Lesson Plan

Hoofin' It! Vertebrate Mysteries

A Dall sheep stretches its neck to eat vegetation
A Dall sheep stretches its neck and back to reach vegetation
NPS Photo

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Biology: Animals
45 - 60 minutes
Group Size:
8 or fewer
teamwork, classification, discussion


The lesson plans in our 'Hoofin' It!' unit help students learn the basics of animal classification and wildlife ecology by studying Dall sheep. Each lesson contains several activities.

Lesson three focuses on distinctions between types of vertebrates.


Students will be able to define "vertebrate" and describe characteristics that distinguish mammals from other vertebrates.

Students will also be able to describe and discuss overall characteristics of all five groups of vertebrates.


The "Hoofin' It!" unit explores the natural resource management of Dall sheep in the national parks of northwest Alaska. Students will learn about Dall sheep, where they live, how they have adapted to their environment, and how wildlife biologists study them to understand how to protect their populations within national parklands. Links to other lessons in the unit can be found at page bottom.

Dall sheep are a wild sheep that lives on steep mountain slopes across the Alaska. The sheep are an integral part of the natural ecosystem, and they are prized by subsistence and recreational hunters. In the early 1990s, the Dall sheep population in the Baird Mountains of Noatak National Preserve declined dramatically, losing half its population in two years. Wildlife managers closed the sheep hunting season for seven years to allow the population to grow again.

Why did the population drop so suddenly? What are the natural and human factors that affect the Dall sheep population? In the spring of 2000, Brad Shults, a wildlife biologist for the National Park Service, began a research project to learn more about Dall sheep population dynamics. Shults hopes to better understand sheep by studying the number of lambs that are born, how long sheep live, what are the most common causes of death, where do they go from season to season, and just how many sheep are there?


Before You Begin
  1. Review the student answers from the brainstorming activity in part one of this lesson plan. Use the vertebrate fact sheet and give a copy to each student. Discuss differences between the five vertebrate groups. Define vertebrate vs. invertebrate for the students.
  2. Make copies of the “Vertebrate Mystery Stories”. There are five mystery stories, one for each of the five groups of vertebrates. Make one complete set for each team of students.

    With each set, cut each story into strips, with one strip for each clue. Keep each story separate from the other stories and put the strips for each story into an envelope. Label each envelope VM1 - group #1 through VM5 - group #1. Each set of stories will have it’s own group number depending on the number of student teams you have.

    For example, if you have three teams of students, you’d label the set of envelopes with VM1, VM2, VM3, VM4, VM5 -group #1, VM1, VM2, VM3, VM4, VM5 -group #2, and VM1, VM2, VM3, VM4, VM5 -group #3.
  3. The answers to the mysteries are: Number 1, Mammals, Number 2, Fish, Number 3, Reptiles (note: there have been “pet” snakes that have gotten away from households and/or escaped cargo), Number 4, Birds, and Number 5, Amphibians (note: the one species of amphibian found in Alaska is the Wood Frog).

    Make sure you do not label the envelopes with the “type” of vertebrate or the name of the mystery vertebrate the story is related too (i.e. mammals or blue whale).

Divide the class into teams, no more than 5 students each. Give each team a complete set of prepared vertebrate mystery stories (i.e. should be 5 envelopes, one cut up story for each vertebrate group).

Instruct each team to open one of the envelopes (any one) and pass out the strips of paper to each team member. Divide the strips equally among the team. Leave the other envelopes to the side and do not open them until this story is complete.

Each team member will then read their strips aloud to the rest of the team. Once all the strips have been read, one person will be designated “Lead Detective” and write down clues or team ideas on a piece of paper or chalk board.

Once the team has examined the clues, they write down what type of vertebrate group the mystery story is depicting. After one story is complete, they go on the the next envelope until they are finished with the set.

When the whole class is done with the activity, each team can present their answers to the class.

A discussion about the process can be used as a follow-up.


To make this activity shorter: Give each team only one or two stories to solve.

To make this activity easier: Give examples of animals that represent each of the five vertebrate groups and write names on the board.

To make this activity harder: Don’t let students use the “Just the Facts” sheet or books about vertebrates and separate teams from each other or into different rooms. Take out some of the more obvious descriptions or characteristics from each envelope (e.g., this animal has feathers).


Set up stations around the classroom with pictures, bones, feathers, hair, fur, plastic or toy models, sounds, etc., that represent major characteristics of a vertebrate class. At each station have a question about that object that relates to what vertebrate group it represents. Have each student go to each station and answer the questions about that object. For example, station one may have a bird feather with the question, “Name the vertebrate group that this belongs too. What does this feather tell you about this vertebrate group?” The student answer would be, “Birds. This vertebrate group has feathers so it can fly. In order to fly, they have hollow bones.” (This assessment can also be done with slides of vertebrates instead of the stations.) Include this activity as one piece of overall unit project or evaluation.


Have students discuss and/or research the major differences between vertebrates and invertebrates. Develop a timeline of the evolutionary changes of the vertebrates from one group to the next.

Additional Resources

The "Hoofin' It!" unit explores the natural resource management of Dall sheep in the national parks of northwest Alaska. Students will learn about Dall sheep, where they live, how they have adapted to their environment, and how wildlife biologists study them to understand how to protect their populations within national parklands.

This unit is designed for grades K-12. Many of the lesson plans are appropriate for younger grades, although the later part of the unit are geared towards middle and high school. A class needn't do every lesson in the unit to gain insights into wildlife management - each can be approached as a stand-alone lesson on a particular biology-related topic.

Lesson 1
Hoofin' It! - What Do You Know?

(Understanding taxonomy; k - 12th grade)
Lesson 2
Hoofin' It! - Vertebrate Grab Game

(Exploring types of vertebrates; 3rd - 6th grade) 
Lesson 3
Hoofin' It! Vertebrate Mysteries

(A vertebrate matching game; 8th - 12th grade)
Lesson 4
Hoofin' It! Special Parts

(Animal adaptations; k - 12th grade)
Lesson 5
Hoofin' It! Hard to See?

(Camoflague; k - 8th grade)
Lesson 6
Hoofin' It! - Sheep Maneuvers

(A predator-prey game; k - 12th grade)
Lesson 7
Hoofin' It - Year of the Sheep

(Life cycle of a Dall sheep; 3rd - 12th grade)
Lesson 8
Hoofin' It! - Who's Got My Habitat?

(Habitat and wildlife populations; 3rd - 12th grade)
Lesson 9
Hoofin' It! - Habitat Grid

(Exploring wildlife habitat; k - 3rd grade)
Lesson 10
Hoofin' It! - Through the Seasons

(A game looking at seasonal impacts on wildlife; 2nd - 11th grade)
Lesson 11
Hoofin' It! - Population Art

(Intro to counting wildlife populations; k - 2nd grade
Lesson 12
Hoofin' It! - Population Calculation

(Graphing and analyzing sheep population data; 6th - 10th grade)
Lesson 13
Hoofin' It! - Scavenger Hunt

(A game connecting students to wildlife; k - 6th grade)
Lesson 14
Hoofin' It! - Field Sampling

(How scientists count wildlife populations; k - 12th grade)
Lesson 15
Hoofin' It! The Bean Counters: Mark-Recapture

(Learning to use the mark-recapture method for population surveys; 5th - 12th grade)