Lesson Plan

Fossil Teeth: Changing Climates and Evolutionary Responses Preserved in the Fossil Record (Lesson Plan by Geoscientist-in-the-Park Gina Roberti)

two color graph as used in lesson
Grade Level:
High School: Ninth Grade through Twelfth Grade
Literacy and Language Arts,Math,Science,Social Studies
Lesson Duration:
90 Minutes
State Standards:
Biology Standard 1: Nature of Science, Goal 1.2: Understand Concepts and Processes of Evidence, Models, and Explanations;Goal 1.3: Understand Constancy, Change, and Measurement; Goal 1.8: Understand Technical Communication; Goal 3.1: Understand the Theory
Additional Standards:
NGSS Disciplinary Core Ideas
-HS LS2 Ecosystems
-HS LS4 Biological Evolution
-HS ESS2 Earth's Systems

NGSS Scientific and Engineering Practices
-HS SEP 4 Analyzing and Interpreting Data
-HS SEP 7 Engaging in Argument from Evidence
Thinking Skills:
Remembering: Recalling or recognizing information ideas, and principles. Understanding: Understand the main idea of material heard, viewed, or read. Interpret or summarize the ideas in own words.

Essential Question



Students will look at changes in tooth size and shape (morphology) in the fossil record of herbivorous mammals in North America using data from a recent paleontological study. Students will infer factors which caused the observed evolutionary adaptions and link biological adaptation with global climate change and localized habitat change.


Earth’s climate and biosphere are linked. As climate conditions change, species adapt to new environments. This lesson examines the spread of open areas and grasslands in North America as a result of changing climate, with a focus on specific morphological adaptations in the teeth of herbivorous land mammals.

A major development in the evolution of herbivores was the shift from a diet of browsing leaves to grazing grass in the last 30 million years.

Prerequisite Knowledge:
- Students should be aware that the Earth’s climate has changed in the past, and continues to change today. This has influenced the diversity and distribution of life on our planet throughout geologic time.
- Students should be comfortable with the concepts of evolution and adaptation. Living organisms on our planet are continually adapting to new climates and environments. Evidence for these changes are preserved in the fossil record.
- This lesson involves reading line-graphs and pie-charts. Quantitative skills, such as defining axes and interpreting trends, are practiced through the graph activity.

-Lesson Plan was developed by a GeoScientist-In-Park intern. Materials are original or used with permission.


Skulls and Teeth: Clues to diet and behavior. Students will explore similarities and differences between the size and shape of skulls and teeth of different mammals.

Download PreLesson Skulls and Teeth

Teacher uses PowerPoint “Fossil Teeth” to provide background about the specific research study from which data for the lesson was derived. Presentation is then followed by accompanying worksheet: Student Graph Analysis (Activity A). Both worksheet and PowerPoint Presentation provide introduction on how to read the graphs used in lesson activities.

Download Fossil Teeth Activity with Powerpoint

Worksheets on tooth types in PDF format.

Download PreLesson Plan Tooth Types

Background data and information about the studies referenced and general paleontology references in a helpful PDF.

Download Teacher Brackground

Ready to use PDF assessement pages and answer keys

Download Student Assessment

Ready to use PDF surveys for both students and teachers

Download Final Surveys

Educational PDF download provided to original paper by Christine Janis included for teachers as a reference. This paper is not open access so is attached here for teacher use.

Download 2012 Scientific Paper

Lesson Hook/Preview

Pre-Lesson (45 minutes). Two activities (“Guess the Skull” and “Tooth Types”) explore similarities and differences between the size and shape of skulls and teeth of different mammals.



Main Lesson Activities and Extensions
- Teacher PowerPoints (2): “Grasslands and Teeth”, “Fossil Teeth”
- Activity A: Graph Analysis Student Worksheet (with Answer Key)
- Activity Extension B: Student Timeline Worksheet (with Answer Key)
- Activity Extension C: Primary Reading and Student Opinion Article


Adaptation: Genetic changes in a species in response to evolutionary and environmental pressures. For example, modern horses evolved longer limbs than their shorter ancestors in response to more open grassland environments and the need to outrun predators.
Convergent Evolution: The process by which organisms of different lineages independently evolve similar traits to adapt to similar environments. For example, in North America, a variety of types of mammals evolved teeth that were better adapted for chewing grass when grasslands become more prevalent.
Divergent Evolution: The process by which species accumulate enough distinct traits and behaviors to distinguish themselves as a new species. For example, humans, bats and whales are all derived from a prehistoric family of mammals with 5 fingers and toes, but have evolved into very different physical forms due to different environmental pressures.
Evolution: The process by which life on Earth has developed and diversified over time.
Fossil: The remains of any past life form that has died and been preserved in the rock record. Most commonly, soft organic parts decompose while hard body parts, such as bones, teeth, shells and exoskeletons, are chemically dissolved and mineralized () into rock.
Fossil Record: The combined set of evidence from past life forms preserved in the rock record.
Hypsodonty: “High- crowned teeth,” regarding the ratio of the height of a tooth relative to its overall size. The ratio of tooth height to its overall size (called the “hypsodonty index”, or HI) is used by scientists that study changes in tooth morphology as a result of diet.
Morphology- The form and structure of certain features of an organism. Example: Tooth morphology varies amongst browsers and grazers depending on their diet.
Paleoclimatology: The study of how Earth’s climate has changed in the past.
Paleontologist: A scientist who studies the fossil record to understand the diversity of life that existed on our planet in the past. Paleontologists use a diversity of techniques to decipher the fossil record, including tools from chemistry, genetics, biology and geology.

Assessment Materials

Grassland Evolution, Climate and Ecosystem Change

Student worksheets, Powerpoint, Matching Vocabulary, Timeline Sequencing, Critical Thinking Questions, Student and Teacher Surveys

Enrichment Activities

Extension Activities (30-45 minutes each). Students probe deeper into the fossil record of tooth-shape change. ‘Why do we see a shift in the dominant tooth type of herbivorous mammals in North America 30-15 million years ago?’ The activities encourage students to connect patterns in the tooth data with broader patterns of climate and habitat change. Extension activities are structured around guiding worksheets: Activity B (Student Timeline) and Activity C (Student Opinion Article).


Additional Resources

There are a number of companies that supply hands-on educational materials for teaching about paleontology and natural history. Special education kits specific to skull morphology (sets of skull replicas, etc.) are available through Skulls Unlimited (www.skullsunlimited.com) and Bone Clones (www.boneclones.com); discounts are often available for classroom teachers.

Many scientists have websites in which they publish pages that explain the basis and broader context of
their research. One such example is the website of Caroline Stromberg, a prominent author in the study of plant evolution and the spread of grasslands. Below is a link to a sample to one of her pages. It is very much acceptable to contact researchers and scientists directly, using contact information listed on the web. Students can be encouraged to reach out as well!

Further resources on teaching evolution for teachers can be found on the PBS website:
http://www.pbs.org/wgbh/evolution/educators/index.html and, for information specific to human evolution at the Smithsonian Museums’ Human Origin’s webpage: http://humanorigins.si.edu/

Skulls and Bones: A guide to the skeletal structures and behavior of North American Mammals is a well written and comprehensive book about the shape of skulls and how to read them (Glenn Searfoss, 1995). The University of Arizona offers a printable lesson on identifying skulls of common wildlife, free to view
and download at the following web address:

A lesson on the evolution of horse teeth including templates for 3D printing was developed by the University of Florida Museum of Paleontology in 2015. It is free to use and download, and available at the following link: https://www.cpet.ufl.edu/wp-content/uploads/2015/07/Horse-Evo.pdf.

For another lesson involving interpretation of quantitative data from the fossil record (for high school students), see the following lesson plan published on Earth Education Online:

Related Lessons or Education Materials

More information about Geoscientists-In-the-Parks is at https://www.nps.gov/subjects/geoscientistsinparks/index.htm

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Last updated: March 8, 2019