Cephalopods

Cephalopods

Cephalopods (pronounced: /ˈsɛfələˌpɒd/, from the Greek words kephalē meaning "head" and pous meaning "foot") are a class of marine mollusks that include species like squid, octopus, cuttlefish, and nautilus. They are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles.

Etymology

The term "cephalopod" is derived from the Greek kephalē, meaning "head", and pous, meaning "foot". This refers to the way the cephalopod's head is connected to its foot-like tentacles.

Characteristics

Cephalopods are known for their advanced nervous system and complex brain, compared to other invertebrates. They have excellent vision and possess unique adaptations like jet propulsion and the ability to change skin color and texture.

Arms and Tentacles

All cephalopods possess flexible appendages extending from their heads known as arms. Squids and cuttlefish have eight arms and two longer tentacles, while octopuses have eight arms and no tentacles. The nautilus, however, has more than 90 tentacles and no arms.

Classification

Cephalopods are classified into two subclasses: Coleoidea, which includes squids, octopuses, and cuttlefish, and Nautiloidea, which includes the nautilus.

Habitat and Distribution

Cephalopods can be found in all of the world's oceans, from the warm waters of the tropics to the colder regions near the poles. They inhabit a wide range of depths, from the intertidal zone to the abyssal depths.

Related Terms

• Mollusks: The phylum to which cephalopods belong.
• Beak: A hard, sharp structure found in the mouths of all cephalopods.
• Ink sac: An organ found in many cephalopods, used to expel a cloud of dark ink to confuse predators.
• Chromatophores: Pigment-containing and light-reflecting cells in cephalopods that allow them to change color.

This WikiMD.org article is a stub. You can help make it a full article.