Question 5, page 870
Answers to many of these questions can be found on the "Answers to End-of-Chapter Questions" page at the text website.
Web Resources for Ecosystems in Time
Objectives:
After studying this material you should be able to:
- Describe an ecosystem and explain how the biological community interacts with its environment.
- Explain the role of disturbance in (natural and managed) ecosystems and its relationship to succession.
- Explain what primary succession is and give some real world examples.
- Explain what secondary succession is and distinguish it from primary succession.
- Describe what soil is.
- Describe how living components in the ecosystem change nonliving components during succession.
- Explain what disclimax is and how some ecosystems are maintained in a state of disclimax.
Key Terms:
| succession | climax community | pioneer species |
| disturbance | primary succession | secondary succession |
| disclimax | environmental change |
soil formation |
| prescribed burning |
Ecological Succession
From the Latin, succedere, to follow after
- Change in structure of the biological community over time.
- Pioneer species
- Change the environment favoring the growth of other species.
- soil stabilization
- soil nutrient enrichment (organic matter and biological nitrogen fixation)
- increased moisture holding capacity
- light availability
- temperature
- exposure to wind
- Factors influencing community change
- disturbances of all scales
- invasion of species from other areas (exotics)
- Invasive Species
- Zebra mussels and their spread: 1988, 1992, August 1999
- Asian Long-horned beetle
- Purple loosestrife
- climate change
- Invasive Species
- Climax community
Primary Succession
- The processes involved in changing an area from one lacking any community (no plants, no animals, no insects, no seeds, etc.) to one consisting of individuals, populations, communities, and ecosystems. CAUTION!!The text definition is misleading.
- Starts WITHOUT SOIL
- No organic matter, only mineral material (e.g. sand, bare rock, gravel from glacial outwash, volcanic ash and lava (CAUTION!! different from text).
- Pioneer plants (e.g. lichens and mosses)
- Examples
Secondary succession
- Follows disturbance
- Starts WITH SOIL.
- Faster
- Examples
A summary of changes that occur during succession:
- Pioneer species colonize first.
- Newly arriving species alter the conditions.
- New species of plants displace existing plants.
- Animals come in with or after the plants they need to survive.
- With infrequent disturbance a climax community will become established.
Take me home.