cephalization, the differentiation of the anterior (front) end of an organism into a definite head.

What is the best definition of cephalization?

: a tendency in the evolution of organisms to concentrate the sensory and neural organs in an anterior head.

What is cephalization give example?

The definition of cephalization means the trend in evolution for the nervous system and the sensory organs to be positioned near the human or animal head. An example of cephalization is the tendency for an animal’s ears to be on its head.

What is cephalization and why is it important?

Cephalization is the formation of a central nervous system in organisms. Cephalization is important in that it allows for the organism to make quick movements. It also allows for the organism to have an axis of symmetry, further making quick movements possible as the organism can either find prey or avoid being prey.

What happens cephalization?

Cephalization is an evolutionary trend in which, over many generations, the mouth, sense organs, and nerve ganglia become concentrated at the front end of an animal, producing a head region. This is associated with movement and bilateral symmetry, such that the animal has a definite head end.

Are roundworms cephalized?

Compare and contrast the body plans of flatworms with roundworms. Similarities: Both have three germ layers and bilateral symmetry. They both have anterior and posterior ends allowing cephalization to occur. The roundworm has a body cavity called a coelom.

Are humans cephalized?

Examples of Cephalization Three groups of animals display a high degree of cephalization: vertebrates, arthropods, and cephalopod mollusks. Examples of vertebrates include humans, snakes, and birds. Animals from these three groups exhibit bilateral symmetry, forward movement, and well-developed brains.

What is bilateral in biology?

noun, plural: bilateral symmetries. A form of symmetry in which the opposite sides along a midline is a duplicate of the other in terms of body parts or appearance. Supplement. In biology, symmetry is a characteristic of certain organisms in which there is regularity in parts on a plane or around an axis.

What is radial symmetry in zoology?

Radial symmetry is the arrangement of body parts around a central axis, like rays on a sun or pieces in a pie. Radially symmetrical animals have top and bottom surfaces, but no left and right sides, or front and back. Radial symmetry: Some organisms, like sea anemones (phylum Cnidaria), have radial symmetry.

Are anemones Cephalized?

So many organisms exhibit cephalization that describing noncephalized animals may be the easiest way to give an idea of just how many animals are cephalized. These organisms include Cnidarians, such as coral, jellyfish, sea anemones and simple mollusks like scallops. Echinoderms, or sea stars, also lack cephalization.

What is the group that comprises all animals called?

The animal kingdom is divided into Parazoa (sponges) and Eumetazoa (all other animals). As very simple animals, the organisms in group Parazoa (“beside animal”) do not contain true specialized tissues.

Are sponges Cephalized?

Sponges have no particular symmetry; they are not radially or bilaterally symmetrical. Cephalization means having a head. Cephalization only occurs in bilaterally symmetrical animals.

Where are the sense organs located in most animals with bilateral symmetry?

Sense organs around the front end or head help bilaterally symmetrical animals find food. Bilateral symmetry also helps animals avoid enemies.

What is Cephalisation zoology?

cephalization, the differentiation of the anterior (front) end of an organism into a definite head.

Are all worms Cephalized?

Though not obvious, cephalization does exist in an earthworm. Hence, the earthworm exhibits cephalization.

Are all molluscs Cephalized?

Mollusks represent another group in which cephalization has been lost and regained. For example, bivalves are not particularly cephalized (although some scientists have argued that they are “all head”). However, as with the echinoderms, certain mollusks regained cephalization.