Lesson – Oh Deer!

This activity demonstrates how populations fluctuate with the availability of resources within a habitat. It will teach the students that a good habitat (one with plenty of food, water, and shelter) is essential to wildlife survival, and a population will continue to increase until these basic needs are diminished. This lesson is adapted from the Project Wild lesson, Oh Deer.

Time Allotment

one 50-minute session

Materials

Per Student:

  • Deer Population Graph (attached)

Per Classroom:

  • playing area (classroom or schoolyard)
  • chalkboard or poster board
  • rope (about 50 ft.)

Lesson Assessment

When evaluating the lesson, consider the following: did the student complete the worksheet properly? Can they discuss and identify the components of within a habitat without prompting? How much assistance do they need to correctly identify the habitat components? Also, can they explain the pattern of population increase and decline, depending on how much is available within the habitat? Do they realize that fluctuations in wildlife populations are natural occurrences as ecosystems undergo a constant change. These questions can often be answered during the discussion following the lesson.

Procedure

Tap Prior Knowledge

  1. Begin this lesson with a brief discussion on habitat. Ask the students if they know what the word habitat means. After brainstorming, mention that a habitat is simply the place where a plant or an animal lives. All plants and animals have habitats, even humans.

Share with Neighbor

  1. Ask the students to discuss with their neighbors the importance of habitats, using deer as an example. What are the three main things deer need to live? The answer: food, water, and shelter, though the groups may include others. When the class gets back together, discuss the groups findings and the importance of food, water, and shelter as components of all habitats. Another important component of all habitats, space, will be ignored here. However, students should not forget that all animals and plants need a certain amount of space to survive!

Engage Students in a Hands-On Activity

  1. Spread out a length of rope in a line either on the classroom floor or school yard, depending on where you hold this activity. Then, have the students stand in a line on top of the rope. Number the students off by fours, and have all the 1's step forward and form a line parallel to, but well away from the rope; all the 2's, 3's, and 4's stay on the rope.
  2. At this point the 1's become the deer, and the 2's, 3's, and 4's become the habitat. Remind the students that all deer need a good habitat to survive; a habitat with plenty of food, water, and shelter. Explain to the deer that their job is to search for one of these three "needs" within their habitat. Explain to the habitat students that they will all become one of the three things that deer need to live, and their role will be to supply the deer with what they need to survive!

At this point, all of the students, both the deer and the habitat, must choose a habitat component. The deer will be looking for the component (such as food) they chose and the habitat student will be providing one of the three components. The deer and habitat students will let others know which they have chosen by displaying a sign to represent their selections. The signs for the various components are as follows:
a) Food : hands over stomach
b) Water : hands over mouth.
c) Shelter : hands over head.

  1. Demonstrate the signs, so there is no confusion. Then have the students turn around so that the lines are back-to-back. Tell the students to choose their habitat components.
  2. Give the students a few seconds to get their hands in place. When the student are ready, count ''one....two....three''. At the count of three, the deer and the habitat turn to face each other, displaying their signs. When a deer sees a habitat component with a matching sign, it should walk over and grab it! At this point, the chosen student becomes part of the deer population and follows the deer back to the deer community (survival = reproduction). A deer that fails to find all of its habitat needs "dies" and becomes part of the habitat. At the end of the round, the "dead" deer become part of the habitat, and the consumed habitat becomes part of the deer community.
  3. Habitat components must remain in line until a deer needs them. If they are not used in a round, they remain habitat, and can change their habitat type in the next round.
  4. Record the total number of the deer (including the new ones added from the habitat) on the worksheet after each year.
  5. Repeat this process for several rounds, and keep track on a separate sheet of paper the number of deer at the beginning of each year and the number of deer end of each round for eventual analysis.
  6. At the end of the game, gather the students together to discuss the activity. Encourage them to talk about what they experienced and observed. For example, at the beginning of the game, there was plenty of habitat for the deer population; the deer had more than enough to live. After a few rounds the number of deer grew while the amount of habitat diminished, causing some of the deer to die of starvation or thirst, or lack of shelter. Then, after some of the deer died off, the habitat became larger once again, and was able to provide for a growing deer population.

Introduce Scientific Principle

  1. Population numbers can increase or decrease depending on the availability of resources. With many resources, animal populations continue to grow. When their numbers become too great, and they run out of resources, animals die and their numbers decline. The maximum number of animals in a population that can be sustained by a habitat is called the carrying capacity.

Scientists monitor population numbers to determine how healthy a population is (too many or too few animals is not good). If it a species where they want more or fewer individuals in the population, they may add or remove resources. For example, to protect an endangered hawk population, scientists may try to protect habitat to increase their numbers. Scientists try to decrease populations of rats, which cause many problems in cities, by encouraging residents securely package their garbage, removing the rats' food source.

Relate Activity and Concept

  1. Using your records, calculate the net gain or loss between the beginning or end of each year. Which years showed the biggest gain in numbers? The biggest loss? What size was the population before these events? Why did the population rise or fall?
  2. In pairs or small groups, have the students discuss how humans effect this process. Ask the groups to share examples of things that increase or decrease animal populations.

Background Information

As you watch the students sometimes the students might copy each other resulting in several students showing the same sign. When this happens, don't encourage it, but remark on it as a special situation. For example, if all the students in habitat decide to be shelter, that could represent a drought with no available food or water. Many of the deer should die in this situation.

You'll also notice that the deer may tend to run towards the habitat, competing for the remaining food, shelter, and water. Holding the game outside is more accommodating in this respect. Always discourage running when holding the game indoors.

One of the greatest difficulties that students find when playing the role of the deer is "dying." For example, there may be only 4 habitat pieces in a round, yet all deer claim to have survived. If this happens, discuss the situation. Could such a thing happen in real life? Is "dying" really such a bad thing? What happens when an animal dies? (it becomes part of the habitat so that more can survive later).

Animals, like people, have things they need to survive. These needs include: food, water, shelter, and space. Everything that they need must be found in their habitat, or where they live, or the animals will not survive. Habitats are often classified by the weather conditions, such as rain, and the plant life found in them.

A population is defined as a group of individuals that are found within a given area. For example, you can talk about the population of grey wolves in YellowstoneNational Park, or the population of squirrels or birds in your neighborhood. The number of animals in this population are influenced by a variety of factors. These factors include the availability of food, shelter, and water. They can cause the population size to increase or decrease over time. In many cases it is difficult to maintain a stable, or the same size, population over time. As humans alter their environment, we become more interested in how population can be increased (in the case of endangered species), decreased (in the case of disease-carrying animals), or remain the same (at a healthy level).