Chapter 33

Question 1

3 modes of feeding:

Answer 1

Suspension, Bulk, and Fluid feeding

Question 2

Important common characteristics of Animals:

Answer 2

• Multicellular
• Heterotrophs
• No cell walls
• Extracellular matrix
• Unique cell junctions

Question 3

Other common characteristics of Animals:

Answer 3

Nervous tissue, Muscle tissue (for movement), Sexual Reproduction, Special clusters of HOX genes, very similar rRNA

Question 4

Definition of Animal:

Answer 4

Multicellular heterotrophs with cells that lack cell walls. Most animals have nerves, muscles, the capacity to move at some point in their life cycle, and the ability to reproduce sexually, with sperm fusing directly with eggs.

Question 5

Animals and Fungi both use:

Answer 5

Absorptive nutrition: Secrete enzymes to break down complex materials into small digestible food molecules.

Question 6

When did multicellular animals first appear?

Answer 6

At the end of the Proterozoic eon, about 630 mya.

Question 7

When did animal phyla rapidly diversify and many new species appeared?

Answer 7

During the Cambrian explosion, about 533-524 mya.

Question 8

3 explanations for Cambrian explosion:

Answer 8

Evolutionary “arms race” (predators and prey), evolution of HOX gene complex, ideal environment (warm, oxygenated oceans and atmosphere, ozone layer)

Question 9

Adaptations that allowed animals to live on land:

Answer 9

Lungs, Internal fertilization, Amniotic egg