Fossils

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Fossils

• Unit 4

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What are fossils?

• Fossils are the petrified remains of ancient
  objects.
• Petrified means turned to stone.
• Ancient means very, very old.

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Kinds of fossils?

• Fossils can be of animals, plants, or other
  objects.
• Most of the time we think of dinosaurs when we
  hear the word fossil.

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Fossils, big or small.

• Fossils can be very large or very small

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More Fossils.

• Scientists even have found fossilized dinosaur
  teeth and claws!

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Paleontology is much more than finding dinosaur
bones like Dr. Grant did in the movie Jurassic
Park. Fossils can be found on all seven
continents and even right here in Texas.
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Paleontology and You
Paleontology is the scientific study of the
fossilized remains of early life on Earth. The
remains can be from different types of life, such
as

• Animals

• Plants

• Bacteria

• Fungus

(Stromatolite)
Brought to you by the Corpus Christi
Museum of Science and History
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Paleontology and You
A Paleontologist is not the same as an
Archeologist.
Paleontologist
Archeologist
Studies prehistoric people and their culture
Studies fossilized remains of early life
VS.
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What is a Fossil?
A fossil is any remains, traces, or imprints of
life that has been preserved at some time in the
geologic past. Fossils must be at least ten
thousand years old. Only a very small number of
organisms get fossilized.
The three main types of fossils are
1. body fossils
2. trace fossils
2. pseudofossils
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Body Fossils
1. Body Fossils are the actual body or body parts
of an organism that has been preserved. These
fossils may or may not be altered (fossils that
have gone through a chemical change or physical
change). The two main types of body fossils are
(A) unaltered remains and (B) altered remains
A. Unaltered remains of fossils means that the
remains have gone through little or no chemical
or physical change.
There are four main types of unaltered remains of
fossils
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Body Fossils
A. Unaltered remains
- Original skeletal material this means that the
hard parts of the organism are preserved as the
original material.
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Body Fossils
A. Unaltered remains
- Tar impregnation tar pits are excellent areas
to preserve life as a fossil. La Brea tar pits in
California is one of the most famous areas
because of the large number of preserved life
forms found in it.
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Body Fossils
A. Unaltered remains
- Amber entombment some trees make a sticky and
thick liquid called pitch or resin. Small
animals such as insects and spiders or plant
seeds and spores can get trapped in the pitch and
become preserved. If this gets buried it can
become amber.
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Body Fossils
A. Unaltered remains
- Refrigeration doesnt mean putting it in the
fridge. Animals can get trapped in cracks of ice
sheets, called glaciers, and freeze. Mammoths
have been found frozen in ice.
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Body Fossils
Lets review the five main types of unaltered
remains of fossils
Unaltered remains of fossils have gone through
little or no chemical or physical change. Fossils
must also be at least ten thousand years old.
The types of unaltered remains of fossils are
- Original skeletal material
-
Tar impregnation
-
Amber Entombment
-
Refrigeration
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Body Fossils
B. Altered remains of fossils means that the
organisms have gone through chemical or physical
change.
- Permineralization means that the hard parts of
bones, shells and plants have microscopic (too
small to see with our eyes) holes in them. When
these hard parts are buried, water that has
dissolved minerals in it can soak into the hard
parts and collect on them. Can you see the how
well the pine cone is preserved?
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Body Fossils
B. Altered remains
- Replacement means that groundwater with
dissolved minerals in it can replace the hard
parts of buried organisms with minerals.
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Body Fossils
B. Altered remains
- Recrystallization means that there is a
chemical change of the atoms that make up the
hard parts of the organism. In this ammonite, the
hard parts have been changed to Calcite, a
mineral.
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Body Fossils
B. Altered remains
The soft parts of organisms might also get
preserved.
- Carbonization when the soft parts of organisms
get buried in sediment, they can get squeezed and
preserved.
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Body Fossils
Lets review the four main types of altered
remains of fossils
Altered remains of fossils means that the
organisms have gone through chemical or physical
change and must be at least ten thousand years
old.
The types of altered remains of fossils are
- Permineralization
- Replacement
- Recrystallization
- Carbonization
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Lets review Body Fossils
Do you remember what body fossils are?
They are the actual body or body parts of an
organism that has been fossilized.
Do you remember what the two types of body
fossils are?
The first type is the unaltered remains of
fossils that have gone through little or no
chemical or physical change.
The second type is the altered remains of fossils
that have gone through chemical or physical
change.
Now, we are going to talk about trace fossils.
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Trace Fossils
2. Trace Fossils are not the actual body or body
parts of life that has been preserved. These
fossils show how an organism lived, how it moved,
what its feet looked like, how it raised its
offspring (its children), what it ate and what
its shape was.
There are five main types of trace fossils
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Trace Fossils
2. Trace Fossils
- Mold This isnt the green fuzzy stuff that
grows on old food. In paleontology, a mold is the
imprint that an organism makes in the sediment as
it is fossilized. When you push your finger into
clay, the hole you made is the mold.
This fossil seed was found in Nueces County.
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Trace Fossils
2. Trace Fossils
- Cast A cast is the same shape as the original
organism. Not all organisms will have these.
Casts are formed when the original parts are all
dissolved away and the empty space is filled with
sediment or minerals. None of the original
material is in the cast.
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Trace Fossils
2. Trace Fossils
- Burrows These trace fossils show how an animal
such as a worm (an annelid) moved through the
soft sediment.
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Trace Fossils
2. Trace Fossils
- Tracks can show how an animal moved and what
its footprint looked like. These tracks can tell
us a lot about the animal that made them in the
geologic past.
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Trace Fossils
2. Trace Fossils
Ok, now were going to talk about a fun trace
fossil
- Coprolite This is fossilized poop, called
dung. Dont worry, its ok to touch it because it
has been turned to stone. Coprolite can tell a
lot about how an animal ate and what it hunted.
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Lets review Trace Fossils
Do you remember what trace fossils are?
They are not fossilized body or body parts. Trace
fossils help us find out what prehistoric life
was like.
Do you remember what the five types of trace
fossils are?
- Mold
- Cast
- Burrow
- Track
- Coprolite
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Pseudofossils
Pseudofossils (meaning fake fossils) are not
fossils at all even though they may look like
one. These fossils may look like many different
things such as small branches.
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How is a fossil made?
Ok, now that we have talked about body fossils,
trace fossils and pseudofossils, lets talk a
little bit about how a fossil is made. Only a
small number of organisms get fossilized. This is
because they must be preserved under special
conditions.
In general, dead organisms that
get buried in soft sediment quickly
and have hard parts have a better chance to get
preserved.
The soft parts of dead organisms that
get buried in soft sediment with little or no
oxygen help to preserve those soft parts. Little
or no oxygen means that there will not be many
bacteria to eat the soft parts.
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Paleontology and You
Why should we study paleontology?
Paleontology helps us to find out what Earth was
like in the geologic past. Studying fossils helps
us to find out the age of rocks. Paleontology
also helped to prove that the continents move and
were all connected together into supercontinents.
.
It helps us to find out what animals, like
dinosaurs, were like.
The study of paleontology also made it possible
to make the movies Jurassic Park and Walking
with Dinosaurs.