Molluscs

INDEX

-How are molluscs?

-Anatomy of a snail.

-Types of molluscs

-Relation with humans.

-Curiosities.

Molluscs are invertabrate animals, so they dont have a bony skeleton. They are heterothrophic multucellular organisms that have eukaryotic cells.Most molluscs are aquatic, but some of them live in land. All of them have:- A visceral mass, that contains all internal organs.-An external layer that surrounds the internal organs inside the visceral mass.-An internal ot external shell. Some molluscs, like the octopus don´t have a shell.-A complete digestive system, which includes the radula in all individualds except in bivalves.-They reproduce sexually.

This is the anatomy of a snail, that is part of gastropods. It has a foot use for moving, the lung, anus, heart, mouth (with a radula use for biting and chewing) , eyes, tentacles and anus.

Types of

molluscs

There are three types of

molluscs:-Bivalves

-Gastropods-Cephalopods

Gastropods and

cephalopods have foot,

separed head and a radula.

Bivalves is the only

group that don´t have

them.

Types of molluscs

Bivalves have no separed head from their bodies. They don´t have a radula, like other molluscs, and don´t move because they don´t have foot. They usually live in water. They have gills to respire.

Gastropods hava a muscular foot, that they use for moving. They have a complete digestive system and they are herbivores. They have an external shell.

Cephalopods live in water and they have tentacles. They use their tentacles to cath their pray, because they are carnivores. Not all of them have a shell.

Relation with humans Some of them can be pets, like the famous ``Pulpo Poll´´. They have also beneficies in pharmaceuticas industries, because some of the substances they segregate can be used to make cream or medicines. For example, the snail secretion is used to make cream and the squid ink, was used to make pen´s ink.And some people like me, considerate molluscs as a delicious dish.

Some molluscs are completelly simetric on both sides, for exaple the snails. There are 100.000 different types of molluscs, and the 80% are gastropods.The gigant squid is the biggest mollusc in the word.Another curious date is that are 35.000 extint species in thw word, because thay had soported radical changes.

Bibliography

www.moluscos/wikipedia.com

www.bivalves/wikipedia.com

www.10curiosidadessobremoluscos.com