3 Make a Fossil Cast. 4 Footprint Forensics ... Please keep the objects away from radiators and ...... with a can opener and push the cast out), and clean off the ...
Portable Collections Program
Fossils
Table of Contents
Checklist: What’s in the Case? –––––––––––––––––––––––––––––––––––––––– 1
Information for the Teacher: –––––––––––––––––––––––––––––––––––––––––– 3 How to Handle and Look At Museum Specimens An Introduction to Fossils Information About the Specimens in the Case
Activities to Do with Your Students: –––––––––––––––––––––––––––––––––– 11 1 Introductory Activity: Paleo Puzzle 2 Examining and Classifying Fossils 3 Make a Fossil Cast 4 Footprint Forensics 5 Create A 3-D Geologic Time Model 6 Additional Activities and Curricular Connections
Resources and Reference Materials: –––––––––––––––––––––––––––––––––– 24 Vocabulary Words Connections with New York State Learning Standards Corresponding Field Trips Bibliography and Web Resources
■ CHECKLIST: WHAT’S IN THE CASE? ■
What’s in the Case? Specimens
Ammonites (2) #0996, 0997
Trilobites (2) #0731, 0995
Brachiopods (3) #0052, 0946
Tabulate coral #658
Fossil fish #1380
Pelecypod #0978
Gastropod #0042
Echinoderm #0538
Shark tooth #1283
Baculite #0984, 0996, 0997
Ichthyosaurus vertebra #1278
Eurypterid #1117
Dinosaur footprint #1343
Gastrolith #1264
Oreodont jaw section #1329
FOSSILS 1
■ CHECKLIST: WHAT’S IN THE CASE? ■
What’s in the Case? Specimens
Graveyard #0658
Insect in amber #0999
Fern leaf #0908
Petrified wood #1787
Tools & Resources Geologic Time Chart (laminated poster) from Brooklyn Children’s Museum Eyewitness: Fossil by Paul D. Taylor Fossils Tell of Long Ago by Aliki Brandenberg
FOSSILS 2
■ INFORMATION FOR THE TEACHER ■
Guidelines for Handling Museum Notes about Object-Based Specimens Learning and Inquiry Learning to handle objects from the Museum’s natural history collection with respect can be part of the educational experience of the case. Please follow these guidelines in handling objects in the case: • Students may handle the specimens, carefully, under your supervision. • Hold larger specimens with two hands. Hold them by the solid part of the body or by the strongest area rather than by rims, edges or protruding parts. • Do not shake objects or the plexiglass cases they may be housed in. • Temperature differences, direct sunlight, and water can be very harmful to museum objects. Please keep the objects away from radiators and open windows, and keep them secure.
Learning about paleontology by examining fossil specimens is much different from reading about it in a book. Specimens have the power to tell us many things, provided we are willing to look at them in detail and think about what those details mean. Encourage your students to carefully examine the fossils and touch them gently. Have them describe the specimen’s shape, size, and color. Ask them questions about what they see, and what their observations might tell them. For example: • What do you see in the specimens? Describe their shape, color, and structure. (It is important that your students use visual clues based on their observations when giving their answers.) • What do you want to know about them? • What else can you see? You can assist this process by encouraging your students to examine individual fossils in detail, and to think about what those details might mean. Ask them questions about what they see, and what that might tell them. As the conversation begins to grow, you can ask more questions about the specimen: • What does this fossil look like? How does it compare to other specimens in the case? • What kind of fossil is this? How was it preserved? How can you tell? Providing books and Internet access for researching these and other questions encourages students to make discoveries that further their knowledge about fossils.
FOSSILS 3
■ INFORMATION FOR THE TEACHER ■
An Introduction to Fossils To the teacher Millions of years ago, the world looked very different from how it does now. Trilobites and ammonites lived in New York City. Dinosaurs roamed Connecticut and New Jersey. In Wyoming, there were ancient seas full of fish where now there are grassy plains and hills. How do we know all this? Through fossils! Fossils provide us with a record of life on Earth from its earliest times, a topic that has fascinated generations of children (and adults) and continues to inspire movies, books, and even toys. The authentic fossil specimens in this Portable Collections case let your students hold in their hands a piece of ancient history. You can use these fossils to fuel students’ curiosity and enthusiasm about ancient life, and to introduce its scientific side as well. The activities in this teacher guide support exploration into how fossils are made, discovered, and classified. Wherever possible, we have also included connections to other curriculum areas, including the arts and language arts.
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What is a fossil? A fossil is the remains of an organism (plant or animal) that lived long ago. There are the two types of fossils: body fossils, where the organism itself or some part or impression of it was preserved, and trace fossils, that preserve evidence of the organism’s presence but not the organism itself. Trace fossils are more common, since a single organism will move around and leave lots of evidence over time, whereas it has only one body.
How are fossils created?
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The methods by which fossils are formed are quite varied and often dramatic, ranging from simple footprints that have hardened into molds to actual, whole bodies preserved by freezing. • • Simple burial. The organism died and was buried
under successive layers of soil. Its hard parts— usually bones or shells—were all that survived decay. Shark and mammal teeth and tusks are good examples of unaltered fossils. Alteration. This is a variation of burial in which the hard parts are dissolved by circulating water and are replaced by minerals. If this happens very slowly, the microscopic structures of the organism are duplicated. If it happens quickly, only the general form shows. Fossils formed by alteration are called replacement fossils. Petrifaction, which means “turning to stone,” and involves replacement of organic material by the mineral silica, is a type of alteration. Freezing. Organisms that froze after death and have not changed are very rare and never very old. They are usually mammoths and rhinoceroses of the last ice age that fell into pits of ice and were frozen. (There are no examples of frozen fossils in the case.) Compression or carbonization. Compression occurs when layers of sediment press so hard on the organic remains that they are flattened. At its most extreme, the plant or animal is reduced to a shiny black carbon film in the form of its original shape. Many leaf fossils are the result of carbonization. Molds and casts. Sometimes shells, tree stumps, or other remains were trapped in sediment that ▲
FOSSILS 4
■ INFORMATION FOR THE TEACHER ■ An Introduction to Fossils (continued)
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hardened. Eventually the dead organism decayed and dissolved, leaving a cavity known as a natural mold. It may fill up with other sediments, in which case it becomes a cast. Amber. Amber is the fossilized sap of ancient pine trees. Sometimes it contains fossil insects or other small animals that got trapped in the sticky sap. Other methods. Animals caught in asphalt pits (such as the La Brea tar pits in Los Angeles) are fossils. So are animals that were mummified naturally in semi-arid climates. Tracks, trails, burrows, and borings are impressions left by an organism’s movements. The most famous fossils of this type are dinosaur footprints, like the one in the case. Gastroliths, coprolites, and eggs and nests are other examples of trace fossils. They are evidence of the organism, but not the organism itself.
Stone tools and weapons made by ancient peoples are also sometimes called fossils, although they are different from natural history fossils in that they were made by humans instead of by nature. They have been found in many parts of the world. Some of the oldest artifacts belonged to hunters and have been found with the bones of extinct animals.
The study of fossils is called paleontology. Paleontologists study fossils to help us understand the life of the distant past. They use their knowledge of living organisms to bring life to fragments of bones and shells millions of years old. They compare the remains of ancient life with present-day plants and animals in order to determine what the ancient creatures were like. Through their study of fossils, they are able to identify plants and animals that flourished millions of years ago and to reconstruct the environments they inhabited. Fossils enable paleontologists to determine the sequence of change and adaptation as the number of species increased and became more complex. They can document the evolution of elephants from pigsized creatures which lived 20 to 40 millions years ago to the giants they are now. Fossils indicate that horseshoe crabs and cockroaches, however, have not changed in hundreds of millions of years. Paleontologists also identify extinct creatures, such as dinosaurs, which dominated life millions of years ago, but are known today only through fossil remains. The history of early humans is based on fossil remains found in many parts of the world. Many gaps in our knowledge of earlier life still exist, but new discoveries are always possible as paleontologists strive to complete the picture of the past.
Why are fossils important? Throughout geologic time the earth has been in the process of change. These changes have drastically altered environmental conditions and all living organisms. The earth is still in the midst of many changes that cannot be detected during the relatively short span of our lives. Most geologic change must be considered in terms of millions, or even billions, of years. Continents have drifted apart and together, glaciers have advanced and retreated, mountains have formed and eroded, groups of plants and animals have appeared, flourished and disappeared. This is the history of our planet, and its story has been recorded for us in fossils.
Fossils are also important economically. Coal, oil, and natural gas are all examples of fossil fuels. Coal is a shiny black rock formed from the remains of great trees, some 150 feet high, and other plants that thrived in low swamps during the Carboniferous period. Oil, which is millions of years old, is believed to have formed from plant and animals remains. Natural gas may have come from oil that heated up inside the earth or from ancient plants that rotted in swamps. The topic of fossil fuels can spark lively discussions of conservation, since we are rapidly depleting these non-renewable underground resources in our quest for energy.
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FOSSILS 5
■ INFORMATION FOR THE TEACHER ■ An Introduction to Fossils (continued)
Where are fossils found?
How do we know how old a fossil is?
The majority of fossils are found in sedimentary rock. Sedimentary rock is formed from pieces (sediments) of mud, sand, and clay that settle in layers and gradually harden into rock. The sediments were produced by the processes that wear down the earth’s surface. Other rocks (igneous and metamorphic) are subject to forces that usually destroy fossils. The materials in sedimentary rock provide ideal conditions for preserving fossils. Remains of organisms are buried in the sediment and lie undisturbed throughout the long process of fossilization. In many places the sedimentary rock is covered with soil or glacial deposits, so fossil-bearing rock lies deep beneath the surface. Consequently, fossil hunting is restricted to places where the sedimentary rock is exposed, such as cliffs, riverbanks, road cuts and quarries. Paleontologists organize expeditions similar to those of archaeologists to dig for fossils in areas known for their scientific significance. Some fossils of great importance, however, have been unearthed by chance during the course of building construction, mining, or natural disasters that expose layers of earth previously inaccessible to scientists.
The history of the Earth is told not in months, years, or even centuries, but in millions of years. Scientists estimate that the earth is 4-1/2 billion years old and that life began to evolve from a few single-celled organisms at least 3.4 billion years ago. This vast span of time is known as geologic time. Geologists (the scientists who study the entire history of the earth, not just fossils) have devised a special time scale, based on millions of years. By studying the rate at which sediments form in bays and basins, they estimated how long it took for each layer of sedimentary rock to form. They also use index fossils—fossils that are found only in a particular layer of sedimentary rock—to prove that different layers of rock, miles or even continents apart, were formed at the same time. Finally they determined that the layers fit into four great divisions called eras. The eras are divided into smaller units called periods. The Geological Time Scale poster in the case shows the eras and periods, the changing life forms in each, and the relative scale of the eras.
Even with this scale, however, geologists cannot date individual fossils or rocks in years. Instead they use a method based on the breakdown of radioactive elements (such as uranium) in the rocks around the fossil. These elements have unstable atomic nuclei that break down at a steady, measurable rate to form more stable elements. By measuring the rate of the unstable element to the stable element associated with it, they can get an accurate measure of the age of the rock. This is called the atomic clock method. ❑
Words in boldface have been included in the Vocabulary Words section on page 24.
FOSSILS 6
■ INFORMATION FOR THE TEACHER ■
Information About the Specimens in the Case AMMONITES
BRACHIOPODS
Ammonites are extinct marine mollusks similar to the nautilus. These small, soft-bodied creatures had a hard outer shell divided into chambers. The colorful, pearly luster of one of the specimens is what remains of the inside of the animal’s shell. Another specimen is embedded in rock (called the matrix). Ammonites lived from the early Devonian period until the end of the Cretaceous period (about 400 to 65 million years ago). They thrived all over the earth and were easily preserved, so they are very common fossils. They also evolved into different species quite rapidly. These two facts combine to make them a very useful index fossil for paleontologists; since they know when different species of ammonites existed, they can often determine the age of a layer of rock by looking at the ammonites found within it.
Brachiopods are small marine invertebrates with two shells that encase the animal’s soft body (like a modern clam). Brachiopods are commonly known as lamp shells because many of them are shaped like ancient Roman oil lamps. There are about 325 living species and about 12,000 fossil forms. Brachiopods were a dominant form of life in the oceans for much of the Paleozoic era, which spanned millions of years. Brachiopods evolved into many different species, and members of the largest species grew to more than one foot in diameter. Billions of their shells accumulated in sea beds and fossilized. Since fossil brachiopods are so abundant and diverse, paleontologists use them as index fossils to determine the age of the rocks in which they are found.
TABULATE CORAL TRILOBITES Trilobites are extinct members of the arthropod family (which includes spiders, insects, and lobsters). They lived from the beginning of the Cambrian period through the end of the Permian period (about 542 to 248 million years ago). These small marine animals fed on the mud of the ocean floor. A trilobite's body was divided into three parts— the head, thorax (middle section), and tail—which gave the animal its name ("tri" means "three" in Latin). Trilobites are common and well-known fossils, with more than 15,000 species documented in the fossil record.
Corals are simple aquatic animals lacking advanced organ systems. They live together in colonies. Corals secrete a hard, limy skeleton whose durability accounts for the fact that they are well represented in the fossil record. Tabulate corals were confined to the Paleozoic Era.
FOSSIL FISH Sometime between 36 and 58 million years ago, this fossil fish was buried in an ocean bed located in what is now Wyoming. It was preserved in a mud shale matrix. The brown color defining the shape of the fish is a thin layer of carbon left as the organic matter decayed. The backbone and other parts of the skeleton are visible.
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FOSSILS 7
■ INFORMATION FOR THE TEACHER ■ Information About the Specimens in the Case (continued)
PELECYPOD
SHARK TOOTH
Pelecypods are marine bivalves that count oysters, mussels and clams among their living members. This fossil pelecypod is between 13 and 25 million years old. The shell still contains most of its original material. It has lost much of its color, but the hardy limy substance has changed very little.
This shark’s tooth is between 25 and 36 million years old. The outer layers are all original material. According to the fossil evidence, sharks first appeared in the Devonian period (385 million years ago), when marine life was especially abundant. Since that time sharks evolved into a wide range of shapes and sizes. Today there are over 1100 species of cartilaginous fishes, all of which evolved from the earliest sharks.
GASTROPOD Gastropods are mollusks, like snails, clams, and other shelled animals. Gastropods have a well-developed head and a muscular foot, and most have a spiral-shaped shell. This fossil gastropod dates from the Cretaceous period. Nothing remains of the animal’s soft body, but the gloss of its shell’s inner layer can still be seen in some places. The rest of the gastropod has been replaced by other minerals.
ECHINODERM Echinoderms are marine animals whose bodies are covered with hard plates or spines. Starfish, sand dollars, and sea urchins are echinoderms. This specimen is a sea biscuit that lived during the Carboniferous period. Small hairs that covered the body are missing, and the original shell material and its interior have been replaced by other minerals. The tiny holes that form the petal design on its surface were used for breathing. Sand dollars appeared in the Paleocene and, of course, can still be found in warmer waters today.
BACULITE Collected in South Dakota, this fossil is a piece of a shell belonging to a baculite that lived during the Cretaceous period. Baculites were marine animals related to ammonites. Most of the original material from this shell has been replaced by other minerals. The patterns of white, squiggly lines are from sutures (the part of the shell where the walls dividing it into chambers connected with the inner surface of the shell wall). Paleontologists use suture patterns to identify different species of baculites.
ICHTHYOSAURUS VERTEBRA This is an example of an altered fossil, meaning that the original bone matter dissolved and was replaced by other minerals. Ichthyosaurs (Greek for "fish lizards") were carnivorous marine reptiles that lived from the Triassic to the Cretaceous period. They had streamlined, fish-like bodies with a long snout, a large tail fin, and limbs adapted for use as steering paddles. Although they looked like fish, they weren’t; instead, ichthyosaurs evolved from unidentified land reptiles that moved back into the water. ▲
FOSSILS 8
■ INFORMATION FOR THE TEACHER ■ Information About the Specimens in the Case (continued)
EURYPTERID
GASTROLITH
Also known as a “sea scorpion,” a eurypterid is an extinct animal whose closest living relative is the horseshoe crab. Eurypterids were hunters, feeding on trilobites and cephalopods. They could be as big as six and a half feet long, but most were much smaller. They had a fused head and thorax with two pairs of eyes and six pairs of appendages. Twelve tapering segments, usually ending in a spike, completed the body. This specimen shows some of those segments. Eurypterids lived in the Paleozoic era, from the Ordovician to the Permian periods. Their fossils are relatively rare, but have been found on nearly every continent. The eurypterid is the state fossil of New York State, where it lived in the Silurian period.
Smooth, round pebbles like this one have often been found near dinosaur bones, or even inside dinosaur rib cages. Some dinosaurs (especially plant-eaters) did not have teeth suitable for grinding up their food, so they swallowed large, rough stones. The stones came to rest in a dinosaur's stomach, where they pounded food into smaller pieces to help the animal's digestion. That is how gastroliths (“stomach stones”) got their name. Eventually the gastroliths would be worn down to the point where they were too small or too smooth to be useful for grinding. Then the dinosaurs would get rid of the stones (by either vomiting them up or passing them out in their dung), and swallow new ones.
DINOSAUR FOOTPRINT
OREODONT JAW SECTION
This rock contains a footprint left by a Tuberosis dinosaur during the Jurassic period. The dinosaur stepped in mud, and over time the mud turned into red sandstone. This specimen was collected from a rock formation in Connecticut. Since dinosaurs are now extinct, it is difficult for scientists to know much about how they lived, moved, and behaved. However, fossils like this footprint may provide paleontologists with a rare window into dinosaur behavior. For example, the depth and shape of footprints may demonstrate that certain species of dinosaur walked upright or on all four legs. Also, the distance between two footprints in a set of dinosaur tracks may yield clues about that dinosaur's posture or how fast it could run.
Oreodonts were sheep-sized herbivores (plant eaters). This specimen shows how their broad, flat teeth were well adapted for grazing. Oreodonts thrived all over North America from the Eocene (55 million to 37 millions years ago) through the Pliocene (from 5 million to about 1.8 million years ago) epochs. It is difficult to explain their appearance in terms of modern animals; some scientists have compared them to small deer with pig-like heads. These animals also have a rather strange family tree; while they were most closely related to the modern sheep, they were distantly linked to both pigs and camels!
GRAVEYARD “Graveyard” is the term for a conglomeration of fossils. This conglomeration of marine fossils includes sponges, corals, and crinoids, all preserved in this one specimen. ▲
FOSSILS 9
■ INFORMATION FOR THE TEACHER ■ Information About the Specimens in the Case (continued)
INSECT IN AMBER Millions of years ago, the insect inside this piece of amber landed on a tree and got stuck in its sticky resin. Over time, that resin (or sap) grew harder and eventually turned into a type of fossil known as amber. The same chemical processes that turned the fresh resin into fossilized amber also preserved the insect trapped within it. Many insects, spiders, and even small animals (like frogs or lizards) have been preserved this way.
You and your students can learn more about these specimens and other objects from around the world by visiting Collections Central Online at www.brooklynkids.org/emuseum.
FERN LEAF This fern fossil dates from the Carboniferous period. It is a mold of the original plant, and was exposed when a fossil hunter split the rock open. For millions of years, ferns dominated the earth's greenery. They covered the floors of damp forests and swamps all around the globe. But the majority of fern species that existed in the era of this fossil fern are now extinct. For the most part, modern ferns look the same as ferns that lived millions of years ago. However, the fern in this specimen would have looked more like a tree than a small plant. It had a hard trunk and grew to a height of 13 feet!
PETRIFIED WOOD This ancient piece of wood has turned to stone after millions of years. The original organic material dissolved and was replaced by other minerals (probably a silicate, like quartz). This process occurred underground, when the wood was buried under sediment. Mineral-rich water flowing through the sediment deposited minerals in the wood’s cells, and as the plant decayed away, a stone cast was left in its place.
FOSSILS 10
ACTIVITY 1
Introductory Activity: Paleo Puzzle
Grades 3–5 Related Specimens: All Right or wrong, children tend to have already an assortment of knowledge about fossils. This class discussion is intended to make that knowledge public and shared among the group. It provides a starting place for the next activity. The word puzzle introduces some basic fossil terms, which you may define for students or ask them to look up on their own and/or share.
Materials: • Blackboard or chart paper • A small selection of specimens from the case • Copies of Paleo Puzzle worksheet on the next page, one per student
What To Do: 1 Lead a discussion on the topic of fossils. Start by asking students what they know about fossils and about life on earth millions of years ago. List their statements on the board or chart paper, without comment or contradiction. Together the comments create a baseline of information, imagery, and questions for the whole class to pursue. 2 Ask the students the Discussion Questions below and any others that you think will stimulate their thinking. They will not have answers to everything, but even paleontologists may not. Remind them that by asking questions they are helping to define the scope of the topic for the class’s work. 3 Pass around one or two of the fossils from the case (such as the eurypterid and a gastrolith) without telling the class what they are. What makes each object a fossil? What kind of fossil do they think it is? Ask each student to come up with a question about one (or both) of the fossils. List these in a second column on the board or chart paper.
4 Hand out the Paleo Puzzle worksheet that introduces fossil terms and have the students fill it out. After they compare their results (the answers are below), you can define the terms for them, or have students work individually or in groups to look the terms up in books or on the Internet.
Discussion Questions: • • • •
What is a fossil? What kinds of things can be fossils? Is a fossil a real animal or plant? What parts of an animal might become fossils? Why might some parts become fossils and not others? • What could a fossil be made of? • How old does something have to be to be considered a fossil? • How do we know how old a fossil is? How might a scientist be able to tell?
See page 25 for details on how this activity meets New York State Learning Standards.
Worksheet Answer Key: T R K K T C V X H V Z H S A F U W I A M D E Q R Y
A D E MMB M J G O E J N T I I S T T G Y E P I T WK E W S R W I A X R X R C UW X P E M T A L T F U T K T L B A I C T F O V U B E A L T R I O UWC
S U H K Z B A J A C H X O L I T H T C R D O R R S
U N R B Y Q G A S T R O L I T H R D U A C H Y S W
T Y H I V B Y C J P O H E L MQ L I C N E E Z W R Y N T L A U A T R C S L I Z P R U OM S A X P Y G
R E I B E T F B J I M N A S C I P I T Y L Y A T O
A G K Q M B E Z H L O G O Q I P T R E R U D A D L
T R J D J O L R P M A N E Z G C T T R K A J Y N O
N O L N J Y M N I S I N P F O Y S Q I L H C R O T
E M O U A N X B T Y S Q T E M Y I A D I S L B C C R U P L O I M A C B Y BW O A A D L C E H Z A N O
I D V Z I E M P L H Z J C L U E T R B L C N R P N J T O E G F Q I B T I P A R R L N K E Z W L C E L
E S O C O J M C U U N Z P C MC U S U V R R OW A F S P O T H E T R H N Y A H N C O I D I D K G A P
Identify some of the questions generated by the discussion for students to RESEARCH AND LITERACY EXTENSION: research. They can share their answers in a subsequent discussion, or write a short report on their findings. GRADES 3–5
FOSSILS 11
Paleo Puzzle CIRCLE THE FOLLOWING TERMS: Ammonite Baculite Cast Cenozoic Dinosaur Eurypterid Era Gastrolith Geological Time Mold Paleontology Sedimentary Trace
T R K K T C V X H V Z H S A F U W I A M D E Q R Y
A D E MMB M J G O E J N T I I S T T G Y E P I T WK E W S R W I A X R X R C UW X P E M T A L T F U T K T L B A I C T F O V U B E A L T R I O UWC
S U H K Z B A J A C H X O L I T H T C R D O R R S
U N R B Y Q G A S T R O L I T H R D U A C H Y S W
T Y H I V B Y C J P O H E L MQ L I C N E E Z W R Y N T L A U A T R C S L I Z P R U OM S A X P Y G
R E I B E T F B J I M N A S C I P I T Y L Y A T O
A G K Q M B E Z H L O G O Q I P T R E R U D A D L
T R J D J O L R P M A N E Z G C T T R K A J Y N O
N O L N J Y M N I S I N P F O Y S Q I L H C R O T
E M O U A N X B T Y S Q T E M Y I A D I S L B C C R U P L O I M A C B Y BW O A A D L C E H Z A N O
I D V Z I E M P L H Z J C L U E T R B L C N R P N J T O E G F Q I B T I P A R R L N K E Z W L C E L
E S O C O J M C U U N Z P C MC U S U V R R OW A F S P O T H E T R H N Y A H N C O I D I D K G A P
ACTIVITY 2
Examining and Classifying Fossils
Grades 3–5 Related Specimens: All This activity gives your students a chance to look closely at real fossils and form hypotheses about what these organisms were and how they survived to tell us about the past.
Materials: • Fossils from the case • Timeline poster from the case • Copies of the “What Can Specimens Tell Me?” chart, one per student OR, for a whole class exercise, a transparency of the chart and an overhead projector • Blackboard OR chart paper for recording group observations
What To Do: 1 Depending on the age and interests of your students and the amount of time you would like to spend, you can do this activity using a handful of specimens or every specimen in the case. It can be done in small groups or as a class, looking at the specimens in turn and filling out the chart using an overhead projector or large chart paper. 2 For small groups, prior to the presentation of the lesson, set the classroom up into stations (make sure there are enough stations that you have only 3–4 students working at each one). Place one or more specimens at each station. 3 Distribute the “What Can Specimens Tell Me?” chart and go over it with the students. Ask them to pay special attention to the physical properties of each of the specimens. You may want to practice with the class, using one of the specimens to model the activity, if you have not already done the Introductory Activity.
SCIENCE EXTENSION: GEOLOGIC TIME
4 Have the students fill in their charts as they look at the specimens. After a few minutes, the groups should rotate to a new station. Repeat this step as many times as you like. 5 Have the students reconvene as a class to discuss their findings. You may want to use the chart paper to make notes about the students’ observations. 6 When you feel they have gone as far as they can with what they observed, introduce information from your own knowledge, this guide, or other resources about the different types of fossils (how they were made). Then have students sort the fossils into categories according to how they were made.
Discussion Questions: • How could a living organism (such as a plant or an animal) turn into a rock? What might make that happen? • How are some of the fossils alike or different? • Which fossils give a more complete image of the organism? Why might that be? • Which fossils are the actual organism and which ones are a “print” or impression of it? • Which fossils are the oldest? How might a paleontologist tell? • Why are gastroliths and shark’s teeth considered fossils?
See page 25 for details on how this activity meets New York State Learning Standards.
Using the timeline poster provided, have students re-sort the fossils according to geologic era and period. Which fossils are the earliest? (There will be a number for which no clear date is possible. You can point out that paleontologists face this dilemma, too. How do they figure out the dates?)
FOSSILS 13
What can specimens tell me? What color and texture is the background of the fossil? Is the rock layered?
What type of plant or Is the fossil an actual animal created this fossil? plant or animal, or a “print” of it? Why do you think so?
Use your senses to observe each specimen carefully, using a hand lens if necessary. What can you tell about the fossil just by looking at the specimen in detail? Use this chart to record what you discover.
What can you see of the original plant or animal? What color is it?
PREDATORS AND PREY 14
What can specimens tell me? What color and texture is the background of the fossil? Is the rock layered?
What type of plant or Is the fossil an actual animal created this fossil? plant or animal, or a “print” of it? Why do you think so?
Use your senses to observe each specimen carefully, using a hand lens if necessary. What can you tell about the fossil just by looking at the specimen in detail? Use this chart to record what you discover.
What can you see of the original plant or animal? What color is it?
PREDATORS REPTILES AND 15 PREY 15
What can specimens tell me? What color and texture is the background of the fossil? Is the rock layered?
What type of plant or Is the fossil an actual animal created this fossil? plant or animal, or a “print” of it? Why do you think so?
Use your senses to observe each specimen carefully, using a hand lens if necessary. What can you tell about the fossil just by looking at the specimen in detail? Use this chart to record what you discover.
What can you see of the original plant or animal? What color is it?
REPTILES 16
What can specimens tell me? What color and texture is the background of the fossil? Is the rock layered?
What type of plant or Is the fossil an actual animal created this fossil? plant or animal, or a “print” of it? Why do you think so?
Use your senses to observe each specimen carefully, using a hand lens if necessary. What can you tell about the fossil just by looking at the specimen in detail? Use this chart to record what you discover.
What can you see of the original plant or animal? What color is it?
REPTILES 17
ACTIVITY 3
Make a Fossil Cast
All Grades Related Specimens: Brachiopod, tabulate coral, pelecypod, baculite, eurypterid This is a fun and simple way to demonstrate how some body fossils are made!
6 Remove the cast from the cardboard container or tin can (it may be easiest to open the bottom of the can with a can opener and push the cast out), and clean off the clay. Voila! Everyone now has a “fossil” cast of the object they chose.
Materials:
Alternatives for Younger Students:
• Plastic toy animals, coins, rocks, or other objects • Empty tuna cans or similar small, shallow containers; alternatively, use strips of oak tag cut about 2” wide, cardboard squares, and a stapler • Modeling clay • Plaster of Paris, water, container and spatula for mixing • Optional: can opener
What To Do:
• Have students roll the clay into a ball and press it flat on a cardboard square. Then have them press one hand into the clay hard enough to make a print. Have them hold their prints up to show and talk about how animals and plants millions of years ago printed mud and soft rocks in the same way and left their traces for us to find. • Have students make a leaf print art by rubbing a crayon over a piece of paper that has leaves underneath it.
1 Introduce the activity by reviewing what a body fossil is and telling the class that they will be creating a “fossil” and making a cast of it.
Discussion Questions:
2 Give each student a can or, if using oak tag, have them create a small container by stapling the ends of the oak tag together to make a ring and place it on a cardboard square. 3 Give each student a small piece of clay and have him or her pick an object to “fossilize.” First have them roll the clay into a ball and press the ball flat, filling the bottom of the container to not less than one inch in depth. 4 Ask students to pick one of the small objects to “fossilize,” press it into the clay, and remove it, leaving a “fossil” mold of the body. 5 Mix the plaster of Paris to the consistency of pancake batter. Pour it into the containers on top of the clay mold, and let it harden for at least 24 hours.
• How is the toy (or other small object they use to stand for the organism) different from a real specimen after it dies? What happens to an animal after it dies and is buried? • What is the difference between the way you made the mold and the way a fossil mold would be created? (Hint: The fossil mold would be created after the organism was buried and then decayed, leaving a cavity.) • How might a buried fossil mold be exposed so that someone today could discover it?
See page 25 for details on how this activity meets New York State Learning Standards.
Have students imagine themselves as paleontologists looking for fossils, and tell or LITERACY EXTENSION: write the story of how they came across the fossil they just made in the activity above. What kind of land were they exploring? What adventures did they have getting to where they were digging? How deep did they dig? What tools did they use? What happened afterwards?
FOSSILS 18
ACTIVITY 4
Footprint Forensics
Grades 3–5 Related Specimen: Dinosaur footprint By studying footprint patterns revealed in stages, students examine the evidence and make hypotheses about the story the footprints tell.
Materials: • Copies of each of the Footprint Patterns, one per student (see page following this activity) OR an overhead transparency of each of the Footprint Patterns
What To Do: 1 To prepare for this activity, make copies of the Footprint Pattern and cut the panels apart. You will hand out these panels to your students one at a time. Alternatively, you can copy each section onto a separate transparency for use with an overheard projector. 2 Ask the class what they know about reading evidence to reconstruct an event. Have they seen movies or TV programs where detectives or scientists find traces of incriminating evidence? Or where skilled hunters have interpreted footprints to track a person or an animal? 3 Explain that paleontologists use evidence to make deductions about what happened millions of years ago, and that they are going to do the same thing. Emphasize that they will get the evidence in stages and at each stage they will be forming a hypothesis about what happened. 4 Hand out or project panel 1 of the Footprint Pattern. Ask students to examine the panel closely. Can they tell anything about the size or nature of the animals that made the footprints? How many were there? Were all the tracks made at the same time? How might the students figure that out if they were paleontologist working in the field? What might have happened? Encourage students to point out what evidence supports their idea. Help them distinguish between what they see and what they infer. For example, they might state that the animals were walking around, that they met each other (or didn’t), that they were large or small, etc.
5 Hand out copies of panel 2 (or project it overhead), place it to the right of panel 1, and repeat the discussion. Now what do the students think happened? What parts of their previous deductions still hold water? What parts do they have to change? Elicit alternative hypotheses. For example: Someone will probably say the two animals fought, but there are other possibilities, such as a mother picking up her baby. Or perhaps the animals weren’t there at the same time, but there was some reason for both to circle around the same spot. Could there have been a source of food or water there? 6 Finally, hand out or project panel 3, and place it to the right of panel 2. Now what do your students think might have happened? There is no one correct answer to any of these questions. 7 Conclude by asking if the evidence supports any one of the students’ hypotheses in particular. What other evidence might shed light on the circumstances and the events that created these footprints? What could a paleontologist learn from this exercise? One lesson should be that it is important to gather as much evidence as possible, and to remember that there might be parts of the story that are not represented by the evidence.
Discussion Questions: • In what directions did the animals move? • Did they change their speed and direction? How can you tell? • Were there trees or bushes that might have kept the animals from seeing each other? • Do we know if they were there at the same time? • How might you know what the climate was like? • What conditions were necessary for the preservation of the footprints?
See page 25 for details on how this activity meets New York State Learning Standards.
FOSSILS 19
ACTIVITY 4
Footprint Forensics (continued)
SCIENCE AND • Take students outdoors on a damp day. Have them find animal tracks in a nearby park and try to interpret them. LITERACY EXTENSIONS: • Put large sheets of brown paper on the floor of the classroom. Have one or two students sponge water on the soles of their shoes and then step on the paper, leaving footprints. (You can use flour instead of water.) Then have them act out a scene—walking along in opposite directions and stopping to greet each other, for example, or just passing by. Have them think of other ways to interpret the footprints. Extend the activity by having some students leave the room while others act out a footprint story that the others interpret (out loud or in writing) on their return to the room. • With pencil and paper, have students design their own footprint patterns. They can use tracks of animals, birds, humans, marine creatures, and even leaf prints. Have students share their footprint patterns with the class, or divide students into teams and have them interpret each others’ stories out loud or in writing.
FOSSILS 20
Footprint Pattern Panel 1
Panel 2
Panel 3
ACTIVITY 5
Create a 3-D Geologic Time Model
Grades 3–5 Related Specimens: All The purpose of this activity is to engage students in thinking about how the various layers of the Earth in which fossils are found help us map geologic time.
Materials: • Geologic Time poster, from the case • 3x5 cards or similar-sized paper and pencils • Tape measure
What To Do: 1 Introduce the activity by showing students the Geologic Time poster, if you have not already done so. Review the concept of eras and periods of geologic time. Point out how eras and periods are shown on the poster in uneven layers. The layout of the layers on the poster is analogous to the layers within the Earth. The earliest eras and periods are at the bottom. 2 Have the students re-imagine the classroom as representing different areas of the Earth’s landscape. If the ceiling represents the present-day level of the earth’s surface, then the heights of the room’s features— desks, chairs, tables, bookshelves, the floor—all represent different layers beneath the surface of the Earth. As a class, figure out what era or period each surface should represent. In the classroom landscape, what level represents the Paleozoic era? What level represents the Cenozoic era? [Note: These layers do not have to be uniform throughout the classroom—the layers within the earth are not all the same thickness everywhere. A desk in one corner may represent the Paleozoic, while a desk across the room may represent the Cenozoic.]
4 Have students place the fossils and their labels on shelves, bookcases, tabletops, or other surfaces around the room, at the level of the classroom corresponding to their geologic era or period. Again, do not worry about the levels being uniform around the classroom—they are not uniform within the Earth either! 5 As a class, sit back and study the results. Looking at the landscape of fossils the students have created, have them imagine they are paleontologists on a field expedition. They encounter different fossils everywhere and at different levels. They do not know the relationships among the fossils or how old any of them is. How might they go about finding answers to their questions?
Discussion Questions: • Do all specimens from the same period have to be at the same height off the floor? What forces of nature could cause them to be at different levels? • If you were a paleontologist, where would you look for fossils, given that most of them are formed underground? • Among the fossils in the case, are there more marine organisms or more land organisms? Do you think this is typical for all fossils? Why? • On the Geological Time poster, how does the proportion of marine and land animals change as time goes on? When do plants appear?
See page 25 for details on how this activity meets New York State Learning Standards.
3 Point out how the Geologic Time poster shows the major life forms present in each era and period. Hand out the specimens from the case and have students write a label for each specimen with its name, geologic era and, if available, its geologic period. This information can come from the Information About the Specimens section of this guide (pages 7–10), the Geologic Time poster, the books in the case, or other library or Internet resources. If there are not enough specimens for each student, you may also hand out pictures of fossils or extinct creatures found in books or on the Internet.
FOSSILS 22
ACTIVITY 6
Additional Activities and Curricular Connections
Science: Archaeological Dig Grades 1–5
Science: Research a Fossil Grades 3–5
Simulate an archaeological dig in the classroom. In a shallow plastic container or cardboard box, have children bury chicken bones that have been boiled clean in unset plaster of Paris. (You can bury them in a single layer of plaster, but if you would like to simulate the different layers found in the earth, you can also create layers by adding food coloring to different bowls of plaster. Pour each layer in one at a time, and allow it to set at least partially before adding the next.) When the plaster sets, the students can use spoons, chopsticks, and other dull instruments to “dig” them out. Remind them to be gentle when digging around the bone itself, so as not to damage their “fossil.”
Have students choose one of the geologic periods and research its common plants and animals. Using the Paleontology Portal (see www.paleoportal.org/index.php), they can find out where in the U.S. (or New York State) those plants and animals lived. With this information, have them fill in a map with those locations. Alternatively, they may draw an imaginary scene of a landscape during the period they selected, featuring all the plants and animals belonging to it.
Literacy: Dinosaur Word Puzzle Grades 4–5 Print out a copy of the dinosaur word puzzle at www.sdnhm.org/kids/dinosaur/search/print.html, and challenge your students to see who can finish first.
Science and Health: Edible Fossils All Grades Who knew that eating fossils could be so much fun? See www.uky.edu/KGS/education/ceph_celery.htm for recipes for making celery cephalopods, ammonites in a blanket, and prehistoric desserts.
Literacy and Music: Create a Geological Rap Grades 4–5 Have students put the names of geologic eras and periods into a rap song. Since many of the terms have rhyming endings, this should not be difficult. The lyric structure of a rap song is a series of couplets—two lines that end in a rhyme, followed by two lines with a different rhyme, and so on. Students can accompany themselves by making a variety of percussive sounds with their bodies (www.wiki.ehow.com/Be-a-Human-Beatbox tells you how). If students would rather sing than rap, they can write new words to go with a familiar tune (such as “Dem Bones,” found at www.niehs.nih.gov/kids/lyrics/bones.htm).
See page 25 for details on how these activities meet New York State Learning Standards.
FOSSILS 23
■ RESOURCES AND REFERENCE MATERIALS ■
Vocabulary Words body fossil:
matrix:
a part of the actual animal or plant, or even its whole. Things like bones, teeth, shells, and leaves are considered body fossils. Body fossils also include casts and molds that reveal the external and internal structure of the organism.
the rock surrounding a fossil, in which it is embedded.
burrow:
organism:
a hole or holes in sedimentary rock that were dug by an animal
any living thing, such as a plant or animal.
molten:
cast:
in a hot, viscous (thick liquid) state.
in paleontology, a positive version of a mold, i.e., when a mold has been filled in with sedimentary material and takes on the shape of the organism that made the mold.
paleontologist:
coprolites:
in geological time, a period is a unit of an era.
the fossil dung of an animal.
mold: in paleontology, a mold is the hollow shape left in sedimentary rock by a decayed organism.
a scientist who studies the history of life through its fossil remains.
period: petrifaction:
era: a large unit of geologic time, each comprising millions of years and a number of sub-divisions called periods. Some eras include the Pre-Cambrian, Paleozoic, Mesozoic, and Cenozoic.
the state of being petrified, that is, the replacement of organic matter by silica over a long period of time, such that the original organism has become rock.
replacement fossil:
when all individuals of a species have died out, the species is said to be extinct.
a fossil created when inorganic minerals gradually replace the original organic material, at a molecular level, so that the structure and form of the organism are retained.
fossil:
sedimentary rock:
extinction:
the remains or traces of organisms, including microscopic organisms, that lived at least 10,000 years ago.
fossilization: the process by which a living organism, plant or animal, becomes a fossil.
gastrolith: a smooth, rounded stone found with dinosaur remains; long a mystery, such stones are now thought to have been a digestive aid for dinosaurs who swallowed them to help grind up food in their stomachs.
geologic time
layered rock formed by sequential deposits by water, wind, or ice of small rocks or organic matter, solidified by pressure, over a long period of time.
trace fossil: includes things like footprints, burrows, and fossilized dung, that trace the movements or activity of an organism. A single animal can make thousands and thousands of traces in its lifetime, but it will only leave behind one body when it dies. Because of this, trace fossils are much more common than body fossils.
track:
the time in which the history of the Earth has unfolded.
an impression, or trace, made by a single foot.
trail:
geologist: a scientist who studies the entire history of the earth, not just fossils.
an impression, or trace, made by an animal without legs.
index fossil: a fossilized creature that lived only in one specific time period can be used as an indicator (index) of the date of the rock in which it is found.
FOSSILS 24
■ RESOURCES AND REFERENCE MATERIALS ■
Correlations with New York State Learning Standards The activities included in this guide meet the following New York State Learning Standard Performance Indicators for elementary students (K–5):
New York State Learning Standard Performance Indicators (Elementary Level)
Activity
Standard Area Standard #
1 2 3 4 5 6
Subject
Letter
Students will
a
Create short pieces consisting of sounds from a variety of traditional, electronic, and nontraditional sound sources
Arts
1
Music
Arts
1
Visual Arts
Experiment and create art works, in a variety of mediums (drawing, painting, sculpture, ceramics, printmaking, video, and computer graphics), based on a range of individual and collective experiences
English Language Arts
1
Listening & Reading
Gather and interpret information from children's reference books, magazines, textbooks, electronic bulletin boards, audio and media presentations, oral interviews, and from such forms as charts, graphs, maps, and diagrams
•
ELA
1
Listening & Reading
Ask specific questions to clarify and extend meaning
• • • • • •
ELA
1
Speaking & Writing
Present information clearly in a variety of oral and written forms such as summaries, paraphrases, brief reports, stories, posters, and charts
• • • •
ELA
1
Speaking & Writing
Use details, examples, anecdotes, or personal experiences to explain or clarify information
• • • • • •
ELA
1
Speaking & Writing
Observe basic writing conventions, such as correct spelling, punctuation, and capitalization, as well as sentence and paragraph structures appropriate to written forms
• • • •
•
ELA
2
Speaking & Writing
Create their own stories, poems, and songs using the elements of the literature they have read and appropriate vocabulary
• •
•
ELA
2
Speaking & Writing
Observe the conventions of grammar and usage, spelling, and punctuation
• • • •
•
ELA
4
Speaking & Writing
Listen attentively and recognize when it is appropriate for them to speak
• • • • • •
ELA
4
Speaking & Writing
Take turns speaking and respond to other ideas in conversations on familiar topics
• • • • • •
Math, Science, & Technology
1
Scientific Inquiry
Ask "why" questions in attempts to seek greater understanding concerning objects and events they have observed and heard about
• • • • •
MST
1
Scientific Inquiry
Question the explanations they hear from others and read about, seeking clarification and comparing them with their own observations and understandings
• • • • • •
MST
1
Scientific Inquiry
Develop relationships among observations to construct descriptions of objects and events and to form their own tentative explanations of what they have observed
• • • • •
MST
1
Scientific Inquiry
Carry out their plans for exploring phenomena through direct observation and through the use of simple instruments that permit measurements of quantities (e.g., length, mass, volume, temperature, and time)
• •
FOSSILS 25
•
• •
•
• •
•
• •
■ RESOURCES AND REFERENCE MATERIALS ■
Correlations with New York State Learning Standards The activities included in this guide meet the following New York State Learning Standard Performance Indicators for elementary students (K–5):
New York State Learning Standard Performance Indicators (Elementary Level)
Activity
Standard Area Standard #
1 2 3 4 5 6
Subject
Letter
Students will
MST
1
Scientific Inquiry
Organize observations and measurements of objects and events through classification and the preparation of simple charts and tables
•
MST
1
Scientific Inquiry
Share their findings with others and actively seek their interpretations and ideas
• • • • •
Physical Setting
Describe the relationships among air, water, and land on Earth
• • • •
Physical Setting
Observe and describe properties of materials using appropriate tools
MST
4
MST
4
Physical Setting
Describe chemical and physical changes, including changes in states of matter
MST
6
Models
Analyze, construct, and operate models in order to discover attributes of the real thing
• •
MST
6
Models
Discover that a model of something is different from the real thing but can be used to study the real thing
• •
MST
7
Strategies
Work effectively-Contributing to the work of a brainstorming group, laboratory partnership, cooperative learning group, or project team; planning procedures; identifying and managing responsibilities of team members; and staying on task, whether working alone or as part of a group
FOSSILS 26
• • • •
• • • • • •
■ RESOURCES AND REFERENCE MATERIALS ■
Corresponding Field Trips
Bibliography and Web Resources
In addition to the organizations below, look for special National Earth Science Week activities held annually in October.
The following books and websites may help you to enrich your experience with the objects in the case.
American Museum of Natural History
Moss, Jeff. Bone Poems. New York, New York: Workman Publishing, 1997.
79th and Central Park West, Manhattan (212) 769-5200 The AMNH has the world’s most spectacular collection of fossils. Several corresponding websites for educators offer downloadable guides to the galleries and activities to go along with your visit: www.amnh.org/education/resources/rfl.php?set= b&topic_id=5&subtopic_id=80
Press, Judy. The Kids' Natural History Book: Making Dinos, Fossils, Mammoths & More! Charlotte, Vermont: Williamson Publishing Company, 2000.
Rhodes, Frank H.T. and Paul R. Shaffer, Herbert S. Zim, and Raymond Perlman. Fossils, A Golden Guide. New York, New York: St. Martin’s Press, 2001.
Fossil Walking Tour Many buildings in the city are made of limestone, a sedimentary rock, or marble, a metamorphic rock. Lincoln Center, to name a prominent example, is made of limestone and fossils are abundant in the buildings. Scout out some local locations (perhaps even your own school building has fossils in it) and take your students on a walking tour to find the fossils. Once the students get the hang of looking for them, there’s no end to where they can use this skill. The Brooklyn Children’s Museum also offers programs on a variety of natural history topics. For a listing of programs currently available, please see our website at www.brooklynkids.org, or contact the Scheduling Assistant at 718-735-4400, extension 118.
Ward, David. Fossils (Smithsonian Handbooks). New York, New York: DK Adult, 2002.
The Paleontology Portal: Good for looking up fossils by period or type of organism; interactive map showing life in the U.S. in geologic time. www.paleoportal.org/index.php
Petrified Forest National Park Triassic World: Reading and pictures for kids about what lived in the Triassic period. www.nps.gov/pefo/triassicweb.htm
Petrified Forest National Park Aetosaur Virtual Dig: A slide show illustrating a paleontologist digging up an aetosaur. www.nps.gov/pefo/vtour/aetodig/aetostart.htm
San Diego Natural History Museum Field Guide to Fossils: Find out more about individual fossils. www.sdnhm.org/fieldguide/fossils/index.html
Indianapolis Children’s Museum Dinosphere: Activities for kids, guides for teachers. www.childrensmuseum.org/dinosphere/index.html
University of California, Berkeley: Information and activities about fossils. www.ucmp.berkeley.edu/forsec/Learning.html
Museum Victoria: Information about dinosaurs. www.museum.vic.gov.au/dinosaurs
The Natural History Museum, London: Great information and activities on dinosaurs www.internt.nhm.ac.uk/jdsml/natureonline/dino-directory/about-teachers.dsml FOSSILS 27
Acknowledgments Beth Alberty Chrisy Ledakis Tim Hayduk Nobue Hirabayashi Whitney Thompson
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Portable Collections Series Coordinator Melissa Husby
■
Special Thanks Daniel Dixon The Teachers of the New York City Department of Education
■
Funding The revision of this Portable Collections Program caset guide is made possible by a Learning Opportunities Grant from the Institute for Museum and Library Services.
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© 2006 Brooklyn Children’s Museum 145 Brooklyn Avenue Brooklyn, New York 11213 718-735-4400 ext. 170 www.brooklynkids.org
For information about renting this or other Portable Collections Program cases, please contact the Scheduling Assistant at 718-735-4400 ext. 118.
