Name: _____________________
Peirod: ____________
Owl Replacement Lab
Virtual Owl Pellet Dissection
Website: http://kidwings.com/virtual-pellet/
INTRODUCTION
Owl pellets are the undigested remains of prey ingested by an owl. The owl
swallows its prey whole, and during the process of digestion, the soft parts of the
prey are dissolved and passed on to the intestine for absorption. The hard,
non-digestible parts-bones, teeth, fur, feathers, and chitonous remains of insects
are compressed in the gizzard and passed on to the proventriculus where the pellet
remains until it is expelled. These pellets are not eliminated as feces, but are
regurgitated through the mouth.
Pellets are not found exclusively within the owl families. There are many species
of birds known to regurgitate pellets; hawks, eagles, kites, harriers, falcons, and
even robins are some of the more familiar ones. Out of all types of pellet ejectors,
the efficiency of the process is probably as high in owls as in any other bird.
The Common Barn Owl feeds in early morning and early evening and will usually
produce one to two pellets per day. Glossy black when fresh, the pellet remains
smooth and dark in color when dry. These pellets can provide valuable information
pertaining to the diet of owls. By studying the contents of owl pellets, one may
discover seasonal, regional, and habitat differences and even differences in
individual tastes between owls. Also, pellets can be used to effectively illustrate
the nature of food chains, to demonstrate the role of avian predators within the
ecosystem, and to provide information about the presence and relative abundance
of animals in a particular area. As an educational tool, pellets can also be used to
introduce students to skeletal anatomy and to teach others how to identify and
animal by its skull and jawbones.
The pellets in this Pak are from one of the two owl families, Tytonidae or
Strigidae. Each pellet has been fumigated to eliminate the presence of any insects
and then individually wrapped for preservation. Unless otherwise stated, the
pellets in this Pak are from the family Tytonidae and more specifically, the Common
Barn Owl (Tyto alba).
PURPOSE
1.
To successfully extract prey bones from a barn owl pellet.
2.
To explain how pellets are made and how they can be used to do a prey study.
3.
To label and arrange bones on a chart.
4.
To explain the role of owls in a food web.
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PROCEDURE
1. Open up Internet Explorer and go to this website
http://www.kidwings.com/owlpellets/flash/v4/index.htm
2. Click on the pellet to remove the fur. Fur will automatically move to a pile in
the corner.
3. Click on the bones and drag them to the skeleton. Match the bones correctly
and they will snap in place. Note: Be sure to have your earphones so you can hear the
name of the bones as you click on them.
4. At any time you can click on the label button to turn the labels on or off.
5. When you have correctly matched the bones you will have a chance to download a
certificate that you can print.
6. In order to get credit for your dissection, you must save your certificate and staple it
to the back of the student answer document.
Student Answer Document
Name___________________________Date_______________Class_______________
Answer the following questions from the introduction information.
1.What are owl pellets? __________________________________________________________
2.What happens to the soft parts of the prey? ________________________________________
3.What is the purpose of the gizzard in the owl pellet formation? _________________________
______________________________________________________________________________
4.Where does the pellet remain until it is expelled? ___________________________________
5.These pellets are not eliminated as _________________, but are regurgitated through the __
_________________.
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6.List 6 other birds that are known to regurgitate pellets. _______________________________
______________________________________________________________________________
7.Of all the birds that are pellet ejectors, which type of bird is probably the
most efficient at this process? ____________________________________________________
_____________________________________________________________________________
8.How many pellets does the common barn owl produce per day? ________________________
______________________________________________________________________________
9.What color are the pellets when fresh? ____________________________________________
_____________________________________________________________________________
10.Describe the appearance of a dry owl pellet. ______________________________________
_____________________________________________________________________________
11.The pellets are from what owl family? ____________________________________________
_____________________________________________________________________________
12.Why are the pellets fumigated? _________________________________________________
______________________________________________________________________________
13.How do food webs and food chains differ? ________________________________________
______________________________________________________________________________
14.Why does the number of organisms decrease as you move up the pyramid? _____________
______________________________________________________________________________
15.In terms of energy flow in an ecosystem, why is the amount of energy passed
from one trophic level to the next so small? Since we know energy cannot be
destroyed, account for the loss of energy that occurs between the prey and
the owl.
_____________________________________________________________________________
______________________________________________________________________________
16.We know that about 50% of the energy in an organism is not digested by the
consumer and is simply passed through as waste or feces. Is the energy
stored in the feces lost to the ecosystem? Why or why not? ____________________________
______________________________________________________________________________
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C. Energy Pyramid
An energy pyramid is an ecological pyramid that indicates the amount of energy in each trophic
level. According to the terms of thermodynamics, only about 10% of the energy available
within one trophic level is transferred to organisms at the next trophic level.
1. Assume that the producers in this pyramid, plants, contain a total of 500,000 Calories of
food energy. Label the base of your pyramid with this value.
2. Calculate the amount of energy for the 1˚ consumers by
multiplying the food energy of the producers by 0.10. Write this
value in your pyramid.
3. Complete your energy pyramid by calculating and labeling the
energies for the top two trophic levels.
Example
Energy Pyramid
Anyone who has the link can access. No sign-in required.
STAAR Questions
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1. A science class is planning a field trip to a local farm that has a large pond. Which of the
following lists the order of biological organization from smallest to largest that the students
can expect to find at the pond?
A. Organism, community, population, ecosystem
B. Organism, population, community, ecosystem
C. Population, organism, community, ecosystem
D. Population, organism, ecosystem, community
2. In recent years humans have interfered with the natural balanced within deer populations
in various ecosystems. The interference includes eliminating predators of the deer. Which of
the following statements correctly describes the long-term outcome of this interference?
A
B
C
D
The deer that are the fastest and most agile will survive and reproduce.
The deer population will be too large to be supported by producers.
Other browsing species will thrive and outcompete the deer.
The producers will evolve into species that are less palatable to the deer.
3. As ecosystems move through the stages of succession, the populations of organisms in
them change. Which of the following describes the stage of succession likely to have the
most species diversity?
A
B
C
D
A newly formed volcanic island
An agricultural field that has not been plowed for one year
A temperate forest that has never been cleared by logging
A field that is regularly mowed
4. A student is asked to draw a food web in which the same organism is a primary consumer
as well as a secondary consumer. How should the organism be represented in the food
web?
A The organism must have an arrow pointing from it to a tertiary consumer and
another arrow pointing from it to a decomposer.
B The organism must have an arrow pointing from it to a secondary consumer and
another arrow pointing to it from the top predator.
C The organism must have an arrow pointing to it from a producer and another arrow
pointing to it from a primary consumer.
D The organism must have an arrow pointing from it to a primary consumer and
another arrow pointing away from it to a decomposer.
5. Two populations of mice living in the same forest are separated by a large water-filled ditch.
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After a rainstorm, flooding brings several mice from one population to the other population.
When the mice from the first population reproduce with members of the second
population,which of the following will likely occur?
A
B
C
D
All the offspring will die as a result of reproductive mutations.
The offspring will be forced to leave the second population.
The offspring will be genetically identical to their parent from the first population.
The offspring in the second population will have greater genetic variety.
6. The food web shows the flow of energy through a sagebrush-steppe ecosystem.
Which of these organisms are in a trophic level that receives a larger percentage of the energy
captured by the producers than the percentage received at the bats’ trophic level?
A Mountain lions
B Ground squirrels
C Snakes
D Hawks
7. On March 24, 1989, an oil tanker ran aground on Bligh Reef in Prince William Sound,
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Alaska, and spilled millions of liters of crude oil. The graph shows pink salmon populations in
Prince William Sound from 1970 to 1999.
What do these data suggest about the effect the oil spill had on pink salmon?
A Pink salmon were nearly eliminated after the oil spill.
B Pink salmon populations steadily declined in the 10 years following the spill.
C Pink salmon populations declined and never fully recovered.
D Pink salmon populations seemed to be minimally affected.
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