Chapter 12: The History of Life

Fossils that consists of minerals that have filled in an open model of an organism is called

• permineralized

• natural casts

• preserved remains

• trace fossils

A mammoth frozen in ice in Siberia is an example of

• preserved remains

• a trace fossil

• an amber-preserved fossil

• a natural cast

Which of the following characteristics musta good index fossil have?

• very rare, easy to identify, existed fora brief time, occurs in a local area

• somewhat rare, ard to identify, existed for a brief time, widespread

• common, hard to identify, existed for a long time, widespread

• very common, easy to identify, existed for a brief time, widespread

Which of the following would be a good index fossil?

• a crab species that existed for more than 250 million years

• a trilobite species that had a very small population

• a dinosaur species that existed only in what is now Utah

• a mollusk species found worldwide for 5 million years

The bacterium shown in Figure 12.1 may have evolved into a mitochondrion after going through the process of

• oxidation

• photosynthesis

• endosymbiosis

• colonization

The smallest unit of geologic time is a(n)

• epoch

• period

• era

• eon

The Cretaceous is an example of a(n)

• epoch

• era

• period

• eon

What do scientists estimate as the age of Earth?

• 100 million years old

• 4.6 billion years old

• 10 billion years old

• 3.8 million years old

The Miller-Urey experiment demonstrated that

• organic molecules first could have come to Earth on a meteorite

• iron-sulfide bubbles may have acted as the first cell membranes

• liposome membranes containing organic molecules preceded true cells

• energy from lightning might ahve helped create Earth's first organic molecules

The "RNA word" theory of the origins of life proposes that on early Earth, genetic information was stored and copied by

• ribozymes

• cyanobacteria

• iron-sulfied bubbles

• liposomes