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 is the 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 phylum are trochophore larvae?
Trochophore larva occurs in phylum annelida.
What is a trochophore larva quizlet?
trochophore. a free-swimming, ciliated larva of many worms and some mollusks. visceral mass. the central section of a mollusk’s body that contains the mollusk’s organs.What is the difference between trochophore and Veliger larvae?
Unlike the trochophore, the newly hatched veliger may have or will develop many of the characteristic features of the adult including such structures as a muscular foot, eyes, rhinophores, a fully developed mouth, and a spiral shell (in fact, the veliger of nudibranchs has a shell, although the adult does not).
Do all mollusks have trochophore larvae?
Molluscs include such familiar creatures as clams, oysters, snails, and octopi. They share a distant common ancestor with the annelid worms, an evolutionary heritage suggested by their larval form, called a trochophore larva, found in all molluscs and in certain marine annelids called polychaete worms.
What is the trochophore function?
A trochophore (/ˈtroʊkəˌfɔːr, ˈtrɒ-, -koʊ-/; also spelled trocophore) is a type of free-swimming planktonic marine larva with several bands of cilia. By moving their cilia rapidly, they make a water eddy, to control their movement, and to bring their food closer, to capture it more easily.
Do annelids have a lophophore?
The Annelida are worms with thorough segmentation of the body. The phoronids, bryozoans, and brachiopods are all filter-feeders that share a ciliated feeding organ called a lophophore.Which feature of mollusks is a rasping tongue like organ?
You won’t find a radula anywhere in the human body, but it’s a common anatomical feature among animal species in phylum Mollusca. Biologists describe it as a rasping dental ribbon that replaces the tongue found in mammals. Oysters, clams and other bivalves are the only mollusks that lack this organ.
What is the visceral mass that every mollusk has?The visceral hump, or visceral mass, of gastropods is always contained within the shell; it generally holds the bulk of the digestive, reproductive, excretory, and respiratory systems. A significant part of the visceral hump consists of the mantle, or pallial, cavity. In…
Article first time published onDo sponges have trochophore larvae?
They account for 95% of known animal species. Lophotrochozoan- have a lophophore (a crown of cilia that surrounds the mouth) or a trochophore (larvae that have cilia around their middle). … Porifera- Sponges are basal animals that lack true tissues.
What is the larva of Arthropoda?
This larval stage, called a nauplius, is found in barnacles, copepods, penaeid shrimps, and ostracods. It swims by using its jointed appendages that are moved by muscle contraction. These larvae have a nauplier eye, made up of photoreceptor cells that are thought to give rise to the photoreceptors in some adult forms.
Do arthropods have trochophore larvae?
Trochophore larvae are characterized by two bands of cilia around the body. Previously, these were treated together as the Trochozoa, together with the arthropods, which do not produce trochophore larvae, but were considered close relatives of the annelids because they are both segmented.
What type of larva is molluscs?
veliger, larva typical of certain mollusks such as marine snails and bivalves and a few freshwater bivalves. The veliger develops from the trochophore (q.v.) larva and has large, ciliated lobes (velum).
What are juvenile mollusks called?
Like many invertebrates, the mollusk life cycle includes one or more juvenile or larval stages that are very different from the adult form of the animal. Both mollusks and annelids develop through a larval stage called a trochophore larva.
Which class of mollusks contain octopi and squids?
Cephalopods are a group of molluscs that include the pearly chambered Nautilus, squids, and the octopus. They can be divided into three categories: the Nautiloidea (chambered Nautilus), the Ammonoidea (the extinct ammonites), and the Dibranchiata (squids, the extinct belemnites, and octopuses).
What is Trochophore 11?
Trochophores are spherical or pear-shaped and are girdled by a ring of cilia the prototroch, that enables them to swim. In some mollusks (such as gastropods and bivalves), the trochophore develops into a second stage, the veliger, before metamorphosing to an adult form. Hence, option A is the correct answer.
What is the evolutionary importance of Trochophores?
Many workers are of the opinion that the Trochophore larva serves as a bridge between radial and bilateral symmetry. They have opined that the bilateral symmetry has evolved from the radial one.
What is the larval stage of echinoderms?
Echinoderms show a complicated metamorphosis in the course of development. Their larva is strikingly bilaterally symmetrical whereas the adult shows radial symmetry. Larva swims with the help of ciliated bands , which may be complicated by a number of short or long slender projections or arms from the body wall.
Do molluscs have gills?
Respiration. Most molluscs have only one pair of gills, or even only a singular gill. Generally, the gills are rather like feathers in shape, although some species have gills with filaments on only one side. They divide the mantle cavity so water enters near the bottom and exits near the top.
Are earthworms molluscs?
Mollusks are invertebrates such as the common snail. Most mollusks have shells. Annelids are worms such as the familiar earthworm. … Annelids look like roundworms on the outside, but on the inside they are more like mollusks.
Which class of mollusks contain clams oysters and scallops?
bivalve, (class Bivalvia), any of more than 15,000 species of clams, oysters, mussels, scallops, and other members of the phylum Mollusca characterized by a shell that is divided from front to back into left and right valves.
Does a Mollusca have a shell?
mollusk, also spelled mollusc, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body.
Can we use mollusk as painkillers?
That organism is a cone snail, a mollusk known to beachcombers and marine biologists alike for its toxic venom, which was recently developed into a clinically used painkiller. The cone snail is just one example of the opportunities the world’s biodiversity offers the pharmaceutical industry.
How do molluscs breathe?
Aquatic mollusks “breathe” under water with gills. Gills are thin filaments that absorb gases and exchange them between the blood and surrounding water. Mollusks have a circulatory system with one or two hearts that pump blood.
Is a snail a Lophotrochozoan?
The name Lophotrochozoa comes from the names of the larval type of the two major animal groups included: the Lophophorata and the Trochozoa. The Trochozoa contain many worm-like forms, including the segmented worms (Phylum Annelida) but it also includes the Mollusca (snails, squid, octopods, clams, etc).
Are jellyfish Lophotrochozoan?
The Cnidarians (jellyfish and their relatives) represent the basal animals. The Lophotrochozoans (Phyla Platyhelminthes, Mollusca, Annelida and Rotifera) represent one of the major groups of invertebrates outside of the arthropoda.
Does a clam have a lophophore?
Clams are mollusks and their shells are very different if you look closely. Each valve (shell) of a clam looks just like the other half. … Mollusks do not have a lophophore.
How do mollusks get rid of waste?
Mollusks have a coelom and a complete digestive system. Their excretory system consists of tube-shaped organs called nephridia (see Figure above). The organs filter waste from body fluids and release the waste into the coelom. … Aquatic mollusks “breathe” under water with gills.
What does a mollusk eat?
Many mollusks eat mostly algae. They use the radula to scrape algae off rocks. But larger mollusks have a greater appetite. Snails and slugs eat plants and fruit.
Do all molluscs have eyes?
Molluscs have eyes of all levels of complexity, from the pit eyes of many gastropods, to the pinhole eyes of the Nautilus, to the lensed eyes of the other cephalopods. Compound eyes are present in some bivalves, and reflective ‘mirrors’ have been innovated by other lineages such as scallops.
