Comparing Vertebrates: Endotherms vs. Ectotherms1/16

Integrated Science 4Name 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 birdas a basis for comparison with an ectotherm vertebrate – either 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 organism. Title your illustration. 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.

Organism: ______
View (top down, or side): ______/ Approximate scale: ______: ______
  1. Complete the chart below by listing three or more observed external physical characteristics of the organism related to following categories of adaptations.

Sensory
Adaptations / Movement Adaptations / Defense
Adaptations / Body Temperature Adaptations
Physical Characteristics
  1. 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 the key to indicate adaptation categories, and label each characteristic in this color.

Scale: / Key: ☐sensory, ☐movement, ☐defense, ☐body temperature
  1. Draw a magnified view of one of the organism’s limb 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 the key to indicate adaptation categories, and label each characteristic in this color.

Scale: / Key: ☐sensory, ☐movement, ☐defense, ☐body temperature

Part B. Internal Anatomy

  1. Complete the chart below by listing three or more of observed internal physical characteristics of the organism related to following categories of adaptations.

Feeding
Adaptations / gas exchange Adaptations / reproductive Adaptations / Body Temperature Adaptations
Physical Characteristics
  1. 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 the key to indicate adaptation categories, and label each characteristic in this color.

Scale: / Key: ☐feeding ☐gas exchange ☐reproductive ☐body temp.
  1. 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 the key to indicate adaptation categories, and label each characteristic in this color.

Scale: / Key: ☐feeding ☐gas exchange ☐reproductive ☐body temp.
  1. 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.

Sensory
Adaptations / Movement Adaptations / Defense
Adaptations / Body Temperature Adaptations
Similarities
differences
  1. Now compare the internal adaptations of both organisms. Identify one similarity and one difference for each category of adaptations.

Feeding
Adaptations / gas exchange Adaptations / reproductive Adaptations / Body Temperature Adaptations
Similarities
differences
  1. 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.

Vertebrate Class / Heart Mass (g):
Total rinsed specimen mass (g) / Small Intestine Length (cm):
Snout-Vent Length (cm) / Explanation
Fish
(prediction)
Amphibian
Reptile
(prediction)
Bird
(prediction)
Mammal
  1. 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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