I. Haeckel and His Opponents

In artificial breeding human intelligence chooses the conditions so that the new forms coming into existence answer to the purposes which the breeder is following out. Now, the organic forms living in Nature are in general purposefully adapted to the conditions under which they live. A mere glance into Nature will teach one the truth of this fact. Plant and animal species are so constructed that they can maintain and reproduce themselves in the conditions under which they live.