Fossil Diversity Patterns Practice Test

Fossil records show patterns of diversity over time, though they are incomplete. In a stack of layers (oldest to youngest), fossils are:

• Layer 6 (oldest): 3 types (shell A, shell B, algae)
• Layer 5: 3 types (shell A, shell B, algae)
• Layer 4: 1 type (algae)
• Layer 3: 1 type (algae)
• Layer 2: 4 types (shell C, crab, fish, algae)
• Layer 1 (youngest): 4 types (shell C, crab, fish, algae)

What evidence shows a change in diversity over time in this fossil record?

Fossil records show patterns of diversity over time, but fossils are incomplete samples. A student writes four statements after studying layers from oldest to youngest:

• Layer 5 (oldest): 1 fossil type
• Layer 4: 2 fossil types
• Layer 3: 4 fossil types
• Layer 2: 4 fossil types
• Layer 1 (youngest): 3 fossil types

Which statement about diversity change is supported by the fossil evidence over time?