We recently directed many various animals. The purpose of this was to learn the anatomy of different organisms and how evolution changed creatures into us and what we are today. We dissected sponges, mollusks, jellyfishes, squids, fish, and frogs (which was awfully disgusting in my opinion).
Sponges
Mollusks
Types of Mollusks:
There are three major classes of mollusks. They are the gastropods, the bivalves, and the cephalopods. The gastropods include snails, slugs, and others. They are shell-less or single-shelled mollusks that move by using a muscular foot located on the ventral side. Their shell usually protects their bodies and they can pull completely into their shells when threatened. Bivalves have two shells that are held together by one or two powerful muscles. Bivalves include clams, oysters, mussels, and scallops. Most bivalves lead inactive lives and stay in one place for most of the time. Cephalopods are the most active of the three groups. These include octopi, squids, cuttlefishes, and nautiluses. They are usually soft-bodied and the head is attached to a single foot, which divides into tentacles or arms. They have eight or more tentacles equipped with sucking discs that grab and hold prey.
Ecology of Mollusks:
Mollusks feed on plants, animals, and filter algae out of the water and eat deritus. The last two points “clean up” their surroundings. Some are hosts or parasites. They are also an important source of food for numerous species. Scientists use mollusks to monitor water quality. Checking bivalves can warn biologists and public health officials about water problems. Mollusks are also important to biological research, especially because scientists believe that they are immune to cancer. Study of mollusks could possibly stop cancer in humans.
There are three major classes of mollusks. They are the gastropods, the bivalves, and the cephalopods. The gastropods include snails, slugs, and others. They are shell-less or single-shelled mollusks that move by using a muscular foot located on the ventral side. Their shell usually protects their bodies and they can pull completely into their shells when threatened. Bivalves have two shells that are held together by one or two powerful muscles. Bivalves include clams, oysters, mussels, and scallops. Most bivalves lead inactive lives and stay in one place for most of the time. Cephalopods are the most active of the three groups. These include octopi, squids, cuttlefishes, and nautiluses. They are usually soft-bodied and the head is attached to a single foot, which divides into tentacles or arms. They have eight or more tentacles equipped with sucking discs that grab and hold prey.
Ecology of Mollusks:
Mollusks feed on plants, animals, and filter algae out of the water and eat deritus. The last two points “clean up” their surroundings. Some are hosts or parasites. They are also an important source of food for numerous species. Scientists use mollusks to monitor water quality. Checking bivalves can warn biologists and public health officials about water problems. Mollusks are also important to biological research, especially because scientists believe that they are immune to cancer. Study of mollusks could possibly stop cancer in humans.
Annelids
Ecology of Annelids: The word annelid derives from the latin word annellus which when translated means “little ring”. The na is a basic description of its ring like appearance.
Annelids spend their lives burrowing through soil and mixing it. The tunnels they make provide passages for plant roots and water and help the ecosystem, this helps plant matter decompose. They also “mine” minerals and bring them to the surface. Earthworm excretion is filled with nitrogen, phosphorus, potassium, micronutrients, and bacteria. Earthworms are important to many species because they are so low on the food chain.
Annelids are divided into three classes: oligochaetes, leechees, and polychaetes. Oligochaetes contain earthworms. most worms in this class either live in soil or in fresh water. Leechees are external parasites that suck the blood and body fluids of their host. Most leechees are carnivor. Polychaetes contain sand worms, blood worms, and their relatives. They live in the water and have paired, paddle-like structures appendages tipped with setae. Setae are brush like structures.
Annelids spend their lives burrowing through soil and mixing it. The tunnels they make provide passages for plant roots and water and help the ecosystem, this helps plant matter decompose. They also “mine” minerals and bring them to the surface. Earthworm excretion is filled with nitrogen, phosphorus, potassium, micronutrients, and bacteria. Earthworms are important to many species because they are so low on the food chain.
Annelids are divided into three classes: oligochaetes, leechees, and polychaetes. Oligochaetes contain earthworms. most worms in this class either live in soil or in fresh water. Leechees are external parasites that suck the blood and body fluids of their host. Most leechees are carnivor. Polychaetes contain sand worms, blood worms, and their relatives. They live in the water and have paired, paddle-like structures appendages tipped with setae. Setae are brush like structures.
Fishes
Perch Observations & Critical Thinking and Application
Propels fish forward.
- Describe the general body shape of a perch. In what way does the body show adaptations for life in the water?
- What could be one function of the gill rakers?
- Observe a fish swimming in an aquarium. Describe the function of each fin used for movement. Tell whether the action provided by each fin is for propelling, steering, or maintenance balance. Which of the fins contains spines in the perch?
- Pectoral and pelvic fins?
- Pectoral and pelvic fins?
- Dorsal Fin?
- Caudal Fin?
Propels fish forward.
- Describe the scales of the perch. Which directions do they face? What is the advantage of this?
- How many nostrils does the perch have? How they different from your nostrils?
- What characteristics can you observe in the gills that make them an efficient respiratory organ?
- Describes the lateral line. What is the function of the lateral line of a perch?
- While many invertebrates have an exoskeleton, vertebrates such as fishes have an endoskeleton. Of what advantage is the endoskeleton to these animals?
- The perch fertilizes its eggs externally and leaves them exposed on rocks. The guppy fertilizes its eggs internally and gives birth to live young. Which fish produces fewer eggs? Compare the survival rate of these two species.
- The Perch possesses a gas-filled structure called the swim bladder. What is the function of the swim bladder?
I think we all worked pretty well together, but sometimes we didn't. Honestly, none of us wanted to dissect a frog. So we had a little quarrel over who did what depending on how disgusting the dissection was. Another problem was that sometimes we couldn't stay on task. However, we worked pretty well together and got all of the dissections done.