-JO The Living Things of the Earth unit i 



stand for several days; then add a little pond water. In about ten days you 

 should have a good hav infusion. To slo\\' up the protozoa for study vou 

 can add to your slide a little gum tragacanth (ask for it at the drug store). 

 You ^\•ill find instructions for the use of the microscope on pages 1 13-1 14, 

 How many kinds of protozoa do you see? Draw some. 



11. How does a paramecium move? Which seems to be its front end? 

 As it swims forward it rolls over. Does it roll clockwise or counterclock- 

 wise? Which way does it roll \\'hen it swims backward? 



12. Perhaps the most fascinating object to watch under the microscope 

 is a large ameba. Do not use a bright light. How many pseudopods do 

 \ou see? What seems to happen to the particles just inside the tip of a 

 pscudopod at the "front" end of the animal? Does it ever lose a pseudo- 

 pod? How do you know? How fast does it move? How does it change 

 direction? Does it ever reverse the direction of its movement? 



Further Activities in Biology 



1. How to raise and observe grasshoppers. Construct a cage. Cover the 

 bottom of a terrarium with sod on which grass is still growing. The grass 

 must be watered regularly for the grasshoppers eat the grass and are 

 dependent on the water which they get from the surface of the leaves. 

 Cover the cage with a wire top or with a mosquito netting. Watch the 

 insects eat. Observe all other activities. 



2. How does the grasshopper jump? If you can obtain live grasshoppers, 

 watch' them jump. How many times its own length does a grasshopper 

 jump? In what position are the hind legs when the insect is about to 

 jump? Compare a grasshopper with a man doing a broad jump. Explain. 

 Does the grasshopper use its legs for anything but jumping? 



3. If you have any plants in the house or garden, examine the stems 

 and leaves carefully for aphids or scale insects. Describe any that you 

 find. Some kinds can be removed by holding the leaves and stems in soapy 

 water. 



4. Perhaps your class or biology club could buy an observation beehive 

 to keep at the window of your laboratory. You will learn a great deal 

 about the life of bees. 



5. Alany books have been wTitten on the social insects. Prepare a full 

 report on one of the social insects. 



6. Daphnia is a tiny crustacean that is easy to obtain and raise. Write 

 to an\' large biological supply house and ask for directions. 



7. rhe development of the snail is easy to follow if you use a hand 

 lens. Keep several snails in an aquarium. The eggs are laid in masses, often 

 on the glass. Note whether all the offspring of snails with right-handed 

 shells also have right-handed shells. 



8. Shell collecting is so popular a hobby that there are dealers all over 

 the world who publish catalogues of both common and rare kinds. 

 Encyclopedias contain pictures in color of some of the most beautiful. 



