The Beaver Creek

Far back in the woods, where a small river flowed, lived a very busy beaver. One day, Leo and his grandpa were hiking when they saw something amazing! A tall tree near the river had been chewed almost all the way through, and the water in the river looked a little deeper and wider than usual.

"Wow, look at that!" Leo exclaimed. "What happened here?"

Grandpa smiled. "That's the work of a beaver, Leo. In nature, when an animal does something (that's the cause), it creates a change (that's the effect). If we watch closely, we can see some very clear observable patterns."

They looked around the riverbank.

• Observable Pattern 1: Many trees along the river had been chewed by strong teeth, and some had fallen down.
  • Cause: The beaver needs wood to build its home and to block the river.
  • Effect: The beaver chews down trees.
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• Observable Pattern 2: Sticks, mud, and small logs were piled up across the river, slowing down the water.
  • Cause: The beaver needs a still, deep pond to protect its home from predators and to store food underwater.
  • Effect: The beaver builds a dam to make the river wider and deeper.
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• Observable Pattern 3: A sturdy, dome-shaped house made of sticks and mud sat in the middle of the new, wider pond.
  • Cause: The beaver needs a safe place to live, raise its babies, and store food away from danger.
  • Effect: The beaver builds a lodge in the pond.
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Leo couldn't believe it! The beaver wasn't just chewing trees for fun. Its strong instincts (the causes) made it do all this amazing building (the effects), creating a whole new environment! He saw clearly how one busy animal could cause so many big, observable changes.