A PIONEERING WORK OF EXOBIOLOGY. Wallace's Man's Place in the Universe (1900) had argued that advanced life was unique to the planet earth. Is Mars Habitable? developed these arguments further in response to Percival Lowell's influential theory that the "canals" he had observed on the Martian surface were evidence that the planet was home to an intelligent civilization. Wallace concluded that the low average temperature, thin atmosphere, and absence of water, meant that the red planet was absolutely uninhabitable.