What is planula larva in biology?

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 larva of coelenterates has an elongated shape and cilia covering its entire surface.

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In this regard, what is a planula larvae?

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.

what causes a planula larvae to settle? The fertilized eggs develop into free-swimming planula larvae that settle to form primary polyps. Polyps also bud medusae that become sexually mature males or females. A fertilized egg develops to form a planula larva that then develops into a polyp.

Also asked, what is the larva of cnidarian called?

The zygote (fertilized egg) develops into what is called a planula larva—the larvae of cnidarians.

What type of symmetry do cnidarians have?

Radial symmetry

Related Question Answers

What is Parenchymula?

parenchymula A sponge larva in which the area of non-flagellate cells is very small. A Dictionary of Zoology. × "parenchymula ." A Dictionary of Zoology . .

Does Coral have sperm?

Coral reproductive methods vary according to the species. Some species, such as brain and star corals, are hermaphrodites, meaning they produce both sperm and eggs at the same time. In these species, all of the polyps in one colony produce only sperm, and all of the polyps in another colony produce only eggs.

What is Parenchymula larva?

involves a ciliated parenchymula-larva. The released larva swims around for a while and then, after a period of between 3 and 48 hours, it attaches, usually with the anterior, larval cavity-bearing pole, onto the sub- stratum.

What is baby coral called?

When an egg and a sperm meet they form a larva known as a planula. The baby coral looks like a little tiny jellyfish and floats around near the surface at first, and then in the water column until it finds a suitable space to call home - usually a hard surface to attach to.

How do Medusa reproduce?

polyp and medusa: Reproduction. The medusae then produce new polyps by sexual reproduction. A medusa produces eggs or sperm, which are usually shed into the water; when an egg is fertilized, it develops into a swimming larva, which eventually settles and grows into a polyp.

How do Planulas move?

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 is a Trochophore larva?

Trochophore, also called trochosphere, small, translucent, free-swimming larva characteristic of marine annelids and most groups of mollusks. Trochophores are spherical or pear-shaped and are girdled by a ring of cilia (minute hairlike structures), the prototroch, that enables them to swim.

What are the functions of nematocysts?

The functions of nematocysts are to attack predators. Nematocysts are small stinging cells that are located on the tentacles of jellyfish.

What are 3 characteristics of cnidarians?

Basic Characteristics of Cnidaria

• Classes of Cnidarians. The four recognized classes of Cnidaria are: Hydrozoa, Cubozoa, Scyphozoa and Anthozoa.
• Body Symmetry. The majority of Cnidarians share the characteristic of radial symmetry.
• Body Structure. All Cnidarians share particular trait: tentacles with stinging nematocysts.
• Reproductive Cycle.
• Capturing Food.

What is Nematocyst in biology?

nematocyst. noun. 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. Related Forms: nem′a·to·cys′tic.

How do Cnidaria reproduce?

Reproduction of Cnidarians In general, polyps primarily reproduce asexually by budding, however, some produce gametes (eggs and sperm) and reproduce sexually. Medusae usually reproduce sexually using eggs and sperm. Jellyfish of the class Scyphozoa are dioecious.

Why are Cnidaria important?

Cnidarian ecology is a complex subject indeed, because it is cnidarians, in particular corals, that are the builders of some of the richest and most complex ecosystems on the planet, coral reefs. Other cnidarians are important as predators in the open ocean.

How does a Medusa swim?

The medusa is a free-swimming form; it moves by rhythmic muscular contractions of the bell, providing a slow propulsive action against the water. The other principal body type of the adult cnidarian is the polyp, a stalked, sessile (attached) form.

What is the common name for scyphozoa?

true jellyfish

How many life stages does a jellyfish go through?

The fact is, though, that jellyfish have complex life cycles, in which they go through no less than six different developmental stages. In the following slides, we'll take you through the life cycle of a jellyfish, all the way from fertilized egg to full-grown adult.

Is a jellyfish a medusa or polyp?

A polyp is the form that attaches to a surface, while a medusa is the form that is free-floating; a species of cnidarian may take each form in a different phase of its life. The medusa form predominates in the classes Scyphozoa (the common, colourful, large jellyfish) and Cubozoa.

Where are Cnidocytes found on a jellyfish?

Located on their tentacles, jellyfish's stinging cells are called cnidocytes. They are small compartments that house a mini needle-like stinger.

What specialized cells do cnidarians use for protection?

Cnidarians contain specialized cells known as cnidocytes (“stinging cells”), which contain organelles called nematocysts (stingers). These cells are present around the mouth and tentacles, serving to immobilize prey with toxins contained within the cells. Nematocysts contain coiled threads that may bear barbs.