Chapter 15 Bio 112

Place the levels of the geologic timescale in order from largest to smallest.

• Period > Epoch > Era > Eon

• Eon > Era > Period > Epoch

• Era > Eon > Epoch > Period

• Epoch > Period > Era > Eon

Which eons are considered part of the Precambrian Supereon?

• Hadean, Archean, and Proterozoic

• Archean, Proterozoic, and Phanerozoic

• Hadean, Phanerozoic, and Mesozoic

• Paleozoic, Mesozoic, and Cenozoic

What was the atmosphere composed of during the Hadean eon?

• Oxygen, nitrogen, and argon

• Carbon dioxide, hydrogen gas, water, methane gas, ammonia gas

• Nitrogen, oxygen, and carbon monoxide

• Helium, neon, and argon

Which hypothesis suggests that organic molecules could form at hydrothermal vents?

• Miller experiment/primordial soup hypothesis

• Deep sea (hydrothermal) vents hypothesis

• Meteor hypothesis

• Endosymbiont theory

What is the approximate age of the first eukaryotic organisms?

• 4.6 billion years ago

• 3.5 billion years ago

• 2 billion years ago

• 1.2 billion years ago

Which event is associated with the "age of fishes"?

• Cambrian explosion

• Middle Paleozoic era

• Late Paleozoic era

• Mesozoic era

What is the main difference between mass extinction and background extinction?

• Mass extinction is gradual, background extinction is rapid.

• Mass extinction affects a few species, background extinction affects many.

• Mass extinction is the disappearance of many species over a short time, background extinction is a steady, gradual loss.

• Mass extinction is caused by human activity, background extinction is natural.

What is adaptive radiation?

• The gradual loss of species over time.

• The rapid evolution of diversely adapted species from a single common ancestor.

• The process by which species become extinct.

• The formation of new species through natural selection.

Which eon marks the rise of multicellular life?

• Hadean

• Archean

• Proterozoic

• Phanerozoic

What major event ended the Mesozoic era?

• The Cambrian explosion

• The rise of mammals

• A mass extinction event

• The formation of the ozone layer