Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
LS2 - Matter cycles and energy flows through an ecosystem.
LS3 (9-11)-8 -Students demonstrate an understanding of classification of
organisms.
LS4 (9-11) - 9b providing an explanation of how the human species
impacts the environment and other organisms
Background:
The owl pellets used in this lab come from barn owls which are an endangered
species found in RI.
Safety: All of the owl pellets have been sterilized. Wash hands after lab.
Materials:
Tray, toothpicks, owl pellet, glue, owl pellet bone chart, rodent skeleton diagram,
ruler, construction paper.
Procedures:
1. Carefully inspect the outside of the pellet and observe its size, the materials
that make it up, and any additional features. Record.
2. Gently pull apart the pellet, being careful not to break any of the bones inside
it. Use toothpick or fingers to separate the bones from the fur or feathers. Take
special care when removing the skulls and jawbones, since they are the best
way to identify the animals that the owl ate.
3. Group similar bones together. When
you've finished sorting the bones, roll the
last bits of fur between your fingers to find
little bones or teeth that might have been
overlooked.
4. Use the owl pellet bone chart to classify
the bones. The jawbones and the location
of teeth will be most useful for this task.
One animal that is not found on the chart
is the vole. This animal has a jawbone with
similar teeth placement as the rat, but the
jaw is smaller.
a) Record the number of each type
of bone found on data table.
b) Record the types of skulls found
5. Choose the skeletal remains of one
animal (the one with the greatest number
of bones) and piece it together. Glue as
seen on rodent skeleton diagram. Label
bones.
Rodent skeleton diagram
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
Data and results:
A. Description of owl pellet: Size, shape, color, consistency, make-up
B. How many of the following bones did you find?
Table #1 Title: _______________________________________________________
Type of Bone
Number of Bones
Skull
Mandible (lower jaw)
Vertebrae
Sacrum
Scapula (shoulder blade)
Ribs
Humerus (upper forelimb)
Radius/ulna (lower forelimb)
Innominate (pelvic bones)
Femur (upper hindlimb)
Tibia/Fibia (lower hindlinb)
What types of skulls did you find?
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
Additional Results:
C. Food web
Use the following facts about the prey to CREATE A FOOD WEB that is
common name of a minimum of 15 possible species. Be sure to label each
component (primary producer, primary consumer, secondary consumer, etc.).
ARROWS MUST SHOW DIRECTION OF ENERGY FLOW…Arrows point towards the
predator! Include those species identified in your dissection.
Useful website: http://www.fws.gov/ninigret/complex/wildlife_lists.html
Prey
Diet
Mouse
It eats a wide variety of plant and animal matter depending on what is available,
including insects and other invertebrates, seeds, fruits, flowers, nuts, and other plant
products. Deer mice sometimes eat their own feces (coprophagy).
Mole
A mole's diet is mostly insects and other invertebrates, including earthworms, centipedes,
millipedes, snails, slugs, grubs, ants, sowbugs, termites, beetles, and crickets
Shrew
Food habit studies have revealed that shrews eat beetles, grasshoppers, butterfly and
moth larvae, ichneumonid wasps, crickets, spiders, snails, earthworms, slugs, centipedes,
and millipedes. Shrews also eat small birds, mice, small snakes, and even other shrews
when the opportunity presents itself. Seeds, roots, and other
Rat
Bird
The rat's diet typically includes seeds, nuts, grains, vegetables, fruits, meats and
invertebrates. They consume about one-third of their weight in food every 24 hours.
Because of their inability to vomit, rats are very hesitant to try new foods that may be
poisonous. They will take a small nibble and wait to see if they feel sick and, if so, will avoid
that food in the future.
Insects; terrestrial non-insect arthropods, seeds, grains, and nuts; fruit
Ecological Pyramids
The amount of energy or matter in an ecosystem can be illustrated by a drawing
called an ecological pyramid. In this activity you will construct three types of
ecological pyramids: a number pyramid, a biomass pyramid and an energy
pyramid.
Each pyramid you construct will consist of four trophic
levels. The top of each will relate to your owl, the only
tertiary consumer (3o). The next level down will relate to
the owl’s prey, the secondary consumers (2o). For the
purposes of this activity, assume that all of the prey
found in the owl pellets are secondary consumers. The
next trophic level down will relate to the organisms eaten
by the owl’s prey, the primary consumers, (1o). The
base of each pyramid will relate to the organisms eaten
by the primary consumers, the producers.
Use the information obtained from your owl pellet
dissection to comlete the data tables and construct the ecological pyramids
below.
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
D. Number Pyramid, for one 24 hour period
A number pyramid is an ecological pyramid that indicates the total number of
organisms in each trophic level
Create and fill in a chart on your paper – Please note that a vole is ‘equivalent’ to a mouse
Table #2 Title: _________________________________________
CREATE A NUMBERS PYRAMID for the owl based on the number eaten per
year with one owl on the top with total annual number of all prey below. Use
the assumption that an owl produces an average of 2.5 pellets per day.
1. Draw your pyramid, labeling the number of 3o, 2o and 1o consumers. (Reminder:
There is only 1 owl, which is the 3o consumer, and you have calculated the
number of prey found in each pellet).
2. Determine the ratio, R, of the number of 2o consumers to the number of 3o
consumers.
R = # 2˚ consumers
# 3˚ consumers
3. Use your ratio, R, to calculate the number of 1o consumers by multiplying
the number of 2o consumers by R. Label your pyramid with the number of 1o
consumers.
# 1o consumers = R (# 2˚ consumers)
4. Calculate the number producers by multiplying the number of 1o consumers by
the ratio, R. Finish your pyramid by labeling it with the number of producers.
# producers = R (# 1˚ consumers)
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
E. Biomass Pyramid, for a 2.5 year lifespan
A biomass pyramid is an ecological pyramid that indicates the total mass of
organisms in each trophic level
E. Create and fill in the following chart on your paper.
Date table #3 title: _______________________________
Total biomass of prey (kg) =
F. Use your data to CREATE A BIOMASS PYRAMID. For the top carnivore level
the mass of one owl is about 0.6 kg.
1. Draw your pyramid and label the total biomass of the 3o consumer, assuming the
owl’s biomass is 600 g (0.6 kg). Label the biomass of the 2o consumers.
(Reminder: You have already calculated the biomass eaten over a year. Multiply
this by 2.5  the average lifespan in years)
2. Determine the new ratio, R, of the total biomass of the 2˚ consumers to
the total biomass of the 3˚ consumers.
R = biomass of 2˚ consumers
biomass of 3˚ consumers
0.6
kg
3. Use your ratio, R, to calculate the total biomass of the 1˚
consumers by multiplying the total biomass of the 2˚
consumers by R. Label your pyramid with the total
biomass of the 1˚ consumers.
biomass of 1˚ consumers = R (biomass of 2˚ consumers)
4. Calculate the total biomass of the producers by multiplying the total
biomass of the 1˚ consumers by R. Do you see a pattern in your
calculations? Finish your pyramid by labeling it with total biomass of the
producers.
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
F. 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.
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
Analysis Questions: Use notes, textbook and internet. These questions
must be woven into your conclusion in COMPLETE SENTENCES and MUST BE
RICH IN DETAIL AND EVIDENCE!!! NO CUTTING AND PASTING AT ALL!!! This
will result in a zero…cite all sources! This must also be written in paragraph
form!
1. Using the classification system (kingdom, etc.), which groups are
shared by owls and rodents? What are the specific names of the
groups shared by both?
2. Each vertebra of the rodent has an opening in the middle. Why? How
does the function of the vertebrae relate to the rodent’s classification
(look at the name of the phylum)? Describe the skeleton of a rodent
as seen in the pellet (teeth, ball and socket versus hinge joints)
3. Why do the ends of the limb bones end in a ball? Why do the sholder
and pelvis have rounded depressions? Explain how they are related.
4. Describe the complete diet of a barn owl in RI.
5. How many and what type of animals did your specific owl eat?
6. What is the trophic level of an owl? A rodent? Explain your answer in
terms of the food web you researched and created.
7. Would you expect to find more rodents or owls in an ecosystem?
Explain why in terms of energy pyramids and biomass pyramids.
Define both of these terms in your answer.
8. Describe the habitat of a barn owl in RI.
9. Are barn owl numbers increasing or decreasing in RI? What could be
some reasons for this change?
10. What impacts have humans had on barn owl numbers in RI? Describe.
(Hint: “Humans don’t eat owls” OR “humans don’t interact with owls” is
incorrect)
11. Do barn owls have an impact on the human population? Explain your
answer. Hint: “Humans don’t eat owls” OR “humans don’t interact with
owls” is incorrect)
12. What could be done to increase their numbers? Describe a plan to
increase the numbers of barn owls in RI. Be specific?
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
***You will be required to use Turnitin.com...
Class ID number: ____________________
Class enrollment password: _________________________
Submit formal lab report:
A. Introduction – purpose and background. (Hypothesis not required for this
lab.)
1. What is the purpose of the lab?
2. Background - Information on barn owls:
 general description,
 predatory behavior,
 senses,
 habitat in RI.
 Formation of the pellet.
 Background - Information on energy flow and matter cycles in an
ecosystem
 Importance of habitat restoration
4. Background - Information on importance of habitat restoration
B. Materials list – Can copy from handout and put into lab
C. Procedures – Can copy from handout and put into lab
D. Data – All observations and tables (titled correctly with all units)
E. Food web, Numbers pyramid, Biomass pyramid, Energy Pyramid
F. Analysis/Conclusion – Make sure to weave the above questions into this
section…IN PARAGRAPH FORM! Don’t forget the other components of a
proficient lab report conclusion!
G. Works Cited page related to information gathered for
background/conclusion facts or statistics.
H. Skeleton – evaluated based on accuracy of bone placement and labels,
completeness of skeleton, and neatness. One skeleton is submitted for lab
partners. Can take a photo and place in the Data Section as a Figure.
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
Honors Biology
Common Biology Lab
Name_________________________
Ecology of Owl Pellets
South Kingstown High School Name_____________________________________Class: Biology Common Course Assessment
Proficiency Requirements: Applicable GSE’s:
LS2 - Matter cycles and energy flows through an ecosystem.
LS3 (9-11)-8 -Students demonstrate an understanding of classification of organisms.
LS4 (9-11) - 9b providing an explanation of how the human species impacts the environment and other organisms
A proficient lab report must:
1. Demonstrate that the student understands the nature of science and the scientific process
2. Demonstrate that the student understands the applicable GSE's and other content and concepts presented and analyzed in the
experiment..
3. Demonstrate the student's ability to analyze their data and use their data to draw conclusions relative to the validity of their
hypothesis.
Nov.07
CATEGOR
Y
None
Exceeds Standard (3.5)
Meets Standard (3)
Approaching Standard (2)
Wt.
Below Standard (1)
Proficiency Exemplary demonstration
Requireme of the 3 proficiency
nts
standards.
(Introductio Insight included in the
n)
purpose or question. Is in
Question
the students own words.
Purpose
Adequately demonstrates
the 3 proficiency standards.
Adequately demonstrates 2
out of 3 of the proficiency
standards
The purpose of the lab or the
question to be answered
during the lab is clearly
identified and stated.
The purpose of the lab or the The purpose of the lab or the
question to be answered
question to be answered
during the lab is identified,
during the lab is erroneous.
but is stated in a somewhat
unclear manner.
(Introductio
n)
Backgroun
d
Information
Background information is
sufficient, concise, wellresearched and gives
context to the purpose of
the lab.
Exemplary understanding
of the applicable GSE’s
Background information is
Background information is
concise and gives context to correct but does not give
the purpose of the lab.
context to the purpose of the
lab. May be too short or too
Adequate understanding of long.
the applicable GSE’s.
Emerging understanding of
applicable GSE’s
Background information is
incorrect.
(Results)
Data and
Observatio
ns –
Bone Data
Table and
skeleton
picture
Accurate representation of
the tabular data and
observations.
Tables are, numbered,
labeled and titled.
Correct units.
Observations only – NO
interpretation.
Data and observations are
complete, but include
occasional errors.
Data and observations are
incomplete and inaccurate.
Table format is evident, but
some units are missing.
Data and observations are
completely inaccurate,
incomplete and poorly
organized.
Observations only – NO
interpretation.
Extensive interpretation of
Some interpretation of data. data.
Pts.
Proficiency standards not
demonstrated.
1
2
No understanding of the
applicable GSE’s
2
(Results)
Type of graph is
80 % of criteria are
Diagrams – appropriate for the
completed
Food Web application. Variables are
plotted on the correct axis.
Units are correctly plotted
and scaled Graph includes
figure number, title, axis
labels and units.
60% of criteria completed.
40% of criteria completed.
2
Discussion/ Meets the standard with
Conclusion exceptional insight and
analysis.
Some misconceptions in
interpretation and discussion
of data/observations and
calculations. One of the
"meets standards" condition
has not been met.
Many misconceptions in
interpretation and discussion
of data/observations and
calculations. Two or more of
the "meets standards"
condition has not been met
No understanding of the
applicable GSE’s
4
Format incomplete and
difficult to follow. Very
poorly written. No citations
1
Format
Exemplary understanding
of the applicable GSE’s
Hypothesis is restated and
rejected or accepted based
on the data. Analyzes and
interprets essential data
used to draw conclusions.
Sources of error identified
Discusses applications and
or extensions of experiment
Adequate understanding of
the applicable GSE’s.
Accurate and complete
format. Well-written.
Avoids personal pronouns.
Excellent citations in
correct format.
Accurate and complete
Format incomplete. Poorly
format. Adequately written. A written
few grammar or spelling
mistakes. Adequate citations Citations included
in correct format.
Emerging understanding of
applicable GSE’s