Which example of Darwin’s poetry represented his idea of revolution most?

Erasmus Darwin, grandfather of Charles Darwin, was a deist, not an atheist. Seperate from his work in science, he was also a well-known poet. Much of his ideas would lay the groundwork for his grandson’s evolution theory. 

An example of his poetic representations of the idea of evolution from “Animals are the first Aquatic” is the following: 

ORGANIC LIFE beneath the shoreless waves 

Was born and nurs'd in Ocean's pearly caves; 

First, forms minute, unseen by spheric glass, 

Move on the mud, or pierce the watery mass; 

These, as successive generations bloom, 

New powers acquire, and larger limbs assume; 

Whence countless groups of vegetation spring, 

And breathing realms of fin, and feet, and wing. 

Thus the tall Oak, the giant of the wood, 

Which bears Britannia's thunders on the flood; 

The Whale, unmeasured monster of the main, 

The lordly Lion, monarch of the plain, 

The Eagle soaring in the realms of air, 

Whose eye undazzled drinks the solar glare, 

Imperious man, who rules the bestial crowd, 

Of language, reason, and reflection proud, 

With brow erect, who scorns this earthy sod, 

And styles himself the image of his God; 

Arose from rudiments of form and sense, 

An embryon point, or microscopic ens! 

Again, Erasmus was not an atheist. He believed in deism and presented the idea of evolution within the framework of a deistic perspective. He said: “The great CREATOR of all things has infinitely diversified the works of his hands, but has at the same time stamped a certain similitude on the features of nature, that demonstrates to us, that the whole is one family of one parent.”