Fossil quiz

This task is about how scientists believe fossils are formed.

Fossils are formed in different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt.

Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.

Question

a) A geologist discovered fossilised imprints of primitive sea animals in rocks found high in some coastal mountains.

The best explanation for the find is that ...

- sea creatures once lived on land.
- the mountains have risen from below sea level.
- the first animals on land came from the sea.
- ancient seas rose to cover the mountains at some time in the past.
- tidal waves that occurred centuries ago deposited the sea creatures there.

b) A creature is least likely to be fossilised in ...

- a stagnant swamp.
- an underground limestone cave.
- a high-altitude grassy plain.
- a seabed adjacent to a large river.
- a river estuary.

c) Fossils of prehistoric animals that lived near the coast are much more common than fossils of animals living in inland forests.

What is the best explanation for this?

- The sea salt in the soils helped preserve the coastal animals.
- There were fewer animals living in the forests than near the coast.
- Forest animals did not have bodies which would form fossils readily.
- The remains of forest animals were more frequently destroyed by earth movements than those of coastal creatures.
- Coastal animals were more likely to be buried in sediment than were forest animals.

	Y7 (03/1997)	Y8 (03/1997)
a) B (the mountains have risen from below sea level)		moderate
b) C (a high-altitude grassy plain)	difficult	difficult
c) E (Coastal animals were more likely to be buried in sediment than were forest animals)	very difficult	difficult