Filed at 3:37 p.m. ET

ANN ARBOR, Mich. (AP) -- The Dalai Lama said Sunday the need for environmental responsibility dovetails with Buddhist teachings on valuing human life, whether that is one person or the world's entire population.

The exiled Tibetan spiritual leader addressed crowds of more than 7,000 during a weekend of lectures at the University of Michigan.

''Taking care of our planet, environment, is something like taking care of our own home,'' he told a Sunday afternoon audience at Crisler Arena. ''This blue planet is our only home.''

During Sunday's lecture, ''Earth Day Reflections,'' the Dalai Lama said he has learned about the need for environmental responsibility from meetings with scientists and other experts.

Outside the arena, hundreds of pro-China demonstrators held signs and waved Chinese flags. Many wore T-shirts that read ''Support Beijing 2008,'' a reference to the upcoming summer Olympics, and a small airplane flew overhead pulling a banner that read ''Dalai Lama Please Stop Attacking Olympic Flame.''

That protest led to heated verbal exchanges between pro-Chinese and pro-Tibetan demonstrators, who traded shouts of ''One China'' with ''Open the door! Let's see what's happening inside Tibet.''

Pro-Tibet demonstrators have disrupted Olympic torch runs in protest of China's treatment of the Dalai Lama's follows. He has denied Chinese claims that he and his followers have used the Olympics to foment unrest.