Three Species, Three Homes: teacher key

Electric Eels, grade 9 edition, written for 9th grade. Electric eels turned out to be three species that look nearly alike but live in different places. Their electricity has a long history in the fish family.

Read the book. Print this page for the key.

Questions and answers

1. Where does E. varii live?
   • On the Guiana Shield highlands
   • In the lowland Amazon basin (answer)
   • In a Brazilian lake only
2. What do the three species look like to each other?
   • Nearly alike (answer)
   • Nothing alike
   • Exactly the same
3. Along how much of the body do the electrocyte stacks run?
   • The rear 80 percent (answer)
   • The front 8 percent
   • Only the head
4. How many times have electric organs evolved in different kinds of fish?
   • Once
   • At least six times (answer)
   • Never
5. Why might scientists have counted only one kind for 250 years?
   • The kinds look nearly alike (answer)
   • The eels hide in trees
   • The eels live on mountains
6. When did the hunting eels in Brazil stir?
   • At dusk and dawn (answer)
   • At noon
   • In winter only

Words

• electrocytes: power cells
• knifefish: long swimming fish
• lineage: family line
• lowland: low ground
• doublet: two quick pulses