Mollusks may be a group of animals from the invertebrate family, these include very different creatures in appearance, behavior such as snails, shellfish, and cuttlefish. Learn more about How Fast can a Mollusk Run: Characteristics and Types.
Mollusca is divided into several groups including animals that can swim in the ocean and there is also land. Example bivalves, as an explanation for more, learn how to do mollusks move.
What is Mollusca?
Mollusca is a group of animals that are triploblastic selomata and invertebrates of soft stature and multicellular. The term Mollusca comes from the Greek word mollusks which means soft.
Mollusca belongs to soft animals either with shells or without shells. Such as from various types of shellfish, snails, kiton, and squid, and their relatives.
Mollusca is the second largest phylum of the animal kingdom (Animalia) after the arthropod phylum. It is estimated that at this time there are 75 thousand types, with an added 35 thousand types in the form of posil.
Is Mollusca dangerous?
The animals of the Mollusca group are not a deadly group of animals but some of them are still worth watching out for because usually, the way to survive these soft animals is to suck or suck their enemies, including humans.
Some examples of animals that belong to the Mollusca group are snails, shellfish, cuttlefish, and squid. The animals are scattered not only on land but also in the water. Similar to other groups of animals, mollusks have unique characteristics and classifications that are interesting to study.
History of Evolution
Because modern mollusks vary greatly in anatomy and behavior, sorting out their exact evolutionary relationships is a major challenge. To simplify the problem, naturalists have proposed “hypothetical ancestral mollusks” that display most, if not all, characteristics of modern mollusks, including shells, muscular “legs”, and tentacles, among others.
We have no fossil evidence that this particular animal ever existed. The thing most trusted by all experts is that mollusks descended hundreds of millions of years ago from small marine invertebrates known as “lophotrochozoan”.
Characteristics of Mollusca
As a unique group of animals due to their soft stature, Mollusca animals have several distinctive characteristics that distinguish them from other group animals. Here are some of the characteristics of Mollusca:
- Has a variety of sizes and bodies
- Has soft and non-segmented
- Is tripoblastic selomata
- Is an invertebrate
- Living in water and on land
- Has a conditioning ring that is the nervous system
- Excretory organs in the form of nephridia
- Has radula
- Heterotrophic animals
- Sexually biased
- Mollusca has a bilaterally symmetrical body structure
- The body consists of legs, visceral mass, and minerals
- It is a hermaphrodite animal that has 2 genitals (male and female) in one body.
Its body consists of muscular legs, with a head that develops varying by class. The legs are adapted to survive in the substrate, digging and drilling the substrate.
Where is Mollusca Habitat?
Most mollusks are marine animals that live in habitats from shallow coastal areas to deep waters. Most remain in sediment at the bottom of the body of water, although some like cephalopods swim freely.
Mollusks live in seawater, freshwater, brackish, and land. Mollusca habitats can be in troughs of the ocean-continent to high mountains, and can even be found easily around our homes. Mollusks are studied in a branch of zoology called malacology.
How fast can a mollusk run?
Snails compete on a 13-inch (33 cm) surface coated in cotton fabric that is more attractive than the track. The racer is placed in the middle circle and when the order is given to them it is then released towards the finish line.
The snail’s average speed was around 0.03 mph, although a snail named Archie nearly doubled in 1995, setting a world time record of 2 minutes and 20 seconds. The 2012 winner, taken to the championship by a 5-year-old, took home the grand prize with a record time of 3 minutes 20 seconds.
Besides Do, You Know? How Fast Can a Squid Run is an animal that is only widely known as a serving of good food and is widely sold in roadside food stalls. And famous among marine lovers and diving lovers as one of the animals that have its uniqueness.
How is Mollusca’s Body Structure?
There are many unique animal body structures, one of which is the animals that belong to the group of soft animals or Mollusca. In Biology, groups of soft animals belong to the phylum Mollusca. As the name implies, those belonging to the Mollusca group are usually soft-bodied, slippery, and slimy.
After studying its characteristics, you should also get to know the structure of the Mollusca body more specifically. The structure of the body consists of:
- Legs are the stretching of body parts consisting of muscles. Mollusca’s legs serve to move, creep, or dig. Some types of Mollusca legs are replaced with tentacles whose function is in catching prey.
- Visceral mass, which is a soft part of the body where the organs of the body are present. The mass is shrouded by a thick tissue called the mantle.
- The coat is the part that envelops and protects the visceral mass. In the mantle, there is a fluid cavity that is the place of gill holes, anus, and excretory fluid. The coat can secrete the components that make up the shell.
The last discussion of the Mollusca animal review is to know its classification because it turns out that there are some more specific groupings. Here’s the classification of Mollusca:
Amphineura is a primitive type of Mollusca. Amphineura has a bilateral system body. It has some gills in its mantle cavity. Live around the panta.
Scaphopoda lives in the sea ATU on the beach, has a sharp shell, is shaped like a trumpet, has small legs, on its head, there are several tentacles, and has no gills.
Example: Dentalium Vulgare.
Gastropods are animals that use their stomach as legs. His life on land, freshwater, and at sea. Generally, Gastropods have shells.
The cephalopod uses its head as a means of motion. have an endoskeleton, exoskeleton, or without both. His body is bilaterally symmetrical. The body consists of the head, neck, and body.
Pelecypods have the shape of an ax-like foot located in the anterior. Bivalvia is a barge consisting of two parts. It has a well-developed nervous system and brain. Living in fresh water and the sea.
Examples: Meleagrina, Anadonta, Ostrea, Panope Generosa.
Except for cephalopods, mollusks are generally gentle vegetarians. Land gastropods such as snails feed on plants, fungi, and algae, whereas most marine mollusks live off plant matter dissolved in water, which they consume by filtering food.
The most advanced cephalopod mollusks of octopus, squid, and cuttlefish eat everything from fish to crabs to fellow invertebrates. Octopuses, in particular, have terrible table manners, inject their soft-bodied prey with poison or drill holes in shells and suck up delicious contents.
How Does Mollusca Behave?
The invertebrate nervous system is generally very different from the nervous system of vertebrate animals such as fish, birds, and mammals. Some mollusks, such as ivory shells and bivalves, have a group of neurons rather than the actual brain, whereas more advanced mollusk brains such as cephalopods and gastropods wrap around their esophagus rather than being isolated in a hard skull.
What’s even weirder is that most of the octopus’s neurons are not located in its brain, but in its arms, which can function independently even when separated from its body.
Reproduction and Heredity
Mollusks generally breed sexually, although some are hermaphrodites, they still have to mate to fertilize their eggs. Eggs are laid individually or in groups in a mass of jelly or coarse capsules.
Eggs hatch into veliger larvae, small larvae that swim freely and metamorphose into different stages, depending on the species.
Extinct Fossil Family
Examining fossil evidence, paleontologists have determined the existence of two classes of now-extinct mollusks.
Rostroconchians lived in the world’s oceans from about 530 – 250 million years ago, and appear to have been the ancestors of modern shellfish.
Helcionelloidans lived about 530 – 410 million years ago, and have many of the same characteristics as modern gastropods.
Somewhat surprisingly, cephalopods have existed on earth since the Cambrian period; Paleontologists have identified more than two dozen genera that inhabited the world’s oceans more than 500 million years ago.
On top of their historical importance as a food source especially in the eastern and Mediterranean parts mollusks have contributed in many ways to human civilization. Cowry shells are used as money by Indigenous groups, and pearls grown in oysters, as a result of sand grain irritation, have been appreciated since time immemorial.
Another type of gastropod, murex, was cultivated by the ancient Greeks because of its dye, known as the “royal purple”, and the robes of some rulers were woven from long threads secreted by the pinna Nobilis shell species.
There are more than 8,600 species listed in the ICUN, 161 of which are considered Critical, 140 Endangered, 86 Vulnerable, and 57 Almost Endangered. One, Ohridohauffenia drimica was last seen in 1983 in a spring that flows into the Drim River in Macedonia, Greece, and was listed as extinct in 1996. Additional surveys failed to find him again.
Most mollusks live in the deep sea and are relatively safe from habitat destruction and destruction by humans, but this is not the case with freshwater and terrestrial mollusks.
Perhaps not surprisingly from the point of view of human gardeners, snails are most vulnerable to extinction today, since they are systematically eradicated by agricultural problems and taken by invasive species that are indiscriminately incorporated into their habitat.