In the wild, ecosystems are complex webs of organisms, weather and landscapes interacting in delicate equilibrium to create a hubbub of life. No two ecosystems are alike. So it is, too, with the microcosms that form around start-ups. Those that thrive – think Silicon Valley and Israel – are invariably hothouses of mutually supporting entrepreneurs, investors, regulators and researchers. Are start-up ecosystems born or can they be made? Both, says …