Name-__________________
Earth’s Past Party Planner
Directions: Refer to your notes in your notebook, your rock fossil graphic organizer, 9.2
funsheet, and your earth’s past research. If you did not receive any of these assignments back,
then check the tray. DO YOUR BEST ANSWERING THESE QUESTIONS…. DO NOT
STRESS OUT!!!!! Please restate your question and put your answers in complete sentences.
1. Explain what conditions help preserve organisms as fossils.
original remains- A fossil that is the actual body or body parts of
an organism.
There are 3 different substances original remains are found are the following
Fossils in Rocks- These fossils are impressions or traces made of rock and provide
indirect evidence that the organisms were there
2. If the same types of fossils are found in two separate rock layers, explain the relationship
between the two rock layers. The relationship between the two rock layers are that
they existed during the same period based on the organisms that were found.
3. What type of dating is determining the order of events of rocks by examining the position
of rocks relative to one another is called relative.
4. A limestone bed containing fossils that are 550 million years old is older to a bed of
sandstone containing fossils that are 400 million years old.
5. Radioactive dating uses the properties of atoms in rocks and other objects to find their
ages.
6. Explain what evidence scientists collect on how rock layers are alike.
Scientists collect evidence of common fossils, common minerals in rock, and types of rock.
7. If a layer of sandstone lies on top of a layer of limestone in which a 300-million-year-old
fossil is found, and there are no disturbances, the layer of sandstone must be younger.
8. Create a Venn diagram representing the relationship between absolute dating and relative
dating.
RelativeApproximately/
Range in years
Alike
Absolute
Both used in dating Exact/
rock
half-lives
9. Geologic time is divided into units based upon types of climate and plate tectonic
changes.
10. Explain what the longest period is on the geologic timeline and why.
Cretaceous period was the longest due to the break of the super continent Pangea
and the steady warm tropical climate.
11. What organisms and environment existed during the Mesozoic Era.
The organism that existed during the Mesozoic Era was reptiles, dinosaurs, and
birds. The climate was warm and tropical.
12. Explain the Cenozoic Era life-forms.
Warm blooded mammals evolved to adjust to the earth’s changing climate, birds
became lighter to adjust to the air pressure changes and humans.
13. The development of ozone layer factored in the development of complex organisms.
14. Explain the life-forms that existed during the Paleozoic Era.
The life-forms that existed were sea organisms due to the earth being covered in
shallow sea for the majority of the Paleozoic Era such as crinoids, coral, trilobites,
and sponges.
15. The end of the Paleozoic Era was signaled by an ice age.
16. Explain how plate tectonics affected organisms’ evolution.
The organisms’ evolution was affected by plate tectonics movement because it
interfered with the ocean currents which in turn affected the environment for the
organisms to live in.
17. Pangaea separated into two continents, Gondwanaland and Laurasia..
18. Humans first appeared during the Cenozoic Era.
Figure 13-1
19. List events A–F shown in Figure 13-1 in the order that they occurred, beginning with the
oldest event. F, E, D, C, B, A
20. Explain when the fault in Figure 13-1 occurs?
The fault occurs between layers B and A
21. If horizontal layers of sedimentary rock have a vertical fault running through them, how
might a geologist use relative dating to determine when the fault occurred? A geologist
might use relative dating to determine when the fault occurred by observing index
fossils used in each layer and perform carbon dating on the fossils to find out
relatively how old that layer of rock is.
22. Do all rocks contain fossils? Describe the conditions necessary for fossils to form. Not all
rocks contain fossils because of the process they go through to become that rock.
Sedimentary rock is the only rock that has the conditions necessary for fossils to
form because they go through weathering and erosion, compaction and cementation
which would preserve the fossil and sediments would forms layers upon one
another.
23. Explain what the term half-life means and how knowing the half-life of an element can
help a geologist establish the age of a rock or fossil.
Half-life means how much time that an element breaks down and decays into
another element. Observing how many half-lives a rock has went through can tell
scientist how old that rock is.
24. What changes were necessary in Earth’s atmosphere to allow complex organisms to
evolve? The changes that were necessary in Earth’s atmosphere were the
development of the ozone layer to protect complex organisms from harmful
radiation.
25. What is one theory to explain the sudden disappearance of many animals at the end of the
Mesozoic Era? One theory was a meteorite hitting Earth which triggered volcanoes
to erupt and block out the sun for years causing an ice age.
26. Describe some of the changes in the land and in life-forms that occurred at the end of the
Paleozoic Era. The changes inland and life forms at the end of the Paleozoic Era was
the development of land mass based on plate tectonic movement which triggered
fish to evolve into land animals by developing legs and lungs.
Figure 13-2
27. A sample of a radioactive element has a mass of 80 g. How much parent and daughter
materials are in the sample after two half-lives?
25% parent material 75% daughter material
28. According to Figure 13-2, if 25 percent of the parent material remains in a rock sample,
how many half-lives have occurred?
2 half-lives
29. Refer to Figure 13-2 and determine how much parent material will be left after five half-
lives.
3.125%