earthsciencech9and10

Which of the following is NOT a likely reason for global sea level change in the Proterozoic?

changes in the volume of water in the Earth system

Stromatolites are layered structures produced by the activity of

cyanobacteria.

Which of the following is NOT an example of a cyclic change in the Earth system?

faunal succession cycle

The Great Oxygenation Event occurred ~2.4 Ga and forced large amounts of __________ to precipitate out of the ocean.

iron minerals

The beginning and end points of eras, epochs, and periods on the geologic time scale are set by __________ ages. (numerical)

numerical age

Within the world's sedimentary rocks, fossils

occur in an ordered sequence.

Oxygen in Earth's atmosphere is derived from ()

photosynthesis.

The evolution of shells was important for the diversification of life because shells

protect organisms from predators and environmental conditions.

The geologic time scale is broken into a series of eras, epochs, and periods based mainly on the fossils found in each section. This is an example of __________ dating. (relative age)

relative age dating

In an undisturbed sequence of sedimentary rocks, younger layers overlie older layers, according to the principle of

superposition.

Which of the following organisms first evolved during the Cambrian Explosion?

trilobites

What is the parent-to-daughter isotope ratio if 1 half-life has passed?

8:8

The first continents, the first life, and the first cratons appeared in which geologic time interval? (Archean Eon)

FEEDBACK: By the Archean Eon, Earth had cooled enough to allow its surface to solidify and form continents, cratons, and plates, and contain ocean waters. Proterozoic means "first life," but it's a misnomer; life was well established in Archean times.

(Uniformitarianism means) geologic processes that operate today operated in the past at about the same speed.

FEEDBACK: Features of the Earth are constantly changing, and the same physical laws apply over Earth's history. The present is a key to the past and to the future because geologic processes operate today as they did in the past, at about the same rate. While the rates of individual geologic processes are the same today as they were in the past, different geologicprocesses do not all operate at the same rate. In other words, a landslide today moves rock as fast as a landslide would a million years ago, but all landslides move rock much faster than glaciers.

Footprints, feeding traces, burrows, and dung are considered to be (trace fossils.)

FEEDBACK: Footprints (tracks), feeding traces, burrows, and dung (coprolites) are considered to be trace fossils. Chemical fossils are distinctive chemicals left behind from the breakdown of an organism. Molds and casts form when sediment hardens around a fossil; when the fossil dissolves, it leaves behind a cavity called a mold. The mold may later be filled with minerals from groundwater, forming a cast. Permineralized fossils form when minerals from groundwater precipitate in the pores of wood or bone.

Geologists estimate that the Earth is 4.54 billion years old, based on (isotopic dating of meteorites from the first differentiated bodies of the Solar System.)

FEEDBACK: Geologists assume all objects in the Solar System developed at roughly the same time; therefore, the age of the oldest differentiated meteorites should represent the age at which the Earth formed. The ages of the oldest Canadian craton rocks, Australian zircons, and Moon rocks are greater than 4 billion years but must be younger than the age of the Earth because they formed after the differentiation of Earth.

An organism is most likely to be fossilized if it (dies in an oxygen-poor environment.)

FEEDBACK: Organisms are most likely to be fossilized if their remains can be buried before they are scavenged or weathered and before they decay. Therefore, an organism is most likely to be fossilized if it dies in an oxygen-poor environment that has few decomposers, is buried rapidly, and contains hard, durable parts.

The Cambrian explosion refers to (a dramatic increase in species diversity at the beginning of the Paleozoic.)

FEEDBACK: The Cambrian explosion refers to the dramatic increase in biodiversity in the fossil record at the beginning of the Paleozoic, beginning with the appearance of shelled organisms.

If you equate all Earth history to one calendar year, our species (Homo sapiens) would appear on (11 P.M. on New Year's Eve.)

FEEDBACK: The existence of the human species, Homo sapiens, represents an incredibly small portion of Earth history, equivalent to the last hour before midnight on New Year's Eve if all of Earth history were equated to one calendar year.

If a sandstone contains pieces of basalt, then the sandstone is younger than the basalt according to the principle of (inclusions)

FEEDBACK: The principle of inclusions states that a rock containing an inclusion (fragment of another rock) must be younger than the inclusion. The principle of superposition states that the oldest layer is at the bottom and the youngest layer at the top in an undisturbed sedimentary sequence. The principle of cross-cutting relationships recognizes that if one geologic feature cuts across another, the feature that has been cut is older. The principle of baked contacts states that the rock that has been baked is older than the intrusion.

The great oxygenation event, which added abundant oxygen to the atmosphere beginning about 2.4 Ga, was possibly caused by (a large increase in photosynthetic organisms in the oceans.)

FEEDBACK: The rise of photosynthetic organisms, which take in CO2 and produce O2, played an essential role in the development of atmospheric oxygen. It is important to note, though, that all life at this time in Earth's history was still in the oceans and had not yet colonized land.

The continents that comprised Pangaea began to split apart during the (Late Triassic through Early Jurassic.)

FEEDBACK: The supercontinent Pangaea didn't exist until the late Paleozoic, and it existed for "only" about 100 million years. It began to split apart during the Late Triassic and Early Jurassic periods.

Because humans have dramatically altered the environment, a new geologic interval beginning in the past few centuries has been proposed, named the (Anthropocene.)

FEEDBACK: The term Anthropocene has been coined to reflect the human-caused changes to Earth that have taken place in the past few centuries.

The eon represented by abundant deposits of strata with shelly fossils is the

Phanerozoic.

A geologist in South Dakota finds an assemblage of dinosaur bones in an outcrop for the Hilltown Formation, and his colleague in China discovers an assemblage of bones from a different dinosaur in the Liaoning Formation. What can be said about the two formations?

They are no younger than Cretaceous in age.