Topic: LIVING BIOLOGICAL COMMUNITIES IN YOUR OWN BACKYARD

Source: A seminar presented in Central Illinois Saturday Science Education Seminars for Elementary Teachers

Presenter: Laura Johnson-Hechtel Department of Biological Sciences Illinois State University Normal, IL 61790

Funded by: Scientific Literacy Center Illinois State Board of Education 1990-1993

Abstract: The emphasis of Predator and Prey Relations is exposure to the processes, techniques, methods, equipment, and available technology of science. Here, students will be able to develop an understanding of such terms as predator, prey, camouflage, and protective coloration. Also, students will develop understanding of the advantages and disadvantages of flocking behavior. Activities are designed for early grades (1-4), but all can easily be adapted to grades 5-8. Tables and graphs are provided as samples to be used or modified as desired.

BIOLOGICAL COMMUNITIES (Teacher Copy)

INTRODUCTION

Predator and prey relationships have existed among animals of the earth for thousands of years. Since these relationships influence every organism on earth, children need to begin to understand these relationships.

Objectives

At the end of this lab, the student will be able to:

1. Understand such terms as predator, prey, camouflage or protective coloration, 2. Understand the advantages and disadvantages of flocking behavior.

Background

Terrestrial habitats in temperate climates seem to "shut down" even more completely than aquatic habitats in winter. The stream we sampled could still hold plants and cold-blooded animals because part of the water remained above freezing even when the air temperature was below freezing. Terrestrial organisms, other than the warm-blooded birds and mammals, have to "shut down" in winter because the subfreezing air temperatures will freeze exposed tissue and stop photosynthesis in plants. As a result of freezing air temperatures in winter, there is no production or increase in plant or invertebrate biomass in winter.

At the start of winter there is a set quantity of plant and insect biomass in a field or forest. It can only stay constant or decrease until spring allows new growth. The warm-blooded birds and mammals have to depend on this biomass to maintain themselves and their warm-blooded condition through the winter or else migrate or hibernate. In this laboratory exercise we will try some experiments to demonstrate the effects of foraging behavior of warm-blooded animals on the overwintering plants and insects.

At the same time, these foragers are threatened by becoming a meal themselves. Their natural predators may hinder the foragers' ability to get food. This laboratory exercise will also examine means in which prey have adapted in order to avoid predation.

BIOLOGICAL COMMUNITIES (Teacher Copy)

LESSON 1 GENERAL FORAGING

Materials plot of ground 10' x 10' 100 pieces of bright macaroni scattered evenly over each plot small cup

Procedure

In this experiment, you are a bird foraging in an area 10 x 10 foot square. The type of insect you eat is a "u" shaped bug named Macaronus elbos. Your nest is in the center of the territory, so place a cup there. In this world, a day lasts 60 seconds. In order to survive, you must find 5 bugs per day (60 second) and return them to the nest or else you die. To see how good a forager you are, another student will time you and record the number of seconds it takes you to find 5 bugs each day until you die of starvation. Compare your results with other birds.

BIOLOGICAL COMMUNITIES (Teacher Copy)

LESSON 2 NOT ALL BUGS AND BIRDS ARE CREATED EQUAL

Materials plot of ground 10' x 10' 50 pieces of bright elbow 50 pieces of shells 50 pieces of swirl macaroni scattered evenly over each plot

Procedure

Not all birds have the same needs and not all bugs have the same caloric value. In this experiment, you are a bird again, in one of the following conditions: (1) normal, (2) raising a brood of 6, (3) raising a brood of 3, or (4) with a broken leg. Your instructor will assign a condition to you. You also forage on 3 species of bugs: (1) Macaronus elbos, (2) Macaronus shellus, and (3) Macaronus swirlus. The caloric value of each differs, meaning you do not need to find as many of some, while more of the other in order to fulfill you caloric needs. If you are a normal bird, you must find 50 calories of food/day. If you have a brood of 6 or 3 young, you must get 110 or 80 calories per day respectively. If you have a broken leg, you must hop around on one foot and find 50 calories/day. Each bug provides different caloric needs: M. elbos provides you with 10 calories per bug while M. shellus provides you with 20 calories per bug. M. swirlus provides you with 5 calories per bug. You may forage on any combination of food as you wish. You must take each individual bug back to the nest one at a time if you are raising young and you must meet your caloric need each day or you will die of starvation. Proceed as before, and have your partner record the number of seconds it takes to find the required amount of food each day until you starve. Compare your results with other classmates.

BIOLOGICAL COMMUNITIES (Teacher Copy)

LESSON 3 PROTECTIVE COLORATION

Materials one plot of ground 10 feet on a side for each of 4 students 50 pieces of orange, green, purple, and yellow elbow macaroni

Procedure

Over evolutionary time, several animals have developed protective coloration, or camouflage in order to hide from their predators. Examples are everywhere: Leaf hoppers, walking sticks, Woodcock, snowshoe hare, etc. To illustrate the advantages of camouflage, or bug, M. elbos can be found in 4 colors: purple, green, orange, and yellow. Spread 50 bugs of each color over a 10 x 10 foot plot. This time, 4 birds will forage in each plot. The middle of one side of the plot will be considered the nest site for each bird. Each bird's partner is responsible for timing the bird's success. At the end of the experiment, count the number of each type of bug and record your results. Compare your results with other students. What evolutionary implications does this have on the preferred color of bugs?

BIOLOGICAL COMMUNITIES (Teacher Copy)

LESSON 4 PREDATOR DEFENSE BY FLOCKING

Materials one plot of ground 10 feet on a side for each student 100 pieces of macaroni one plot of ground 20 feet on a side for each group of 4 students 400 pieces of macaroni

Procedure

Boy, do you birds have trouble now! Several Hawks have come into the area, and they're hungry for bug eating birds. To illustrate the advantages of flocking behavior in birds this experiment will be done in two parts.

1. Individual birds are to forage in 10 x 10 foot plots on 100 M. elbos as done in the first experiment. But now, you must also watch out for hawks. Our hawks will be perching approximately 60 yards away. They will try to attack the birds by running 30 yards towards the birds. If they come within 30 yards of the birds, before a bird sees them, they have successfully made a kill. The individual birds must watch for the hawks and silently signal to their partner when they see the hawk approaching. Among the birds not seeing the hawk approach, one will be chosen by the hawk as its dinner. Again, timers need to record the time it takes to find food each day and the number of days the bird survives.

2. Now birds are allowed to forage in groups of 4 on 400 bugs in a plot 20 x 20 feet. As before, they must find 5 bugs/day and return to their nest, but they must also cooperate in looking out for hawks. Hawks will have the same approach as before, but the birds are allowed to give warning calls to their flock. The hawk must again get within 30 yards of the birds before a warning call is sounded in order to get a successful kill. Timers are again needed to record the amount of time needed per day to forage and the number of days survived by the forager. Compare your results here with foraging alone.

BIOLOGICAL COMMUNITIES

DATA SHEET

General Foraging

60 ______________________________________________________________________________ ______________________________________________________________________________ 50 ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 40 ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 30 ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 20 ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 10 ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 0 ______________________________________________________________________________ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Seconds Day

Day Time Day Time Day Time Day Time (in sec) (in sec) (in sec) (in sec) 1 ________ 6 ________ 11 ________ 16 ________ 2 ________ 7 ________ 12 ________ 17 ________ 3 ________ 8 ________ 13 ________ 18 ________ 4 ________ 9 ________ 14 ________ 19 ________ 5 ________ 10 ________ 15 ________ 20 ________

BIOLOGICAL COMMUNITIES

DATA SHEET

Not all Birds and Bugs are Created Equal Condition: __________________________

Seconds Day

BIOLOGICAL COMMUNITIES

DATA SHEET

Protective Coloration

Seconds Day

Number of each bug color: Purple: ________ Green: ________ Yellow: ________ Orange: ________

BIOLOGICAL COMMUNITIES

DATA SHEET

Predator Defense by Flocking: Foraging as an individual

Seconds Day

Number of days survived: _______________________ Number of birds killed by hawks: _______________________

BIOLOGICAL COMMUNITIES

Predator Defense by Flocking: Foraging in a flock

Seconds Day

Number of days survived: _______________________

Number of birds killed by hawks: _______________________

BIOLOGICAL COMMUNITIES (Teacher Copy)

LESSON 5 PREDATOR AND PREY BEHAVIOR DURING FLOCKING

INTRODUCTION

Objectives

After completion of this lab, students will be able to:

1. Understand such terms as predator, prey, flocking, adaptation.

2. Describe why flocks are an adaptation to avoid predation.

Background

Earlier, we considered the advantage of foraging in a group or flock as a means of giving warning calls when a predator is approaching. In this part of the laboratory we will demonstrate how flocking, such as you see in minnow, starlings, and some antelopes, might provide protection for the prey by confusing the predator.

Materials per group 20 white wiffle balls (golf ball sized) 5 pink wiffle balls

Procedure

1. The class will divide into groups of 7 persons each. In each group one person will be the predator, 5 the prey, and one person the recorder.

2. Each `prey' takes randomly 4 balls from the container.

3. The predator (catcher) stands 2 meters from a wall and the prey station themselves in a semi-circle 3 meters away.

4. The recorder stands behind the predator so he/she is only visible to the prey.

5. The recorder signals when the prey `provides' food by tossing a ball toward the predator. The balls should be thrown in a gentle arc.

6. The predator can drop the balls as soon as they are caught and mentally tallies the number caught.

7. A total of 20 balls are thrown during each of the following volleys:

a. 1 ball every 3 seconds (Recorder points to one of the prey every 3 seconds in a random order until all 20 are thrown.)

LESSON 5 Continued

b. 1 ball every 2 seconds

c. 1 ball per second

d. 2 balls per second (Recorder points to random pairs)

e. 5 balls per second (all prey throw a ball simultaneously every second)

f. 10 balls per second (all prey throw 2 balls simultaneously every second)

g. 20 balls per second (all 5 prey throw all balls simultaneously)

8. The recorder tallies the total number of balls caught after each of the 7 volleys in Table 1 below.

9. Repeat e., f., and g. above with 5 pink wiffle balls (1 per prey) and 15 white balls. The pink balls are meant to simulate sick and old prey that would appear distinctive from most members of a milling herd, flock, or school. After each volley the recorder should tally the number of pink vs. white balls caught in Table 2.

10. Now plot the results from Tables 1 and 2 on Figure 1. Represent the percent white balls caught with a solid line and the percent pink balls caught with a slash line.

Discussion

11. What was the general predator success as "flock density" increased? Why?

12. Our results seem to indicate that the larger the flock, the more likely individuals within the flock are safe from being caught. This seems to make one believe that flocks should be infinitely large. Yet, flocks usually are of certain maximum sizes, depending on the species of animal. What factors might favor flocks? What factors might limit flock size?

BIOLOGICAL COMMUNITIES

Table 1. PREDATOR SUCCESS WITH DIFFERENT FLOCK DENSITIES

Flock Density (volley rate) Number Caught Percent Caught

a. 1 ball/3 sec

b. 1 ball/2 sec

c. 1 ball/1 sec

d. 2 balls/1 sec

e. 5 balls /1 sec

f. 10 balls/1 sec

g. 20 balls/1 sec

Table 2. RELATIVE ESCAPE SUCCESS OF NORMAL VS. ODD FLOCK MEMBERS

Flock Density Pink Balls Caught White Balls Caught (volley rate) No. % No. %

5 balls/sec

10 balls/sec

20 balls/sec

100 � Figure 1 � 90 � � 80 � � 70 � � 60 � � 50 � � 40 � � 30 � � 20 � � 10 � � 0 0.3 0.5 1 2 5 10 20 Prey available/second