Image: Steve Boer / shutterstock.com More than a century after humans wiped them out, California's grizzly bears may be getting a second chance, as lawmakers consider a carefully managed plan to restore a missing keystone species to its native ecosystem. "The fears articulated about bringing grizzlies back, and all the chaos and carnage that they fear will ensue, is completely overblown," Brendan Cummings, conservation director at the Center for Biological Diversity, told SFGATE. "They're big and fierce animals, but at the end of the day, they're mostly vegetarian, minding their own business, looking for food and other things in life. And we're an annoyance at most, and they'll do everything in their power to avoid us."  If a grizzly reintroduction were to take place in California, it would likely be "the most studied and carefully managed and scrutinized species reintroduction ever done in the United States," Cummings added.…