Use the following words and phrases to answer the questions below with the best possible answer. some phrases will be used more than once.

succession primary succession secondary succession
soil climax community pioneer species

1. a forest of pine trees is burned over a 10 mile area when lightning strikes a tree. in the spring, a few seedlings begin to sprout. this is an example of:

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. this is an example of:

3. an old-growth forest has remained the same combination of hickories and oaks for 100 years. this is an example of a:

4. small organisms, such as lichens, break up bare rock into soil. a lichen is an example of a:

5. a pond slowly fills in as algae and other plants die and fall to the bottom. this is an example of:

6. a volcano erupts creating a new island. this is an example of:

7. the process of primary succession begins with the formation of over time the once empty rock surfaces will become populated with organic material.

occurs when ecosystems change over time through the progressive replacement of species.