Potassium-40 is useful for dating very old rocks because it has a(n)_______ of 1.3 billion years.
Question 10
10.
A(n) _______ is a gap in the geologic record where some rock layers have been lost because of erosion.
Question 11
11.
A(n) _______ fossil forms when dissolved minerals replace the remains of an organism and then harden to form rock.
Question 12
12.
A _______ is a scientist who studies fossils
Question 13
13.
The_______ is combined information about fossils collected by scientists throughout history.
Question 14
14.
In the process of _______ the atoms of one element break down to form atoms of another element.
Question 15
15.
Question 16
16.
Question 17
17.
Question 18
18.
Question 19
19.
Question 20
20.
Question 21
21.
Question 22
22.
Question 23
23.
Question 24
24.
Question 25
25.
Question 26
26.
Name the earliest form of life known on Earth.
Question 27
27.
Describe what scientists can learn about the past while studying fossils. Please use complete sentences.
Question 28
28.
Compare and contrast molds, casts, and trace fossils.
Question 29
29.
In the beginning, why was there no liquid water on Earth?
Question 30
30.
In detail, tell me how scientists think the Earth was formed. What processes happened? Please include the formation of oceans and continents in your answer as well. Please use complete sentences.
Question 31
31.
How do layers B and D compare in age? If rock layers between B and D have eroded away,
what is the boundary between B and D called?
Question 32
32.
Layer F is an igneous extrusion. How could a geologist use layer F to infer the age of layer A?
What has the study of fossils allowed scientists to do?
describe past environments and the history of life
study present ocean temperatures at different depths
analyze the chemical composition of sedimentary rocks and minerals
predict which organisms will become extinct in the future
Earth’s earliest atmosphere lacked which gas that is necessary for life as
nitrogen
argon
carbon dioxide
oxygen
The relative age of a rock is
its age compared with the ages of other rocks.
less than the age of the fossils the rock contains.
the number of years since the rock formed.
its age based on how much carbon-14 the rock contains.
Geologists use radioactive dating to
determine the relative ages of rock layers.
tell the difference between molds and casts.
tell where one soil horizon ends and the next one begins.
determine the absolute ages of rocks.
What are fossils?
molds and casts of organisms that live today
drawings of ancient animals and other organisms
footprints or burrows of small animals that live today
the preserved remains or traces of organisms that lived in the past
The time it takes for half of the radioactive atoms in a sample of a radioactive element to decay is the element’s
relative age
absolute age.
potassium-argon date
half-life.
What does the principle of uniformitarianism state?
Organisms that lived in the past can be preserved.
Processes that operate today also operated in the past.
There are no gaps in the geologic record.
Earth’s eras occurred during uniform time spans.
What change in Earth's atmosphere allowed organisms to live on land.
A collision with a comet.
The development of the ozone layer.
A strong burst of particles from the sun.
The absorption of of carbon dioxide by oceans.
Fossils usually occur in metamorphic rock.
True
False
The law of superposition helps geologists determine the absolute age of a rock layer.
True
False
Geologists divide Earth’s long history into smaller units called eras and periods that make up the geologic time scale.
True
False
Sometimes layers of rock are overturned so much that the youngest rock layer may appear on the bottom, which is the reverse of what is ordinarily expected.
True
False
Most fossils form from animals or plants that once lived in or near quiet water such as swamps, lakes or shallow seas where sediment builds up.
True
False
Extinction of a type of organism occurs when the environment changes and the organisms can not survive and reproduce in the changed environment.
True
False
Around 1896, Marie Curie was involved in the discovery of radioactivity.
True
False
Radioactive elements always decay at the same rate.
True
False
Carbon-14 is a non-radioactive form of carbon.
True
False
Scientists have determined that the Earth is about 4.6 billion years old.
True
False
Scientists developed the Geologic Time Scale by studying rock layers and index fossils.