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

Circle the best answer.
a shell on a sea floor being covered by mud. What two things most raise the odds that remains become a fossil, by Ari's reading (NPS)?
- Lying on the surface for years
- Rapid burial and hard parts
- Slow burial and soft parts
- Warm air and bright sunlight
How likely is any one living thing to become a fossil, by Kira's reading (NPS)?
- Very unlikely; the odds are very small
- Certain, if it lived long enough
- About as likely as a coin landing heads
- Very likely; most living things become fossils
A footprint in rock is which kind of fossil, by Jun's reading (NPS)?
Drawing: a trail of footprints in rock. Drawing: a trail of footprints in rock. - A piece of amber
- A preserved remain of the foot
- A trace fossil
- A body fossil, since a foot made it
A shell pressed into mud leaves a hollow, three-dimensional print. What is that print called, by Luz's reading (NPS)?
Drawing: a hollow shell-shaped print in rock. Drawing: a hollow shell-shaped print in rock. hollow shell-shaped print rock - A cast
- A mold
- A steinkern
- A trace fossil, since no body is there
Sediment later fills that hollow print and hardens into the shell's shape. What is the filling called, by Milo's reading (NPS)?
Drawing: a hollow print beside its filled copy. Drawing: a hollow print beside its filled copy. hollow print filled copy - A mold
- A cast
- An amber fossil
- A burrow, which is a trace fossil
Fossil reef animals, such as brachiopods and crinoids, are found in limestone high in the Guadalupe Mountains (NPS). What does this show, by Noah's reading?
Drawing: a reef on a sea floor, then the same rock raised as a mountain. Drawing: a reef on a sea floor, then the same rock raised as a mountain. Drawing a reef sea floor then raised as a mountain same rock - Sea animals once lived on mountaintops
- The animals climbed the mountain
- The rock formed in a sea and was later lifted up
- The fossils formed in the last 100 years
Most fossils are found in which kind of rock, by Pia's reading (NPS)?
Drawing: rock layers with fossils. Drawing: rock layers with fossils. fossil rock layers - Sedimentary rock
- Rock from deep in the mantle
- Metamorphic rock baked deep underground
- Igneous rock cooled from deep magma
A layer holds fossil fish and clams. Where did the layer most likely form, by Ren's reading?
Drawing: a rock layer with fish and clam fossils. Drawing: a rock layer with fish and clam fossils. fish fossil clam fossil - Under water, such as a lake or sea
- On a dry mountaintop
- Inside a volcano
- In a desert dune field
Why does the fossil record have gaps, by Tala's reading (NPS)?
Drawing: a long rock layer with a few fossils far apart. Drawing: a long rock layer with a few fossils far apart. long rock layer fossils far apart - Gaps mean no life existed at those times
- Gaps mark times when the oceans dried up
- Few remains are buried fast enough to become fossils
- Scientists have already found each fossil there is
the middle one has no Q fossils. In one model layer, no fossils of animal Q appear, though layers above and below have them. What is the most careful reading, by Esme's reading?
Three rock layers; the middle one has no Q fossils. Three rock layers; the middle one has no Q fossils. Q Q - Q may have lived then but left no fossils here
- Q did not exist at that time
- Q vanished and later came back
- The middle layer must be younger than both