Natural Selection and the “rare enemy

effect”

Earthworms

• #1 enemy is the mole• A mole can eat its weight in worms

in a day• A worm knows a mole is coming by

“hearing” its feet thumping

Other organisms eat worms

• Sea Gulls perform “foot paddling behavior”

• Brings worms to the surface• Wood turtles stomp, brings up worms• BUT• Turtles and seagulls do not eat as

many worms as moles, so worms behavior has not changed.

Humans can worm grunt

• Apalachicola Forest• Drive a stake into the ground in

the forest• Rub top with a piece of steel called

a rooping iron

• Video clip: Worm grunting Sopchoppy Florida

• Video Clip: Worm grunting: Science behind it