Activity 6: Background Information

Succession
Succession involves change that is not immediate but rather slow and gradual. Succession can either be primary or secondary. Primary succession occurs in an area where initially no community existed. For example, primary succession takes place when a glacier recedes and leaves behind barren land. It can also occur on a newly formed volcanic island. Secondary succession takes place when a community replaces an already existing community. For example, secondary succession takes place when a forest community is destroyed by fire. A community was already there before its destruction by the forest fire. For primary succession to take, rocks must first be broken down into soil. In secondary succession, soil is already present. This explains why it takes longer for primary succession to happen.

In the “lifeless” environment, the very first community to appear is the pioneer community. They are plants that lie close to the ground and can withstand high temperatures from full exposure to the Sun. Despite their short life, they make up for it by their fast dispersal of a lot of seeds. These short annual plants contribute organic material to the soil resulting in more favorable conditions present for taller plants that cannot tolerate full sunlight.

Replacements continue until a mature or a stable community called the climax community is established. A climax community is reached when no other community replaces it. Communities that are formed between the pioneer and the climax communities are referred to as seral stages.

A climax community is best exemplified by biomes like the desert with its characteristic flora and fauna, which are dictated by specific temperature and rainfall patterns.

This activity focuses on the observational skills of the students as they visually note the changes that occurred: nine months, 3 years, 13 years, 23 years, and 47 years after a volcano erupted. As they do their visual inspection, the students are encouraged to compare the events along the coastal areas and those in the inland areas. After their comparisons are made, the students are expected to explain why there is a difference and how the difference occurred.