Reading the Story in Fossils
Aligned to MS-LS4-1 — Next Generation Science Standards.
What this lesson teaches
Fossils are preserved traces of past life found in layers of rock, with older fossils generally deeper down. The patterns in this record show that life has existed for a very long time, that many forms have gone extinct, and that species have changed over time.
Worked example
In a canyon wall, the deepest layers hold only simple sea creatures, higher layers add fish, then reptiles, then mammals — a pattern of change and extinction recorded from bottom to top like pages of a book.
Practice questions
- Stack layers of colored clay with a small object in each and note which layer is oldest.
- Order a set of fossil pictures from oldest to newest based on rock-layer position.
- Explain, using the layer pattern, how fossils provide evidence that life forms have changed and some have gone extinct.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Leer la historia en los fósiles
Los fósiles son huellas conservadas de vida del pasado que se hallan en capas de roca, y los fósiles más antiguos suelen estar más abajo. Los patrones de este registro muestran que la vida ha existido durante muchísimo tiempo, que muchas formas se han extinguido y que las especies han cambiado con el tiempo.
Ejemplo: En la pared de un cañón, las capas más profundas contienen solo criaturas marinas simples, las capas superiores agregan peces, luego reptiles, luego mamíferos — un patrón de cambio y extinción registrado de abajo hacia arriba como las páginas de un libro.
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