Gradualism vs Punctuated Equilibrium

Scientist can use the fossil record to determine changes in an environment. What does the abrupt appearance of a new organism show?

The abrupt appearance of the new organism is evidence of an ​ (a)   environment and ​an (b)   in biodiversity.

• unstable
• increase
• stable 
• decrease

Certain species of coral-like sea organisms called bryozoans, first appeared about 140 million years ago. They remained unchanged for the first 40 million years and then underwent a sudden rapid genetic change.

Which process would BEST account for the pattern of evolution in bryozoans?

• convergent evolution

• differentiation

• punctuated equilibrium

• gradualism

Two scientists studied patterns of evolution in the fossil record. Many species they analyzed showed periods of slow changes interrupted by a period of rapid changes.

This pattern of periods of slow changes interrupted by periods of rapid change with few, if any transitional fossils, best describes the theory of

• natural selection

• genetic drift

• punctuated equilibrium

• gene flow

When multiple transitional fossils are found in many rock layers, they provide evidence of -

• seasonal variation in the diets of a species

• gradual changes of a species over time

• DNA functioning as the genetic material of organisms.

• an unchanging environment

The diagram shows data on the evolution of horses.

The date in the diagram is evidence that -

• a new species of horse suddenly appeared

• horses slowly developed over time

• Horses have similar stages of rapid embryological development

• horses have a common ancestry with other hovved animals