The Proof Problem: teacher key

Giant Squid, grade 9 edition, written for 9th grade. A picture is not proof of a species. See how scientists checked a bait-line photograph with DNA, and how DNA later tied giant squid worldwide together.

Read the book. Print this page for the key.

Questions and answers

1. How did scientists prove the squid in the 2004 photographs was a giant squid?
   • A weight scale
   • DNA from a piece of its tentacle (answer)
   • A satellite
2. How many giant squid did the 2013 DNA study analyse?
   • 4
   • 430
   • 43 (answer)
3. What is eDNA?
   • Genetic material animals shed (answer)
   • A kind of squid
   • A camera light
4. Why did scientists use red lighting?
   • Red is brighter
   • Giant squid see best in blue light and are less likely disturbed by red (answer)
   • Red attracts fish
5. Why is measuring a dead giant squid hard?
   • They are too small
   • They are always whole
   • The eyeballs collapse and the head sags (answer)

Words

• species: kind of animal
• eDNA: shed DNA
• analysed: studied closely
• tentacle: long arm