The Biodiversity Crisis · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The Biodiversity Crisis

Science · Animals of the World · ages 12-14
Name ______________________   Date ____________

  1. Which tool ranks species by how close they are to extinction, from Least Concern to Extinct?

    • The species-area relationship
    • The IUCN Red List
    • Minimum viable population

  2. The background rate is about 1 species lost per million species-years. Scientists measure one ocean region losing about 300 species per million species-years. How does that region compare?

    • About 300 times the background rate, inside today's 100 to 1,000 times range
    • About 3 times the background rate
    • Slower than the background rate

  3. In 1995, wolves were reintroduced to Yellowstone National Park.

    Circle one:   True   False

  4. A biologist counts only 40 breeding adults left in a population and worries it can't survive long-term even without new threats. Which concept is she applying?

    • Minimum viable population
    • Species-area relationship
    • IUCN Red List category

  5. After wolves returned to Yellowstone, elk changed their grazing habits. What effect did this have on willow and aspen trees?

    • They died out completely
    • They were unaffected
    • They grew back because elk grazed less in open, exposed areas

  6. The background extinction rate is about 1 species per million species-years. If today's rate is 500 times higher, how many species per million species-years is that?

    Answer: ______________

  7. A student claims: 'Wolves eating elk explains why Yellowstone's rivers changed course.' What's missing from this explanation?

    • Nothing, the explanation is complete
    • Wolves have no connection to rivers at all
    • The chain from wolves to elk behavior to plant regrowth to beavers to riverbank stability

  8. A conservation team has limited funding and must decide which endangered species to save first. Choosing to prioritize species with the best chance of long-term survival is called...

    • Rewilding
    • Conservation triage
    • Population viability analysis
LightMySky · lightmysky.comW1-mt_44HkROUnzE-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

The Biodiversity Crisis W1-mt_44HkROUnzE-s1

  1. The IUCN Red List · The IUCN Red List sorts species by how close they are to disappearing, from Least Concern all the way to Extinct.
  2. About 300 times the background rate, inside today's 100 to 1,000 times range · 300 compared with 1 is 300 times faster. That sits inside the 100 to 1,000 times range scientists see worldwide today.
  3. True · Wolves had been missing from Yellowstone since the 1920s. They were brought back in 1995.
  4. Minimum viable population · A minimum viable population is the smallest group likely to survive for generations, because small groups are more vulnerable to disease, inbreeding, or a bad year.
  5. They grew back because elk grazed less in open, exposed areas · Wolves made elk nervous about grazing in open valleys, so young willow and aspen trees finally got the chance to grow tall.
  6. 500 · If the background rate is 1 and today's rate is 500 times higher, multiply 1 by 500 to get 500.
  7. The chain from wolves to elk behavior to plant regrowth to beavers to riverbank stability · Wolves alone didn't move the rivers. It took the whole chain: fewer elk in open areas, plant regrowth, returning beavers, and stronger riverbanks.
  8. Conservation triage · Conservation triage means putting limited resources where they can do the most good, even if that means a very endangered species gets less help.
Worksheet · LightMySky