ECOLOGICAL SUCCESSION. 149 



problem-, tin' attempt at the solution of which has made modern 

 biology what it is. 



If we assume the attitude that nothing can be done in the 

 organization of natural history materials into a science, we are 

 do-in- the que-tion to investigation, much as the id. -pecial 



creation closed other lines of biological in\ v-ti-ation. Still an 

 occasional biologist appear- to take this point of view. 



A-ide from tin- general questions which we have been di-cu - 

 an- many practical applications of pond successsion 

 dy of behavior .md t<> the economic and quantitative 

 >idc of l>iol"L;\. The-,- we will di>cus in a succeeding pa- 



under tin- In ad < if t : ; '>n in pond-. 



VII. -M MM \KV. 



i. Then- i- s of ponds at the south end of Lake Michigan 



arranged in ihe .-rder of their - i- determine<l by the 



jili\ .hie history; b\- the relative amount of huinu^ and 



ban bolt.iin. and b\ tin- ijualitv' and (|uantit\ <>!' vegetation. 



.f li-li are arran^-d in the-r |oiid> in an i-rderK' 



fa -hi 1. 1 1 : i In- order Is related to the age of the ponds. 



j. I he p'Hid- 'I dittt-r'-i in the hi-i'>r\ 



of c.ldcr |" nub. 



4. Tin- horizontal -h cr.iiimunitii-- i- i-.-..|.i-irally 

 repn-veiitati\e "f tin.- MI, -iv imi nf ti-li coinmunii ie> \\itliintlie 

 older puihb. 



5. Tin method employed here i- similar to |)h> M'< i^r 

 anaK-i-; the m..ti\e- ami po-Mble re-ult- are -imilar but 

 strictK' bi..l. i^ical. because the caus the SU< n are the 



iUJMll- tllem>el\ 



II- . : / 



,11. 



VIII. ACKNOWLEDGMENTS AND Bir.i.i' \\< \I-HN . 



i. .[<(' -The writer i- indebted t,. I >r. II. C. 



Cowles for assistance with the plant >ide. of the pond problem: 

 to Mr. \\ . C. All-' '"r assistance in mapping the p<>nd-. The 

 ideiititicalion ,.f the ti>h i- b\- Dr. S I M k and Mr. S. I 



