Comparative Physiology Symmetry in Marine Organisms

Transcription

1 Series 1 Name Date Don t forget to have your worksheet stamped at the front desk when you finish! Comparative Physiology Symmetry in Marine Organisms Part One: Learning Symmetry The body plans of organisms found in the Monterey Bay demonstrate many different types of symmetry. You will learn about three different types in the activity below. 1. In the space below, draw a pizza and divide it into eight equal slices. This pizza demonstrates Radial Symmetry; body parts are arranged in a repeating pattern around a central axis (like a wagon wheel), or are completely symmetrical about a central axis (like a dinner plate). 2. In the space below, draw a star and divide it into five equal pieces (there should be one point per piece). This star demonstrates Pentamorous Radial Symmetry. This means that body parts are arranged around the center in five equal parts. 3. In the space below draw a person and divide him/her into two equal pieces, vertically down the center of the body. This person demonstrates Bilateral Symmetry, which means an organism has two halves that are mirror images. Page 1 of 5 (5/08)

2 Part Two: Applying Symmetry In this part of the activity you will take what you have learned about the different types of symmetry and apply it to different groups of animals found at the Seymour Center. This portion of the activity is a bit of a scavenger hunt, so open your eyes and remember to look at the signs next to the aquaria. 1. Echinoderms The Monterey Bay is home to many invertebrates that belong to the Phylum Echinodermata. Literally translated, Echinodermata means spiny skin. The Seymour Center has at least eight species of echinoderms on exhibit. Walk around the aquaria and the sea water table (touch tank) and find five echinoderms using the hints in the table below. When you find each animal, complete the missing information in the table. Remember, you may ask the docents questions to help you along. How many arms? Or, if it doesn t have arms, how many body segments? Type of Symmetry Bat Star Strongylocentrotus purpuratus 5 Sea Cucumber A. Were there any echinoderms that did not seem to have the same type of symmetry as the others? Which organisms were they? B. If your answer to A included sea urchins or sea cucumbers, you may be surprised that their bodies are actually divided into five equal parts. Knowing this fact, what type of symmetry do they have? Fun Fact: When echinoderms are larvae floating freely in the ocean, they are actually bilaterally symmetrical! Page 2 of 5 (5/08)

3 2. Cnidarians The Monterey Bay is also home to many invertebrates in the Phylum Cnidaria. The Greek word Cnidos means stinging nettle. Some of these organisms live attached to the sea floor, while others float with the currents. The Seymour Center has at least eight species of cnidarians on exhibit. Walk around the aquaria and the sea water table and find six cnidarians using the hints in the table below. When you find each animal, complete the missing information in the table. Remember, you may ask the docents questions to help you along. Pachycerianthus fimbriatus Is it attached or free floating? Type of Symmetry Gorgonian Lophogorgia chilensis Free floating Urticina lofatensus Attached Plumose Anemone A. Were there any cnidarians that did not seem to have the same type of symmetry as the others? Which organisms were they? B. If your answer to A included gorgonians, you may be interested to find out that they are actually a colony of small individuals living together. What type of symmetry do you think each of the individuals have? Page 3 of 5 (5/08)

4 3. Vertebrates It is also possible to find many vertebrates from the Subphylum Vertebrata swimming around in the Monterey Bay. The name Vertebrata comes from vertebrae, the bones that make up the spine. Walk around the aquaria and the sea water table and find five vertebrates using the hints in the table below. When you find each animal, complete the missing information in the table. Remember, you may ask the docents questions to help you along. How many fins does it have on each side of its body? (Do not count the dorsal and caudal fins.) Symmetrical? If so, what type? Cebidichthys violaceus Wolf Eel 1 Sanddab Cephaloscyllium ventriosum Round Ray A. Were there any vertebrates that did not seem to have a clearly defined type of symmetry? Which organism(s)? B. If your answer to A included sanddabs, you are correct. When sanddabs are juveniles, they are bilaterally symmetrical, but as they mature, one eye migrates to the other side of its head and the organs inside its body shift around. The fish is no longer bilaterally symmetrical, although it is close! C. As you leave the aquarium, go take a look at the blue whale skeleton. What type of symmetry does this whale have? Do you think all whales have the same type of symmetry? Page 4 of 5 (5/08)

5 4. Terrestrial Organisms Your last task is to think of one terrestrial (living on land) organism that demonstrates each type of symmetry you learned about today. Each of these can be a plant or an animal. Be creative with your answers and try to stay away from answers like people or dogs. Bilateral Symmetry: Radial Symmetry: Pentamorous Radial Symmetry: Page 5 of 5 (5/08)