Name:  Peter Nelson   

Subject: Biology I (ecology)

Period: 3rd

Approximate Time: 50 minutes

Objectives:

The student will examine long and short term changes to the environment as a result of natural events and human actions (Biology, 7.e).

Materials:

Writing utensil, whiteboard markers, whiteboard

Bell work:

You are a biologist researching a recent climate change in the Mississippi deciduous forest. An alien insect has invaded the ecosystem and has demolished the crops in the area. Your job is to predict the consequences in the ecosystem due to this invasion.

During the bell work, define ecological succession, primary succession, pioneer species, climax community, and secondary succession.

Set:

Yesterday we got a chance to talk about ecosystem interdependency,  what does ecosystem interdependency mean? remember to give more time for questions!  Up to this point we have been giving drastic examples (aliens, all the trees gone etc.) and haven’t talked about how ecosystems might compensate. The truth is, they can compensate for some things. Think of an example when something went wrong, but instead of everything changing, people adapted to the change or made up for the change. (2 min). Things also can go very wrong and people can rethink or redo the operation. (Wal-mart example: one person is stealing and they are fired, which may make you work harder for awhile until they find a replacement. Everyone is stealing...start from scratch. Depends on how drastic. The same is true for ecosystems. Today we will be talking about this “re-building” or compensation. And you will take a look at two different types of what is called ecological succession.

Procedure:

1. Define on board (pre-written)

primary succession: Occurs after a major disturbance such as a volcano eruption that has removed or covered the soil.

Poineer species: first species to live in the new environment. In this case, usually lichens

Lichens: Fungus that can break down ricks and begin to make a thin layer of soil.

2. Lichens --> Mosses --> Grasses (earthworms enrich soil, insects) --> Shrubs (birds and small mammals) --> Pine Trees (provide shelter for larger mammals and other trees). The final community of organisms is know as the climax community.

3. Climax Community: Little change, but still affected by changes in climate and non-native species.

4. Ask them to write down an example of a progression within the deciduous forest biome, finishing with a climax community. 2-3 min.

5. Are there ponds in your climax community? NO! Why might that be? 3-4 min.

6. Ponds are never climax communities. In a pond ecosystem what might be the primary producers? (bacteria, algae) For what? invertebrates, small fish, amphibians. At the same time, water plants may begin to grow. But how does the water go away? Particles brought from the wind and air and other sources are deposited at the bottom of the pond and it becomes shallower and shallower.  Eventually the grass will then change to trees.

7. So that is primary succession, what needs to happen for primary succession? Start from the beginning, make new soil etc.

8. Secondary Succession: A different type of succession. It doesn’t remove the soil. What might be some examples of secondary succession? 3 minutes.  (ex. wildfire, human disturbances, disease, HURRICANE KATRINA).  The stages are the same except it doesn’t take as long because it doesn’t start from scratch.

9. Knowledge of primary and secondary successions helps foresters determine how mature a forest is and they can predict what it will look like in the future. Ex.) You come upon a forest full of low growing trees and grasses, several ponds and small mammals. Where is this community and what is it going to look like next? (give the time for this if time allows, or give them a worksheet on succession).

Closure:

Great job today. Review examples of primary succession, poineer species, climax community, secondary succession. Tomorrow we will be talking about humans and their role in ecosystems. Can anyone think of some examples in which humans might impact the environment?

Assessment/Evaluation:

Objective: The student will examine long and short term changes to the environment as a result of natural events. (Biology, 7.e).

Informal: The teacher will assign and monitor many short independent assignments (M) designed to foster exploration of long and short term changes (primary and secondary successions) to the environment as a result of natural events (C).

Formal: The teacher will assign a worksheet (M) on primary and secondary succession (C)  that will be graded and recorded in the grade book (D).