Ernst Mayr

Evolution is not a theory, it is a fact. It is the backbone of biology, and biology is thus in the peculiar position of having its central theory, evolution, so widely accepted that it is often treated as a fact.

The great conceptual innovations of science are not always the result of new facts, but often of a new way of looking at old facts.

Biology is the science of life. It is the science of living things, their structure, function, development, and evolution.

The species is the fundamental unit of evolution.

Natural selection is not an all-or-none phenomenon, but a matter of degree.

The history of science shows that the most important advances are often made by those who are not afraid to challenge established dogma.

The ultimate goal of science is to understand the world around us.

Science is a human endeavor, and as such, it is subject to human error.

The greatest challenge facing science today is to integrate the various disciplines into a unified whole.

The concept of species is one of the most fundamental and controversial concepts in biology.

The biological species concept defines species as groups of interbreeding natural populations that are reproductively isolated from other such groups.

Evolution is a two-step process: the production of variation and the sorting of that variation by natural selection.

The history of life on Earth is a history of continuous change.

The diversity of life on Earth is a testament to the power of evolution.

The study of evolution is essential for understanding the living world.

The scientific method is a powerful tool for understanding the natural world.

Science is not a collection of facts, but a way of thinking.

The progress of science depends on the free exchange of ideas.

The future of humanity depends on our ability to understand and protect the natural world.

The concept of teleology has been a major impediment to the progress of biology.