On the basis of what geologic or biological events is

Which statement is not true? (24.1) (a) Fossils are indications of prehistoric life. (b) Fossils help determine the relative ages of rocks. (c) Fossils can be tracks imprinted in rocks. (d) Fossils are irrelevant to our understanding of geologic time.

What is the name for the branch of science that specifically studies fossils? (24.1) (a) petrology (b) mineralogy (c) paleontology (d) fossiligraphy

What type of remain is a shark tooth? (24.1) (a) replacement (b) index (c) original (d) trace

What is the name for the type of fossil formed when mineral material fills a rocks hollow depression that once contained an embedded bone? (24.1) (a) mold (b) cast (c) trace fossil (d) nodule

What geologic principle tells us that each sediment layer is younger than the layer beneath it? (24.2) (a) superposition (b) original horizontality (c) cross-cutting relationships (d) faunal succession

What is obtained when rocks and geologic events are put into chronologic order without regard to the actual dates? (24.2) (a) absolute (numerical) geologic time (b) relative geologic time (c) a geologic formation (d) a correlation period

Into what time spans are eras next divided? (24.2) (a) eons (b) ages (c) epochs (d) periods

What is the name of the time period when plants lived that eventually became coal? (24.2) (a) Devonian (b) Pennsylvanian (c) Cambrian (d) Triassic

What kind of fossil is widespread and easily identifiable? (24.2) (a) index (b) trace (c) replacement (d) amber

What radioactive element gradually decays to lead and can be used to date ancient rocks? (24.3) (a) rubidium (b) potassium (c) carbon (d) uranium

If the half-life of a radioactive specimen is 100 years, then how long will it take for the specimen to reach 25% of its original amount? (24.3) (a) 25 years (b) 50 years (c) 100 years (d) 200 years

Radiometric dating is used to determine which of the following? (24.3) (a) absolute (numerical) geologic time (b) relative geologic time (c) a geologic formation (d) a correlation period

Which radiometric dating method is most useful for dating bones and wood? (24.3) (a) uraniumlead (b) potassiumargon (c) carbon-14 (d) rubidiumstrontium

What is the age of the Earth as determined by radiometric dating? (24.4) (a) 150 million years (b) 1200.2 years (c) 4.56 billion years (d) 320 million years

Which of these rocks are useful in helping us determine the age of the Earth? (24.4) (a) Earth rocks (b) Moon rocks (c) meteorite rocks (d) all the preceding

Which became the dominant life form in the Ordovician period? (24.5) (a) dinosaurs (b) plants (c) mammals (d) fish

Fossils from Precambrian time could include which of the following? (24.5) (a) human skulls (b) dinosaur bones (c) algae, bacteria, and sea worms (d) leaf impressions and shark teeth

In what era were dinosaurs common? (24.5) (a) Mesozoic (b) Paleozoic (c) Cambrian (d) Cenozoic

In what era were trilobites common? (24.5) (a) Mesozoic (b) Paleozoic (c) Cambrian (d) Cenozoic

When did the K-T extinction event take place? (24.5) (a) at the end of the Paleozoic era (b) at the start of the Paleozoic era (c) at the end of the Mesozoic era (d) at the start of the Mesozoic era

In which period of the Mesozoic era did dinosaurs thrive?

Name the two periods of the Cenozoic era, with the older first.

The Mississippian and Pennsylvanian periods in North America go by what name in Europe?

What is meant by Precambrian time?

What is the daughter product of potassium-40?

What type of rock is commonly dated with rubidiumstrontium dating?

Carbon-14 dating measures the ratio of carbon-14 not to its daughter, nitrogen-14, but instead to what isotope?

What are the three conditions for using an isotope in a rock to date that rock?

Distinguish between primordial lead and radiogenic lead.

Give examples of objects dated with carbon-14.

Give evidence that the Earth is about 4.56 billion years old. Include in your answer the age of the Sun (see Chapter 18.2).

About how old are the oldest rocks found on Earth? On the Moon?

Briefly, how can the absolute age of a sedimentary rock be determined?

On the basis of what geologic or biological events is Precambrian time split into three eons? Name the three eons.

Which era on the geologic time scale encompasses the shortest time span?

In what era do you live? What period? What epoch?

What are some of the explanations for the Great Dying?

What geologic event separates the Pleistocene epoch from the Holocene epoch?

What biologic event is used by geologists to separate the Tertiary period from the Quaternary period?

What is the biological event that started the Paleozoic era called?

What probably caused the demise of the dinosaurs and other species?

To what was the extinction at the end of the Mesozoic probably due? State some evidence for that explanation.

What evidence points to the K-T event being astronomical in origin?

What are the starting and ending dates of the Paleozoic era?

Briefly, what effect would a supercontinent, such as Pangaea, have on the distribution of land plants and animals of the time?