Why the fossil record has gaps, and what fossils say about past environments
Grade 9 Science Worksheet

Circle the best answer.
Minerals from groundwater fill the tiny pores in a buried bone. What is this process called, by Bo's reading (NPS)?
- Carbonization
- Freezing
- Permineralization
- Making a trace fossil
Four pair cards, labeled A to D. Which pair are both preserved remains, by Esme's reading (NPS)?
- A mold and a cast of a shell
- An insect in amber and remains in natural asphalt
- A burrow and a coprolite
- A footprint and a burrow preserved in hardened mud
Sediment fills the inside of a shell, and the shell later dissolves. What do NPS paleontologists call the stony filling, by Jun's reading?
Drawing: a shell's inside filled with sediment. Drawing: a shell's inside filled with sediment. sediment - A mold
- A steinkern
- A trackway
- A coprolite
NPS: in the Badlands, Cretaceous marine fossils lie below Paleogene fossils of land mammals. What change does this show, by Kira's reading?
Cross-section: marine fossils below, land mammal fossils above. Cross-section: marine fossils below, land mammal fossils above. Cross-section land mammal fossils marine fossils above below - The area changed from land to sea
- The area stayed the same
- The mammals lived in the sea
- The area changed from sea to land
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?
Drawing: a trail of footprints in rock. Drawing: a trail of footprints in rock. - They show the animal's bones and teeth in fine detail
- They are carried in from other places
- They form long before body fossils
- They record activity right where the animal lived
“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?
Cross-section: layer L above layer K. Cross-section: layer L above layer K. layer L layer K - Corals grew among the trees on land
- Land gave way to a sea
- A sea gave way to land with plants
- Both layers formed in a desert
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
- Their light bodies fossilize easily in open air
- They seldom lived where sediment buries remains fast
- They lived too recently to fossilize
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
- Bare rock in open sun
- A forest floor with no new sediment
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)?
- Uplands get little new sediment to bury remains
- Upland animals had no hard parts
- Few animals lived in uplands
- Upland fossils turn into casts and vanish
A layer of model lake mud preserves feathers, skin and leaves in fine detail. What does NPS call this rare kind of site, by Ari's reading?
Drawing: a rock slab with a feather and leaf in fine detail. Drawing: a rock slab with a feather and leaf in fine detail. rock slab feather leaf - A Lagerstätte
- A trackway
- A trackway of footprints
- A steinkern