Theodosius Dobzhansky said this quote

Nothing in biology makes sense except in the light of evolution.

~ Theodosius Dobzhansky

Seen in the light of evolution, biology is, perhaps, intellectually the most satisfying and inspiring science. Without that light it becomes a pile of sundry facts -- some of them interesting or curious but making no meaningful picture as a whole.

~ Theodosius Dobzhansky

The evolution of life, and the evolutionary origin of mankind, are scientifically established as firmly and completely as any historical event not witnessed by human observers. Any concession to anti-evolutionists, suggesting that there are scientific reasons to doubt the facticity of evolution, would be propagating a plain untruth.

~ Theodosius Dobzhansky

Nature's stern discipline enjoins mutual help at least as often as warfare. The fittest may also be the gentlest.

~ Theodosius Dobzhansky