© 2014 Shmoop University, Inc. All rights reserved.
Animal Evolution and Diversity

Animal Evolution and Diversity

Animal Evolution and Diversity Questions

Bring on the tough stuff

1. Explain the difference between radial and bilateral symmetry.

2. The phyla Cnidaria and Ctenophora have two basic differences from the rest of the eumetazoa. What are they?

3. What is the major way sponges (Porifera) are different than the rest of the animal kingdom?

4. What is an open circulatory system?

5. Are humans and the rest of the anthropoids related and how?

6. Why aren't echinoderms classified with the radiata, when they have radial symmetry?

7. What are some ways birds produce the large amount of energy needed for flight and endothermy?

8. Arthropods exoskeletons made life on land possible. Exoskeletons also produced new restraints. Explain.

9. Sea jellies have muscles, but no skeleton. They can still move. How do they do this?

10. What does amphibian mean and why are they called that?

Possible Answers

1. Explain the difference between radial and bilateral symmetry.

Radial symmetry is where there is a top and bottom but no front and back or left and right. Think of a perfect pumpkin. You know which end is up but the sides are all the same. Bilateral symmetry is where there is a top and bottom, but also front and back and left and right.

2. The phyla Cnidaria and Ctenophora have two basic differences from the rest of the eumetazoa. What are they?

These animals have radial symmetry and have diploblastic embryos (embryos that form two distinct germ layers). The rest of the eumetazoa have body plans with bilateral symmetry and triploblastic embryos.

3. What is the major way sponges (Porifera) are different than the rest of the animal kingdom?

Sponges do not have real tissues. This means that they do not have specialized cells, or cells that have the same structure, that work together for the same purpose. This puts them in their own unique group, the parazoa.

4. What is an open circulatory system?

An open circulatory system does not have vessels for carrying blood. Instead, internal organs are surrounded by blood and food and gases are exchanged on the surface.

5. Are humans and the rest of the anthropoids related and how?

Yes. Humans are most closely related to apes. Humans and the other anthropoid primates descended from a common ancestor a few million years ago.

6. Why aren't echinoderms classified with the radiata, when they have radial symmetry?

The radial symmetry of echinoderms evolved separately from that of the radiata. Echinoderm ancestors were bilateral and evolved after the split between the radiata and bilateria. Echinoderms are also deuterostomes, giving them something else in common with chordates.

7. What are some ways birds produce the large amount of energy needed for flight and endothermy?

Eat a lot and eat constantly. Utilize an efficient, four-chambered heart that circulates more oxygen. Keep a constant supply of oxygen to the cells using air sacs.

8. Arthropods exoskeletons made life on land possible. Exoskeletons also produced new restraints. Explain.

Exoskeletons act as support on land and prevent desiccation. However, exoskeletons don't grow and the rest of the animal does. Arthropods need to get rid of exoskeletons and grow new ones periodically. This is called molting. Exoskeletons also block sensory information, so arthropods have evolved various other ways to sense their environment like compound eyes and other sensory organs.

9. Sea jellies have muscles, but no skeleton. They can still move. How do they do this?

The pressure of the water-filled cavity inside them acts like a skeleton. Muscles can push and pull against this surface to create a little intentional motion.

10. What does amphibian mean and why are they called that?

It means "double-life." Amphibians spend part of their life in water and part on land. They switch from breathing water to air.

We’re adding new materials and resources all the time.

Sign up for our newsletter to stay up to date.

An informed Shmooper is the greatest weapon against pop quizzees.

Advertisement
Advertisement
Advertisement