Why the fossil record has gaps, and what fossils say about past environments

Grade 9 Science Worksheet

Circle the best answer.

1. 1.

   Minerals from groundwater fill the tiny pores in a buried bone. What is this process called, by Bo's reading (NPS)?

   • Permineralization
   • Making a trace fossil
   • Carbonization
   • Freezing
2. 2.

   Sediment fills the inside of a shell, and the shell later dissolves. What do NPS paleontologists call the stony filling, by Jun's reading?

   • A coprolite
   • A steinkern
   • A trackway
   • A mold
3. 3.

   NPS: in the Badlands, Cretaceous marine fossils lie below Paleogene fossils of land mammals. What change does this show, by Kira's reading?

   • The mammals lived in the sea
   • The area stayed the same
   • The area changed from land to sea
   • The area changed from sea to land
4. 4.

   NPS: trace fossils are very rarely moved from where they formed. Why does that make them good clues to past environments, by Luz's reading?

   • They record activity right where the animal lived
   • They are carried in from other places
   • They show the animal's bones and teeth in fine detail
   • They form long before body fossils
5. 5.

   “Cross-section:” Model layer K holds coral and shell fossils; layer L above it holds fossil leaves and tree roots. What does this suggest, by Milo's reading?

   • Corals grew among the trees on land
   • Land gave way to a sea
   • Both layers formed in a desert
   • A sea gave way to land with plants
6. 6.

   a riverbank with mud and a dry hillside. NPS: fossils of birds and flying insects are fairly rare, except some water birds. Why, by Noah's reading?

   • Their fossils turn into casts and vanish
   • They lived too recently to fossilize
   • They seldom lived where sediment buries remains fast
   • Their light bodies fossilize easily in open air
7. 7.

   Four setting cards, labeled A to D. Which setting gives the best odds for a fossil, by Pia's reading (NPS)?

   • A windy mountain peak
   • A river floodplain with fresh mud piling up
   • A forest floor with no new sediment
   • Bare rock in open sun
8. 8.

   A sandstone layer shows ripple marks and footprints of model animal Z. What kind of setting fits, by Ren's reading?

   • A high, dry peak
   • Deep inside the mantle
   • Inside a glacier
   • Wet sand at a shore or riverbank
9. 9.

   Model layers hold fossil A below and fossil C above, with no B between. Fossil B is found elsewhere from that time. What best explains the gap, by Tala's reading?

   • The record here must be complete
   • Conditions here did not preserve B
   • B did not live at that time
   • B lived here and left fossils elsewhere instead
10. 10.

    a riverbank with mud and a dry hillside. Why are upland animals rarer in the fossil record than river animals, by Zee's reading (NPS)?

    • Upland animals had no hard parts
    • Few animals lived in uplands
    • Upland fossils turn into casts and vanish
    • Uplands get little new sediment to bury remains