OVERVIEW:
Several of the workshops have touched on ecosystems and plant-animal interactions.
In this workshop we will go into predator-prey interactions in more detail.
Pairs of students will be assigned a particular type of predator. Students
will examine the behaviors of zooplankton (“prey” in test tubes),
and then observe their particular predator and share observations with the
other pair of students at the work station. Students will then follow the
procedures for their assigned predator/prey experiment. While the experiment
is “in progress” (about 40 minutes), student will play a role-playing
predator-prey game. Students will collect data on the number of surviving
prey, and share results during Science Seminar.
TERMS
USED:
Process related—observation,
hypothesis, comparison, classification, prediction, independent variable,
dependent variable, inference, data
Content related—camouflage,
carnivore, consumer, decomposer, community, ecosystem, food chain, food web,
herbivore, niche, omnivore, predator, producer, refuge
OUTLINE
OF ACTIVITY:
This month’s workshop is an extension of the Animal Behavior activity,
in that it goes into more detail on predators, prey, and basic food web concepts.
After reviewing content of Activity 4, students will see a presentation on
SREL researcher Whit Gibbons, who studies reptiles, amphibians, and their
habitats. Whit is a herpetologist. The content emphasized in the slides will
be trophic levels (i.e., producers, primary consumers, secondary consumers,
decomposers) and how organisms interact among trophic levels to form food
webs. Adaptations that both predators and prey have will also be illustrated.
Activity1—The hands-on experiment on predation will use organisms common to local Carolina bays: zooplankton (prey), and larval salamanders, adult salamanders (newts), and fish as predators. Students will go to work stations in groups of four. Each pair of students will examine the effects of a selected predator on its prey. Predator treatments in the experiment include: male Betta (Siamese fighting) fish, larval marbled salamanders, and adult red-spotted newts. Each pair of students will begin by observing the prey and the predator separately (pre-counted zooplankton will be given to them in test tubes; predators will be given to them in the observation chambers). Then prey will be added to the observation chamber. Students will record observations, and then cover the chambers and set them aside to begin Activity 2 (see below). After completion of Activity 2, students will re-examine their chambers, count the remaining zooplankton, and calculate the number eaten by the predator. These data will be used to determine the effects of different predator treatments on prey.
Activity 2—Students
will assume the role of “predator” and be asked to locate appropriate
prey items that instructors have placed throughout the room. Predator categories
include: bobcat, Marsh Hawk, alligator, bullfrog, kingsnake, and praying mantis.
Prey categories are snakes, frogs, mice, fish, insects, and rabbits. Students
will “stalk”, “kill”, and “eat” as many
prey as they can in five minutes. Individual predator successes will be compared,
and concepts related to food quality, energy allocation, and prey adaptations
discussed.
