Chapter 32 Animal Diversity

Question 1

What are the different types of heterotrophs?

Answer 1

• Fungi are heterotrophs that grow on or near their food and that feed by absorption
• most animals feed by ingesting their food and then using enzymes to digest it within their bodies.

Question 2

Cephalization

Answer 2

The evolutionary trend toward concentrating nervous tissue, the mouth, and sense organs toward the front end of an animal. Fully cephalized organisms have a head and brain.

Question 3

Bilateral Symmetry

Answer 3

have a head, dorsal side, ventral side, and tail end

Question 4

Describe predator-prey relationships that began during the Cambrian Explosion

Answer 4

Predators acquired novel adaptations for catching prey, such as claws, prey species acquired new defenses, such as protective shells. As new predator-prey relationships emerged, natural selection may have led to the decline of the soft-bodied Ediacaran species and the rise of various bilaterian phyla.

Question 5

What are the 3 germ layers?

Answer 5

Ectoderm, Mesoderm, and Endoderm

Question 6

Explain Gastrulation

Answer 6

• Gastrulation is the process that gives rise to different tissues
• One end of the embryo folds inward and produces the ectoderm and endoderm

Question 7

Why are sponges not considered animals?

Answer 7

Sponges lack tissues

Question 8

Compare and contrast all the major animal groups

Question 9

Explain the evolutionary history of animals

Answer 9

• animals arose 710 million years ago
• the common ancestor of animals and choanoflagellates may have been a suspension feeder
• Animals fall under Unikonta, and are more specifically Ophistokonts along with Fungi and Choanoflagellates

Question 10

Ectoderm

Answer 10

the germ layer covering the surface of the embryo; gives rise to the outer covering of the animal

Question 11

Endoderm

Answer 11

the innermost germ layer, lines the pouch that forms during gastrulation (the archenteron) and gives rise to the lining of the digestive tract (or cavity) and to the lining of organs such as the liver and lungs of vertebrates.

Question 12

Mesoderm

Answer 12

fills much of the space between the ectoderm and endoderm; forms the muscles and most other organs between the digestive tract and the outer covering of the animal.

Question 13

Coelomate

Answer 13

an animal that possesses a coelom between the body wall and digestive tract; has a body cavity in which well-developed organs can be accommodated

Question 14

Pseudocoelomate

Answer 14

an organism with body cavity that is not derived from the mesoderm

Question 15

Acoelomate

Answer 15

an animal that has no internal, fluid-filled body cavity separating its body wall from its digestive tract.