Fossils

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.Fossils
Powerpoint Notes
Name_______________________
Per____________
Paleontology is:
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Fossils are any evidence of ancient organisms.
What can we learn from them?
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They can help us study how
_____________________________________________________________________________
______________________________________________________
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They can be used to determine _______________ geologic ages.
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They tell us about __________________________________________________
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Sedimentary environments can include
________________________________________________________________________
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They can help determine the positions of Earth’s lithospheric plates during the geologic past.
How is evidence of life preserved?
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_______________________________
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________________________________
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Body fossils are any ______________________________ of prehistoric life.
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This includes whole bodies of animals, plants, or other organisms
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Or any parts of bodies such as ___________________________________________
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Trace fossils are any ______________________________ of prehistoric life
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This includes tracks, trails, burrows, boreholes, bite marks, and coprolites
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Trace fossils are useful for studying _______________________ of ancient organisms.
Fossilization
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What is necessary to preserve a body fossil?
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____________________________ (bone, teeth, shell, wood)
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Hard parts stand a greater chance of preservation than do soft tissues (skin and muscle)
because soft parts readily decay or decompose after death.
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____________________________
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Rapid burial helps to prevent decomposition, erosion, and disarticulation (separation of
the body parts or bones).
Body fossils are preserved as:
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Unaltered remains
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Many marine organisms build their skeletons with the mineral _________________, which is
chemically stable over geologic time.
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Mummification: An organism may dry out so fast that their soft parts
_______________________________________________________
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Fossilization in amber: Amber is fossilized tree sap. If an insect gets caught in the sap, it may
become part of the fossil.
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Frozen fossils: Animals may get trapped in ice and preserved. Wooly mammoths have been
found preserved this way.
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Animals may have been stuck in naturally occurring pools of tar. A famous example is
_______________________________________
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Altered remains
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Replacement
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This is the __________________________________________ and replacement by
another mineral.
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Example: calcite shells that are replaced with pyrite.
Permineralization
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This is the filling of pore spaces in porous material such as wood or bone by
___________________________________________.
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Example: petrified wood, or dinosaur bones
Dissolution
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This is the _______________________ of the original skeleton, leaving a hollow
impression called a ______________________.
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A cast of the object is formed when ___________________________________
_______________________________________________________________
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Carbonization
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This is where the only compounds left of the organism is a carbon film in rock.
Index Fossils
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Fossils of organisms that ___________________________________________
___________________________________________________________________
They help to give a relative age to rock layers.
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Ammonites and Trilobites are examples of index fossils.
Earth Science
Name________________________
Fossil Lab
Per________
__________________________________________________________________________________
Objectives:
 Describe how the fossil record documents the appearance and diversification of many life
forms.
 Interpret successive layers of sedimentary rocks and their fossils to document the age and
history of the Earth
__________________________________________________________________________________
Procedure:
1. In the left side of each box, sketch an example of the organism listed. Fill in any information
and answer all questions. Use Chapter 6 of your book as a reference. Marine = Ocean,
Nonmarine = lakes or other fresh water environment.
2. For fossils 11-14, you need to determine the relative age of these fossils based on the
stratigraphic column attached at the end of the lab. You may also be able to answer some of the
other questions about the fossils by examining this figure.
3. Fill in the blanks next to each layer of rock with their geologic age.
4. Write each fossil name by the fossil number in the stratigraphic column.
5. Complete the questions/analysis.
1) Bryozoan
Bryozoan – tiny microscopic animals that live in
colonies. They form skeletons around their soft bodies.
The skeletons will often fossilize.
Geologic Age from label:
What kind of rock was this found in?
Is this a Marine or Nonmarine animal?
2) Plant
Plant – This plant fossil is great for understanding past
climates.
Geologic Age from label:
What kind of rock was this found in?
Why are fossil plant remains important for us
today?
Describe what kind of climate this plant may
have been growing in.
3) Trilobite
Trilobite – meaning 3 lobes, was a common fossil in
the Paleozoic era and went extinct during the great
Permian extinction. This type of fossil is a great index
fossil.
Geologic Age from label:
What kind of rock is this found in?
What makes this a good Index Fossil?
4) Coral (Rugose or “Horned” coral)
Corals – Still living today, you can find this animal in
todays oceans. Rugose corals build reefs and are
confined to shallow warm waters.
Geologic Age from label:
What rock type is this found in?
What part of the animal has been fossilized?
5) Gastropod (Snail)
Gastropod (snail) – Snails are related to clams, but
they only have one valve (living chamber). Some snails
coil in one direction and sometimes the other, depending
on the temperature of the water.
Geologic Age from label:
What kind of rock is this found in?
Is this animal marine, nonmarine, or both?
Is this the original unaltered fossil? What is it?
6) Nautiloid Cephalopod
Nautiloid Cephalopod – When this animal was
young it created a small shell. When the animal grew, the
shell became too small, so more material was added on to
the end where it lived and a new chamber was formed.
Geologic Age from label:
What kind of rock is this found in?
How can you tell the difference between this
fossil and a gastropod?
7) Crinoid Stem
Crinoid – Another name for crinoid is sea lily. Early
seas were populated by crinoids.
Geologic Age from label:
What kind of rock is this found in?
Is this a plant or animal fossil? Why?
Describe two differences between this fossil and a
nautiloid cephalopod (other than size).
8) Brachiopod 1 (sketch top and side views)
Brachiopod 1 – These are clam like animals, but are
different from clams because their shells fit together
differently.
Geologic Age from label:
What kind of rock is this found in?
Give two reasons these might commonly
become fossils.
9) Brachiopod 2
Brachiopod 2 – Most brachiopods were solitary
animals. Their shells have an opening between the valves
where a fleshy foot came out that may have been used for
attachement.
Geologic Age from label:
What kind of rock are these found in?
This fossil is a body fossil. What part of the
brachiopod does this fossil represent?
10) Pelecypod (Clam)
Pelecypods (Clams) – Clams are often very good
indicator of the conditions at the bottom of the ocean
since very few could swim around much. This fossil
shows growth of the animal that lived inside as the shell
expanded, just like the rings of a tree.
Geologic Age from label:
What kind of rock is this found in?
11) Coprolite
Coprolite – This fossil represents the feces of an
animal.
Determine approximate geologic age from
stratigraphic column.
What kind of rock is this found in?
What makes a coprolite a trace fossil?
12) Sharks Tooth
Shark Tooth – The shark is considered a primitive fish
because its skeleton is made up of cartilage instead of
bone.
Determine approximate geologic age from
stratigraphic column.
What kind of rock is this found in?
Why wouldn’t the entire skeleton of the shark
fossilize?
13) Porifera (Sponges)
Porifera (Sponges) – This is not the kind of sponge
you would use in the shower! This animal does not have
a mouth, but instead pumps water with tiny animals or
nutrient rich particles though its tiny pores.
Determine approximate geologic age from
stratigraphic column.
What kind of rock is this found in?
14) Burrow
Burrow – This trace fossil represents the burrowing of
an animal.
Determine approximate geologic age from
stratigraphic column.
What kind of rock is this found in?
In what kind of environment did the animal
create this trace fossil?
Questions/Analysis:
1) Describe how fossils can be used to determine the ages of rocks?
2) Explain how we can know the approximate ages of newly discovered fossils.
3) Give a possible geological reason or story why we don’t see rocks or fossils that are Mississippian
age (354-323 million years ago) in this stratigraphic section of geologic history.
Conclusion: