Question

Are most animals vertebrates or invertebrates?

How does bilateral symmetry differ from radial symmetry?

What is cephalization?

Answer 1

Answer-

• most of animal species are invertebrates.
• More than 95% animal species are invertebrates.
• Invertebrates are especially important as agricultural pest and parasites.
• Invertebrates acts as good for human and are main element in food chain of birds, fish, and many other vertebrates.
• Example of invertebrates are - sea star, sea urchin, earworm, crabs, spiders, sponges, jellyfish.
• Invertebrates distributed between more thank 35 phyla .however vertebrates are distributed only single phylum Chordata ( phylum chordata also contain some invertebrates)
• There are currently around 65000 known apecies of vertebrates. This sound like a lot , but this is more less than invertebrates.
• Except Chordata all animal phyla consist of invertebrates.
• So most animal species are invertebrates.

DIFFERENCE BETWEEN BILATERAL SYMMETRY AND RADIAL SYMMETRY-

CEPHALIZATION-

• animals with bilateral symmetry have a definite head.
• Cephalization is the concentration of sense organs and nerve cells at the anterior end or front end of the body.
• Animals with bilateral symmetry exhibits Cephalization.
• Animals with this trait tend to respond in more complex ways to their environment.