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Assignment 7:
1. - scales
2. - tail fin
3. - lateral line
4. - gill slit
5. - dorsal fin
6. - eye
1. Make the body streamlined so that it offers as little resistance as possible while the fish swims.
2. Slime that is secreted by the glands in the epidermis makes the scales smooth and slimy. This helps the fish to move through the water more easily.
3. The water flows in at the gill slit and flows over the gills so that oxygen can be taken up by the blood vessels. The gill slit also covers the gills.
4. It has powerful muscles and is moved back and forth so that the fish can move forwards.
5. It is there to keep the fish upright and to help it maintain its balance.
The lateral line consists of a long row of openings that house nerve cells. These enable the fish to become aware of differences in pressure and thereby to determine its depth in the water.
Assignment 8:
PIGEON
1. To peck up food; to build its nest; to feed its chicks; to preen itself and for defence
2. The feathers, in particular the light quills, enlarge the wing surface.
3. Feathers are poor conductors of heat and therefore maintain the body heat of the pigeon. The covert feathers occur over virtually the entire body and the plumules are found underneath them.
4. The toe that points backwards helps to balance the pigeon. The feet also help the pigeon when it walks on the ground and to support its weight when it sits on a branch.
5. It makes the neck very mobile and the pigeon therefore can move its head in any direction.
6. To protect the foot and keep it dry.
7. It makes the pigeon even more streamlined and reduces the air resistance when the pigeon flies
(i) Differences with regard to external build
Animals are adapted to be able to survive in their habitat, e.g. fish are adapted to be able to live in water.
Study the sketch of the carp (freshwater fish) and identify the external body parts. Write down the name of the body part next to the correct number:
1.___________________________________________________________________2. ___________________________________________________________________
3. ___________________________________________________________________
4. ___________________________________________________________________
5. ___________________________________________________________________
6. ___________________________________________________________________
Each of these external body parts plays an important role in the survival of the fish in the water. Indicate the function of each of the following:
| CHARACTERISTIC | FUNCTION |
| spindle-shaped body | ___________________________________________ |
| scales | ___________________________________________ |
| gill slit | ___________________________________________ |
| tail fin | ___________________________________________ |
| dorsal fin | ___________________________________________ |
| lateral line | ___________________________________________ |
Assignment 8
Also study the sketch of the external build of the pigeon and answer the questions that follow:
1. The pigeon has a short, horny beak. Name five functions of the beak.
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
2. Its front limbs have been modified into wings so that the pigeon can fly. The strong pectoral muscles on either side of the sternum move the wings like oars that press against the air. In this manner the pigeon is propelled upwards and forwards. What helps to enlarge the surface of the wings?
3. Covert feathers and plumules are also found on the pigeon’s body. What is their function?
_____________________________________________________________________
_____________________________________________________________________
4. The feet of the pigeon also have been adapted to its habits. The three toes that point forwards and the one that points backwards are specially adapted. For what?
_____________________________________________________________________
_____________________________________________________________________
5. The neck is quite long and mobile. What is the advantage of this for the pigeon?
_____________________________________________________________________
_____________________________________________________________________
6. The feet are covered in scales. Why?
_____________________________________________________________________
_____________________________________________________________________
7. The free tips of the feathers point backwards and the body is boat shaped. Why is this so?
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
| CRITERIA | NO/YES |
| I easily could identify the function of the various body parts | ______________ |
| I could draw logical conclusions | _____________ |
| I could work independently | _____________ |
Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.
Assessment Standard 2.3: We know this when the learner interprets information.
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