PROBLEM 3. Houo Complex Vlants Reproduce 41^3 



of spore cases; each case is too small to be seen. Mount some of this mate- 

 rial and study a spore case under the low power of the microscope. De- 

 scribe. Do you see spores? About how many spores would fit into one 

 case? Why do you say that these spores have been formed asexually? 



12. How may the vegetative parts of plants reproduce? With the class 

 organized into committees try to propagate plants vegetatively. Use a 

 geranium or coleus for slipping (place in water or sand), a potato to 

 show reproduction by the underground stem (tuber), and the bulb of an 

 onion, narcissus, etc. Remove the leaf from a begonia, cover the end of 

 the leaf-stalk with soil; keep moist. In each case note the length of time it 

 takes for roots to form, or a new plant to appear. How many plants can 

 you name which can reproduce by vegetative propagation? Try propa- 

 gating other plants. 



Further Activities in Biology 



1. If you have patience you can raise fern prothalli from spores. 

 Sprinkle spores of the Christmas fern on moist sterile soil (in a dish) and 

 cover with a plate. Watch for the tiny green structures; it will take sev- 

 eral weeks. 



2. Make an exhibit of flowers or of a series of charts to show how 

 flowers are constructed to prevent self-pollination or to secure wind or 

 insect pollination. 



3. Devise and perform experiments to discover whether moisture and 

 air are needed by germinating seeds. Report on your work. 



4. Does light affect the germination of seeds? Devise an experiment. 



5. Report on the pollination of the Yucca flower by the Pronuba moth. 



hi UNIT IX yoii will consider these problems: 



Problem i. Why Do Offspring Resemble Their Parents? 



Problem 2. How Can Some of the Differences between Parents 

 and Ofltspring Be Explained? 



Problem 3. How Can New Hereditary Characters Appear? 



Problem 4. How Does the Environment Affect the Charac- 

 ters of an Organism? 



Problem 5. What Have We Learned about Producing New 

 Types of Animals and Plants? 



Problem 6. To What Extent Can Mankind Be Improved? 



