geology chapter 12

What processes created the Earth's moon?

-Debris from Earth and another planetesimal accreted. -Earth was struck by a large planetesimal.

How is Earth unique from other planets? Choose all that apply.

-Earth's atmosphere supports varied forms of life. -Earth's core creates a magnetic field that is just strong enough to protect the surface from the solar wind.

About 2.2 billion years ago, a significant amount of oxygen appeared in the atmosphere. How does this relate to life on Earth during this time and after?

-Significant amounts of oxygen in the atmosphere contributed to the formation of ozone. This protected life from ultraviolet radiation. -Photosynthesis became a successful way to convert energy from the sun, and oxygen was a significant by-product.

What is the relationship between planetesimals and protoplanets? Choose all that apply.

-planetesimals are smaller than protoplantes. -planetesimals combine to form protoplants

When did the supercontinent Pangaea form?

250 million years ago

What is the age of the oldest rock found on Earth?

4 billion years old

Zircons found in continental rocks give evidence that continental crust was forming as long ago as ________.

4.4 billion years ago

The earth formed approximately ________ years ago.

4.6million

When did dinosaurs go extinct?

65 million years ago, at the Cretaceous-Paleogene boundary

Which of the geologic provinces in Figure 1 might have been added in the time leading up to the formation of Pangaea?

Appalachian Province

The modern oceans are a major repository for the greenhouse gas ________, which some organisms utilize to make their shells.

CO2

What group of reptiles led to the evolution of birds?

Dinosaurs

The first bacteria probably used ________ instead of water as a source of hydrogen.

H2S

What two elements made up most of the very early universe?

Hydrogen and helium

Why is the molten metallic outer core and the magnetic field important to life on Earth?

If we did not have the molten core and the magnetic field, we would be bombarded by cosmic rays that would strip away our atmosphere.

Why is it important that we have a rigid lithosphere overlying a weak asthenosphere?

If we did not have the rigid lithosphere and weak asthenosphere, the earth would not have plate tectonics and would be covered entirely by water.

Which planet in the solar system had more mass accreted to it via a comet that impacted in 1994?

Jupiter

How was low-density continental crust produced by Earth's rocky mantle?

Low-density, silica-rich minerals rose to Earth's surface from the mantle, eventually creating Earth's crust.

What animal group became the dominant land animals of the Cenozoic era?

Mammals

__________ were able to diversify after the extinction of the dinosaurs.

Mammals

As they formed, due to their high temperatures and comparatively weak gravitational fields, which planets were unable to retain appreciable amounts of hydrogen, helium, and ammonia?

Mercury and Earth

Which region of North America has the oldest parts of the continent?

Northern Canada

What would have happened if Earth were located 10% further out from the Sun?

Our oceans would all be frozen.

By the close of the Paleozoic, all the continents had fused into the single super continent of ________.

Pangaea

Which one of the following represents the greatest expanse of geological time?

Precambrian

________ are the earliest life forms identified on Earth and they date back to nearly 3.5 billion years ago.

Prokaryotes

Which of the following statements regarding prokaryotes is true?

Prokaryotes did not have nuclei.

Using Figure 2, determine when the majority of the African craton had been formed.

Proterozoic Eon

What is the name of the cataclysmic event in which an exploding star produces all the elements heavier than iron?

Supernova

How did the mass extinction at the end of the Cretaceous time period influence evolution?

The demise of the dinosaurs led to diversification of mammals.

Much of the early hydrogen and helium escaped the earth's atmosphere into space because ________.

The earth's gravity was weak

Why is Earth's molten, metallic core important to humans living today?

The molten core provides Earth with a magnetic field, which prevents cosmic rays from stripping away Earth's atmosphere.

Why was the evolution of photosynthesizing bacteria important to most modern organisms?

These bacteria released free oxygen into Earth's atmosphere for the first time; as their numbers grew, the amount of oxygen in Earth's atmosphere grew.

Why was rainwater highly acidic early in Earth's history?

Volcanic eruptions released large quantities of sulfur dioxide into the atmosphere, which combined with water to form acid that fell as acid rain.

Early Earth was hot because ________.

a combination of collisions and radioactive decay produced heat

What organic compounds are essential for DNA and RNA to form?

amino acids

Birds evolved from ________.

archaeopteryx

Put the following events in the order they occurred to lead to the formation of the solar system: A. Earth was bombarded by new materials after formation. B. Earth separated into layers based on the weight of materials. C. Hydrogen and helium formed atoms. D. Outgassing of volcanoes produced a primitive ocean.

cabd

Which geologic event was responsible for adding the Grenville Province to North America approximately 1.2 billion years ago?

formation of Rodinia

Which of the following was an important factor in determining where the small rocky planets formed as opposed to where the light, gaseous planets formed?

gravity

The first elements to form after "Big Bang" were ________.

helium and hydrogen

What common bone structure is shared in the forelimbs of the lobefin fish and amphibians?

humerus, radius, ulna, and finger bones

The heaviest element produced by nuclear fusion in a young star is ________.

iron

Which animal are all tetrapods derived from?

lobefin fish

The dominant life forms during the Cenozoic Era were ________.

mammals and angiosperms

The waste gas released by plants as they synthesize food sugars from carbon dioxide and water is ________.

oxygen

The process in which plants use light energy to synthesize food sugars from carbon dioxide is called ________.

photosynthesis

Following the reptilian extinctions at the close of the Mesozoic, two groups of mammals, the marsupials and ________, evolved.

placentals

The ________ means "the Sun in the making."

protosun

Which processes created the magma ocean that used to exist on the planet Earth?

radioactive bombardment

Mammals are derived from __________, which are derived from __________.

reptiles; amphibians

The most common Precambrian fossils are ________, layered mounds of calcium carbonate.

stromatolites

The Laramide Orogeny at the end of the Mesozoic produced ________.

the Rocky Mountains in the western U.S.

The Appalachian Mountains formed as a result of ________.

the collision of North America and Africa

An important evolutionary step for reptiles was ________.

the development of shell-covered eggs

Hydrogen and Helium would have been the first elements to form after the Big Bang. How were heavier elements produced?

the supernova of early stars

A distinctive characteristic of prokaryotes is ________.

their lack of a separation between the DNA and the rest of the cell

One important reason we do not know much about the geologic history of the Precambrian is that ________.

there are very few fossils preserved in Precambrian rocks

The Goldilocks scenario suggests that ________.

we are very fortunate to be in the right place in the universe and to have had the right condition to develop and sustain life

The Archaeopteryx is an early bird that came into existence at the time of the dinosaurs. It had a mix of reptilian and bird features. Of the physical features listed below, which are reptilian features?

wing claws -long tails teeth