Comparing Vertebrates: Endotherms vs Ectotherms
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Integrated Science 4
Name ____________________________ Per. _______
Introduction
Organisms are classified based on similarities and differences in order to make sense of the millions of
organisms on record and to predict the evolutionary relationships among them. In this activity, you will
gather evidence on an endotherm’s anatomy and physiology by observing a prepared specimen of either a
mammal or bird as a basis for comparison with an ectotherm vertebrate – a reptile, amphibian, or fish.
Procedures
Obtain an either an endothermic OR an ectothermic specimen. You’ll have a chance to observe both and
endotherm and an ectotherm vertebrate. Keep the specimen vertical and make detailed observations.
Observations/Data
Part A. External Anatomy
1. Construct a scaled drawing of your assigned organism. Indicate the view and approximate scale of the
drawing in the space provided.
2. Label the following regions: dorsal, ventral, anterior, posterior, cranial region, pectoral region, pelvic region, and
caudal region. In addition, note the areas where the thoracic cavity and abdominal cavity are found.
View (top down, side):
Approximate scale:
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3. Complete the chart below by listing three or more observed external physical characteristics of the
organism related to following categories of adaptations.
MOVEMENT
ADAPTATIONS
DEFENSE ADAPTATIONS
BODY TEMPERATURE
ADAPTATIONS
PHYSICAL CHARACTERISTICS
SENSORY ADAPTATIONS
4. Draw a magnified view of the organism’s head. Indicate the approximate scale of the drawing in the space
provided. Label the physical characteristics of the head that correspond to the chart completed in procedure
#3. Color code each labeled characteristic and create a key to indicate the adaptation category to which it
corresponds.
Approximate scale:
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5. Draw a magnified view of one of the organism’s limbs and foot. Indicate the approximate scale of the
drawing in the space provided. Label the physical characteristics of the limb and foot that correspond to the
chart completed in procedure #3. Color code each labeled characteristic and create a key to indicate the
adaptation category to which it corresponds.
Approximate scale:
Part B. Internal Anatomy
6. Complete the chart below by listing three or more of observed internal physical characteristics of the
organism related to following categories of adaptations.
GAS EXCHANGE
REPRODUCTIVE
ADAPTATIONS
ADAPTATIONS
PHYSICAL CHARACTERISTICS
FEEDING ADAPTATIONS
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BODY TEMPERATURE
ADAPTATIONS
7.
Draw a magnified view of the organism’s thoracic cavity. Indicate the approximate scale of the
drawing in the space provided. Label the physical characteristics of the thoracic cavity that correspond
to the chart completed in procedure #6. Color code each labeled characteristic and create a key to
indicate the adaptation category to which it corresponds.
Approximate scale:
8. Draw a magnified view of the organism’s abdominal cavity. Indicate the approximate scale of the
drawing in the space provided. Label the physical characteristics of the abdominal cavity that correspond
to the chart completed in procedure #6. Color code each labeled characteristic and create a key to indicate
the adaptation category to which it corresponds.
Approximate scale:
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DIFFERENCE:
SIMILARITY:
9. Observe an organism with the other type of metabolism. Compare the external adaptations of their
organisms with the other metabolic type. Identify one similarity and one difference for each category of
adaptations.
MOVEMENT
BODY TEMPERATURE
SENSORY ADAPTATIONS
DEFENSE ADAPTATIONS
ADAPTATIONS
ADAPTATIONS
DIFFERENCE:
SIMILARITY:
10. Now compare the internal adaptations of both organisms. Identify one similarity and one difference
for each category of adaptations.
GAS EXCHANGE
REPRODUCTIVE
BODY TEMPERATURE
FEEDING ADAPTATIONS
ADAPTATIONS
ADAPTATIONS
ADAPTATIONS
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11. Using measurements from the demo dissection of a mammal and an amphibian complete the
following table. Make predictions for the vertebrate classes not represented in the dissection.
12.
SMALL INTESTINE
HEART MASS (G):
LENGTH: (CM)
VERTEBRATE CLASS
TOTAL RINSED SPECIMAN
EXPLANATION
SNOUT-VENT LENGTH
MASS (G)
(CM)
FISH
(PREDICTION)
AMPHIBIAN
REPTILE
(PREDICTION)
BIRD
(PREDICTION)
MAMMAL
12. Answer the following analysis questions:
 Describe at least three structural differences observed in endotherms and ectotherms.

For each difference described above, explain the most likely reason for the changes. Consider how
adaptations are related to the evolution of vertebrates.
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