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Science Unit #6

Geologic Time

QuestionAnswer
Magma that forces its way into rocks and hardens is called... Intrusion
A petrified fossil forms when... Minerals replace all or part of an organism
The earliest forms of life appeared during the... Precambrian Time
On the geologic time scale, eras are divided into... Periods
Fossils don't provide evidence for... How the Earth originally formed
In the Cambrian Explosion... A great number of different organisms evolved
Most fossils form when organisms die and are buried in... Sediment
The Mesozoic Era is often called the... Age of Reptiles
Scientists use radioactive dating to... Determine the absolute ages of rocks
Reptiles evolved from... Amphibians
The gradual change in living things over long periods of time is called __________. Evolution
The ________ of a radioactive element is the time it takes for half of the radioactive atoms to decay Half-life
Fossils are almost always found in __________ rock. Sedimentary
Plant and animals first reached land during the _________ Era. Paleozoic
The earliest life forms were probably similar to present-day _________. Bacteria
T of F: A scientist who studies fossils is called a *paleontologist* True
T of F: Geologist often use *potassium-40* to date materials that lived up to about 50,000 years ago. False, Carbon-14
T of F: Animals without backbones are called *invertebrates* True
T of F: Index fossils are useful because they tell the *absolute* ages of rock layers. False, Relative
The Mesozoic Era is often called the... Age of Reptiles
Scientists use radioactive dating to... Determine the absolute ages of rocks
Reptiles evolved from... Amphibians
The gradual change in living things over long periods of time is called __________. Evolution
The ________ of a radioactive element is the time it takes for half of the radioactive atoms to decay Half-life
Fossils are almost always found in __________ rock. Sedimentary
Plant and animals first reached land during the _________ Era. Paleozoic
The earliest life forms were probably similar to present-day _________. Bacteria
T of F: A scientist who studies fossils is called a *paleontologist* True
T of F: Geologist often use *potassium-40* to date materials that lived up to about 50,000 years ago. False, Carbon-14
T of F: Animals without backbones are called *invertebrates* True
T of F: Index fossils are useful because they tell the *absolute* ages of rock layers. False, Relative
Age:
Created by: 100001396555506
 

 



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