Lab04_3

Lab Activity 4.3
Molluscs and Jointed Legged Animals

Study the instructional material below. Be sure to click on each of the photographs for an enlarged view in a separate window. The larger version is necessary to complete the assignment. It opens in a separate window which can be resized by grabbing the bottom right corner and dragging it. It can also be moved by grabbing the top heading bar and dragging it. Be sure to close the extra window by using the X in IBM, or the close box in MAC when you are finished using them.

Introduction

Marine invertebrates are animals without backbones that live in the sea. Over 97 percent of all animal species are invertebrates and the majority of these are marine. These species are divided into 33 phyla of which two very successful but unrelated phyla the Mollusca (soft bodied animals) and the Arthropoda (jointed legged animals) will be featured in this lab activity.

Instruction

Examine the photographs of the invertebrates depicted below. Study the descriptions that go with each photograph and learn the stated information about the biology of each one.

Be sure to write about what you are learning in the lab section of your notebook. You will be expected to answer questions about the lab activity during the lab self test and lab quiz. It helps to have your text and coloring books open beside you for support.

Supporting Information

Refer to the Assigned Readings Below:
Marine Biology Textbook	Chapter 7, pages 130 to 139
Marine Biology Coloring Book	Plates 29 to 37

Phylum Mollusca (soft bodied animals): Snails, Slugs, Chitons, Clams, Mussels, Oysters, Squid, and Octopi
1. The shells of bivalves have two parts, called valves, connected together by a ligament.
2. Most bivalves are filter-feeders that use their gills to collect phytoplankton and other food particles from the water.
3. Mussels are unusual bivalves that attach themselves to the bottom with threads of protein called byssal threads, produced by a gland located near the base of their foot.
4. Most marine snails have a tough, proteinaceous structure called the operculum, carried on their foot and used to shut the shell aperture.
5. The shells of most gastropods have a spiral shape.
6. Many shell-less gastropods are brilliantly colored, warning predators of their bad taste.
7. Chitons have 8 overlapping shell valves that cover their backs.
8. Chitons have a broad, muscular foot on their underside that is used for clinging and crawling.
9. Chitons are restricted to living on hard substrates.
10. The nautilus is the only living cephalopod with a large, external shell.
11. Squids can swim rapidly by using water for jet-propulsion.
12. The suckers on the arms of an octopus are arranged in 2 rows.

Phylum Arthropoda (jointed leg animals): Horseshoe Crabs, Crabs, Shrimp, Lobsters, Crayfish, Copepods, Isopods, Amphipods, and Barnacles
1. Horseshoe crabs have a long, spike-like structure on their abdomen called a telson, which they use to flip themselves if they get turned over.
2. Horseshoe crabs are not true crabs. They are more closely related to scorpions.
3. Horseshoe crabs are relics of a past age. They first appeared on earth some 200 million years ago.
4. Copepods are among the smallest and most abundant of all crustaceans.
5. Isopods get their name from the fact that their legs are all the same shape.
6. Amphipods have claw-like gnathopods which are used in feeding.
7. Barnacles live inside an exoskeleton made up of shell plates.
8. Goose neck barnacles have a fleshy stalk for attachment, but acorn barnacles attach themselves directly to the bottom with shelly cement.
9. Barnacles feed by extending feathery cirri which are used to filter food particles from the water.
10. Shrimps, lobsters, and crayfish all have 10 legs.
11. Lobsters and crayfish have two large claws called chelipeds.
12. The eyes of shrimps, lobsters, and crayfish are located on stalks.
13. The abdomen of a hermit crab is large and soft.
14. The hermit crab's abdomen is kept tucked into a snail shell for protection.
15. The hermit crab's posterior legs are small and used to cling to their shell.
16. All true crabs have a small, flexed abdomen.
17. Swimming crabs, like the blue and calico crabs, have paddles on their rear legs.
18. Fiddler crabs live on muddy shores. The males have one large claw, which is used to attract females.

Lab Activity 4.4 Spiny Skinned Animals and Chordates