FREE BOOKS

Author's List




PREV.   NEXT  
|<   147   148   149   150   151   152   153   154   155   156   157   158   159   160   161   162   163   164   165   166   167   168   169   170   171  
172   173   174   175   176   177   178   179   180   181   182   183   184   185   186   187   188   189   190   191   192   193   194   195   196   >>   >|  
and the mistake in supposing that the American forms grew smaller than their ancestors in the Old World, certainly smack of the principle of isolation and segregation, and this is Buffon's most important contribution to the theory of descent. "It is probable, then, that all the animals of the New World are derived from congeners in the Old, without any deviation from the ordinary course of nature. We may believe that, having become separated in the lapse of ages by vast oceans and countries which they could not traverse, they have gradually been affected by, and derived impressions from, a climate which has itself been modified so as to become a new one through the operations of those same causes which dissociated the individuals of the Old and the New World from one another; thus in the course of time they have grown smaller and changed their characters. This, however, should not prevent our classifying them as different species now, for the difference is no less real though it dates from the creation. _Nature, I maintain, is in a state of continual flux and movement. It is enough for man if he can grasp her as she is in his own time, and throw but a glance or two upon the past and future, so as to try and perceive what she may have been in former times and what one day she may attain to._"[137] Buffon thus suggests the principle of the struggle for existence to prevent overcrowding, resulting in the maintenance of the balance of nature: "It may be said that the movement of Nature turns upon two immovable pivots--one, the illimitable fecundity which she has given to all species; the other, the innumerable difficulties which reduce the results of that fecundity, and leave throughout time nearly the same quantity of individuals in every species; ... destruction and sterility follow closely upon excessive fecundity, and, independently of the contagion which follows inevitably upon overcrowding, each species has its own special sources of death and destruction, which are of themselves sufficient to compensate for excess in any past generation."[138] He also adds, "The species the least perfect, the most delicate, the most unwieldy, the least active, the most unarmed, etc., have already disappeared or will disappear."[139] On one occasion, in writing on the dog, he anticipates Erasmus Darwin and Lamarck in ascribing to the direct cause of modification the inne
PREV.   NEXT  
|<   147   148   149   150   151   152   153   154   155   156   157   158   159   160   161   162   163   164   165   166   167   168   169   170   171  
172   173   174   175   176   177   178   179   180   181   182   183   184   185   186   187   188   189   190   191   192   193   194   195   196   >>   >|  



Top keywords:
species
 

fecundity

 

prevent

 
nature
 
Nature
 
individuals
 

smaller

 

Buffon

 

overcrowding

 

movement


destruction
 
principle
 

derived

 

quantity

 

results

 

sterility

 

reduce

 

difficulties

 

balance

 

suggests


struggle
 

existence

 

attain

 
perceive
 

resulting

 
maintenance
 
illimitable
 

pivots

 

immovable

 

innumerable


disappear

 

occasion

 
disappeared
 
active
 

unarmed

 
writing
 

direct

 

modification

 

ascribing

 

Lamarck


anticipates

 

Erasmus

 
Darwin
 

unwieldy

 
delicate
 
special
 

sources

 

inevitably

 
closely
 

excessive