Level 1 — Absolute Beginner
Scientists found tiny fossils. They are 97 million years old.
The fossils are magnetic. They can feel the Earth's magnetic field.
Maybe an animal used them like a map. It helped the animal know where to go.
The fossils are very small. They are not bigger than one tiny cell.
- scientist
- A person who studies nature.
- fossil
- A very old animal or plant kept in rock.
- million
- One thousand thousand.
- magnetic
- Pulled by a magnet.
- field
- An area where a force works.
- animal
- A living thing that can move.
- map
- A drawing that shows where places are.
- tiny
- Very, very small.
Level 2 — Elementary
Scientists at the University of Cambridge and the Helmholtz-Zentrum Berlin studied tiny magnetic fossils. They are 97 million years old and come from ancient sea floor mud.
The fossils are called magnetofossils. Some look like spearheads, spindles, bullets or needles. Each one is no bigger than a bacterial cell.
For the first time, the team made 3D pictures of the magnetic structure inside them. The shapes seem built to sense both the direction and the strength of Earth's magnetic field.
This may be the oldest evidence of an animal using Earth's magnetic field like a built-in GPS. The creature that made them is still unknown.
- sea floor
- The ground at the bottom of the sea.
- sediment
- Mud and sand that settle at the bottom of water.
- spindle
- A thin shape that is wide in the middle and pointed at the ends.
- bacterial
- Of tiny single-cell living things.
- structure
- The way something is built.
- sense
- To notice with a body part or tool.
- strength
- How strong something is.
- evidence
- Facts that show something is true.
Level 3 — Intermediate
Researchers from the University of Cambridge and the Helmholtz-Zentrum Berlin have described 97 million year old magnetofossils that may be the earliest evidence of an animal using Earth's magnetic field as a navigation aid. The fossils were preserved in ancient seafloor sediments.
Shaped like spearheads, spindles, bullets and needles, each crystal is no larger than a bacterial cell. The team captured the first three dimensional images of their magnetic structure, and found features that appear optimized to detect both the direction and the strength of the field.
The producer of the fossils remains unknown, which keeps the interpretation cautious. Even so, the work supports the idea that magnetic navigation is far older than the birds and fish that rely on it today.
Understanding how it began could help explain how modern animals manage migrations of thousands of kilometers, a long standing puzzle in biology.
- magnetofossil
- A tiny fossil made of magnetic crystals.
- navigation
- Finding the way from one place to another.
- crystal
- A solid with atoms arranged in a regular pattern.
- optimized
- Made as effective as possible.
- detect
- To notice or discover.
- interpretation
- An explanation of what evidence means.
- migration
- A regular long journey made by animals.
- puzzle
- A problem that is hard to solve.
Level 4 — Advanced
Embedded in 97 million year old seafloor sediment, microscopic magnetofossils are now being read as the earliest direct evidence that an animal exploited Earth's magnetic field for navigation. The finding comes from researchers at the University of Cambridge and the Helmholtz-Zentrum Berlin.
The crystals, which resemble spearheads, spindles, bullets and needles, are each smaller than a bacterium. By producing the first three dimensional images of their magnetic architecture, the team showed features seemingly tuned to register both the orientation and the intensity of the geomagnetic field, the pairing a compass alone cannot supply.
Crucially, the organism that fashioned them has not been identified, so the work stops short of naming a culprit. That restraint is warranted, but it does not diminish the implication: a biological GPS was in operation tens of millions of years before humans first looked at a compass.
For biologists, the result offers a deep time anchor for a sense that still baffles researchers, helping to explain how modern birds and fish evolved the capacity to cross oceans and continents with remarkable accuracy.
- exploit
- To make full use of something.
- microscopic
- Too small to see without a microscope.
- architecture
- The way something is designed and organized.
- orientation
- The direction in which something points.
- intensity
- The strength or force of something.
- geomagnetic
- Relating to the Earth's magnetic field.
- restraint
- Careful self control in claims or actions.
- baffle
- To confuse or puzzle completely.
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