August Weismann

"The organism exists not for itself, but as a vehicle for its hereditary substance."

"Nature selects not for virtue, but for reproductive success in the present moment."

"What is inherited determines the possibilities; what is accomplished determines the actualities."

"Evolution is not about progress toward something better, but adaptation to what is."

"The germ-plasm is immortal; only the soma dies."

"To live is to vary, and to vary is to be subject to selection."

"The mechanism of heredity is the mechanism by which life perpetuates and changes itself."

"Life's answer to the problem of survival is always adaptation, never perfection."

"In each organism lives the history of all its ancestors, compressed into heredity."

"The organism is built by heredity and modified by environment, but controlled by selection."

"What appears as design is the accumulated effect of countless small selections."

"Life advances through variation; stability is maintained through inheritance."

"The struggle for existence is not a metaphor but the literal description of life's condition."

"To understand evolution is to understand that life has no final form."

"Every organism alive is a solution that worked, expressed in flesh and blood."

"Nature's laboratory is vast, and the experiments number in the billions."

"What is selected is not the individual, but the line through which heredity flows."

"Life is the only system that improves through competition."

"The persistence of life through change is the greatest mystery of nature."

"What survives survives not because it is superior in any absolute sense, but because it fits."

"The organism is the expression of its heredity in its particular environment."

"Evolution is both the simple fact of change and the mechanism by which change occurs."

"Life's diversity is life's strength, and life's strength is diversity."

"To live is to be part of a lineage that stretches back to life's origin."

"The future of life depends on the variation that exists in the present."

"Nature is indifferent to suffering, progress, or perfection; it selects only for fit."