Invertebrates & The Fetal Pig
Dissection Partners’ Names:
General Overview: We will spend the rest of the semester on our animal dissections. First, you will dissect the earthworm and crayfish to allow you to examine two invertebrate species. Then, your lab group of 4 students will spend 4-5 days identifying parts of the fetal pig and participating in a comparative vertebrate dissection where your group will be the “expert” on one type of vertebrate, but you’ll also have to learn the other vertebrates from the other groups. You will also be individually completing this lab packet which includes diagrams and questions. Finally, you will have your lab practical exam on your final exam day. This practical will count as your Performance Exam for this semester.
Grading: The pig dissection is worth 3 grades: *80 total points for 8 days of dissection participation (10 pts per day). This grade will typically be assigned to the entire group, but some students may receive different grades because of amount of participation. Your group can earn up to 10 bonus points for exceptional participation. *100 total points for completion of your individual lab packet (10 pts per page). *5% of your average for the lab practical test.
Suggested Timeline: Thur 5/6- Earthworm Dissection Friday 5/7- Crayfish Dissection Wed 5/12- Work on Dissection Packet – maybe start external structures Thursday 5/13- External structures, Anatomical planes and directions, sexing the pig, skinning the pig Friday 5/20- Muscles, nervous, respiratory, digestive, circulatory Monday 5/17- Urogenital/ excretory Tuesday 5/18- Complete packet & review Wednesday 5/19 – Performance Final & packet due
Participation: • EACH member of the lab group is responsible for learning all of the parts. At least 2 people in each group must be actively involved in dissection, but everyone must participate in locating the parts. • EACH person is required to put in an equal amount of work. You will be graded on your amount of participation. • EACH person is required to complete an individual lab packet. • You are expected to be appropriate and a cooperative team member. Additionally, you are expected to treat your specimens, materials, classmates, teacher, and work station with respect.
Working Ahead: I strongly suggest that you work ahead since the periods always seem to get shorter as the practical gets closer. However, please work in order and leave time for review! Listen carefully for options for open lab before or after school.
Daily Cleaning: Clean (with soapy water) and dry dissection tools and tray; Bag and box specimens; Colored Pencils, Dissection Notebook, Pig Mat, and Soaps where they belong; All trash thrown away (in the garbage can); Sink clean; Tables sprayed and wiped down; Aprons and goggles returned □ You will lose individual points if you do not help your lab group clean! □ You may not leave the classroom until you are checked off! □ If your table is left unclean and not checked off after class ends, everyone will lose points!
Earthworms (Lumbricus terrestris) are representative animals of phylum Annelida and class Oligochaeta. Examining external and internal structures of an earthworm will reveal some major annelid characteristics. Lumbricus is an excellent animal for study because of its body organization. An earthworm is a segmented animal. Its body plan consists of many rings (annelus means “ring” in Latin). Each segment, or ring, of an earthworm is numbered in sequence from anterior to posterior end. Organs can be located by finding the particular segments they are known to be in. An earthworm “map” lists the location of each organ or structure by segment number (see the laminated handout).