Rat Dissection

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Rat Dissection
Prelab
1. Is your left like your right side?
It should be similar to your right but there can be differences like if damage was done to one side or if one side was mutated and disfigured. 2. Name an animal that doesn’t have a left and right side. Snakes don’t have a left and right side but there is an interesting study about that which is that Adult snakes (16 of 20 snakes) preferred to coil in the clockwise direction. Many female snakes (15 of 20 snakes), but few male snakes (only 4 of 10 snakes), also tended to coil in a clockwise pattern. This suggests that the location of internal organs such as the lungs, kidney and stomach may affect coiling direction. For example, in some snakes, the right lung is pushed aside by the stomach and the left lung is smaller than the right lung. These anatomical features may influence coiling direction so that the snake can maximize behaviors such as striking or regulating body temperature. Coiling direction may also be influenced by differences in the anatomy of the right and left sides of the snake brain. Just as humans have a right or left brain dominance for many behaviors, snakes may also have brain asymmetries to control what they do. 3. What kind of symmetry does it have?

Patterns on its skin and the way it coils.
4. Describe the rat’s feet, snout, ears and eyes. How do they function according to where it lives and what it eats? The rat has evolved to match its environment its feet are used to feel around and move very fast at the same time. Snout is developed to smell food or anything bad that it should stay away from. The ears are very sensitive to hearing and can pick up movement. The rats eyes are made to see in dark environments. 5. Familiarize yourself with the compass points and describe the meaning of anterior, posterior, dorsal, ventral, distal, proximal, caudal, and cranial. (The left and right always refer to the specimen’s left and right). Anterior & Posterior: from head end to opposite end of body or tail. Dorsal & Ventral: .from spinal column (back, dorsal) to belly (front, ventral). Distal: from where it joins the body (proximal part), to the tip of an appendage (distal part). Caudal: The polar opposite to the anterior end is the posterior end Cranial: the cranial end (Greek κρανίον (kranion); skull)

6. Explain how there could be a problem if your left and right were the reference point. Because depending on the way you’re standing around the rat or the way the rat is set up is different left and right. 7. What is meant by bilateral symmetry?

Capable of division into symmetrical halves by only one longitudinal plane passing through the axis 8. Explain why a starfish is not bilaterally symmetrical? Humans are bilateral symmetrical since if you cut them down the middle they are symmetrical. Starfish are not bilaterally symmetrical however they are radially symmetrical. Also remember the technical name for starfish is seastar.  9. Are you bilaterally symmetrical?

Yes since you can cut a human down the middle.
10. Explain your answer and name two internal organs that are bilaterally symmetrical. Bilateral symmetry, sometimes called reflection symmetry or mirror symmetry, means that an object or shape has two halves that are mirror images of each other. For example, the capital letter T and an isosceles triangle are bilaterally symmetrical. The biology term is to organisms that have two symmetrical halves when divided along only one plane. 11. What is dissection?

Dissection is the process of disassembling and observing something to determine its internal structure and as an aid to discerning the functions and relationships of its components. 12. Why would a scientist do a dissection?

Scientists perform dissections in order to view the anatomy of the subject, discover the cause of death, or to learn about the course of a fatal disease or the lethal damage inflicted by an accident. Students do...
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