14 On Foraging Theory, Humans, and the Conservation of Diversity: A Prospectus The Tertiary is over. The world of our remote ancestors has nearly vanished. No nostalgia can save it; no yearning can restore it. We have entered the geological era of Homo sapiens. Like it or not, we are the boss. | Illllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll 14 On Foraging Theory Humans and the Conservation of Diversity A Prospectus Michael L. Rosenzweig Prologue The Tertiary is over. The world of our remote ancestors has nearly vanished. No nostalgia can save it no yearning can restore it. We have entered the geological era of Homo sapiens. Like it or not we are the boss. We take what we want where we want it. We take land and sea water and air. We corral a stupendous fraction of the earth s productivity and mineral resources Vitousek et al. 1997 . With clever apparatuses we adapt to an unprecedented variety of environmental conditions turning them all into a semblance of the semiarid tropical climate in which our physiologies evolved. Where we have not yet learned to live we dream of living. No previous era in the history of life has seen our ilk. We have not eradicated in ourselves the basic acquisitive nature that natural selection insists upon in all successful lifeforms. That was the real flaw of Marxist thought it dreamed that Man without unfulfilled needs would become generous. But while a competitive and exploitative Mankind may confound socialist economics and disappoint theologians and moralists it looms as a death warrant for every ecosystem whose resources we expropriate. The rest of life can do little to thwart us. But we can do something. We can abstract. We can contemplate what we are doing. We can even predict the consequences. And we can lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll 484 Michael L. Rosenzweig find alternatives. Our plans have already restructured the world of life unintentionally. Why should they not do so on purpose And who is to say whether that purpose need be malevolent or malicious Fortunately evidence indicates that we would rather share our world with other species conserving at least patches of