Cephalization is associated with what?

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.

1. What is cephalization and its example?
2. Which phylum has cephalization?
3. Is cephalization present in Chordata?
4. What is cephalization in platyhelminthes?
5. What is radial symmetry in zoology?
6. Are humans Cephalized?
7. Where is Cephalisation found?
8. What type of skeleton does platyhelminthes have?
9. Do Chordata have appendages?
10. Are crustaceans cephalized?
11. Are sponges cephalized?
12. Do platyhelminthes have a skeleton?
13. Are platyhelminthes Monoecious?
14. Are all molluscs cephalized?
15. Are jellyfish cephalized?

What is cephalization and its 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. noun.

Which phylum has cephalization?

Members of the Phylum Platyhelminthes (especially true of the planarians, Class Turbellaria) are organized with brain and sense organs at the front of the animal. This is called cephalization. In animals with cephalization, the sense organs come in contact with the environment first.

Is cephalization present in Chordata?

cephalization The tendency among animal groups for the major sense organs, mouth, and brain to be grouped together at the front (anterior) end of the body. These are usually contained in a specialized cephalic region – the head.

What is cephalization in platyhelminthes?

Most flatworms have a distinct head region that includes nerve cells and sensory organs, such as eyespots. The development of a head region, called cephalization, evolved at the same time as bilateral symmetry in animals.

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 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.

Where is Cephalisation found?

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.

What type of skeleton does platyhelminthes have?

Phylum Platyhelminthes

Despite this, they still possess a hydrostatic skeleton. These animals are of a flattened nature and possess muscle cells arranged in layers with a loose packing of cells derived from the mesoderm called mesenchyme.

Do Chordata have appendages?

All other chordates are craniates: they have a brain and a skull. There are two subphyla: the Agnatha, which lack jaws and paired appendages, and the Gnathostomata, which have jaws and usually have paired appendages as well.

Are crustaceans cephalized?

The evolutionary trend in cephalization is that more advanced organisms have a larger concentration of neurons at one end of their body. ... Flatworms began to show cephalization, and arthropods (crustaceans, insects, and spiders), annelids (earthworms), and chordates (including humans) have all undergone cephalization.

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.

Do platyhelminthes have a skeleton?

They are bilaterally symmetrical (i.e., the right and left sides are similar) and lack specialized respiratory, skeletal, and circulatory systems; no body cavity (coelom) is present.

Are platyhelminthes Monoecious?

Most flatworms can reproduce sexually or asexually. Most are monoecious. Most of these have developed ways of avoiding self-fertilization. Development may be direct (eggs hatch into tiny worms that resemble the adults) or indirect (with a ciliated larval form).

Are all molluscs cephalized?

Both flatworms and molluscs are triploblastic, bilaterally symmetric, and cephalized. But molluscs have developed a true coelom, an internal body cavity enclosed by mesodermal membranes. ... Molluscs are mostly aquatic, and are named from the Latin molluscus, meaning "soft".

Are jellyfish 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.