The Lessons on the Lake Logo Chapter 7: Ecosystems in Delicate Balance
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Lessons on the Lake -> Chapter 7 -> Ecosystem Tumble

Can You Name Some of the Ecosystems Located
around Lake Pontchartrain?




Pine, Beech, Oak, Hickory

Wild Turkey, Deer


Magnolia, Ash, Oak, Sweetgum

Weasels, Skunks, Opossums, Raccoons, Deer


Bald Cypress, Tupelo Gum, Ash

Alligator, Nutria, Heron, Boar, Deer


Bulltongue, Plametto, Cattail

Alligator, Nutria, Ducks


Bulltongue, Cordgrass, Spikerush, Bulrush

Nutria, Blue crabs, Egrets, Ducks


Saltwort, Smooth Cordgrass, Black Needlerush

Hermit Crabs, Speckled Trout, Redfish, Muskrat, Pelicans

ACTIVITY: Ecosystem Tumble


  • Lots of wooden blocks of uniform sizes (these can be obtained from construction sites at no cost and cut to uniform sizes)

  • Colored pencils to draw organisms on the blocks...or...

  • Lots of small photos cut from magazines which depict the various aspects of an ecosystem...plants, insects, fish, bacteria, eagles, etc...use your imagination!

  • Scissors to cut the pictures to size

  • Glue to fasten the pictures to the sides of the blocks

Getting Ready:

  • It is helpful if the blocks have been sanded to minimize splinters.

  • Pictures should be cut out and trimmed to fit on the sides of the blocks (this can be an entire exercise…i.e., “find and cut-out pictures of organisms in a...[insert what type of ecosystem here]...ecosystem”). This prompts a discussion of food webs and eco-pyramids...

  • A sturdy low table is necessary, as is some clear space around it (for the falling blocks)


  • Glue or draw pictures of organisms onto the blocks. It can be helpful to try to pay some attention to the relative numbers of organisms (more producers than secondary consumers, etc.) although this is not strictly necessary.

  • Students take turns placing blocks on the table, producers on the bottom, then secondary consumers, etc., spacing them an equal distance apart. Build an “ecosystem” by placing layer upon layer of blocks until a certain ecosystem size (complexity) is obtained.

  • Now, the fun part...Students take turns removing blocks and making up a reason for that particular animal’s (or plant’s) removal from the ecosystem. For example, a block containing a picture of a clam could be removed because of extensive shell dredging.

  • Eventually, the ecosystem becomes less and less stable as blocks are removed. One of the remaining blocks will inevitably cause the ecosystem to crash...Great Fun! This can lead to many interesting discussions if students are guided through the many possible ecosystem concepts.

  • Alternate Suggestion: Place nothing but secondary consumers on the bottom layer and try to determine which of these animals is the keystone species.\

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A manatee's lifespan is estimated to be 60 years or more.

  1. Ch. 7 Intro
  2. Essential Questions
  3. Ecosystems
  4. Energy Flow Through an Ecosystem
  5. Healthy vs. Unhealthy Ecosystems
  6. Biodiversity
  7. Threatened and Endangered Species in the Basin
  8. Decision Making and Issue Analysis
  9. Ecosystem Tumble
  10. Activity: I'm a Survivor