Quiz. Introduction to the Animal Kingdom

Vocabulary Review. What terms are missed:

1. An animal without a backbone is called a (an) _______.

2. In sexual reproduction, the zygote undergoes a series of divisions to form a (an) ________, a hollow ball of cells.

3. A (An) _____ is an animal whose mouth is formed from the blastopore.

4. In _______ symmetry, only a single imaginary plane can divide the body into two equal halves.

5. The concentration of sense organs and nerve cells at the front end of the body is called ______ .

6. A (An) _______ is an immature stage of an organism that looks different from the adult form.

Answer the questions:

7. What are the names of an animal’s three germ layers?

8. What is a body cavity?

Symmetry

Vocabulary list

bilateral symmetry - the fact of the two halves of something on either side of a particular line being exactly the same / radial symmetry - the condition of having similar parts regularly arranged around a central axis

cephalization  - nervous tissue becomes concentrated toward one end of an organism

body cavity - any fluid-filled space in a multicellular organism other than those of vessels

 

Symmetry

With the exception of sponges, every kind of animal exhibits some type of body symmetry. Some animals exhibit radial symmetry, in which any number of imaginary planes can be drawing through the center, each dividing the body into equal halves.

More complex animals have bilateral symmetry, in which only a single imaginary plane can divide the body into two equal halves. Animals with bilateral symmetry usually exhibit cephalization, which is the concentration of sense organs and nerve cells at the front of the body. Most animals have a body cavity, which is a fluid-filled space that lies between the digestive tract and the body wall.

 

Answer the questions:

Can you name asymmetrical animals?

What animal is an example of radial symmetry?

What symmetry do people have?

What is cephalization?