the difference between planula and Amphiblastula?

Planula is the ciliated, bilaterally symmetrical, flattened, free swimming larva of organisms in the phylum Cnidaria. … Amphiblastula is the free swimming larva of certain sponges.

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 the planula stage in cnidarians?

A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula.

Do all invertebrates have planula larva?

Many invertebrates (e.g., cnidarians) have a simple ciliated larva called a planula. Flukes have several larval stages, and annelids, mollusks, and crustaceans have various larval forms.

What is the function of Cnidocytes?

Cnidocytes (‘stinging cells’) are specialized cells that define the phylum Cnidaria (sea anemones, jellyfish, corals and hydras). They contain an explosive organelle called cnidocyst that acts as a 600 million-years-old microscopic injection system and is important for prey capture and anti-predator defense.

What are the characteristics of Coelenterates?

Characteristics. All coelenterates are aquatic, mostly marine. The bodyform is radially symmetrical, diploblastic and does not have a coelom. The body has a single opening, the hypostome, surrounded by sensory tentacles equipped with either nematocysts or colloblasts to capture mostly planktonic prey.

How do you say planula?

noun, plural planulae [plan-yuh-lee].

What is a Amphiblastula in biology?

: a free-swimming larva of certain sponges that is essentially a blastula with small flagellated cells in one hemisphere and large nonflagellated cells in the other.

What does the Amphiblastula do?

amphiblastula A poriferan (sponge) larva in which the area of flagellate cells is equal to the area of non-flagellate cells. At metamorphosis the flagellated cells move to the interior and become choanocytes.

What is Ephyra larva?

Ephyra larva is a kind of jellyfish. Complete answer: – Ephyra larva is an immature medusa stage. It comes into the world through metamorphosis of scyphistoma (which resembles a fixed polyp-like stage in the life of jellyfish). Its size is just a few millimetres.

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.

What are called polyps?

Coral organisms, called polyps, can live on their own, but are primarily associated with the spectacularly diverse limestone communities, or reefs, they construct.

What will the planula develop into over time?

The planula metamorphoses into a sessile (i.e. fixed-position), usually benthic (i.e. bottom dwelling) polyp called a ‘scyphistoma’ and it is the scyphistoma, still attached to the surface on which the planula settled, that produces a new free-swimming medusa.

What is the difference about cnidarians and Ctenophores?

Cnidarians live in both freshwater and marine habitats while ctenophores only live in the sea. … Cnidarians exhibit radial symmetry whereas ctenophores exhibit biradial symmetry. Both contain tentacles, surrounding their mouth. The main difference between cnidarians and ctenophores is their body symmetry.

What is a Manubrium in cnidaria?

The portion of a jellyfish or other cnidarian that bears the mouth at its tip. The uppermost of the three bony segments constituting the breastbone in mammals.

What does a larvae turn into?

The larva thus not only serves for dispersal but also feeds and grows before it transforms into an adult worm. … In insects the larva differs from the adult by the absence of wings but, in addition, may have a different mode of life and different way of feeding.

What is insect larvae called?

A larva (plural larvae) is the juvenile form of an insect. Different types of insect have other names for their larvae, for example, caterpillars are the larvae of butterflies and moths. … For insects that undergo incomplete metamorphosis the larvae are also called nymphs.

Are babies larva?

Insect baby is an informal term for larva, which is the immature form of insects. Larvae are known as a state of a group of animals such as amphibians, cnidarians, and insects that undergoes a metamorphosis before turning into adults. … From there, the larva will become a pupa, before turning into a complete adult.

What does the Gastrodermis do?

Gastrodermis helps in extracellular digestion of food in the gastrovascular cavity.

What are cnidocytes or Cnidoblasts?

A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one giant secretory organelle called a cnidocyst (also known as a cnida (plural cnidae) or nematocyst) that can deliver a sting to other organisms.

What is cnidocytes simple?

Cnidocytes are a distinctive feature of cnidarians (jellyfishes, sea anemones, corals, hydrae, etc.). These are explosive cells used by cnidarians in order to capture their prey (e.g. fish and crustaceans). These cells shoot off threadlike, often toxic, tubule inside the cnidocyst.

What are 5 characteristics of Coelenterates?

General characteristics of Phylum Coelenterata

What are Coelenterates give one example?

The Phylum Coelenterata consists of marine organisms that have a body that is radially symmetrical and a mouth that has sensory tentacles that help in capturing prey easily. Other animals belonging to the Phylum Coelenterata are hydra, comb jellies, true jellies, sea pens, coral animals, sea anemones and more.

Why Coelenterates are called cnidarians?

Coelenterates are called Cnidarians because they contain specialized cells called cnidoblasts. They possess stinging structures called nematocysts.