Last updated: May 9, 2024
Lesson Plan
Oh, Caribou!
Caribou are a great way to learn about the arctic.
NPS Photo (Public Domain)
- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
- Subject:
- Science
- Lesson Duration:
- 30 Minutes
- State Standards:
- AKSS: 2-LS4.1, 3-LS4.3
- Additional Standards:
- • Alaska Content Standards for Health: HL.B.1.
• National K-12 Physical Education Standards: S1.E1., S3.E2., S4.E1., S4.E4., S4.E5. S4.E6. S5.E3.
Essential Question
How do limiting factors influence wildlife population sizes over time?
Objective
• Students will be able to identify the four elements of good habitat that species need to survive (food, shelter, water, and space).
• Students will understand how changes in suitable habitat influence wildlife populations.
• Students engage safely, respectfully, and willingly in physical activity.
Background
• Western Arctic Caribou Herd Working Group website: www.westernarcticcaribou.org
• Alaska Department of Fish & Game web site: www.adfg.alaska.gov/index.cfm?adfg=caribou.main (Click on “Range and Habitat” tab to view map of 32 identified caribou herds in Alaska.)
Preparation
Time needed: Twenty to forty minutes for multiple rounds, including time for instructions(Allow more time for younger students and/or larger class sizes.)
Materials / space needed:• Large, open playing area (e.g. gym or outdoor area).
Other considerations (seasons, etc.): • This activity can take place outdoors or indoors. • This activity is most effective at illustrating biological principals when done with large groups (i.e. 20 or more students) but will work with as few as eight.
Materials
Procedure
• Have students count off by fives.* All number 1s are to line up at one end of the playing area; they will be caribou. Numbers 2, 3, 4, and 5 line up across the other end of the playing area; they represent caribou habitat components (food, water, shelter, and space).*Alternatively, the instructor can divide the class into two groups of approximately 1/5 of the students and 4/5 of the students to represent caribou and habitat, respectively. (Numbers 2, 3, 4, and 5 need not be distinguished as separate groups; number assignments are only to establish starting roles.)• Explain instructions and rules:
- Each student in the caribou group will represent 10,000 caribou, to represent a herd size of 200,000300,000 individuals (for a class of 20-30 students), which is consistent with the current size of the Western Arctic Caribou Herd.
- Each round of the game will represent one year, during which the caribou must find sufficient food, water, shelter and space in a suitable arrangement (i.e. habitat) to survive and reproduce.
- Each student in the Habitat group will choose one of the four habitat elements (food, shelter, water, and space) to represent at the start of each round. He or she must be the selected habitat element for the entire round but may choose to be a different habitat in each successive round.
- Students will use symbols to indicate their respective habitat elements. Ask all students (including Caribou) to practice making each of the following gestures with you as you describe them:
- To represent food, students will hold their hands over their stomachs.
- To represent water, students will hold their hands over their mouths.
- To represent shelter, students will hold their arms over their heads and clasp their hands (like a tent or roof).
- To represent space, students will spread their arms out to the sides.
- Caribou will use the same hand symbols to indicate which habitat component they are searching for during each round. As for the Habitat group, each caribou must be the selected habitat element for the entire round, but they may choose to be a different habitat in each successive round.
- At the beginning of each round, students representing both Caribou and Habitat will be lined up across their respective end lines with their backs to each other. When instructed by the teacher, each student will decide which habitat symbol to display during the upcoming round.
- Neither students in the Habitat group nor the Caribou group will confer with each other about which symbol they will make; each student makes his or her own selection at the beginning of each round and does not disclose this information until given the instruction to turn around display their symbols.
- When the instructor indicates, the students will turn around to face each other, displaying the appropriate symbol for the habitat element they have selected. Students in the Caribou group will look for a Habitat student who is displaying the same symbol that they are and will run to tag him or her. (The habitat components will stay where they are during this step.)
• Caribou who find and tag the corresponding habitat element (teacher might need to validate this for younger students) will return to the Caribou starting area accompanied by the habitat student, who will join the herd as another caribou for the next round.** For older students (e.g. 5th-6th graders), the instructor can choose to make the activity more biologically accurate, albeit slightly more complicated by limiting the number of new caribou added to the herd to reflect births by female caribou (cows) only. To do this, ask the students to pause once the caribou have found their matching habitat element. Use a different “rule” to determine which students in the caribou group represent female (cow) and male (bull) caribou in each round. (The most obvious example would be to determine that for the first round that girls are female caribou and boys are male caribou. In the successive rounds, however, the teacher might decide that students wearing blue are females and all other students are males, or that students with brown hair are females and students with blond, red, or black hair are males.) In each case, those students who represent female caribou and who have found the habitat element they needed during that round will bring their habitat element back to the caribou starting area; the habitat element will become a new caribou for the next round of the activity. However, those students who represent male caribou and find the appropriate habitat element will survive the round but will not add a new caribou to the herd (i.e. give birth). The male caribou who finds the habitat element he tagged will simply return to the caribou starting area to participate in the next round, and the habitat element he matched up with will remain as a habitat component for the next round.
• If a caribou is not able to find and tag a student representing the habitat element he/she is searching for, he or she will not survive that round. In this case, the caribou will become a habitat element for the next round. (This happens in nature when an organism dies and replenishes the ecosystem with nutrients through decomposition of its body.)
• Continue the activity for multiple rounds (“years”), such that you are able to observe fluctuations in the size of the “herd.” Encourage the students to observe what is happening to the size of the caribou herd and the availability of habitat to support it. Pause the activity periodically to discuss the patterns that emerge and connect the activity to the ecological concepts described under the Discussion Topics section.
• Optional modification: Instead of running, the instructor may change the instructions to reinforce other locomotor skills (e.g. skipping, hopping, dribbling a ball with hands or feet) that students have been working on.
• Optional extension: Incorporate a predator, such as a wolf, into this activity. The predator may intersect and tag the caribou between the starting line and the habitat component they are seeking, in which case the caribou and the habitat component become food for the wolf, leading to an increase in the size of the wolf pack.
Vocabulary
Key concepts: Carrying capacity, dynamic equilibrium, population fluctuations, predator-prey relationships, population, habitat
Assessment Materials
Discussion Questions• Did the number of caribou go up or down or both? (This question was directly lifted from NOAT lesson plan.)
• What do animals need to survive? (This question was directly lifted from NOAT lesson plan.)
•Are wildlife populations static, or do they tend to fluctuate? (This question was directly lifted from NOAT lesson plan.)
• Are habitat elements that are suitable for one type of animal (e.g. caribou) the same as those that are needed by another type of animal, e.g. a bear?
• Over the course of several rounds, the size of the caribou herd will usually increase as more caribou calves are added to the herd by caribou who find the habitat element they are searching for, allowing them to survive and reproduce. At some point, however, the herd will increase to the point that there will be more caribou than habitat elements. What did the students observe with regard to the herd size after this point? How can they explain the observed relationship biologically? Can they think of a natural process that might have prevented the herd from growing so fast that it “overshot” its carrying capacity? (Natural predators such as wolves, harvest by humans, disease)
• There was an element of chance in this activity, because nobody knew ahead of time which and how many habitat elements would be available in a given year. This chance element is applicable to real-world natural systems, because they are subject to changes that can happen either suddenly or gradually and that can be either good or bad for a particular wildlife species, population, or individual. Recall a round (“year”) from our game when many caribou could not find the habitat element that they were searching for. For example, was there a year when most or all of the habitat elements happened to choose to be shelter but when the caribou all chose a different habitat element, such as food, water, or space? What might this particular situation represent in nature? (This situation could represent a drought year during which water and food were scarce.) In the game, what happened to the caribou herd in that year? (It decreased in size, as many of the caribou failed to survive and/or reproduce.) Did the population increase again in subsequent years? What might have been different if the situation described above, representing a drought, happened several rounds in a row, or every other round? How would the size of the herd be affected? (If there were several rounds in a row during which the caribou couldn’t find the habitat element that they needed, the herd size could plummet, and it would take a long time for it to increase again. It is even possible in our game that the entire herd could die off if the caribou couldn’t find the habitat elements they needed a few rounds in a row. If a drought situation (or other type of disturbance or extreme event) happened every other round, or every three or four rounds, the population might never grow as large as it once was. Because of changes in the system that persist over a longer a period of time, the carrying capacity for the herd changed (decreased in this case).
• What type of growth did the herd experience in this activity? (Geometric growth; a larger number of individuals was added each year according to the starting size of the herd. For example, if two caribou survived, two calves were added,** causing the population size in the next round to be four caribou. If all of those caribou survived and reproduced, there would be four more caribou added for a starting population of eight in the next year, etc.) Ask students to describe what they noticed and help them make connections to concepts they might have studied in math class regarding geometric versus algebraic (exponential versus linear) growth.
• What were some things about the game that the students thought were not realistic, that is, that did not reflect how biological systems work? Can they think of ways that the game could incorporate these factors to more accurately represent population dynamics? (For example, many calves die in their first year of life, but in this game we are treating every caribou as having the same chance of survival in a given year.)