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3rd Grade

Biological Evolution

2015-12-03

www.njctl.org

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Table of ContentsClick on the topic to go to that section

· Habitats

· Fossils· Adaptations

· Disturbances· How Fossils Are Used

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Compost Time Capsule

How do different items change over time?

Set-up the Compost Time Capsule Activity now.

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Habitats

Return toTable of Contents

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The Forest

Think about the forest in this picture. What organisms live there?

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The ForestMake a list below of what the organisms in a forest need to survive:

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Ecosystems

The forest is an example of an ecosystem. An ecosystem is a combination of all the living and nonliving components of an environment.

· Living components are called biotic factors.

· Nonliving components are called abiotic factors.

Look back at your list of things needed by forest organisms. Can you separate them into biotic and abiotic factors?

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Biotic Factors

Biotic factors include all of the living components of an ecosystem. Living components include plants, animals, bacteria, fungi, etc.

For example, hawks that live in the forest need squirrels, snakes and other small animals for food. These are biotic factors.

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Abiotic FactorsAbiotic factors include all of the nonliving components of an ecosystem. Organisms in the forest need differing amounts of the following to survive:

Soil Air and sun

Water Temperature

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Biotic and Abiotic Factors

Take a look at this coral reef ecosystem. How many biotic and abiotic factors can you think of that affect this ecosystem?

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1 Which of the following is an abiotic factor?

A water

B predators

C disease

D offspring

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2 Which of the following is a biotic factor?

A fire

B forests

C temperature

D fresh air

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HabitatsWithin an ecosystem, there are specific areas where organisms live and grow.

In the forest ecosystem, squirrels live in trees. Frogs live in forest ponds. Earthworms live in the soil.

These different areas are called habitats.

This earthworm's habitat is the forest floor.

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3 The interaction of the living and nonliving parts of an environment make up an ecosystem.

True

False

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4 A small part of an ecosystem, such as a pond, is a

A biotic factor

B habitat

C environment

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A change in an ecosystem can affect how well an organism can survive.

Polar bears live in the Arctic. They have a thick layer of fat to keep warm. They are excellent swimmers and can swim long distances to hunt for food.

Ecosystems and Habitats

Which of the polar bear's needs would not be met if it could no longer swim?

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What if the Arctic became warmer?

How would the polar bear population survive if the seals disappeared?

Decide if the seals and the climate are biotic or abiotic, by drawing an arrow from the correct word to each picture.

BIOTIC

ABIOTIC

Fewer Seals to eat Less Ice to live on

Ecosystems and Habitats

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What if the environment changes?There are three responses that organisms can take if their environment changes.

1. The organisms can adapt and live in the new environment.

2. The organisms can move to a new environment.

3. The organisms do not change or adapt and die out.

Did the dinosaurs adapt when their environment changed?

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5 A change in a habitat does not cause changes in the organisms that live there.

True

False

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6 An individual can survive an ecosystem change if it moves location and finds the resources it needs.

True

False

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7 If an organism does not move locations or adapt to a change, what will happen?

A It will change the environment.

B It will increase in number.

C It will die.

D It will find new biotic factors.

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Coral BleachingHealthy corals have special algae that live inside of the coral. These algae produce their own food that they share with the coral. In exchange, the coral provide the algae with shelter. Each specific type of algae gives coral a different color. That is why corals are so colorful.

These colorful corals are filled with algae.

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Coral BleachingThe algae that exist within corals have very specific requirements for survival. If the water temperature increases above a certain level, the algae will leave the coral. This is called coral bleaching. The corals all turn white because the algae, which had given them the bright colors, have left.

When coral bleaching occurs, the fish that lived in the coral reef will move to a different coral. The coral itself will die.

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8 What causes coral bleaching?

A high salinity

B high water temperature

C too little sunlight

D an increase in fish population

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9 What type of factor causes coral bleaching?

A biotic

B abiotic

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10 How do corals respond to coral bleaching?

A They adapt.

B They move.

C They die.

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11 How do fish respond to coral bleaching?

A They adapt.

B They move.

C They die.

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12 Scientists have discovered a type of algae that can tolerate warm water temperatures. This algae has responded to coral bleaching by ___.

A adapting

B moving

C dying

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Adaptations

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Ecosystems and Habitats

Organisms have characteristics that enable them to survive in their specific environments.

Fresh water pools and trees are different habitats in the same ecosystem. Each frog has characteristics that enable it to survive in its specific habitat. How many can you think of?

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AdaptationsA characteristic that helps an organism to survive in a particular environment is called an adaptation.

In other words, organisms are adapted to their environments.

Clown fish live in sea anemones. They have an adaptation that makes them immune from the anemone sting. They can safely hide from predators in the anemone.

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AdaptationsMany animals that live in cold environments have thick fur to protect them from the low temperature.

Snowshoe hare

Polar Bear

Harp seal Arctic fox

Why do you think all these animals have white fur?

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Adaptations

There is a lizard on this tree trunk. Can you see it?

This lizard has adapted camouflage to help it blend in to its environment. How does this help the lizard to survive?

Click the picture to watch a video about some amazing camouflage.

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Adaptations

Click below to watch a video about the horned lizard. Write down as many adaptations as you can see that help the lizard to survive. Be ready to share your ideas with the class.

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13 A polar bear's sharp teeth are an ____________ that helps him to catch prey.

A survival

B extinction

C adaptation

D artificial selection

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Adaptations

Why do organisms need to be adapted to their environments?

Think about the polar bear again. It has thick fur and webbed feet for swimming.

What would happen to the polar bear if it were moved to the desert environment?

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AdaptationsIf the polar bear were moved to the desert, it would overheat from its thick fur. There would be very little food for it to hunt and no water for swimming.

The polar bear would not survive in the desert.

An organism's adaptations enable it to survive in its environment.

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Within the same type of organism, adaptations can vary slightly. This leads to variation.

Adaptation Leads to Variation

All of these fish are bluestripe snappers. Do you notice slight variations among them?

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Variation

These giraffes and dogs have a lot of diversity. That means there is a lot of variation between individuals.

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Variation Leads to Survival

When variation exists, the organism with the variation that is most suited to the environment has the highest chance of survival.

All three moths are peppered moths. If located in a forest with dark colored tree bark, which moth will most likely survive?

The best adaptation leads to survival!

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Variations Lead to Mating Female peacocks choose a mate that has the longest, brightest feathers. In a population of peacocks, which males will be able to mate most often?

Having long, bright tail feathers is an adaptation that leads to finding a mate. Variation leads to the birds with the longest, brightest feathers finding mates most often.

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Bower bird males build and decorate nests with nuts, berries, stones and petals. The female mates with the owner of the nest she likes best.

These behaviors are adaptations. When the birds mate, the adaptation is passed on to the future generation.

Variations Lead to Mating

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14 Animals are adapted to many different environments.

True

False

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15 Individuals of the same species can have __________ which can make them more or less suited for their environments.

A sharp teeth

B identical traits

C feathers

D variations

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16 The best adaptations will give an individual the __________ chance at survival and reproduction.

A least

B same

C greatest

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17 Some birds build different nests. This behavior helps them to ___.

A attract mates

B find food

C protect themselves

D all of the above are possible

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ExtinctionAn organism must be able to survive changes in their environment to continue to survive.

This is a Wooly Mammoth. A warm woolly coat is an adaptation that was an advantage in the cold, icy climate. When the ice Age ended, the adaptation became a disadvantage. They could no longer survive in their environment. The species became extinct which means it completely dies out.

Not

e

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Extinction

The greater variation among species gives the greatest chance of survival as Earth continues to change over time.

Variation in leopards. Only the saber-toothed cat at left went extinct. Variation in traits led to the others that are alive today.

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18 The woolly mammoth population went _________ because it did not have the adaptations to survive in the current environment.A up and down

B up

C extinct

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Camouflage Lab

Camouflage is a useful adaptation for many organisms.

But...is it useful in all environments?

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Fossils

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Dinosaurs

Dinosaurs first appeared on Earth 231.4 million years ago. For each type of dinosaur, we know what their habitat was, what they ate and how they acted. We even know how big each one was.

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Dinosaurs

If dinosaurs went extinct 65 million years before the appearance of humans, how can we possibly know all of this information about them?

Scientists use evidence to prove ideas. What evidence do we have that proves the existence of dinosaurs?

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FossilsFossils are pieces of animals, plants, and other organisms that have been preserved over time. Fossils are a major source of information about dinosaurs.

Paleontology is the study of fossils over geologic time (Earth's history.) Paleontologists study how fossils are formed.

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FossilsThere are three different ways that fossils can form.

Imprints Preservation Mineralization

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ImprintsSuppose that you go for a walk in the snow, leaving behind a trail of footprints. If the temperature suddenly dropped below freezing for a long time, the snow would turn into ice. Your footprints would be preserved in the ice.

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ImprintsThis is the same way that imprints are formed. An organism makes a formation in the soft ground. If the soft ground becomes solid rock, then that imprint is preserved.

These are imprints of dinosaur tracks.

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ImprintsSome organisms left imprints of their entire bodies. Here is how this happens:

1. An organism dies.2. The organism's body decomposes, leaving empty space in the sediment.3. The only thing left is an imprint of what that organism looked like.

This type of formation is called a mold. It is a mirror image of the organism.

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PreservationWhen an entire organism is found in the same condition as it was when it died, it is called a preserved fossil.

This gnat flew into some amber (sticky sap) and got stuck. Once it died and the amber hardened, the gnat was permanently preserved inside.

Do you think paleontologists can learn more from a preserved fossil or a mold? Why?

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Mineralization

Mineralization is a process that creates a replica of hard body parts. It is what we generally think of when we hear the term fossils.

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MineralizationThe process for mineralization:

1. An organism dies.2. The organism is covered in sediment.3. Soft structures on the organism decompose, leaving

behind only hard structures, like bone and teeth.4. The ground surrounding the structures turns into hard

rock.5. Minerals in water replace the minerals in the hard

structures.6. An exact copy is left in the rock until an event occurs to

bring the fossil to the surface of the Earth.

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MineralizationMineralization begins the same way as a mold.

In a mold, the organism decomposes to leave behind empty space and an imprint.

In mineralization, the hard structures that remain after the soft structures decompose are preserved by mineralization. This creates what is called a cast.

This fossil is a cast of a trilobite, a marine arthropod.

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A mold shows the imprint of the exterior of an organism.

A cast shows a three dimensional representation of the organism or structure.

Cast Versus Mold

Which fossil is a cast and which is a mold? Click in the boxes to see the answer.

Cast Mold

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19 __________ are traces of animals, plants, and other organisms from the past.

A Rocks

B Dinosaurs

C Fossils

D Sand

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20 A studies the fossil record and how it changes over Earth's history.

A botanist

B herpetologist

C paleontologist

D biologist

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21 Certain conditions are needed to make a fossil. Which does not belong?

A Soft body parts, like worms.

B Hard body parts, like a shell or skeleton.

C Sediments cover the body.

D Minerals fill the remains creating a rock like mold.

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22 Which of the following is not a way that fossils are created?

A Mineralization

B Preservation

C Conservation

D Imprint

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23 What type of fossil is this?

A Mold

B Cast

C Imprint

D Both A and C

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24 This crab was preserved via ___.

A Preservation

B Mineralization

C Imprint

D Track

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25 When minerals replace hard structures buried in sediment, the result is a mold.

True

False

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Make a Fossil Activity

What is the difference between a cast and a mold?

Create some fossils to find out!

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Fossils and Rocks

Remember that the three types of rock are:

· sedimentary - formed when sediment hardens· igneous - formed when magma hardens· metamorphic - formed from intense pressure under the Earth's surface

In what type of rock are imprints and mineralized fossils created? Can you exclude one type of rock right away?

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Fossils and Rocks

· sedimentary - formed when sediment hardens· igneous - formed when magma hardens· metamorphic - formed from intense pressure under the Earth's surface

Metamorphic rock forms deep under the Earth's surface. Things on top of the Earth (like a dinosaur) would not be in contact with metamorphic rock.

There are three major types of rocks

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Fossils and Rocks

That leaves sedimentary rock or igneous rock. Discuss these options with a partner and then click on the pictures to see if these rocks are the source of fossils.

Igneous Rock Sedimentary Rock

Igneous rock forms as hot magma cools. Any organism that is covered in hot magma would not survive the heat. Fossils do not form in igneous rock.

Sedimentary rock forms when layers of soft sediment harden into rock. This is how fossils form.

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Fossils and Rocks

Sediments flow on top of each other and slowly harden to rock. Then, more sediment flows on top of the rock, eventually turning into more rock. This creates layers of rock where fossils can be preserved.

Look at the sedimentary rock below. Which fossil was created earlier: fossil A or fossil B?

A

B

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Fossils and Rocks

A

B

Fossil B would have formed first. After the sediment surrounding B hardened, more sediment piled on top where fossil A would have eventually formed.

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FossilsClick the image below to watch a video about fossils. Watch closely - can you find an imprint, a preserved fossil and a mineralized fossil in the video?

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The Geologic Time ScaleThe Geologic Time Scale organizes fossils by their age.

The top represents the present and the bottom represents the past.

Artwork by Ray Troll, copied with permission. http://www.trollart.com

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How do fossils and the Geologic Time Scale help scientists today?

The Geologic Time Scale

By studying fossils and organizing them by their age, scientists can learn about how organisms survived.

They can also identify changes on Earth that caused organisms to go extinct.

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Mass Extinctions

Look closely! There were several "mass extinctions."

A mass extinction means most of the living things died off at once.

Something changed 65 million years ago and organisms, like the dinosaurs, were not adapted to those conditions.

They could not adapt, and did not survive.

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26 In what type of rock are fossils formed?

A Igneous

B Sedimentary

C Metamorphic

D All of the above.

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27 If organisms are buried in magma, the heat would prevent any part of the organisms from being preserved.

True

False

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28 The Geologic Time Scale identifies how fossils have changed over time. Which arrow points to the most ancient organisms?

A

B

C

D

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Fossilization Activity

How are fossils formed? How are they excavated? What information can they tell us?

Find the answers to all of these questions in this activity!

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How Fossils Are Used

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Tracks

Pretend that you are studying a particular dinosaur. These tracks from that dinosaur are discovered and you are called out to examine them. What could these tracks tell you about the dinosaur?

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Studying these tracks could tell you:

· how fast the dinosaur walked· if the dinosaur walked on two legs or four legs· if the dinosaur dragged its tail or carried it in the air

Tracks

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Now look at these tracks. Can you think of an important piece of information that they give us?

Tracks

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Mineralized FossilsMineralized fossils give us a lot of information as well. Suppose that you just finished piecing together this dinosaur fossil. What can you learn from it?

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The dinosaur walked on four legs.

A beak with blunt teeth means this dinosaur was an herbivore.

Used horns as a means of protection.

Mineralized Fossils

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In general, mineralized fossils tell us:

· physical features of a dinosaur· what they ate (look at the teeth)· how smart they were (larger skulls equals larger brains)

Mineralized Fossils

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Dinosaur Egg FossilsClick below to watch a video about dinosaur egg fossils.

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29 Dinosaur tracks can tell us how fast dinosaurs walked.

True

False

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30 This dinosaur has many sharp teeth. This tells us that it was a(n) ___.

A herbivore

B carnivore

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We can understand ancient environments by comparing fossils with living organisms.

Many fossils of fish, starfish and clams have been found in the middle of the US.

These animals are all ocean animals. But the middle of the US is prairie and mountains.

What must have been different?

Comparing Fossils

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Comparing Fossils

Fossils often look similar to modern day organisms. The shape, size and pattern of a fossil can help us to understand what type of organism it was, in comparison to modern organisms.

Based on your knowledge of modern organisms, what type of fossil do you think this is? Click the box to check your answer.

A seastar

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Draw a line from the fossil to the modern day relative.(One doesn't have a match.)

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This is an ancient fern. We know what environment modern ferns live in. This helps us understand where ancient ferns lived.

If the fossil of an ancient fern is found, it tells us that - at that time on Earth - the environment was warm and moist.

Comparing Fossils

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This is a fossil of an ammonite, which had a squid-like body in its shell. The nautilus is a modern day relative. They are both sea creatures.

If an ammonite fossil is found, that means conditions in that area at that time were aquatic.

Comparing Fossils

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These are crinoids, marine organisms.

If a crinoid fossil is found, what does that tell us about that area of Earth at that time?

Comparing Fossils

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This is a trilobite. It doesn't have a match because it is extinct. There are no trilobites today. We know it lived in the sea because of the fossils it is usually found with.

Comparing Fossils

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This is a fossil of an archaeopteryx. It was found with dinosaurs that lived at that time.

This fossil excited paleontologists! What do you see? Look closely!

Archaeopteryx

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Here is a diagram of another archaeopteryx fossil. Now what do you see?

The archaeopteryx is interesting because it is a reptile with feathers!

This is a new adaptation that may have eventually led to the birds that we have on Earth today.

Archaeopteryx

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31 Comparing fossils can tell us about ancient environments.

True

False

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32 The woolly mammoth had a lot of fat, fur, and small ears. Based on these adaptations, we can conclude that the environment at that time was

A incredibly cold for the majority of the year.

B a long rainy season.

C hot and dry all year round.

D mild in temperature with

a raining season.

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33 Look at the fossil. Did this organism live in the sea or on land?

A In the sea

B On land

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34 Look at this fossil. At the time this animal died, this area of Earth was covered in ___.

A mountains

B ocean

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35 This palm leaf fossil was found in the Green River Basin in Wyoming. At the time that this fossil was created, what was the environment in Wyoming?

A It was a cold climate.

B The land was covered in ocean.

C The land was covered in snow.

D It was a warm climate.

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Constructing a Fossil Map Activity

Create a map of fossils in Utah to discover how the environment changed from one period to another.

Notch Peak is part of the House Range in Utah, a site known for its trilobite fossils.

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Disturbances

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Suppose that you are quietly reading your science book at home. What are some things that would possibly disturb you, preventing you from concentrating on your book?

Disturbances

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DisturbancesJust as those disturbances stopped you from functioning, there are also disturbances that disrupt ecosystems.

A disturbance is any event that causes a change in an ecosystem.

How many disturbances can you think of? Write them below:

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Natural DisastersNatural disasters are a disturbance that causes major changes in an ecosystem. Look at the pictures below. Describe one way each disturbance would affect the ecosystem.

Forest fire

Tornado

Flooding

Volcanic Eruption

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LandslideWatch this video about a landslide in the French Alps. How would a landslide like this affect the surrounding ecosystem? Think about biotic and abiotic factors. Share your ideas with the class.

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LandslideA landslide destroys all trees and obstacles in its path.

Remember, a change in one part of an ecosystem will create changes in the remainder of the ecosystem.

Removing the trees not only kills those trees but has the following effects:

· removes habitat for animals· kills any animals in the trees at the time· impacts air quality

Which ones are biotic factors? Which ones are abiotic factors?

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Dinosaurs suddenly went extinct 63 million years ago. Scientists believe that the cause of this mass extinction was a disturbance.

As a class, hypothesize about what type of disturbance could have caused this event. Write your best guess below:

Dinosaur Extinction

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Dinosaur ExtinctionClick below to watch a video explaining different ideas about the dinosaur extinction.

After you watch, complete the "Dinosaur Extinction" worksheet.

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Dinosaur Extinction

The mass extinction started with a change in the environment. A change in one part of the environment, however, causes changes is all other aspects of the environment.

Since the dinosaurs could not adapt to this change, they died out.

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36 Natural disasters do not affect ecosystems.

True

False

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37 A change to one part of an ecosystem will cause changes to all other parts of that ecosystem.

True

False

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38 When a landslide removes trees, this affects air quality. What type of factor is this?

A Abiotic

B Biotic

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39 When the environment on Earth changed, the dinosaurs were not able to adapt so they went extinct.

True

False

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Human Disturbances

The actions of humans sometimes causes disturbances to ecosystems.

Air Pollution Oil Spill Water Pollution

Can you think of other ways that we affect the ecosystems?

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Clearing Land

Suppose that a farmer decides to create a new field of crops. How does clearing land for crops affect that ecosystem?

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Clearing LandThe land being cleared by the farmer is the home of the Great Horned Owl. This owl lives in the trees and hunts small mammals and birds. How will clearing the land affect this owl?

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Clearing LandAfter the farmer clears the land, he plants seeds and applies a generous amount of fertilizer to the land.

Later, there is a heavy rainfall. Where does the fertilizer go?

How does this affect the ecosystem?

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40 Disturbances to ecosystems can be caused by ___.

A natural causes

B humans

C both A and B

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41 When the great horned owl's habitat was removed, what responses could the owl make?

A Adapt to the change.

B Move to a new location.

C Die off.

D All of the above.

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42 When fertilizer runs off into the local waterways, this is creating a direct change in what type of factor?

A Abiotic

B Biotic

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Human Impact

No matter what we do, we are constantly affecting the ecosystem around us. If we are conscious of this, however, we can try to ensure that the changes are positive.

Cities remove important habitat when they are built. This building has made a roof garden to try to restore habitat and to help air quality.

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Human ImpactComposting uses worms and bacteria to create natural fertilizer out of kitchen scraps and yard debris. This decreases the impact of runoff by artificial fertilizers.

Versus

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Sometimes, small changes can make a BIG difference in taking care of our planet.

Complete this activity to learn about some positive changes you can make!

Small Change, Big Range Activity

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Compost Time CapsuleHow do different items change over time?

Analyze your time capsules now.

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