00293nam a2200121 a 450000500170000008200130001710000210003024500230005126000300007430000290010463000120013370000260014520251203091010.0  a577bEHR  aEhrlich, Paul R.  aScience of ecology  aNew YorkbMacmillanc1987  axxv, 710 p.b24 cm.cHB.  aEcology  aRoughgarden, Jonathan