Level 1 — Absolute Beginner
Scientists found very small fossils in old sea mud. They are 97 million years old.
The fossils are magnetic. They are shaped like spears, needles and bullets.
The scientists think a sea animal used them like a GPS. The animal could feel Earth's magnetic field.
We do not know what the animal was. It is still a mystery.
- fossil
- a very old plant or animal kept in rock
- magnetic
- able to pull some metals
- GPS
- a tool that shows where you are
- mystery
- something nobody can explain
- sea
- the large body of salt water
- mud
- wet soft earth
- needle
- a thin pointed thing
- animal
- a living thing that moves
Level 2 — Elementary
Researchers have studied tiny magnetic fossils from about 97 million years ago. They were found in ancient seafloor mud.
The fossils are smaller than a bacterium. Some look like spearheads, spindles, bullets or needles.
Inside each one is a single magnetic whirl called a vortex. Tests show it can notice small changes in the strength of Earth's magnetic field.
The scientists say an unknown sea creature may have used this to travel long distances. It may be the oldest known animal GPS.
- seafloor
- the bottom of the sea
- bacterium
- a very small living thing with one cell
- vortex
- a spinning shape, like water going down a drain
- strength
- how strong something is
- navigate
- to find the way
- tiny
- very small
- evidence
- facts that show something is true
- ancient
- very, very old
Level 3 — Intermediate
Scientists report that microscopic magnetic fossils from the seafloor, about 97 million years old, may be the oldest direct evidence of an animal navigating with Earth's magnetic field.
These so called magnetofossils, shaped like spearheads, spindles, bullets and needles, are no larger than a bacterial cell. They are thought to be biological in origin, left behind by an organism that has not been identified.
Using a technique that maps magnetism in three dimensions, the team found that each crystal holds a single magnetic vortex. That structure responds sharply to small shifts in the intensity of the field, which would let a creature work out its position over long distances.
The finding may help explain how modern birds, fish and other animals developed an internal compass.
- magnetofossil
- a fossil made of magnetic crystals formed by living things
- biological
- connected with living organisms
- organism
- a living thing
- technique
- a method for doing something
- crystal
- a solid with a regular repeating structure
- intensity
- strength or amount
- internal
- inside the body
- compass
- a tool that shows direction
Level 4 — Advanced
Microscopic magnetic fossils recovered from ancient seafloor sediments, roughly 97 million years old, may constitute the earliest direct evidence that an animal navigated by sensing Earth's magnetic field, according to researchers who analysed them in unprecedented detail.
The so called giant magnetofossils, which take the form of spearheads, spindles, bullets and needles yet measure no more than a bacterial cell, are believed to be biological in origin. The organism that produced them remains unidentified, a gap that lends the discovery an air of mystery.
By mapping magnetism in three dimensions, the team showed that each crystal carries a single magnetic vortex, a configuration optimised to register minute variations in field intensity rather than merely direction. Such sensitivity would, in principle, have allowed a creature to infer its location across vast ocean distances, much as a satellite receiver triangulates a position.
If confirmed, the work offers a deep evolutionary backdrop for the magnetic sense of modern birds, fish and turtles, suggesting that biological navigation by geomagnetism is far older than the species that use it today.
- constitute
- to form or amount to
- sediment
- material that settles at the bottom of water
- unprecedented
- never done or seen before
- configuration
- an arrangement of parts
- optimised
- made as effective as possible
- minute
- extremely small
- triangulate
- to find a position using several reference points
- geomagnetism
- the magnetic field of the Earth
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