Part II Use the following words and phrases to fill in the blanks with the best possible match. You will use several of the terms more than once. ecosystem primary succession diversity secondary succession lichens pioneer organisms succession climax community 1. A forest of pine trees is burned over a 10 mile area when lightning strikes a tree. In the spring, a few seedlings are beginning to sprout. 2. A glacier has scraped all soil from a rocky area. As it slowly retreats, some of the rock is broken down by weathering. Some moss begins to grow. 3. A small symbiotic organism secretes acid into the rock to anchor itself in place.