Chapter 22 Review The Precambrian Earth

What information about Earth’s materials can be inferred by their arrangement in layers, as shown here? their relative densities their order of formation their relative ages their temperatures

Which point on this time line should be labeled “Formation of Earth?”

Which line best represents the level of oxygen gas in the atmosphere during the Proterozoic?

Which graph correctly represents the relationship of the Precambrian to the total age of Earth? D

What discovery would weaken the primordial soup hypothesis of the origin of life? Lightning was common on early Earth. Earth’s early atmosphere contained carbon dioxide, water, and trace gases. Earth’s early oceans were warm and shallow. Asteroid impacts were uncommon when life is presumed to have begun.

A scientist can assume that this life form did not exist during the Precambrian because________. it is unicellular it contains a nucleus it contains RNA and DNA it has a cell membrane

What characteristic of Ediacaran biota leads scientists to think that these organisms do NOT represent relatives of present day animals? lack of a mouth, anus, or gut shapes that are dissimilar to all living organisms structures that were used for movement lack of nuclei

Which summarizes the relationship between density of an element and its distribution in Earth? The greater an element’s density, the greater the amount of it found in the crust. The denser an element is, the smaller the amount of it in Earth’s core. The lower an element’s density, the smaller the amount of it found in the crust. The greater an element’s density, the smaller the amount of it found in the crust.

Which diagram best represents the relationship of the landmass of Archean cratons to the total landmass of Earth? A B C D

Which best summarizes the change in number and size of microcontinents during the Proterozoic? the number of microcontinents increased and the size increased the number of microcontinents increased and the size decreased the number of microcontinents decreased and the size increased the number of microcontinents decreased and the size decreased

The oldest known mineral on Earth is ____. fluorite mica zircon quartz

An organism composed of a single cell that does not contain a nucleus and is the simplest kind of cell is a(n) ____. prokaryote eukaryote bryozoan animal

The process by which volcanoes vent water vapor, carbon dioxide, nitrogen, and other substances is called ____. oxidation glaciation differentiation outgassing

oxidation differentiation photosynthesis glaciation Cyanobacteria use the process of ____ to produce energy, and oxygen is given off as a waste product. oxidation differentiation photosynthesis glaciation

____ have been found in the waters of hydrothermal vents, suggesting that proteins and nucleic acids could have formed there during the Archean. Amino acids RNA molecules DNA molecules Dissolved minerals

Ancient continent that contained core of modern-day North America asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

Continental core of Archean and Proterozoic rock asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

Deposit consisting of alternating bands of chert and iron oxide asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

Metallic or silica-rich objects that orbit the Sun between the orbits of Mars and Jupiter asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

Meteor that has fallen to Earth asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

The Precambrian shield in North America asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

Sedimentary rocks younger than 1 Sedimentary rocks younger than 1.8 billion years that are colored by the iron oxides in them asteroid banded iron formation Canadian shield Laurentia meteorite Precambrian shield red bed

Tiny, threadlike photosynthetic organisms amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

Mat or mound composed of billions of cyanobacteria amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

Stable mineral that commonly occurs in granite amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

Glacial event that occurred between 700 and 800 million years ago amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

Hot water vent at volcanic seafloor rift amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

Fossils of soft-bodied Proterozoic organisms amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

Building blocks of proteins amino acids cyanobacteria Ediacaran fauna hydrothermal vent stromatolite Varangian glaciation zircon

The amount of radioactive isotopes contributing heat to Earth is greater now than it was when Earth was newly formed. True False

The movement of the continents was one of the three sources of Earth’s heat when Earth was newly formed. True False

Earth’s oceans and atmosphere formed after life on Earth was established. True False

Eukaryotes appeared later in Earth’s history than prokaryotes. True False

The process of plate tectonics, the movement of Earth’s plates, started at the end of the Precambrian. True False

The average temperature on Earth has changed through the course of Earth’s history. True False

Cyanobacteria are classified as prokaryotes. True False

Accumulation of oxygen in Earth’s atmosphere resulted in greater amounts of UV radiation reaching Earth. True False

The presence of iron oxide in rocks, formed during a specific time period, can be used as evidence of oxygen in the atmosphere during that time period. True False

Volcanic eruptions add great amounts of oxygen gas to the atmosphere. True False

Asteroids orbit the Sun between the orbit of Mars and Jupiter. True False

Granite, which is composed of feldspar, quartz, and mica—high-density minerals—is common at Earth’s surface. True False

Earth’s first granitic crust likely formed from slabs of crust that were recycled into the mantle at subduction zones. True False

The oldest rock samples collected from the Moon are approximately 4 The oldest rock samples collected from the Moon are approximately 4.6 million years old. True False

Early in the Proterozoic, microcontinents began to collide as a result of plate tectonics. True False

Earth’s early atmosphere likely contained large concentrations of water vapor, and oxygen and nitrogen gases vented from volcanoes. True False

Early life, mainly the Ediacaran fauna, modified the atmosphere by generating large amounts of the gas that eventually formed the ozone layer. True False