EXPLORATtONS AND PROJECTS 



1 To find a basis for classifying leaves, collect enough leaves of about 25 

 different plants to supply one of each kind for each pair of workers. Examine the 

 leaves to find details of form, coloring, margins and arrangements that suggest 

 resemblances and differences. Select what seems to be the most obvious character 

 that will serve to divide all the leaves into two groups. Record the names of all 

 the species placed in each group by this first dichotomy, or "forking", and also the 

 basis for the separation. 



Within each group of leaves, select a second prominent characteristic, and divide 

 each pile into two more piles according to the new criterion. (It is sometimes possible 

 on this second sorting to use the same criterion in dividing both piles.) Record the 

 basis for separation used and list the species in each of the four groups. 



Continue subdividing until the leaves left in each pile appear to have enough 

 in common to be considered as of the same family or "kind". 



Check on the adequacy of the criteria and on the consistency of the work by 

 noting whether all the oak leaves, for example, did get into the same pile, and 

 all the clover leaves into another single pile; and by noting whether leaves of 

 different kinds came into the same group. 



From the records of this procedure, it is possible to construct a "key" with 

 which one could quickly identify any of the leaves included. 



2 Select a spot where a variety of living plants can be found and picked. 

 Work in squads or committees, each with definite plants to find and to identify cor- 

 rectly — algae, fungi, lichens, mosses, liverworts, ferns, horsetails, club mosses, coni- 

 fers, monocots and dicots. After each committee has verified or checked its collection, 

 spend the remaining time hunting additional specimens of special interest. 



3 Collect from a brook or pond numerous living animals by pulling a dip 

 net through the clusters of aquatic plants growing there. Bring these living speci- 

 mens to your laboratory in vessels of water. Place them in shallow glass dishes 

 for easy observation. Find, sketch and name as many different kinds of animals as 

 you can. Group them according to outstanding characteristics that you recognize. 



QUESTIONS 



1 What is the use of naming the various forms of living things? 



2 What is the use of classifying the various forms of living things? 



3 What must a scheme of sorting do if it is to be of practical value? 



4 What are some of the common bases used in grouping plants or animals 

 for specific purposes? 



5 What bases are used for grouping plants or animals in the most widely 

 accepted scientific scheme of classification ? 



6 What is meant by a species? 



7 What names are used to designate successive subdivisions, or branches, in 

 the classification of plants and of animals? 



8 Why is it not sufficient to use common names for different kinds of plants 

 and animals? 



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