FOR THE CLASSROOM
These activities align with the following National Science Education Standards:
Content Standard C: Life Science—Regulations and Behavior
Content Standard C: Life Science—Diversity and Adaptations of Organisms
Content Standard D: Earth and Space Science—Earth?s History
The teeth of Apatosaurus were incapable of efficiently crushing or grinding food to prepare it for digestion. How, then, was digestion accomplished? Clues to the digestion system of large herbivorous dinosaurs come from birds, which do not have teeth to chew their food. Parakeets swallow gravel and keep it in their gizzard, a muscular pocket in the digestive tract. As the muscles cause the walls of the gizzard to move, the gravel crushes the food.
BLM's Cleveland-Lloyd Dinosaur Quarry, a National Natural Landmark since 1964, has produced material such as this Allosaurus skull for dinosaur exhibits in over 40 museums worldwide. The remains of over 60 of these Jurassic flesh-eaters have produced one of the most complete growth records of any known dinosaur.
Reasonably strong evidence exists that large dinosaurs like brontosaurs and diplodocids also had gizzard stones, probably several rocks capable of efficiently crushing and grinding ingested food. The large dinosaurs pulled vegetation as needed with their thin, peglike teeth, and rather than waste valuable energy on chewing, swallowed the food. The gizzard "chewed" as the dinosaur walked. This was a far more efficient system because these dinosaurs could ingest new food as they "chewed" the old food.
Materials: You will need a handful of pebbles, 120 mL water, pieces of lettuce or grass, a 2 L plastic soda bottle, a colander, and a bowl or bucket.
Procedure: Place the pebbles, water, and pieces of lettuce or grass in the bottle and put the cap on tightly. Pass the bottle around the room, allowing each student to shake it 15-20 times. After all students have had the opportunity to shake the bottle, have students form a circle. Place a colander over a bowl or bucket and pour out the bottle contents. The vegetables will be crushed. Discuss how they have been pulverized without being chewed. Students can try this experiment with other vegetables or plant materials at home--carrots, celery, tree leaves--and compile a list of how many shakes it takes to pulverize different materials.
Making a Good Impression
Have students determine which types of sediments would best preserve fossils. Students can press shells or bones into various thick mixtures, such as sand and water; clay and water; and gravel, clay, and water. The ability of a mixture to "preserve" should be judged on the clarity of the imprint made. (Clay will hold the best imprint. Gravel will be the least able to hold an imprint.)
In this activity, students fill in a semantic feature analysis chart, a method of graphically analyzing relationships among many different species. This allows students to develop vocabulary, categorization, and classification skills and to identify relationships.
Prepare a grid with prehistoric animal types listed on the left side of the grid and features or characteristics written across the top (such as those shown on the sample chart below). Possible characteristics of dinosaurs or other animals include carnivorous/herbivorous, bipedal/ quadrupedal, horned/not horned, grazer/browser, size, time period during which it lived, and continent(s) where it was found.
If a characteristic is present in a certain type of animal, students should mark a plus (+) in the space; if it is not present, students mark a minus (-). Grids can be prepared individually or in small groups, or a large wall-size grid can be made for use by the entire class.
What's in a Name?
Dinosaur names are often chosen from Latin or Greek on the basis of three categories:
- the place of discovery,
- the name of the discoverer or some expert in the field,
- or a description of the animal or some feature of its anatomy.
By far, the greatest number of dinosaur names are descriptive, revealing the shape, analogy to a modern animal, behavior, size, or some other anatomical feature of the animal. Although they often seem to be merely long strings of random letters, the names of the animals are combinations of word roots that describe something about the animal.
For example, combining the three roots tri-, from Latin meaning "three," cerat-, from Greek meaning "horn," and -ops, from Greek meaning "face" gives the name for Triceratops, a dinosaur with a three-horned face.
Dinosaur names can also describe where the animal was first discovered. For example, Albertosaurus was discovered in the province of Alberta, Canada. Other dinosaur names honor the person who was instrumental in the discovery. For example, Lambeosaurus was named for Lawrence Lambe, a paleontologist with the Geological Survey of Canada.
Activity: Have students decipher the following dinosaur names by looking through the dictionary for words that may contain the various roots. All these names are based on rules established by the International Code of Zoological Nomenclature overseen by the International Commission on Zoological Nomenclature. Fossil plant names are governed by the International Code of Botanical Nomenclature. All of these dinosaur types have been found on America's western public lands:
- Pentaceratops ("five-horned face")
- Camptosaurus ("bent lizard")
- Stegosaurus ("plated lizard")
- Allosaurus ("strange lizard")
- Ceratosaurus ("horned lizard")
- Marshosaurus ("Marsh's lizard")
- Stokesosaurus ("Stokes' lizard")
- Barosaurus ("heavy lizard")
- Camarasaurus ("chambered lizard")
- Haplocanthosaurus ("single-spined lizard")
- Deinonychus ("terrible claw")
- Seismosaurus ("Earth-shaking lizard")
- Diplodocus ("double beam")
- Apatosaurus ("deceptive lizard")
- Dryosaurus ("oak lizard")
- Brachiosaurus ("arm lizard")
- Amphicoelias ("with hollow-ended vertebrae")
- Elaphrosaurus ("light lizard")
- Coelurus ("hollow tail")
- Torvosaurus ("savage lizard")
Boy Scouts examine the partial skull of a baby Triceratops.
University of California, Berkeley, Museum of Paleontology
Body Building--Mesozoic Style
The body structure of animals is a system of balanced beams and masses. The center of mass is the balance point of a body. Explain to students that the bodies of animals must be balanced or they will fall due to the pull of gravity. Bipedal dinosaurs were able to keep both feet on the ground and used their tails to provide balance when they leaned over. The tail likely served as a counterweight, or force to balance the weight of the front end and massive head. As a bipedal dinosaur moved its head up or down, the tail moved in the opposite direction.
Rib cage of a hadrosaur (duckbill) dinosaur from Cretaceous of New Mexico
Keith Rigby, Jr., BLM
Activity: Students can easily demonstrate the concept of a counterweight. Working in pairs, one student places a pencil on the floor and observes as the second student stands on one leg, and without bending the knee (just bending over from the waist), reaches for the pencil on the floor. The observing student should notice that the student bending over extends the second leg backward as a counterweight. Dinosaurs did the same thing using their tails.
To explore other aspects of body balance, students can build any dinosaur body they want using commonly available materials such as straws, pipe cleaners, cardboard tubes, rubber bands, paper clips, elastic bands, marshmallows, or Styrofoam balls. Have students share with the class how balance is achieved in that body system. Encourage them to experiment with both bipedal dinosaurs such as Tyrannosaurus rex as well as quadrupedal dinosaurs such as Diplodocus.
Fossilization: The Road to Immortality
Fossilization is a rare event. The chances of a given individual being preserved in the fossil record are very small. Some organisms, however, have better chances than others because of the composition of their skeletons or where they lived. This also applies to the various parts of organisms. For example, plants, invertebrates, and vertebrates are made up of different parts that can separate after death. The different parts can be transported by currents to different locations and be preserved separately. A fossil toe bone might be found at one place and a fossil rib at another location. We could assume that they are from different animals when, in fact, they came from the same one.
A budding paleontologist studies fossils.
University of California, Berkeley, Museum of Paleontology
Much is lost in the fossilization process. Much of what we consider important about human biology is in the soft tissues, such as skin, hair, and internal organs. These characteristics would usually be unknown in the fossil state, because most of the time only bones and teeth are preserved. Bones and teeth are not always preserved together.
Activity: This exercise is designed to encourage children to think about the quality of information that comes from the fossil record. To begin, have students list facts about a living animal, such as a horse. The list of facts on the horse might include--but not be limited to--large size, fast runner, eats grass, has grinding teeth, has long hair for a mane and tail, whinnies, is intelligent, is sociable with other horses, makes a good pet.
Ask students, "What would we know if this animal were extinct?" Show students an image of a horse skeleton and point out an important generalization of fossilization: most of the time, only the hard parts (bones and teeth) are preserved as fossils. Go through the list of characteristics about the horse and ask the class what we would know about horses if they were extinct and all we had were fossilized bones and teeth. We would know it was a large animal and could probably make some good guesses about its weight. We would know it had grinding teeth and, therefore, we could probably guess that it ate some sort of tough vegetation like grass. The hooves would not be preserved, but the shape of the foot bones would be a good indicator that it had hooves. The skeleton would also be useful to tell us it was a fast runner. Few details of the hair or skin would be known. Everything about social behavior and vocalization would also have to be guesses.
|Scientists are able to determine the "age" of different rock layers as an oil well is drilled. If oil is found in a particular rock layer, geologists will "target" rocks of the same age in each new well they drill in the area. Because rocks of the same age may look completely different from one another, only micropaleontologists who examine the pollen fossils in the rocks can say for sure that they are the same. And if no oil is found, micro paleontologists can tell the geologist when to stop drilling. This can save a great deal of money as drilling can cost hundreds of dollars per foot.|
John Bebout, BLM
Pass out a picture of a Stegosaurus skeleton. Have the class draw muscles and skin on the skeleton. Explain to students that skin color and texture are largely the choice of the artists, since fossil bones provide no clues, although some skin impressions have been found.
Certain of the activities presented above were adapted with permission from the author from Investigating Science with Dinosaurs by Craig A. Munsart (1993).
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