Stone tools record changing behaviour
Definition
Fossil
The preserved remains or traces of an organism from many thousands or millions of years ago, usually found in rock.
- Stone tools survive for long periods and provide evidence of the behaviour and manual skills of the humans who made them.
- The oldest tools are usually simple flakes or stones with a small number of cutting edges.
- Later hand axes are shaped on both sides and are more symmetrical, showing more planning and controlled manufacture.
- More recent tool sets include specialised blades, points, scrapers and small components made for different tasks.
- The long-term increase in complexity suggests changes in dexterity, learning, communication and the ability to plan.
Common Mistake
A stone tool gives evidence about behaviour and technology, but it does not directly reveal the maker's genes or exact species.
The surroundings provide the date
- A tool can be given a relative date from its position in rock or sediment, because deeper undisturbed layers are usually older.
- Scientists can compare a tool with fossils or other artefacts found in the same layer.
- Layers of volcanic ash above or below the tool can be radiometrically dated, which brackets the tool's age.
- The method is reliable only if the layers have not been mixed by erosion, burrowing, earth movement or later human activity.
Example
If a tool lies above ash dated to 1.8 million years and below ash dated to 1.5 million years, its age lies between those dates.
Exam technique
Separate the observation from the inference: describe the tool's shape first, then explain what its complexity suggests about its maker.
Self review
- How did stone tools change over time?
- What can tool complexity suggest?
- How can surrounding layers date a tool?
- Why can disturbed sediment make a date unreliable?
