(5-8) B3

Science Curriculum Preview Committee Clarification of Learning Results

Revised 04/08/04

5-8

B3: Describe succession and other ways that ecosystems can change over time.

Curriculum Organizing Questions

What populations make up this community?

What are some of the stages of succession for this ecosystem?

What are some of the ways we can tell that an ecosystem was disturbed?

What predictions might you make about this ecosystem if the climate were to change?

What are some of the examples of ecosystems in succession in our towns?

What are some of the local examples of ecosystems that have changed due to human activities?

Elaboration
If a natural disaster such as a flood or fire occurs, a damaged ecosystem is likely to recover in a succession of stages that eventually results in a system similar to the original one. Like many complex systems, ecosystems tend to show cyclic fluctuations around a state of approximate equilibrium. However, ecosystems inevitably change when climate or when very different new species appear as a result of migration or evolution (or are introduced by humans). SFAA p. 65

Specific Ideas

Populations of different organisms that live and interact in the same place or ecosystem at a given time form a community.

The process by which one community replaces another is called succession.

When an ecosystem is disturbed, it is likely to go through a series of stages that results in a community very much like the original one. SFAA p. 65

Ecosystems can be relatively stable over hundreds or thousands of years. NSES C4c

Ecosystems always change when climate changes or when one or more new different species appears. Benchmarks 5D2 (gr 9-12)

Human activities alter the stability of ecosystems and can irreversibly affect them. Benchmarks 5D3 (gr 9-12)

Developmental & Instructional Implications
Students may believe that organisms are able to effect changes in bodily structure to exploit particular habitats, or that they respond to a changed environment by seeking a more favorable environment. Teachers should challenge the misconception that the ocean is a limitless resource and that humans are indestructible as a species. Page 62 in Making Sense of Secondary Science is especially informative.

The national standards place this idea at the high school level.

Examples

Back to Big Ideas Grid B Back to Standard B Back to Index

Curriculum Organizing Questions	What populations make up this community? What are some of the stages of succession for this ecosystem? What are some of the ways we can tell that an ecosystem was disturbed? What predictions might you make about this ecosystem if the climate were to change? What are some of the examples of ecosystems in succession in our towns? What are some of the local examples of ecosystems that have changed due to human activities?
Elaboration	If a natural disaster such as a flood or fire occurs, a damaged ecosystem is likely to recover in a succession of stages that eventually results in a system similar to the original one. Like many complex systems, ecosystems tend to show cyclic fluctuations around a state of approximate equilibrium. However, ecosystems inevitably change when climate or when very different new species appear as a result of migration or evolution (or are introduced by humans). SFAA p. 65
Specific Ideas	Populations of different organisms that live and interact in the same place or ecosystem at a given time form a community. The process by which one community replaces another is called succession. When an ecosystem is disturbed, it is likely to go through a series of stages that results in a community very much like the original one. SFAA p. 65 Ecosystems can be relatively stable over hundreds or thousands of years. NSES C4c Ecosystems always change when climate changes or when one or more new different species appears. Benchmarks 5D2 (gr 9-12) Human activities alter the stability of ecosystems and can irreversibly affect them. Benchmarks 5D3 (gr 9-12)
Developmental & Instructional Implications	Students may believe that organisms are able to effect changes in bodily structure to exploit particular habitats, or that they respond to a changed environment by seeking a more favorable environment. Teachers should challenge the misconception that the ocean is a limitless resource and that humans are indestructible as a species. Page 62 in Making Sense of Secondary Science is especially informative. The national standards place this idea at the high school level.
Examples