Applied to the real world, there is an idea known as the Gaia Hypothesis, as proposed by James Lovelock and defended by other scientists including Lynn Margulis. They propose that Earth's biosphere itself may be considered; if not a real superorganism; at least a self-regulatory system with features of a living being itself. According to this idea, the biosphere tends to have a stabilizing effect upon the habitability of Earth, in terms of regulating environmental factors such as temperature and atmospheric composition; the result being that the presence of life helps create an environment adequate for life. Therefore: the biosphere itself is self-perpetuating. The opposite idea; the Medea Hypothesis, as proposed by Peter Ward; claims instead that life tends to destabilize its environment