110 Evolution and Adaptation 
seminated by birds, its existence depends on them, and it may 
metaphorically be said to struggle with other fruit-bearing 
plants, in tempting the birds to devour and thus disseminate 
its seeds. In these several senses, which pass into each other, 
I use for convenience’ sake the general term ‘Struggle for 
Existence.’ ” 
A number of writers have objected to the general and 
often vague way in which Darwin makes use of this phrase ; 
but it does not seem to me that this is a serious objection, 
provided we are on our guard as to what the outcome will 
be in each case. In each instance we must consider the 
question on its own merits, and if it is found convenient to 
have a sufficiently general and non-committal term, such as the 
“struggle for existence,” to include all cases, I see no serious 
objection to the use of such an expression, although it is 
true the outcome has been that it has become a catchword, 
that is used too often by those who have no knowledge of its 
contents. 
Were it not that each animal and plant gives birth, on an 
average, to more than two offspring, the species would soon 
become exterminated by accidents, etc. We find in some of 
the lower animals, and in some of the higher plants, that 
thousands and even millions of eggs are produced by a 
single individual in the course of its life. A single nematode 
may lay sixty million eggs, and a tapeworm one thousand 
million. A starfish may produce about thirty-nine million 
eggs, a salmon may contain fifteen thousand, and a large shad 
as many as one hundred thousand. The queen of a termite 
nest is said to lay eighty thousand eggs a day. 
In the higher vertebrates the number of young is con- 
siderably less, but since the young stages are passed within 
the body of the parent, proportionately more of them reach 
maturity, so that even in man the population may be doubled 
in twenty-five years, and in the elephant, slowest breeder of 
all animals, Darwin has calculated that, if it begins breeding 
