5E Inquiry Lesson Plan
Title: Barn Owl Pellet Lab
Grade level: 7th
National Standards: Interdependence of Life
The student will understand that within ecosystems, complex interactions exist between
organisms and the physical environment.
Animals eat plants or other animals for food and may also use plants (or even other
animals) for shelter and nesting.
Some source of energy is needed for all organisms to stay alive and grow.
Alabama Course of Study:
Standards 1 and 7
Objectives:
The student will be able to dissect an owl pellet.
The student will be able to identify the animal skulls and other bones found in the pellet.
The student will view a Power Point Presentation and participate in an interactive class
discussion to learn basic facts about the barn owl, food chains and food webs.
Procedures
Materials:
Owl pellets; metric ruler; forceps; wooden probes; hand lens; glue stick; 8 cards labeled
with the following bone groups: skull, jaw, scapula, fore limb, hind limb, pelvic, rib,
vertebrae; balance scales; paper plates; zip lock bags; pH paper; distilled water; clear
plastic containers; 4 bone charts and 6 hand-outs.
ENGAGE:
1st Day:
Pre-Test; 3-D Presentation
Time: 15 minutes
EXPLORE:
1st Day:
Complete Handout #1.
Weigh and measure both owl pellets. Record your findings on weight/measurement on
Handout #2. Answer questions 1 and 2 on Handout #2.
Time: 30 minutes
2nd Day:
Record on Handout #2 the predicted number of skulls for each pellet you weighed and
measured on Day 1. Answer question 3 on Handout #2.
Dissect the owl pellets and record the observed number of skulls on Handout #2 for
your individual pellets. Does your prediction correlate with your observation after
dissection?
Save and store bones in zip lock bags for the next day’s activity.
Use pieces of the fur/hair of each dissected owl pellet to determine the pH of the pellet.
Record your results and answer questions 1, 2, 3 and 4 on Handout #3.
Time: 45 minutes
3rd Day:
EXPLAIN:
After all groups have completed their dissections, exchange results with the other
groups and record findings on Handout #4 and answer questions 1, 2, 3.
Use the data from your combined class data (Handout #4) to complete Handout #5.
Using the data from Handout #5 construct a graph (Handout #6) showing the frequency
distribution.
Time: 30 minutes
3rd Day con’t.:
ELABORATE:
Show Power Point Presentation along with interactive class discussion.
Time: 15 minutes
4th Day:
ELABORATE con’t.:
Each group will arrange all the bones from both pellets on the 8 bone cards.
Each group will construct a Food Chain with a one producer and at least 4 consumers
based on your dissection (use the back of Handout #6 for your Food Chain).
Time: 35 minutes
EVALUATE:
Post Test
Time: 10 minutes
Safety:
N/A
Prepared by: Dr. Debbie Payne, Ruth Liddell, Shirley Scarbrough
Alabama State University, Math and Science Partnership (MSP)
2012
OWL PELLET INTRODUCTION and INSTRUCTIONS
Owls are predators. Most larger owls feed on small mammals, birds and
reptiles. Owls usually swallow their food whole or in large chunks. The owl’s digestive
system cannot digest fur/hair, bones, teeth, feathers, etc. Rather, a portion of the owl’s
stomach compresses these parts to form the pellet. The pellet does not pass into the
intestine of the owl; instead, the owl regurgitates (coughs up and spits out) the pellet. In
an owl pellet, in addition to bones, you may find the exoskeletons of insects, feathers,
fur/hair, fish scales, small white grubs and various types of seeds.
By examining what is found in the pellet, you, as well as scientists, can tell what and
how much an owl has eaten. In addition, when the acidity or alkalinity of the pellet is
measured, predictions can be made about the habitat and/or environment and the
possible impact on the owl’s food sources.
1. READ the INTRODUCTION
2. Check your Owl Pellet Study Kit to make sure you have:
2 – Wooden probes
4 – Laminated bone charts showing types of bones commonly found in owl pellets
1 – Hand lens
1 – Pair of forceps
2 – small ziplock bags, labeled Pellet 1 and Pellet 2
1 – Metric ruler
Plastic containers 1 and 2 and 2 pieces of pH paper
3. Your teacher will provide:
Scales
Paper plates, Glue Stick
2 – Owl pellets per group
Distilled water
6 – Handouts associated with the Lab that each group will complete with the required
data and questions to be turned in
8 – Bone charts to be assembled using bones obtained from the pellet dissections
PROCEDURE
1. Before you begin the dissection, complete and turn in Handout #1.
2. Unwrap the aluminum foil from each pellet. Carefully weigh and measure the length
and width of each pellet and record data in Handout #2. Read question 1 and answer in
the space provided. Observe the outer surface of the pellet and answer question 2.
You cannot complete this handout until you have completed the dissection. After
completing the dissection, finish the table on Handout #2 and answer question 3.
3. Place each unwrapped pellet on a paper plate labeled Pellet 1 and Pellet 2. Using
your fingers or a probe, very gently break each pellet in half. You must be very careful
when teasing out the bones from each pellet; the bones are easily broken.
4. Continue to separate small sections of each pellet and remove fur/hair to disclose
the bones. Remember: the bones are small and delicate, so you must be very slow and
careful in extracting any bones from the pellet. Also, if your pellet has a skull, you will
need to pick away all the fur/hair in order to expose the entire skull. You can then try to
identify which type of animal the skull came from using your Owl Pellet Bone Chart
which shows skulls from four different animals.
5. Gently rub small pieces of each pellet between your fingers until you have
completely taken apart and examined the entire pellet and removed all the bones.
There are many tiny ribs and vertebrae that should not be overlooked. You have to be
very focused so that you do not miss any bones. Set aside any other materials you find
in each pellet that are not bones or fur/hair. You will record these on Question 3 on
Handout #2.
6. Once you are certain that no bones remain in the fur/hair, place the bones from
Pellet 1 into the ziplock labeled Pellet 1 and the bones from Pellet 2 into the ziplock
labeled Pellet 2. These will be saved for an activity later in which you will arrange
various types of bones on Bone Charts.
7. After you have completed the dissection, record the number of observed skulls from
each pellet on Handout #2.
8. Using your fingers, pulverize (rub your fingers together) a small amount of the
fur/hair from Pellet 1 and place into the plastic container 1 and a small amount from
Pellet 2 and place into plastic container 2. Pour the distilled water over each pulverized
pellet; stir with a tooth pick until most of the material has dissolved. Place a piece of the
pH paper in each mixture to moisten; remove the paper and compare the color to the
pH color scale provided to determine the pH value of each owl pellet mixture. Record
your results on Handout #3 and answer questions 1, 2, 3 and 4.
9. Compare your findings from Handout #2 with all other groups findings and record
their data in your Handout #4 and answer questions 1, 2, and 3 at the bottom of the
Handout.
10. Look at the data in your Handout #4 (combined class data) to fill in the required
information on Handout #5.
11. Use the data on Handout #5 to construct a graph (Handout #6) showing the
Frequency Distribution**. On the graph, you are developing a frequency distribution
which shows the number of times dissected owl pellets contain different numbers of
skulls.
**A frequency distribution is a statistical concept which uses data arranged to show the
number of times an event occurs in a particular way.
12. When you complete your graph, construct (on the back of Handout #6) a Food
Chain with at least 4 producers and/or consumers.
13. Glue the bones you saved from your two pellets onto the eight Bone Cards,
arranging the bones according to bone type. Label each card with the Study Kit number
(your group number).
BARN OWL PELLET LAB
WHAT DOES A BARN OWL LOOK LIKE?
White heart shaped face
Whitish belly with dark spots
Upper body golden with dark flecks
Dark brown eyes
Body Length: 15 to 21 inches; long legs
Wing span: 43 to 47 inches
HABITAT and SENSES OF THE BARN OWL
The Barn Owl is found on every continent except Antarctica. They are found in farm lands, grass lands
marshes, deserts and suburbs.
Owls are nocturnal and have many adaptations that enable them to hunt at night.
A two pound owl has eyes the same size as the human eye. Both the eyes and the ears are located at the
front of the head which enables excellent depth perception. The feathers around their eyes and ears are
shaped to funnel light and sound to their eyes and ears more precisely. Their ears are at different heights
which enable them to locate their prey with extreme accuracy. Their sense of hearing is so acute they can
hear a mouse’s footsteps 30 yards away flying 10 feet over the field in total darkness.
ear opening
Owls along with hawks, eagles, osprey and other birds of prey are known as Raptors.
RAPTORS
Hawks, eagles, osprey and owls are types of raptors.
Raptors have hooked beaks and talons (sharp claws)
adapted for seizing prey.
NOTE! PELLETS ARE NOT OWL POOP!
Golden Eagle
Red Tail Hawk
Red Tail Hawk
Barred Owl
Osprey
Hawks, eagles and osprey tear and swallow small pieces of flesh and avoid swallowing
most fur and bones. However, owls swallow prey whole or in large pieces and have a
specialized digestive system in which pellets are formed and
regurgitated to dispose of the indigestible parts of their prey.
DIGESTION: OWL PELLETS
A crop is a loose pouch inside the throat of most birds
that stores food and allows birds to pulverize hair, bones
and teeth so that they can be eliminated from the body.
Owls have no crop.
The owl’s stomach has two parts . The anterior part is
called the proventriculus which produces enzymes,
acids and mucus. The second part is called the
ventriculus or gizzard which compresses the indigestible
part of prey (hair, bones, teeth, feathers, etc.) The
stomach muscles form the undigested parts into a wet,
slimy pellet. The pellet passes into the proventriculus
and remains there for up to ten hours before being
regurgitated. When an owl eats more than one prey
within several hours, the remains are consolidated into
one pellet. New prey cannot be swallowed until the
pellet is ejected. Barn owls produce one to two pellets
per 24 hours.
Much can be learned about an owl’s diet and
environment by examining its pellets. Studies of
dissected owl pellets provide information about changes
in feeding habits that occur from season to season as
well as the different species of animals and/or plants that
are found in the owl’s habitat. This information allows us
to see what role an owl plays in the ecosystem and how
they are adapted to their niche.
HOW THE ENVIRONMENT IMPACTS WHAT AN OWL EATS
A food chain shows the relationship between producers
(plants) and consumers (animals that eat the plants or that
eat other animals).
Food chains only go in one direction. A food chain starts
with what gets eaten and has arrows pointing towards what
does the eating.
Food Webs show how plants and animals are interconnected
by different paths. In the wild, animals eat more than one thing
and can belong to several food chains. A food web is an
elaborate version of a food chain.
EFFECTS of ENVIRONMENTAL POLLUTION on pH
Pollution can change a water's pH, which in turn can harm
animals and plants living in the water. Not only does the pH of a
stream affect organisms living in the water, a changing pH in a
stream can be an indicator of increasing pollution or some other
environmental factor. Excessively high and low pHs can be
detrimental for the use of water and can alter the food sources
available.
One quick way of determining the
changing pH of water is to use pH
indicator paper as seen in the
picture to the right.
POWER of the FREE HYDROGEN and HYDROXIDE IONS
pH is a measure of how acidic/basic water is. The range goes
from 0 - 14, with 7 being neutral. pHs of less than 7 indicate
acidity, whereas a pH of greater than 7 indicates a base. pH is
really a measure of the relative amount of free hydrogen and
hydroxide ions in the water. Water that has more free hydrogen
ions is acidic, whereas water that has more free hydroxide ions is
basic. Since pH can be affected by chemicals in the water, pH is
an important indicator of water that is changing chemically.
In ecosystems,
plants and animals
are all connected.
If any one part is
removed, it can
affect the whole
ecosystem.
PRE/POST TEST: BARN OWL LAB
Circle the correct answer for each of the following questions:
1. The major senses an owl uses in locating prey are:
A. Vision and Hearing; B. Hearing and Smell; C. Smell and Taste; D. Vision and Touch.
2. Barn Owls are found on every continent except:
A. Asia; B. Artic; C. Antarctica; D. Africa
3. All raptors have all of the following except:
A. Teeth; B. Hooked Beaks; C. Sharp Claws; D. Crop
4. The owl’s stomach has:
A. One section; B. Two sections C. Three sections; D. Four sections
5. The part of the owl’s stomach that produces enzymes, acids and mucus is:
A. Crop; B. Ventriculus; C. Gizzard; D. Proventriculus
6. In a 24 hour period a typical Barn Owl will produce how many pellets?
A. Zero;
7.
B. One to two; C. Three to four; D. Five or more
pH is a measure of the relative amount of _________________ in water:
A. free oxygen atoms; B. free hydrogen ions; C. free hydroxide ions; D. both B and C
8. If one part of the ecosystem is removed:
A. it affects the entire ecosystem;
B. the affect would only involve a small portion of the ecosystem;
C. the ecosystem would not be affected; D. only human life would be affected.
9. All of the following is true about a food chain except:
A. it shows the relationship between producers and consumers;
B. it shows the relationship between plants and animals that eat the plants or that eat other animals;
C. it only goes in one direction; D. it is a more elaborate version of a food web.
10. Which of the following show how plants and animals are connected by different paths?
A. an ecosystem; B. a food web; C. a food chain; D. none of the above
PRE/POST TEST: BARN OWL LAB
Circle the correct answer for each of the following questions:
1. The major senses an owl uses in locating prey are:
A. Vision and Hearing; B. Hearing and Smell; C. Smell and Taste; D. Vision and Touch.
2. Barn Owls are found on every continent except:
A. Asia; B. Artic; C. Antarctica; D. Africa
3. All raptors have all of the following except:
A. Teeth; B. Hooked Beaks; C. Sharp Claws; D. Crop
4. The owl’s stomach has:
A. One section; B. Two sections C. Three sections; D. Four sections
5. The part of the owl’s stomach that produces enzymes, acids and mucus is:
A. Crop; B. Ventriculus; C. Gizzard; D. Proventriculus
6. In a 24 hour period a typical Barn Owl will produce how many pellets?
A. Zero;
7.
B. One to two; C. Three to four; D. Five or more
pH is a measure of the relative amount of _________________ in water:
A. free oxygen atoms; B. free hydrogen ions; C. free hydroxide ions; D. both B and C
8. If one part of the ecosystem is removed:
A. it affects the entire ecosystem;
B. the affect would only involve a small portion of the ecosystem;
C. the ecosystem would not be affected; D. only human life would be affected.
9. All of the following is true about a food chain except:
A. it shows the relationship between producers and consumers;
B. it shows the relationship between plants and animals that eat the plants or that eat other animals;
C. it only goes in one direction; D. it is a more elaborate version of a food web.
10. Which of the following show how plants and animals are connected by different paths?
A. an ecosystem; B. a food web; C. a food chain; D. none of the above
Virtual owl pellet dissection http://www.kidwings.com/owlpellets/flash/v4/index.htm FEMUR, TIBIA/FIBULA
Upper – Lower Hind Leg Bones
FEMUR, TIBIA/FIBULA
Upper – Lower Hind Leg Bones
HUMERUS, RADIUS
Upper – Lower Front Leg Bones
HUMERUS, RADIUS
Upper – Lower Front Leg Bones
JAWS (mandibles)
JAWS (mandibles)
PELVIC BONES
PELVIC BONES
RIBS
RIBS
SCAPULA
(Front Leg Shoulder Blade)
SCAPULA
(Front Leg Shoulder Blade)
SKULLS
SKULLS
VERTEBRAE
VERTEBRAE
OWL PELLET HANDOUT #1
What does a common barn owl eat and how much?
HYPOTHESIS
What do you think you will find in the owl pellet?
PREDICTION
OWL PELLET HANDOUT # 2
WEIGHT, LENGTH, WIDTH and NUMBER of SKULLS CHART
WEIGHT,
GRAMS
LENGTH,
WIDTH,
NUMBER of NUMBER of
MILLIMETERS MILLIMETERS PREDICTED OBSERVED
SKULLS
SKULLS
PELLET
1
PELLET
2
1. Based on the relative weighs of each pellet, predict the number of skulls in
your pellets and record that number above. The range is usually zero to five.
2. Describe at least three physical characteristics of the pellet:
A. Smell:
B. Color:
C. Texture:
3. List any other materials found in your pellets other than fur/hair and bones.
Examples: feathers, seeds, insect skeletons, etc.
HANDOUT #3
pH ranges from 0 to 14, with 7 being neutral. pHs less than 7 are acidic while
pHs greater than 7 are alkaline (basic). Normal rainfall has a pH of about 5.6—
slightly acidic due to carbon dioxide gas from the atmosphere. You can see
from the chart below, acid rain can be very acidic and it can affect the
environment in a negative way.
Circle the number on the scale above that corresponds with the pH of Pellet 1.
Place a check next to the number on the scale above that corresponds with the
pH of Pellet 2.
Based on your testing of the pH of Pellet 1 and Pellet 2 answer the following
questions:
1. Is Pellet 1 alkaline, acidic or neutral?
2. Is Pellet 2 alkaline, acidic or neutral?
3. The normal pH of an owl pellet is approximately 7.6. Based on your pH
measurements of Pellet 1 and Pellet 2, do they indicate that the food source of the
owls has been exposed to environmental pollution, such as acid rain? Justify
your conclusions.
4. Why is it necessary to use the pH paper to determine the pH of the owl pellet?
Explain your answer.
OWL PELLET HANDOUT #4
GROUP #
1
2
3
4
5
6
7
8
9
10
11
12
PELLET #
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
WEIGHT,
GRAMS
PREDICTED #
of SKULLS
OBSERVED #
of SKULLS
WRITE Y0UR ANSWERS TO THE QUESTIONS BELOW IN THE SPACE PROVIDED:
Question 1: Is there a correlation between the weight of the pellet and the number of skulls? Explain.
Question 2: How might you account for the differences in the number of skulls found in each pellet?
Question 3: How might you account for the absence of skulls in a pellet?
OWL PELLET HANDOUT #5
Using data from the combined class data (HANDOUT #4) fill in the table below.
FREQUENCY of SKULLS PER PELLET
#SKULLS/PELLETS
# PELLETS
0
1
2
3
4
5
6
7
OWL PELLET HANDOUT #6
Use the numbers in HANDOUT #5 to construct a graph showing the frequency
distribution of animal skulls in this sample of owl pellets.
Frequency Distribution Graph of Animal Skulls per Pellet
Data from HANDOUT #5