Lesson 7: Primary and Secondary Succession
Big Idea: Ecosystems change all the time.
Learning Goal: To understand how human and natural interactions can change ecosystems, and how ecosystems respond to these changes.
Succession is the natural process by which a community changes over time causing a natural change to the environment. These changes may be slow and difficult to notice in a short period of time. As you saw in the slideshow, the natural and biological development of a hardwood forest is an example of succession.
1) Primary succession: The process of an ecosystem development by a pioneer species, and takes place in areas lacking soil (bare rocks, sand dunes, and cooled lava for example).
2) Secondary succession: The process by which an ecosystem changes after it has been disturbed, for example by a forest fire. This succession represents the re-growth of a community.
2) Secondary succession: The process by which an ecosystem changes after it has been disturbed, for example by a forest fire. This succession represents the re-growth of a community.
Forest Fires
Forest fires can be very damaging, but they also have benefits. These include:
1) Cleaning the forest floor: Fire removes low-growing underbrush, cleans the forest floor of debris, opens it up to sunlight, and nourishes the soil. Reducing this competition for nutrients allows established trees to grow stronger and healthier.
2) Providing habitat: Fire cleans wild lands of heavy brush, leaving room for new plant species that provide a habitat for wildlife.
3) Killing Disease: Fire kills diseases and insects that prey on trees and provides valuable nutrients that enrich the soil. More trees die each year from insect infestation and disease than from fire.
4) New Generations: Change is important to a healthy forest. Some species of trees and plants are actually fire dependent. They must have fire every 3-25 years in order for life to continue.
1) Cleaning the forest floor: Fire removes low-growing underbrush, cleans the forest floor of debris, opens it up to sunlight, and nourishes the soil. Reducing this competition for nutrients allows established trees to grow stronger and healthier.
2) Providing habitat: Fire cleans wild lands of heavy brush, leaving room for new plant species that provide a habitat for wildlife.
3) Killing Disease: Fire kills diseases and insects that prey on trees and provides valuable nutrients that enrich the soil. More trees die each year from insect infestation and disease than from fire.
4) New Generations: Change is important to a healthy forest. Some species of trees and plants are actually fire dependent. They must have fire every 3-25 years in order for life to continue.
Activity for today:
Journal:
Draw and label and illustrate a diagram showing and explaining these changes.
Make your thinking clear!
Make your thinking clear!