Quote by Charles Darwin
"I was not able to work all day with vigour for more than a couple of hours daily."
More from Charles Darwin
"There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."
"It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change."
"The struggle for existence will always be there."
"Nothing in biology makes sense except in the light of evolution."