232 



LIFE ON THE EARTH 



FIG. 370. LIFE HISTORY OF A FROG 



REFERENCES FOR FURTHER STUDY 



Texts 



Caldwell and Curtis, Science for Today, Chaps. 29-32 

 Hunter and Whitman, My Own Science Problems, Unit 



10; Science in Our World of Progress, Unit 14 

 Powers, Neuner, and Bruner, The World around Us, Units 



2 and 8 ; This Changing World, Chap. 21 

 Watkins and Bedell, General Science for Today, Chap. 27 

 Webb and Beauchamp, Science by Observation and Experi- 

 ment, Unit 9 



Wood and Carpenter, Our Environment: How We Use and 

 Control It, Unit 8 



Special references 



Atwood and Heiss, Educational Biology 



WHAT YOU SHOULD AIM TO ACQUIRE FROM 

 THIS STUDY 



1. A clear understanding of the conception that all 

 living things come from living things. 



2. A knowledge of how simple one-celled animals 

 and plants reproduce. 



3. A knowledge of how flowering plants reproduce. 



4. An understanding of how higher animals, such 

 as frogs and birds, reproduce. 



TEST OF MASTERY OF THE TOPIC 



In your notebook complete the statements, answer the 

 questions, and comply with the instructions. 



1. Is the statement that all life conies from life true, 

 partly true, or false? 



2. How do one-celled organisms such as bacteria repro- 

 duce? 



3. The organs of reproduction of a plant are in the 



4. The parts of flowers which attract insects to them 

 are called __ _ 



5. The transfer of pollen from anther to stigma of flow- 

 ers is called 



6. The embryo of the new plant is contained in the . 



7. Make a diagram of a flower and label the following 

 parts : sepal, petal, stamen, pistil, ovary, anther, stigma, 

 ovule. 



8. What parts of a flower are necessary for reproduc- 

 tion? 



9. What part do bees and other insects play in the re- 

 production of many flowering plants? 



10. When frogs reproduce, a cell called the unites 



with a cell called the This process is called 



TOPIC 4. IMPROVEMENT OF LIVING THINGS 



SUGGESTED PROBLEMS AND QUESTIONS 



1. Are any two living things exactly alike? Ex- 

 plain the term variation as it is applied to liv- 

 ing things. 



2. Why do you resemble your parents? 



3. Who was Gregor Mendel? For what is he 

 noted? 



4. Can mankind be improved? 



5. Have animals been improved by man? 



6. Have plants been improved by man? 



7. What was the work of Luther Burbank? 



SUGGESTIONS AND HELPS FOR STUDY 

 - 1. This is an important topic. The improvement of 

 living things adds greatly to the comfort, happiness, 

 and progress of man. Gather all the scientific knowl- 

 edge you can find relating to the problem in this topic. 



2. Study carefully the meaning of the scientific 

 terms heredity and variation. 



3. A study of the experiments by Gregor Mendel 

 will show you how carefully a scientist works. 



4. A study of the achievements of Luther Burbank 

 will show you how scientific knowledge can be applied 

 to produce practical and beneficial results to mankind. 



5. Society is becoming greatly interested in apply- 

 ing scientific knowledge to the improvement of man. 

 Find out the conditions in human society that need 

 improvement and the ways by which this improve- 

 ment can be made. 



INVESTIGATIONS WHICH WILL HELP ANSWER 

 THE PROBLEM QUESTIONS 1 



Activity 143. How do living things vary? 



Collect a hundred leaves from a tree. Are any two exactly 

 alike? 



1 See workbook, p. 83. 



