What type of tissue is found in mollusks?
Mollusks have a thin layer of tissue called the mantle. The mantle covers the body organs, which are located in the visceral mass. Between the soft body and the mantle is a space called the mantle cavity. Mollusks contain gills.
What is the structure of a mollusk?
Mollusks have a thin layer of tissue called the mantle. The mantle covers the body organs, which are located in the visceral mass. Between the soft body and the mantle is a space called the mantle cavity. Mollusks contain gills. Gills are organs in which carbon dioxide from the mollusk is exchanged for oxygen in the water.
What is the body plan of a Mollusca?
Body Plan. Mollusks have a thin layer of tissue called the mantle. The mantle covers the body organs, which are located in the visceral mass. Between the soft body and the mantle is a space called the mantle cavity.
What type of circulatory system do mollusks have?
The circulatory system of most mollusks is an open system. In an open circulatory system, the heart moves blood out into the open spaces around the body organs. The blood contains nutrients and oxygen. the blood completely surrounds and nourishes the body organs. Most Mollusks have a well-developed head with a mouth and some sensory organs.
Do mollusks have tissues or organs?
Most mollusk have two organs that are unique to this phylum: a specialized feeding organ called a radula and a dorsal layer of tissue called a mantle. Mollusks are the first animals to have evolved organ systems for respiration and circulation.
Do mollusks have tissue layers?
Molluscs have bilateral symmetry and are triploblastic eucoelomate animals (Hickman et al., 2009). This means they have three true germ tissue layers (the ectoderm , the mesoderm, and the endoderm), and a true body cavity (coelom).
What type of tissue Do mollusks have?
All mollusks have a thin layer of tissue called a mantle which covers their internal organs. The mantle produces the mollusk's shell. Clams, oysters, snails, and octopuses are all mollusks. Mollusks live nearly everywhere on Earth.
How many tissues do mollusks have?
Mollusks are acoelomate (contrary to what the text and many other sources say), and the internal chamber is simply a pericardial sac; their bodies are derived from the three embryonic tissue layers. Externally they have three body regions: head, mantle, and foot. They are bilaterally symmetrical.
What is the body structure of mollusks?
Molluscs have a mantle or mass of soft flesh that covers the soft body and encloses the internal organs. In many species, the mantle produces a hard shell. Not all molluscs produce a shell. Many molluscs have a radula, which, in most species, is a rasp-like scraping organ used in feeding (Fig.
What structure is found only in mollusks?
There are also two unusual organs that are found exclusively in mollusks: the mantle and the radula. These organs do not persist in higher organisms, but they were important adaptations to the environments inhabited by mollusks.
What do all mollusks have in common?
Molluscs are a clade of organisms that all have soft bodies which typically have a "head" and a "foot" region. Often their bodies are covered by a hard exoskeleton, as in the shells of snails and clams or the plates of chitons.
What best describes a mollusk?
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.
What is the characteristics of Mollusca?
The animals belonging to the phylum Mollusca have soft-bodies, triploblastic and bilaterally symmetrical and coelomate. The study of Mollusca is called Malacology. They are sluggish invertebrates, with a thin fleshy envelope or mantle covering the visceral organs.
What are the three body parts of a mollusk?
The three distinct parts of molluscs are the head, muscular foot and visceral hump.
How many tissue layers do clams have?
Taxonomic level: phylum Mollusca; grade of construction: organs derived from three tissue layers; symmetry: bilateral; type of gut: complete, with anus; type of body cavity other than gut: coelom; segmentation: absent; circulatory system: usually open to large coelomic cavity; nervous system: brain, with nerve cords ...
What is true Mollusca?
Mollusca have bilateral symmetry and they have CaCO3 (calcareous) shell. Was this answer helpful?
How many tissue layers do annelids have?
three tissue layersTaxonomic level: phylum Annelida; grade of construction: organs derived from three tissue layers; symmetry: bilateral; type of gut: complete with anus; type of body cavity other than gut: coelom; segmentation: present; circulatory system: closed system; nervous system: brain, with nerve cords and bundles (ganglia); ...
How many layers of tissue make up each Gill?
The shell is composed of three layers, formed by secretions from the mantle. The mother-of-pearl layer lines the inner surface of the valve. 2.
What common features do all mollusks have?
WHAT FEATURES DO MOLLUSKS HAVE IN COMMON? As well as a shell, most mollusks have a muscular foot for creeping or burrowing. Some also have a head with sense organs. The soft body includes lungs or gills for breathing, and digestive and reproductive parts, all enclosed by a skinlike organ called the mantle.
What are the 4 parts that characterize mollusks?
The four important body parts in the mollusk could be listed as: Shell, Mantle, Visceral Mass and Foot.
How does the circulatory system work?
Circulatory systems use blood to transport both oxygen from the respiratory system to organs and tissues within the animal and carbon dioxide waste from these tissues back to the respiratory system. These systems are far more efficient than the simple diffusion between tissues and the environment that occurs in simpler invertebrates such as roundworms. The mollusk circulatory system uses a heart to pump blood through the organism, and the respiratory system of aquatic mollusks centers around their gills. Mollusk gills are called ctenidia, and they are made up of a series of thin filaments of tissue that resemble the teeth of a comb. These filaments absorb oxygen from water and transfer it to the blood stream. They also receive carbon dioxide from the blood and release it into the surrounding water. Terrestrial mollusk species have primitive lungs that absorb oxygen directly from the air around them. As we discussed earlier, the gills are located in the water-filled mantle cavity. All mollusks except those in the class Cephalopoda have an open circulatory system. In an open circulatory system, blood is not contained entirely in enclosed blood vessels. The heart pumps blood through blood vessels that lead from the gills into body cavities called hemocoels. A hemocoel is a blood-filled body cavity that is distinct from the fluid-filled coelom. Once the blood is released into the hemocoels, it is no longer contained in blood vessels, and it can diffuse freely to the various tissues of the body in order to deliver oxygen and receive carbon dioxide. The blood then re-enters vessels to be returned to the gills where carbon dioxide is exported to the water in the mantle cavity. A schematic of an open circulatory system is shown in Figure below. This system of gas exchange is not adequate for the fast moving cephalopods. They have evolved a closed circulatory system that is not dependent on diffusion for blood to reach tissues throughout the body.
Why is water pumped into the mantle cavity?
Water is pumped into the mantle cavity to allow the gills to absorb oxygen. Waste eliminated through the anus and excretory pores is released into the mantle cavity and pumped out of the animal into the aquatic environment. The mantle cavity is also where gametes are released to be dispersed by the out-flowing water.
What do mollusks use radula for?
Some mollusks use the radula to scrape food, such as algae, off of rocks and into the mouth, while other predatory species use it to drill holes into the shells of their prey. Figure below shows a diagram of the radula. A diagram showing the detailed structure of the radula.
What is the organ at the top of a mollusk called?
Most mollusks have a scraping feeding appendage known as a radula and an organ at the top of their bodies called a mantle. ... ... You are turning in your score of @@score@@% for this assignment. Continue?
What are the organs of a mollusk?
The basic mollusk body plan showing the relative positions of the head, foot, and shell. The following organ systems are also shown: circulatory and respiratory systems, digestive system, nervous system, excretory system, and reproductive system.
What does the blue radula mean?
A diagram showing the detailed structure of the radula. The blue regions indicate food being scraped into the mouth by the gray teeth of the radula. The letters correspond to the following regions: r = radula, e = esophagus, m = mouth, mu = muscles of the radula.
What is the mascot of the University of California?
But slugs, like all animals, occupy a specific niche and do play a vital role in their ecosystem. Interestingly, this powerful slug, or specifically the Banana Slug Ariolimax dolichophallus, is the mascot of the University of California, Santa Cruz. In February 2008, ESPN Sports named the UCSC Banana Slug as one of the ten best nicknames in college basketball.
What are annelids made of?
They have a variety of forms, ranging from large predatory squid and octopus, some of which show a high degree of intelligence, to small grazing forms with elaborately sculpted and colored shells. The annelids traditionally include the oligochaetes, which include the earthworms and leeches, the polychaetes, which are a marine group, ...
What is the coelomic cavity?
It is a retractable as well as extendable organ, used for locomotion and anchorage. Mollusks are eucoelomates, but the coelomic cavity is restricted to a cavity around the heart in adult animals. The mantle cavity, formed inside the mantle, develops independently of the coelomic cavity.
What are the different classes of phylums?
This phylum is comprised of seven classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Cephalopoda, and Scaphopoda. Class Aplacophora (“bearing no plates”) includes worm-like animals living mostly on deep ocean bottoms. These animals lack a shell but have aragonite spicules on their skin.
What is the second most diverse phylum of animals?
It is the second most diverse phylum of animals with over 75,000 described species. The name “mollusca” signifies a soft body, as the earliest descriptions of mollusks came from observations of unshelled, soft-bodied cuttlefish (squid relatives). Although mollusk body forms vary, they share key characteristics, such as a ventral, ...
What is the mollusk's scraping structure called?
In addition, many mollusks have a scraping structure at the mouth, called a radula (Figure 1). The muscular foot varies in shape and function, depending on the type of mollusk (described below in the section on mollusk diversity). It is a retractable as well as extendable organ, used for locomotion and anchorage.
What are mollusks and annelids?
Mollusks and Annelids. The mollusks are a diverse group (85,000 described species) of mostly marine species. They have a variety of forms, ranging from large predatory squid and octopus, some of which show a high degree of intelligence, to small grazing forms with elaborately sculpted and colored shells. The annelids traditionally include the ...
How do radulas feed?
They feed by filtering particles from water and a radula is absent. They exchange gases using a pair of ctenidia, and excretion and osmoregulation are carried out by a pair of nephridia. In some species, the posterior edges of the mantle may fuse to form two siphons that inhale and exhale water.
What are the organs of a mollusk?
Mollusks contain gills. Gills are organs in which carbon dioxide from the mollusk is exchanged for oxygen in the water. The mantle also protects the body if the mollusk does not have a shell. the shell is made up of several layers. The inside layer is the smoothest but it is usually the thickest layer because it's added to throughout the life ...
What is the body plan of a mollusk?
Body Plan. Mollusks have a thin layer of tissue called the mantle. The mantle covers the body organs, which are located in the visceral mass. Between the soft body and the mantle is a space called the mantle cavity. Mollusks contain gills. Gills are organs in which carbon dioxide from the mollusk is exchanged for oxygen in the water.
What is the role of the heart in the circulatory system?
In an open circulatory system, the heart moves blood out into the open spaces around the body organs. The blood contains nutrients and oxygen. the blood completely surrounds and nourishes the body organs. Most Mollusks have a well-developed head with a mouth and some sensory organs.
Which layer of the body protects the soft body?
The inside layer is the smoothest but it is usually the thickest layer because it's added to throughout the life of the mollusk. The inside layer protects the soft body. The circulatory system of most mollusks is an open system.
Do mollusks have tentacles?
Most Mollusks have a well-developed head with a mouth and some sensory organs. Some Mollusks, such as the squid, have tentacles. The muscular foot, which is used for movement, is in the underside of the mollusk.
What is the circulatory system of the bivalves?
Bivalves have an open circulatory system that bathes the organs in hemolymph. The heart has three chambers, two auricles receiving blood from the gills, and a single ventricle. The ventricle (heart) is muscular and pumps hemolymph into the aorta, and then to the rest of the body.
Why does blood flow faster in cuttlefish?
Cuttlefish blood must flow more rapidly than that of most other animals because hemocyanin carries substantially less oxygen than hemoglobin. Snail (Gastropod) As in other molluscs, the circulatory system of snails is open, with the fluid, or haemolymph, flowing through sinuses and bathing the tissues directly.
What is the phylum of mollusks?
The mollusks compose the large phylum of invertebrate animals known as the phylum Mollusca. Around 85,000 existing species are recognized to be a member of this phylum. Mollusks are the largest marine phylum comprising 23% of all named marine organisms. Numerous mollusks also live in freshwater and terrestrial (on land) habitats.
How many chambers does the aorta have?
In the great majority of species, it has two chambers; an auricle (chamber or space), which receives haemolymph from the lung, and a ventricle, which pumps it into the aorta (artery). The aorta is short, and soon divides into two main vessels, one supplying the visceral mass, and the other supplying the head and foot.
Which mollusks are the most neurologically advanced?
Cephalopod mollusks, such as squid, cuttlefish, and octopus, are the most neurologically advanced of all invertebrates. The gastropods are by far the most numerous mollusks in terms of classified species, accounting for 80% of the total.
