--- title: Fossils: how a living thing turns to stone and how we dig it up — a lesson of Mova's school · trees and pragmatics description: «Fossils: how a living thing turns to stone and how we dig it up», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: A fossil is a living thing, or a mark it made, that was kept in rock: a shell, a bone, a leaf, a footprint --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Fossils: how a living thing turns to s… # Fossils: how a living thing turns to stone and how we dig it up Lesson 275 of the biology course of Mova's primary school: 17 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/0/) — A fossil is a living thing, or a mark it made, that was kept in rock: a shell, a bone, a leaf, a footprint, even a dinosaur's poo. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/1/) — Picture a shell sinking into soft mud at the bottom of the sea; more mud piles on top, and over millions of years water full of dissolved minerals seeps through and slowly fills or replaces the shell with stone. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/3/) — That is why the curly stone you pick up on a beach is so special: it is the shape of a sea animal that died long before the first person walked the Earth. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/4/) — Scientists who study fossils are called palaeontologists, and they dig very slowly with brushes and small picks, because a careless hit can destroy a find that waited millions of years. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/5/) — A fossil is the shape of a living thing turned into stone or pressed into rock; most fossils are of sea animals with hard parts like shells and bones. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/6/) — A shell or bone becomes a fossil when it is buried in mud or sand and minerals carried by water slowly fill or replace it. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/7/) — Ammonites are curly fossil shells of sea animals related to squid and octopus; they died out at the same time as the big dinosaurs, about 66 million years ago. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/8/) — In Whitby in England, people once carved snake heads on ammonites and sold them as snakes turned to stone. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/9/) — Far fewer than one in a million animals becomes a fossil, because most bodies are eaten, rot or are broken up; only a quick burial without air gives a chance. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/10/) — Trace fossils are marks animals left behind, such as footprints, burrows, tooth marks, nests, eggs and fossil poo; they show how animals walked, hid and lived. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/11/) — Palaeontologists dig slowly, map where each bone lies, and wrap big bones in plaster jackets, like a cast on a broken arm, to carry them safely. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/12/) — Cleaning one big skeleton out of hard rock can take years of patient work, because the rock can be harder than the bone itself. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/14/) — Children have found important fossils, such as a young T. rex found by boys in North Dakota in 2022; they told scientists, and the find went to a museum. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/15/) — Some fossils catch a moment, such as a fish with another fish in its mouth, because fast burial froze the scene. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/16/) — Petrified wood is wood turned to stone as minerals replaced it cell by cell; the Petrified Forest in Arizona is full of it, and tree rings can still be seen. - [17](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/17/) — Some historians think ancient people who found Protoceratops skulls in the Gobi Desert imagined griffins, and that mammoth skulls with one big nose hole may have inspired stories of one-eyed giants; this is an idea, not something proven. - [18](https://md.mova.elamur.ai/free/en/corpora/school/biology/275-fossils-how-a-living-thing-turns-to-stone-and-how-we-dig-it-up/18/) — Lucy is a 3.2-million-year-old skeleton of a human relative found in Ethiopia in 1974; her hips and knees show she walked upright, and she was named after a Beatles song playing at the camp. - ← previous: [Terror birds, moas, giant insects and other lost giants](https://md.mova.elamur.ai/free/en/corpora/school/biology/274-terror-birds-moas-giant-insects-and-lost-giants/) - next →: [How old is it? Rock layers, rock clocks, amber and the long story of life](https://md.mova.elamur.ai/free/en/corpora/school/biology/276-how-old-is-it-rock-layers-rock-clocks-amber-and-the-long-story-of-life/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)