Glencoe Online Science Quiz Chapter

The Precambrian Earth

Practice Test


	1.	__________ are rocks that have alternating bands of fine-grained quartz and iron oxides.


	2.	What continent existed around 1.8 billion years ago that now forms the core of modern North America?


	3.	The oldest rocks on Earth are __________.

According to the dates given in the table, when would oxygen start appearing in Earth's atmosphere?

Event Or First Evidence In Fossil Record	Approximate Geological Time
Bacteria	3 b.y.b.p
Green algae	1 b.y.b.p
Jellyfish	600 m.y.b.p
Ediacara organisms	550 m.y.b.p
Eurypterids*	510 m.y.b.p
Horn corals*	500 m.y.b.p
First vertebrates	480 m.y.b.p
Spiders	400 m.y.b.p
Sharks	400 m.y.b.p
First jawed fish*	380 m.y.b.p
Ferns	350 m.y.b.p
Earthworms	300 m.y.b.p
Great Permian Extinction Event	250 m.y.b.p
Drastic geographic and climatic changes	248 m.y.b.p
First dinosaurs*	220 m.y.b.p
First mammals	210 m.y.b.p
Ginkgo biloba	200 m.y.b.p
Abundant ammonites*	180 m.y.b.p
Archaeopteryx*	140 m.y.b.p
First flowering plants	120 m.y.b.p
Ants	100 m.y.b.p
Cretaceous-Paleogene Extinction Event	66 m.y.b.p
Camel	35 m.y.b.p
Grass	20 m.y.b.p
Australopithecus afarensis (“Lucy”)	4 m.y.b.p


	5.	What was the original composition of Earth's atmosphere?


	6.	What evidence supports the hypothesis that Earth is 4.6 billion years?

		a.	the age of rocks from the Moon
		b.	the age of zircon grains in granitic crustal rocks
		c.	all of the above answers are correct
		d.	the age of meteorites


	7.	Why is the age of a zircon grain older than the age of the sandstone that it was found in?

		a.	because of the principle of superposition
		b.	because of the principle of included fragments
		c.	It is much more stable than the sandstone.
		d.	It is much less stable than the sandstone.


	8.	Which type of cell shown in the figure existed first?

		a.	B
		b.	A
		c.	both came into existence at the same time
		d.	it is impossible to tell


	9.	What event caused the extinction of acritarchs near the end of the Proterozoic?

10.

According to the table, what were the first organisms to evolve on Earth?

Event Or First Evidence In Fossil Record	Approximate Geological Time
Bacteria	3 b.y.b.p
Green algae	1 b.y.b.p
Jellyfish	600 m.y.b.p
Ediacara organisms	550 m.y.b.p
Eurypterids*	510 m.y.b.p
Horn corals*	500 m.y.b.p
First vertebrates	480 m.y.b.p
Spiders	400 m.y.b.p
Sharks	400 m.y.b.p
First jawed fish*	380 m.y.b.p
Ferns	350 m.y.b.p
Earthworms	300 m.y.b.p
Great Permian Extinction Event	250 m.y.b.p
Drastic geographic and climatic changes	248 m.y.b.p
First dinosaurs*	220 m.y.b.p
First mammals	210 m.y.b.p
Ginkgo biloba	200 m.y.b.p
Abundant ammonites*	180 m.y.b.p
Archaeopteryx*	140 m.y.b.p
First flowering plants	120 m.y.b.p
Ants	100 m.y.b.p
Cretaceous-Paleogene Extinction Event	66 m.y.b.p
Camel	35 m.y.b.p
Grass	20 m.y.b.p
Australopithecus afarensis (“Lucy”)	4 m.y.b.p


	11.	What was the composition of Earth's first crust?

		a.	iron and quartz
		b.	feldspar
		c.	feldspar, quartz, and mica
		d.	iron- and magnesium-rich minerals


	12.	Minerals with low densities crystallize from a magma at __________ denser minerals do.


	13.	The inner and outer core, mantle, and crust of Earth all have __________.

		a.	been rigid since the formation of Earth
		b.	different densities
		c.	the same densities
		d.	have the same specific gravity


	14.	What did organisms of Earth's first 4 billion years have in common?

		a.	They breathed oxygen.
		b.	They were photosynthetic.
		c.	They were multi-celled organisms.
		d.	They were single-celled organisms.


	15.	What substance in Earth's atmosphere protects organisms from UV radiation?


	16.	Why don't Archean and Proterozoic rocks have iron oxides?

		a.	there was too much iron to be oxidized
		b.	there weren't any stromatolites at that time
		c.	there wasn't any iron in rocks of that age
		d.	there wasn't any free oxygen in the atmosphere


	17.	How were asteroids and meteorites a heat source for Precambrian Earth?

		a.	Their bombardment of Earth caused them to sink to the core.
		b.	Their gravitational contraction generated energy.
		c.	Their radioactive decay of isotopes generated energy.
		d.	Their impact on Earth generated energy.


	18.	Fossils of __________ from late Proterozoic rocks are found in all parts of the world.