Mammalian Dissection: Fetal Pig 11/06 Integrated Science 4 Name ____________________________ Per. _______

Introduction Organisms are classified based on similarities and differences to: 1) make sense of the millions of organisms on record, and 2) predict the evolutionary relationships among them. In this laboratory, you will gather evidence on a mammal’s (fetal pig’s) anatomy and physiology as a basis for comparison with other vertebrates. Pre-Laboratory Part A. External Anatomy Use your Biology book p. 559-560 and http://www.whitman.edu/biology/vpd/main.html or other available resources to label the following items on the diagram below.

1. 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.

2. Label these external structures: umbilical cord, snout (nares), eye, ear (pinna), mouth, leg, hoof, anus.

Part B. Tools Read and highlight the Laboratory Procedures, Part A, B, C and D below. Then, describe the appropriate use of each of the tools listed below being used during the dissection. Additional information can be found online.

Dissection Scissors

Dissecting Probes

Scalpel/Blade

Dissecting Pins

Dissecting Tray

Part C. Respect Pledge I hereby pledge to treat the specimen with utmost respect and use all dissection tools for their appropriate function. If I do not uphold this pledge, I understand I will receive a zero for the assignment and an office referral. I may elect to do an alternate assignment. Signed:

Laboratory Part A. Procedures Beginning of each dissection day: 1. Obtain specimen, gloves, pins (about 8), and dissection kit (with scissors,

probe(s), scalpel/blade).

Dissection: 2. Place the specimen on its dorsal side on a dissecting tray. One or two group

members should hold apart the specimen’s legs while another group member makes incisions through the body wall in the order shown in the figure to the right (numbers 1-4). Make initial incisions with scalpel/blade and longer cuts with scissors. Be careful to cut around the umbilical cord and make your cuts deep enough (use scissors) to cut just through the muscles. Pin the flaps of muscles away to expose the abdominal cavity and other internal cavities.

3. To expose the thoracic cavity make a horseshoe cut out of the ribs with the blunt-tipped dissecting scissors as shown on the figure with the dotted line. To identify gender, look for the urogenital papilla on the posterior end ventral to the anus and tail. If it is there, your pig is female. If not, it is male. Follow additional instructions for dissection in handouts or from your teacher. You can also go online to the website above (see Pre-Laboratory, Part A).

4. Clean up at end of dissection (see Part C). Part B. Observations/Data 1. Using the attached templates, make accurate and detailed biological drawings of the abdominal cavity and

the thoracic cavity. Complete the following: (1) draw the more ventral organs from the both cavities and (2) draw the more dorsal organs from the abdominal cavity (with some ventral organs removed) for each gender. Drawings must have a title and a scale.

2. Label the structures from the chart below on your drawings. You will also be asked by your teacher to identify these structures and their functions on your specimen.

3. Color code organs belonging to the same organ system. Part C. Structure and Function 1. Describe the function and location of the organs listed below that you identified during your dissection of

the fetal pig. Use the Dissection Guide provided for you and your biology book for information. Cardiovascular System

1. Structure: Heart Function: Location in Fetal Pig: 2. Structure: Arteries Function: Location in Fetal Pig: 3. Structure: Veins Function: Location in Fetal Pig:

Respiratory System 4. Structure: Trachea Function: Location in Fetal Pig:

umbilical cord

anus

urogenital papilla

5

5. Structure: Lungs Function: Location in Fetal Pig:

Digestive System 6. Structure: Stomach Function: Location in Fetal Pig: 7. Structure: Liver Function: Location in Fetal Pig: 8. Structure: Pancreas Function: Location in Fetal Pig: 9. Structure: Small Intestine Function: Location in Fetal Pig: 10. Structure: Large Intestine Function: Location in Fetal Pig: 11. Structure: Cecum Function: Location in Fetal Pig: 12. Structure: Rectum Function: Location in Fetal Pig:

Urinary System 13. Structure: Kidney Function: Location in Fetal Pig: 14. Structure: Ureter Function: Location in Fetal Pig:

15. Structure: Urinary Bladder Function: Location in Fetal Pig:

Reproductive System 16. Structure: Testes Function: Location in Male Fetal Pig: 17. Structure: Urethra Function: Location in Male Fetal Pig: 18. Structure: Ovary Function: Location in Female Fetal Pig: 19. Structure: Oviduct Function: Location in Female Fetal Pig: 20. Structure: Uterus Function: Location in Female Fetal Pig:

Part D. Clean up At the end of each dissecting day, return you specimen to a plastic bag, saving all of the dissecting fluid. Clean and dry lab tray, tools, and work area. This will be checked by your teacher. Clean out the sink at your lab station. Wash hands! Post-Laboratory Answer the following questions on a separate sheet of paper using complete sentences.

1. An adaptation is a characteristic of an organism that makes it fit for its environment or for its particular way of life. Identify and describe three physiological adaptations (location and function) you observed during the dissection of the fetal pig. 2. Describe the evolutionary importance for each of the adaptations you identified in the previous question. Consider what purpose each adaptation served in helping the organism survive in it’s environment. 3. Metabolism (endothermy/ectothermy) is a physiological characteristic and is impossible to directly observe with a dead specimen. Nevertheless, indirect evidence is present. Discuss any structural characteristics/features that you have observed that could provide indirect evidence of your specimen’s metabolic rate. Consider, in particular, how the structures you discuss may be different from structures in organisms that use a different metabolic system.

Drawings

Organ System Color Cavity (where primarily found)

Organs (draw and label, identify on specimen,

know function) Cardiovascular/ Circulatory Red Thoracic Heart, Blood Vessel (artery or vein)

Respiratory Blue Thoracic Trachea , Lungs Digestive Green Abdominal

(ventral) Stomach, Liver, Pancreas, Small Intestines, Large Intestines, Rectum

Urinary/ Excretory Orange Abdominal (dorsal) Kidney, Ureter, Urinary Bladder

Reproductive Yellow Abdominal (dorsal)

Male: Testes, Urethra Female: Ovary , Oviduct, Uterus

Ventral View Location: Thoracic and Abdominal Cavities Scale:

Sex: Female Ventral View of Dorsal Organs Location: Abdominal Cavity Scale:

Sex: Male Ventral View of Dorsal Organs Location: Abdominal Cavity Scale: