.:\ame Class Period _ • _ -10-1 How Do Digestive System Lengths Compare?- You know that the diet of different animals may vary. You can buy cat food, dog food, and bird food in most supermarkets. The length of the digestive system may also vary. Animals that eat plants usually have longer digestive systems than animals that eat meat. EXPLORATIOl OBJECTIVES In this exercise, you will: a. measure the length of the digestive system in three animals. b. compare these lengths with the type of food eaten. KEYWORDS Define the following keywords: caecum _ carnivore _ digestive system'- _ tape herbivore ~ _ MATERIALS ~ string metric ruler SCIssors PROCEDURE 1. Place a piece of string down on the outline drawing of the rabbit digestive system in Figure 2 on the next page. Figure 1 shows you how. 2. Tape the end of the string in place at the label marked "start" on the stomach of the rabbit. 3. Position the string only over the entire length of the unshaded organs. It must match, exactly, the many twists and turns of the stomach, the small intestine and the large intestine (the unshaded organs) . . 4. When you reach the anus, cut the string, remove it from the drawing, and stretch it out its full length. CAUTION: Use care with scissors. 5. Measure the length of the string in centimeters and record this number in Table 1. String Start Meaaurlng Inte.tlne with string ~"" J .I -4 • • • •••••• , .& .1 ••• -I ,~ of '. , r,,,,,,,,,,,,,,," , ~ ~ /'1\1\11\1 I IIISs\ I~ I Mea.urlng string with ruler FIGURE 1. Measuring the digestive system 7~ . "
Transcript
.:\ame Class Period _
• _ -10-1 How Do Digestive System Lengths Compare?-You know that the diet of different animals may vary. You can buy cat
food, dog food, and bird food in most supermarkets.The length of the digestive system may also vary. Animals that eat
plants usually have longer digestive systems than animals that eat meat.EXPLORATIOl
OBJECTIVESIn this exercise, you will:
a. measure the length of the digestive system in three animals.b. compare these lengths with the type of food eaten.
KEYWORDSDefine the following keywords:caecum _
carnivore _
digestive system'- _
tape
herbivore ~ _
MATERIALS ~string metric ruler SCIssors
PROCEDURE1. Place a piece of string down on the
outline drawing of the rabbit digestivesystem in Figure 2 on the next page.Figure 1 shows you how.
2. Tape the end of the string in place atthe label marked "start" on thestomach of the rabbit.
3. Position the string only over the entirelength of the unshaded organs. It mustmatch, exactly, the many twists andturns of the stomach, the smallintestine and the large intestine (theunshaded organs) .
. 4. When you reach the anus, cut thestring, remove it from the drawing,and stretch it out its full length.CAUTION: Use care with scissors.
5. Measure the length of the string incentimeters and record this number inTable 1.
6. Position the string over the shadedportion of the rabbit digestive systemand measure the length of thecaecum. Record this measurement incentimeters in Table 1.
7. Add together the two numbers thatyou have now recorded in the table inorder to get the total length of thedigestive system. Record this numberin Table 1.
8. The diagram of the rabbit digestivesystem is drawn 13 smaller than actualsize. Multiply the total digestive systemlength by 3 to complete the first rowof Table 1. This number is the actuallength of the rabbit digestive system.
9. Repeat steps 1 through 8 for thedigestive system of the koala and thedog.
T bl 1 01 tl S t M
FIGURE 3. Measuring caeca of animals
a a Igaa va jya am •• aurement8Animal Length of atomach, Caecum Total dlgaatlva Multiply Actual length
small Int.atlna, length syatem length by 3 9' digestivelarge Intaatlna syatem
Rabbit r i xI I
KoalaI 1 I I+ xI T I I
~ l I IDog x iI I I
QUESTIONS
1. Which animal has the longest actual digestive system? _
2. Which animal has the shortest actual digestive system? _
3. Based on what you already know, tell whether the animals used in thisexperiment are carnivores or herbivores. NOTE: The koala is an Australiananimal that feeds only on the leaves and buds of the eucalyptus tree.• rabbit koala dog ~_
Q1
" . •••. I '. ...-._,
-l. Circle the correct answer to the following questions:.1. The animal that has the longest actual digestive svstern is a
(carnivore. herbivore).
b. The animal that has the shortest actual digestive system is a
(carnivore, herbivore).
c. The animal that has the longest caecum is a
(carnivore, herbivore).
d. The animal that has the shortest caecum is a
(carnivore, herbivore).
:J. By using your answers to question -1. describe how the length of the digestivesystem in animals seems to be related to the type of food the animals eat.
6. Are plants or meat more difficult to digest: _
Explain. _
7. Cse the word long or short to describe what you think the length of the digestivesystem might be in the
lion cat _ horse. deer _
panther donkey cow wolf _--,- _
8. Two different animals of almost the same size have digestive systems that are ofthe following lengths:Animal .'\.-410 em Animal B-145 em
a. Which one of these animals is most likelv to be a carnivore? _
b. Explain your answer. _
c. Which one of these animals is most likely to be a herbivore? _
