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When Dinosaurs RuledWhen-Dinosaurs-Ruled

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

Lesson Plan Sections


Students will understand the following:
1. The age when dinosaurs inhabited Earth (about 250 million years ago to about 65 million years ago) is called the Mesozoic age.
2. The Mesozoic age is divided into three periods, from earliest to latest: the Triassic period, the Jurassic period, and the Cretaceous period.
3. The plants and animals on Earth differed during these three periods.
4. Changes in plant life affected the development of animal life.


For this lesson, you will need:
Research materials on dinosaurs and other plants and animals of the Mesozoic age
Computer with Internet access
Art materials
Large sheets of brown and blue construction paper
Tape or a stapler


1. Introduce the activity by reviewing with students what they have learned about dinosaurs and the Mesozoic age. They should know that the Mesozoic age, or age of dinosaurs, began about 250 million years ago and ended about 65 million years ago.
2. Have students do research to find out more about the plants and animals of the Triassic period, the earliest period of the Mesozoic age. Guide their research by having them focus on the following questions:
  1. What kinds of plants and animals inhabited Earth during the Triassic period?
  2. How did Earth's atmosphere during the Triassic period differ from the present atmosphere?
  3. When did flowering plants first appear?
  4. What affect did the appearance of flowering plants have on the dinosaurs of that period?
Encourage students to find out the sizes of the plants and animals they discover and to include visual representations of plants and animals in their notes.
3. From the students' research, compile a class list of plants and animals of the Triassic period.
4. Assign each student or pair of students one plant and one animal to study. Students could also choose their own plants and animals, making sure not to duplicate each other's choices, or you could write the names of the plants and animals on slips of paper and have each student or pair draw one of each.
5. Tell students they will be drawing pictures of their plants and animals and that their pictures will become part of a Triassic scene on the bulletin board. Before they begin, however, work with the class to decide on a scale so that all the plants and animals in the scene will be sized appropriately in relation to each other. Students should realize that some plants will have to be tiny in order to appear in the same scene with a gigantic dinosaur.
6. Have students draw, color, and label their Triassic plants and animals.
7. Line a bulletin board with brown construction paper, representing soil, on the bottom and blue paper, representing the sky, on top. Have students tape or staple their labeled drawings to the bulletin board.
8. Invite students to present the characteristics of their plants and animals to the class. Ask them to explain, based on their research, whether or not their chosen plants and animals successfully adapted during the Triassic period and hypothesize why.
9. Have students repeat the activity for the Jurassic and Cretaceous periods.

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Adaptations for Older Students:
Have students accompany their drawings with written descriptions of their plants and animals, including a paragraph explaining whether or not their plants and animals successfully adapted and hypothesizing why.

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Discussion Questions

1. List and discuss adaptations of flowering plants that led to their worldwide abundance at the end of the Jurassic period. Evaluate the ability of the dinosaurs to adapt to these changes.
2. An explosion of insect diversity seemed to correlate with the abundance of flowering plants. Debate whether insect abundance led to angiosperm abundance or vice versa. Be sure to support your position with research-based arguments.
3. Why do you think triceratops dominated the Cretaceous period? What adaptation helped this dinosaur survive in the changing environment?
4. The asteroid hypothesis, first presented by Luis Alvarez, became a theory after evidence from a variety of sources supported the original observations. Describe what you know about the research that supports this theory and debate its validity using supporting evidence.
5. The explosion of Mount St. Helens could have been as devastating to its ecosystem, on a small scale, as an asteroid impact was on a large scale to world ecosystems. Consider the rebirth of Mount St. Helens and compare it with theories about the changes after the Cretaceous extinction. As a group, make a list of similarities and differences.
6. Discuss some possible abiotic (nonliving) factors that could have major impact on the evolution of organisms today. Could mankind direct the outcome?

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You can evaluate your students on their drawings and presentations using the following three-point rubric:
  • Three points: drawings accurate and carefully executed; descriptions accurate and clearly presented; explanations logical and based on scientific evidence
  • Two points: drawings fairly accurate; descriptions adequate; explanations lacking in logic or evidence
  • One point: drawings inaccurate; descriptions adequate; explanations incomplete and lacking evidence
You can ask your students to contribute to the assessment rubric by determining a minimum number of details to be included in the descriptions.

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Asteroid vs. Volcano: Dinosaur Extinction Debate
The asteroid theory of dinosaur extinction, though very popular since Luis Alvarez first presented it in 1980, is a theory. Theories are hypotheses supported by interpretations of data; most generate conflicting views. Another explanation for the Cretaceous-Tertiary extinction is the volcano greenhouse theory originated by Dewey M. McLean in 1978.

Divide the class into two groups (asteroids and volcanoes), and have students research the theory they've been assigned. Among the plentiful resources for this debate are the two original papers:

"Extraterrestrial Cause for the Cretaceous-Tertiary Extinction" by L.W. Alvarez, F. Asaro, and H.V. Michael ( Science , vol. 208, 1980: 1095-1108).

"A Terminal Mesozoic Greenhouse: Lessons from the Past" by D.M. McLean ( Science , vol. 201, 1978: 401-406).

When the students have completed their research, invite a third group to act as mediators for a debate. Have the mediators decide the winning theory.

Filling the Niche
On the islands of Galapagos, Charles Darwin observed in finches that animals inevitably fill niches left vacant by other animals. The niches held by dinosaurs were temporarily left empty after their extinction but were soon filled by new organisms—the mammals. Have students make a display to illustrate this process of adaptation in evolution. Students should select an extinct organism to research, define its habitat and range on the display, and propose which organisms could have taken over the niche left vacant.

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Suggested Readings

Living Fossils: Animals That Have Withstood the Test of Time
James Martin and Janet Hamlin. Crown, 1997.
This book examines stubborn animal survivalists that, unlike dinosaurs, adapted through eons and are still with us today. Included are the horseshoe crab, the nautilus, the coelacanth, the Komodo dragon, the crocodilians, and the cockroach.

"Extinction as a Way of Life"
John R. Horner, in Dinosaur Lives: Unearthing an Evolutionary Saga . Harper Collins, 1997.
Jack Horner, the renowned paleontologist, covers the hot topics of the dinosaur world, including whether dinosaurs gave rise to modern birds and whether dinosaurs were decimated by a gigantic meteorite 65 million years ago.

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Dinosauria Online
Resources include a Dinosaur Omnipedia, Dinosaur Picture Gallery, and articles about new discoveries and theories. Appropriate for K-12.

Discovering Dinosaurs
A variety of resources and interactive activities for students.

Dinosaur Links
A compilation of dinosaur curriculum resources and museum Web site links. Developed by Bastrop Independent School District, Texas.

Dino Russ's Lair
A wealth of information, visuals, and videoclips related to dinosaurs and paleontology. Sponsored by the Illinois Department of Natural Resources.

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Click on any of the vocabulary words below to hear them pronounced and used in a sentence.

speaker    angiosperms
Definition: Flowering plants—any of a class (Angiospermae) or division (Magnoliophyta) of vascular plants (as magnolias, grasses, oaks, roses, and daisies) that have the ovules and seeds enclosed in an ovary, form the embryo and endosperm by double fertilization, and typically have each flower surrounded by a perianth composed of two sets of floral envelopes comprising the calyx and corolla.
Context: Angiosperms first appeared at the end of the Jurassic period.

speaker    gymnosperm
Definition: Any of the class (Gymnospermae) of woody vascular seed plants that produce naked seeds not enclosed in an ovary.
Context: Gymnosperms produce seeds in cones.

speaker    herbivore
Definition: A plant-eating animal.
Context: Most Triassic dinosaurs were plant eaters or herbivores.

speaker    Jurassic
Definition: The period of the Mesozoic era between the Triassic and Cretaceous periods or the corresponding system of rocks marked by the presence of dinosaurs and the first appearance of birds.
Context: Dinosaurs became increasingly abundant during the Jurassic period.

speaker    Pangaea
Definition: The hypothetical land area believed to have once connected the landmasses of the southern hemisphere with those of the northern hemisphere.
Context: During the late Paleozoic era, most of the land was joined in one supercontinent known as Pangaea.

speaker    pistil
Definition: A single carpel (one of the ovule-bearing structures in a flowering plant) or group of fused carpels usually differentiated into an ovary, style, and stigma.
Context: The pistil of a flower contains the ovary.

speaker    sauropods
Definition: Any of a suborder (Sauropoda) of four-footed, herbivorous dinosaurs with a long neck and tail, a small head, and five-toed limbs.
Context: Giant sauropods probably used their long necks to reach leaves high in trees.

speaker    tree ferns
Definition: Any of various ferns (especially in the families Cyatheaceae and Marattiaceae) resembling a tree with woody stems.
Context: Giant tree ferns grew in the coal forest of the Carboniferous period.

speaker    Triassic
Definition: The earliest period of the Mesozoic era or the corresponding system of rocks marked by the first appearance of dinosaurs.
Context: The first dinosaurs appeared in the Triassic period.

speaker    triceratops
Definition: Any of a genus ( Triceratops ) of large, herbivorous, Cretaceous dinosaurs with three horns, a bony hood or crest on the neck, and hoofed toes.
Context: Large herds of triceratops grazed during the Cretaceous period.

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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: 9-12
Subject area: life science
Understands how species depend on one another and on the environment for survival.
Knows how the interrelationships and interdependencies among organisms generate stable ecosystems that fluctuate around a state of rough equilibrium for hundreds or thousands of years.

Grade level: 6-8, 9-12
Subject area: life science
Understands the basic concepts of the evolution of species.
(6-8)Understands the concept of extinction and its importance in biological evolution (e.g., when the environment changes, the adaptive characteristics of some species are insufficient to allow their survival; extinction is common; most of the species that have lived on Earth no longer exist).

(9-12)Knows that natural selection leads to organisms that are well suited for survival in particular environments, so that when an environment changes, some inherited characteristics become more or less advantageous or neutral, and chance alone can result in characteristics having no survival or reproductive value.

(9-12)Knows how natural selection and its evolutionary consequences provide a scientific explanation for the diversity and unity of past and present life forms on Earth (e.g., recurring patterns of relationship exist throughout the fossil record; the millions of different species living today appear to be related by descent from common ancestors).

(9-12)Knows that the basic idea of evolution is that the Earth's present-day life forms have evolved from earlier, distinctly different species as a consequence of the interactions of (1) the potential for a species to increase its numbers, (2) the genetic variability of offspring due to mutation and recombination of genes, (3) a finite supply of the resources required for life, and (4) the ensuing selection by the environment of those offspring better able to survive and leave offspring.

Grade level: 6-8, 9-12
Subject area: Earth science
Understands basic Earth processes.
(6-8)Knows how successive layers of sedimentary rock and the fossils contained within them can be used to confirm the age, history, and changing life forms of the Earth, and how this evidence is affected by the folding, breaking, and uplifting of layers.

(6-8)Knows that fossils provide important evidence of how life and environmental conditions have changed on the Earth over time (e.g., changes in atmospheric composition, movement of lithospheric plates, impact of an asteroid or comet).

(9-12)Knows how the evolution of life on Earth has changed the composition of the Earth's atmosphere through time.

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John E. DeMary, biology teacher, Loudoun County Public Schools, Leesburg, Virginia.

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