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T-RexT-Rex

  • Subject:
  • |
  • Grade(s): 6-8
  • |
  • Duration: Two class periods

Lesson Plan Sections

Objective


Students will understand the following:
1. An animal that is a predator gets food by killing and hunting other animals.
2. An animal that is a scavenger eats dead or decaying matter, including animals that are already dead.
3. Scavengers and predators have different physical characteristics that equip them for hunting or scavenging.
4. Tyrannosaurus rex (" T-rex, " for short) may have been a scavenger or a predator. A different set of evidence supports each theory.

Materials


For this lesson, you will need:
• Pictures of dinosaurs, including Tyrannosaurus rex
• Research materials on animals

Procedures


1. Review with your class what they have learned about dinosaurs, focusing the discussion on what students know about Tyrannosaurus rex. In discussion, ask if students know whether T-rex was a meat eater or a plant eater. Ask them how paleontologists—scientists who study prehistoric life—can determine such a fact.
2. Briefly review with your students that with modern as well as prehistoric animals, plant eaters can be distinguished from meat eaters by certain physical traits. For example, plant eaters have teeth that are better for grinding than for ripping and piercing. Also, since most plant eaters are preyed upon by hunting animals, or predators , their eyes tend to be found on the sides of their heads—better to look around and behind to see what or who might be sneaking up on them. A predator, on the other hand, is likely to have eyes in the front of its head—better for spotting prey and chasing it down.
3. Ask students for examples of each kind of animal (prey: rabbit, deer; predator: wolf, lion). Then have them examine pictures of dinosaurs, including one of Tyrannosaurus rex, and try to determine which dinosaurs were meat eaters and which were plant eaters. They should know that T-rex was a meat eater.
4. Ask students if they can think of a way a meat-eating animal could get food without being a predator, or hunter. Then introduce the term scavenger to the class, defining it as "an animal that eats dead or decaying matter, such as animals that have already died." Ask students to brainstorm physical traits they think would characterize a meat-eating scavenger, as opposed to a predator. Stimulate ideas by asking questions such as the following:
  1. Which kind of animal would need better eyesight?
  2. Which kind of animal would need a better sense of smell?
  3. Which kind of animal would need to be a faster runner?
  4. Which kind of animal would need the ability to scare away other animals (i.e., scare away predators from prey they have hunted and killed)?
  5. Which animal would need a keener sense of hearing?
5. Tell students that although scientists agree that T-rex was a meat-eating dinosaur, there is some controversy as to whether it was a predator or a scavenger.
6. List the following physical traits of T-rex on the chalkboard:
  • Poor eyesight
  • Good sense of smell
  • Very large
  • Good hearing
  • Strong jaws
  • Teeth curved backward and inward
  • Fast runner
7. Have each student write a paragraph explaining which traits support the theory that T-rex was a scavenger and which support the theory that T-rex was a predator. Students should support all statements with sound reasoning and comparisons with modern animals. (Some research may be necessary.) Have them end their paragraphs with their own ideas about what further type of evidence could resolve the controversy.

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Adaptations


Have students use the Internet to catch up on and report on the latest research on T-rex.

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Discussion Questions


1. Discuss the possible ancestors of the T-Rex. Which candidates do you think are the most likely and why? What structural features do they have in common with the T-Rex?
2. Are there any animals alive today that were alive during the Cretaceous period? What physical characteristics do they have that may account for their species' survival during periods of relatively sudden and substantial environmental change?
3. Some scientists believe that the extinction of the dinosaurs is due to the impact of a large comet striking the Earth. Others, however, believe that tremendous volcanic eruptions released devastating greenhouse gases into the atmosphere. Still others believe that a change in the Earth's sea level, a supernova explosion, or changes in the Earth's orbit caused a destructive cooling of the Earth's climate. Which theory seems most plausible to you? Defend your answer.
4. Scientists have never seen real dinosaurs, but they seem to know a lot about them. How do they find out so much about animals that have been dead for 65 million years—animals that no one has ever seen alive?
5. Some scientists believe that the T-Rex was a carnivore. Others, however, believe it was a scavenger. Think about the teeth, jaw, brain size, eyes, and overall body size and strength of the T-Rex. Which theory do you think this evidence supports? Discuss your answer.
6. One of the strange facts of science is that experts can often derive entirely different conclusions from the same evidence. How can this happen? Is this a good or a bad thing?

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Evaluation


You can evaluate your students on their paragraphs using the following three-point rubric:
 
Three points: uses all evidence presented; backs up all statements with sound reasoning and valid examples
 
Two points: uses most evidence presented; backs up most statements with reasons or examples
 
One point: uses little evidence presented; backs up few statements with reasons or examples
 
You can ask your students to contribute to the assessment rubric by determining criteria for sound reasoning.

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Extensions


Badlands
Tell students that remains of Tyrannosaurus rex have been found in a part of North America called the Badlands. Have them do research to locate the North American Badlands, discover what this area is like today, and find out what it was like 65 million years ago when T-rex lived and thrived there.

Extinction Theories
Have students research theories that attempt to explain how and why dinosaurs became extinct. They should focus on the current popular theory that suggests the dinosaurs were wiped out when an asteroid hit Earth. Have them explain, in writing or in discussion, why paleontologists favor this theory.

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Suggested Readings


Tyrannosaurus Rex and Its Kin: The Mesozoic Monsters
Helen Roney Sattler, Lothrop Lee & Shepard, 1989.
ISBN 0-688-07747-1
LC 88-1577
Discusses the gigantic flesh-eating dinosaurs of the Mesozoic.

The New Illustrated Dinosaur Dictionary
Helen Roney Sattler, Lothrop Lee & Shepard, 1990.
ISBN 0-688-08462-1
LC 90-33130

The Macmillan Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals
Dougal Dixon, Macmillan, 1993.
ISBN 0-02-042981-9

The Complete T. Rex
John R. Horner, Simon and Schuster, 1993.
ISBN 0-671-74183-3
LC 93-211

Predatory Dinosaurs of the World: A Complete Illustrated Guide
Gregory S. Paul, Simon and Schuster, 1988.
ISBN 0-671-58733-6
LC 88-23052

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Links


Dinosauria On-Line
Dinosauria On-Line is a site that gathers together many resources for people who want to do further research on dinosaurs. The site includes graphics of some dinosaurs, a list of articles written about many different dinosaur topics and an area where a visitor can sign up to join a dinosaur listserv. Dinosauria On-Line caters to all levels of dinosaur enthusiasm.

Dinosaur Paleontology
This site is a teacher-created unit on Dinosaur Paleontology. The focus of the unit is on using the scientific method to investigate dinosaur evolution, anatomy, physiology, and behavior. This site is part of the Access Excellence Activities Exchange.

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Vocabulary


Click on any of the vocabulary words below to hear them pronounced and used in a sentence.
speaker    paleontologist
Definition: One who studies the forms of life existing in prehistoric or geologic times, as represented by the fossils of plants, animals, and other organisms.
Context: "For a paleontologist like Phil Currie, who scours the boneyards of the North American Badlands in search of the real T-rex, a close encounter is a rare and thrilling event."
speaker    fossilized
Definition: When a plant or animal from prehistoric times is preserved by natural methods.
Context: "Fossilized bones are not the only remains that can shed light on the life of an animal."
speaker    scavenger
Definition: An animal, such as a bird or an insect, that feeds on dead or decaying matter.
Context: "One paleontologist suggests that T-rex was not a killer, but a scavenger."

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Standards


This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
 
Grade level: K-2
Subject area: science
Standard:
Understands the basic concepts of the evolution of species.
Benchmarks:
Knows that some kinds of things that live today still resemble once-living things that have completely disappeared.

Grade level: 3-5
Subject area: science
Standard:
Understands the basic concepts of the evolution of species.
Benchmarks:
Knows that fossils provide evidence that some organisms living long ago are now extinct, and fossils can be compared to one another and to living organisms to observe their similarities and differences.

Grade level: 6-8
Subject area: science
Standard:
Understands the basic concepts of the evolution of species.
Benchmarks:
Knows how the fossil record, through geologic evidence, documents the appearance, diversification and extinction of many life forms; millions of species of animals, plants and micro-organisms living today differ from those that lived in the remote past, and each species lives in a specific and fairly uniform environment.

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Credit


Summer Productions, Inc.

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