fossils

other ways fossils form

Fossils may form in other ways. With complete preservation, the organism doesnt change much. As seen below, tree sap may cover an organism and then turn into amber. The original organism is preserved so that scientists might be able to study its DNA. Organisms can also be completely preserved in tar or ice. Molds and casts are another way organisms can be fossilized. A mold is an imprint of an organism left in rock. The organisms remains break down completely. Rock that fills in the mold resembles the original remains. The fossil that forms in the mold is called a cast. Molds and casts usually form in sedimentary rock. With compression, an organisms remains are put under great pressure inside rock layers. This leaves behind a dark stain in the rock. You can read about them in Figure 11.3.

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fossils in sedimentary rock

Most fossils form when a dead organism is buried in sediment. Layers of sediment slowly build up. The sediment is buried and turns into sedimentary rock. The remains inside the rock also turn to rock. The remains are replaced by minerals. The remains literally turn to stone. Fossilization is illustrated in Figure 11.2.

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how fossils form

The process by which remains or traces of living things become fossils is called fossilization. Most fossils are preserved in sedimentary rocks.

what are fossils

Fossils are preserved remains or traces of organisms that lived in the past. Most preserved remains are hard parts, such as teeth, bones, or shells. Examples of these kinds of fossils are pictured in Figure 11.1. Preserved traces can include footprints, burrows, or even wastes. Examples of trace fossils are also shown in Figure 11.1.

learning from fossils

Of all the organisms that ever lived, only a tiny number became fossils. Still, scientists learn a lot from fossils. Fossils are our best clues about the history of life on Earth.

why fossilization is rare

Its very unlikely that any given organism will become a fossil. The remains of many organisms are consumed. Remains also may be broken down by other living things or by the elements. Hard parts, such as bones, are much more likely to become fossils. But even they rarely last long enough to become fossils. Organisms without hard parts are the least likely to be fossilized. Fossils of soft organisms, from bacteria to jellyfish, are very rare.

fossil clues

Fossils give clues about major geological events. Fossils can also give clues about past climates. Fossils of ocean animals are found at the top of Mt. Everest. Mt. Everest is the highest mountain on Earth. These fossils show that the area was once at the bottom of a sea. The seabed was later uplifted to form the Himalaya mountain range. An example is shown in the Figure 11.4. Fossils of plants are found in Antarctica. Currently, Antarctica is almost completely covered with ice. The fossil plants show that Antarctica once had a much warmer climate.

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index fossils

Fossils are used to determine the ages of rock layers. Index fossils are the most useful for this. Index fossils are of organisms that lived over a wide area. They lived for a fairly short period of time. An index fossil allows a scientist to determine the age of the rock it is in. Trilobite fossils, as shown in Figure 11.5, are common index fossils. Trilobites were widespread marine animals. They lived between 500 and 600 million years ago. Rock layers containing trilobite fossils must be that age. Different species of trilobite fossils can be used to narrow the age even more.

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instructional diagrams

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The diagram here shows us the stages of fossil creation. The first picture shows a living dinosaur that may have existed a thousand years ago. The second picture shows us dinosaur bones beneath waterbed. The third picture shows the bones separated and within the earth's rocks. And finally the fourth picture shows a man excavating and discovering the dinosaur bones, also known as fossils. Now what exactly are fossils? Fossils are nothing but the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form. The process by which remains or traces of living things become fossils is called fossilization. Most fossils are preserved in sedimentary rocks. Fossils are our best clues about the history of life on Earth.

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The diagram shows one way that fossils can form. There are 4 main stages. We see it begins when plants and animals die. They sink to the bottom of the sea. The dead animals become covered by sediment. Over time the pressure from the sediment compresses the dead animals into oil. Oil eventually moves up thru rocks. It then forms a reservoir and the process is complete.

questions

Examples of imprint fossils made by compression are

a. drawings on rock made by prehistoric humans

b. frozen remains of elephant-like mammoths

c. footprints and animal tracks

-->  d. fossil leaves

Fossilized insects have been found preserved in amber which is hardened

a. flower nectar

-->  b. tree sap

c. wood

d. None of the above

Fossilized stomach contents may indicate

a. the diet of the animal

b. the vegetation type in its habitat

c. whether an animal walked, swam or flew

-->  d. a b

An animal is more likely to a fossil if it:

-->  a. is buried deeply in the ground

b. is left on the surface of the ground

c. does not contain bones or other hard body parts

d. all of the above are about equally likely to result in fossilization

Marine fossils on the top of Mt. Everest indicate

a. sea level was once higher than the top of Mt. Everest

b. the fossils are not actually marine fossils, but just look like them

-->  c. the rock at the top of Mt. Everest was once under water

d. someone put them up there as a trick.

Preserved traces can include burrows.

-->  a. true

b. false

Scientists have discovered fossil footprints.

-->  a. true

b. false

Complete preservation occurs only when remains are preserved in rock.

a. true

-->  b. false

In the past, fossils inspired legends of monsters.

-->  a. true

b. false

It is very likely that any given organism will become a fossil.

a. true

-->  b. false

Fossils in older rocks are more similar to animals that live today than fossils in younger rocks.

a. true

-->  b. false

Fossils of ocean animals have been found at the top of Mt. Everest.

-->  a. true

b. false

Fossils form when remains are replaced by minerals.

-->  a. true

b. false

Fossils show that Antarctica once had a much warmer climate.

-->  a. true

b. false

Index fossils are the first fossils ever discovered of an extinct species.

a. true

-->  b. false

Complete preservation is valuable because scientists can study the organisms DNA.

-->  a. true

b. false

There are no plants in Antarctica so there are no plant fossils there.

a. true

-->  b. false

Teeth are more likely than feathers to be preserved as fossils.

-->  a. true

b. false

People first started discovering fossils about 150 years ago.

a. true

-->  b. false

All fossils form when remains of dead organisms are covered with sediments.

a. true

-->  b. false

dark stain in rock left by the remains of an organism

a. fossil

b. mold

c. index fossil

d. cast

e. trace fossil

f. fossilization

-->  g. compression

preserved tracks or other evidence of an organism that lived in the past

a. fossil

b. mold

c. index fossil

d. cast

-->  e. trace fossil

f. fossilization

g. compression

type of fossil that can be used to determine the age of rock layers

a. fossil

b. mold

-->  c. index fossil

d. cast

e. trace fossil

f. fossilization

g. compression

process by which remains or traces of living things become fossils

a. fossil

b. mold

c. index fossil

d. cast

e. trace fossil

-->  f. fossilization

g. compression

type of fossil that forms in a mold

a. fossil

b. mold

c. index fossil

-->  d. cast

e. trace fossil

f. fossilization

g. compression

any preserved remains or traces of an organism that lived in the past

-->  a. fossil

b. mold

c. index fossil

d. cast

e. trace fossil

f. fossilization

g. compression

imprint of an organism left in rock

a. fossil

-->  b. mold

c. index fossil

d. cast

e. trace fossil

f. fossilization

g. compression

Which of the following parts of organisms are most likely to be fossilized?

a. skin

b. hair

-->  c. shells

d. internal organs

Preserved traces of organisms might include

a. casts.

-->  b. feces.

c. molds.

d. compressions.

Preserved remains that have become fossils have turned to

a. tar.

-->  b. rock.

c. amber.

d. none of the above

Which type of organisms remains are least likely to be preserved as fossils?

-->  a. jellyfish

b. salmon

c. shark

d. tuna

Fossils can show us

a. how extinct organisms looked.

b. what past environments were like.

c. what geological processes occurred in the past.

-->  d. all of the above

To be used as index fossils, fossils must represent an organism that

a. lived in the water.

-->  b. lived over a wide area.

c. lived for a long period of time.

d. lived less than 5 million years ago.

diagram questions

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Which of those is the older layer?

a. Sedimentary rocks

b. Impermeable rocks

c. Water

-->  d. Trapped fossils

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Fossils need what for fossilization to start?

a. Oil

b. Natural Gas

-->  c. Sedimentary rocks

d. Coal

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The soft parts of organisms almost always decompose quickly after death. In which stage of fossil formation does this occur?

a. 2

b. 3

c. 4

-->  d. 1

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Can underwater animals decompose?

a. no

b. sometimes

c. idk

-->  d. yes

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What causes a fossil to be exposed?

a. sediments

-->  b. Rock erosion

c. the sun

d. water

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How many stages are there to the formation of a fossil?

a. 3

-->  b. 4

c. 2

d. 5

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Identify which of the following does not happen to a fish.

-->  a. It Floats

b. It Dies and sinks to the bottom of the lake

c. The bones become a fossil.

d. It rots and only bones are left

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What is the process being described in this diagram?

a. Organization

b. Evolution

c. Sedimentation

-->  d. Fossilization

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What happens after the fish rots?

a. Gets covered by mud

b. Sinks

-->  c. Only the bones are left

d. Flyes

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How many steps of aquatic fossil formation show the image?

a. 1

b. 2

c. 5

-->  d. 3

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What happens right after a fish dies and sink to the bottom of a lake?

-->  a. The fish rots.

b. The fish floats back up.

c. The water evaporates.

d. Algae feast on the fish.

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What happens after the mud hardens in the soil?

a. Rock Layers Form

b. Erosion

-->  c. Sediments are deposited

d. Track is made

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What does happen after the track is made?

a. Rock layers form.

b. Print is exposed by erosion.

-->  c. The mud hardens.

d. Sediment is deposited.

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Which is the last step of the process?

a. rock layers form

b. mud hardens

c. track is made

-->  d. print is exposed by erosion

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How many stages are there in the fossilization process?

a. 8

b. 3

-->  c. 5

d. 10

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What would happen if the mud never hardened?

a. Nothing would change if the mud didn't harden.

b. A print would be made but it would be fuzzy.

-->  c. No print would be preserved.

d. A print would be made but it would be from a different animal.

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What is the stage of fossilization that is between the formation of lignite and anthracite?

a. peat

b. lignite

c. forrest

-->  d. bituminous and subittuminous coal

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How are arthritides formed?

a. when birds eat vegetation

-->  b. compression of the soil when the vegetation dies

c. when vegetation is burned

d. when animals eat vegetation

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What is formed by the compression of Peat?

a. Anthracite

b. Vegetation

-->  c. Lignite

d. Coal

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How many phases does anthracite need to form?

a. 4

-->  b. 5

c. 6

d. 3

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What happened 300 million years ago?

a. the vegetation and forms peat

b. the peat is compressed between sediment layers to form lignite

-->  c. huge forests grew around 300 million years ago covering most of the Earth

d. eventually anthracite forms

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What needs to happen first before anthracite can form?

a. peat is compresses

b. bituminous forms

c. peat is compressed

-->  d. vegetation dies

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How many steps are in the process of fossilization?

a. 2

-->  b. 4

c. 1

d. 3

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Identify the part of the process where sediment begins to cover the remains.

a. 1

-->  b. 2

c. 3

d. 4

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Which is the last stage in the process of fossilization?

a. 2

b. 1

c. 3

-->  d. 4

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How many stages are there to fossilization?

-->  a. 4

b. 8

c. 6

d. 10

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How many steps are shown in the process of fossilization below?

a. 2

b. 5

c. 3

-->  d. 4

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Which process of fossilization shows the dying and sinking of the fish?

a. 1

-->  b. 2

c. 3

d. 4