Owl Pellet Lab
Before you do this lab, discuss energy flow through an ecosystem using pages 67-73. The owl lab shows a food web and the activities explain the different trophic levels in a food web and the niches of the different organisms involved. The information for this lab is found in the Owl Pellet Lab Kit that should have been purchased for this concept. Go over background information on owls and owl pellet formation as a prelab activity. Emphasize to students that an owl pellet is the regurgitation of what the owl ate the night before, so the pellet represents one day of the owl’s meals. Follow instructions for activity 1 and have them use the key for identifying the prey. The main activity is Activity 3. Students draw arrows and color the owl food web page. You can grade them on this page with criteria for identification of the prey and specific bones. Also, you should grade the questions on the worksheet on the next page.
Some extensions can include tallies of the different prey per class and for all the IS classes at your school. Your students could articulate the skeletons for display and find pictures and do a report on the species.
You can save the skeletons for later when mammals are studied in the second semester or, if you have Zoology or Ecology class, comparisons of the different skeletal remains of the same or different species could be made by mass or dimensions of the bones.
OWL PELLET LAB WORKSHEET
Answer the following questions
1. An owl is a raptor. What does that mean?
2. Name five structural applications that make an owl so successful.
3. If an owl is considered a third-level consumer, what % of energy is available for life processes? How does this affect how many prey an owl must eat? Explain your answer.
4. 99% of a panda’s diet is bamboo. What can this mean to the panda?
5. Do owls have one food source? What does that mean for the owls?
6. Using the owl food web you have constructed, answer the following questions:
a. What is the ultimate source of energy?
b. Name a producer
c. Name a herbivore
d. Name a carnivore
e. Name an autotroph
f. Name a heterotroph
g. Name a first order consumer
h. Name a second order consumer
i. Name a third order consumer
2. What would happen in the owl food web if a drought destroyed a lot of the vegetation in the owl habitat?
3. What would happen if most of the owls in the food web were killed by hunters?
OWL PELLET LAB
Post Lab Activities
After finishing the lab, review and extend the concepts of energy pyramids and biomass pyramids. Explain what happens to the energy remaining and lost as you proceed up each trophic level in an energy pyramid: you are getting about 10% of the energy from the lower level Thus predators at the top of the pyramid have to eat many prey to stay alive at the top of the pyramid. The same thing is true for biomass pyramids. So top predators at the top of the food pyramid are eating a lot of prey animals.
Biomagnification:
Explain that not only energy and biomass can move up the pyramids, but also pollution. Page 152 introduces and gives examples of biological magnification.
If pelicans are at the top of the food chain, they are going to eat a lot from the lower level which ate a lot from their lower level etc. This shows how certain chemicals become concentrated to dangerous and lethal doses at the upper levels of a food pyramid. Also includes humans and the amount of mercury in some of our food fish (tuna) that are also at the top of food pyramid.