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Course: Middle school biology - NGSS > Unit 8
Lesson 2: The fossil recordFossils
Review your understanding of fossils in this free article aligned to NGSS standards.
Key points
- A fossil is the preserved evidence of an organism that lived in the distant past. Some fossils are formed from body parts, such as shells or bones. Others, such as preserved footprints, are from traces of an organism’s behaviors.
- Fossils are usually found in sedimentary rock. This type of rock forms from sediment, which is made up of pieces of rock, minerals, and organic matter. Over millions of years, sediment solidifies, becoming rock. Organisms trapped in sediment can eventually turn into fossils.
- Sedimentary rock forms in layers. New layers form on top of old layers. So, fossils found in older, deeper layers are typically older than fossils found in newer, more shallow layers. Scientists can tell the relative ages of fossils based on which rock layers they are found in.
- Scientists can also use radiometric dating to figure out a fossil's age. Radiometric dating is a way to tell how old something is by studying its chemical properties.
- All of the fossils that have been found on Earth make up the fossil record.
Want to join the conversation?
What is a fossil record and Why do we have a fossil record?(16 votes)
A fossil record is a record of all the fossils and their dates found on the earth. We have it because it helps keep track of things that lived a long time ago.(22 votes)
what is the fossil record(7 votes)
Fossil record, history of life as documented by fossils, the remains or imprints of organisms from earlier geological periods preserved in sedimentary rock.(17 votes)
- Why are scientists so interested in fossils(7 votes)
Scientists are interested in fossils because they are one of the only things that can tell us about prehistoric times.(17 votes)
- What is the fossil records(1 vote)
- Fossil record, history of life as documented by fossils, the remains or imprints of organisms from earlier geological periods preserved in sedimentary rock.(15 votes)
- what is radiometric dating(5 votes)
Radiometric dating is a method used to find the age of fossils. It uses very unstable radioactive isotopes. Over time, radioactive isotopes decay into smaller isotopes. Scientists can calculate the amount of decay in isotopes, calculate how long the isotopes have been there, and estimate the age of the fossils.(7 votes)
- If I die in sap can I be preserved and still live or not.(6 votes)
of course not. you will be dead and you body will decay wether or not you are in side the sap(4 votes)
- Is it true that the person that finds new species can name them?(6 votes)
Traditionally, the person who first describes a newfound plant or animal is entitled to name it.(4 votes)
Feb. 1, 2023 Scientists discovered the first-ever Dickinsonia fossil in India two years ago, changing our understanding of how the continent came to be!!(8 votes)- can they ever bring back the species that long ago was in the world with fossil records?(5 votes)
maybe but that would take lots and lots of work(5 votes)
- Key points
A fossil is the preserved evidence of an organism that lived in the distant past. Some fossils are formed from body parts, such as shells or bones. Others, such as preserved footprints, are from traces of an organism’s behaviors.
Fossils are usually found in sedimentary rock. This type of rock forms from sediment, which is made up of pieces of rock, minerals, and organic matter. Over millions of years, sediment solidifies, becoming rock. Organisms trapped in sediment can eventually turn into fossils.
Sedimentary rock forms in layers. New layers form on top of old layers. So, fossils found in older, deeper layers are typically older than fossils found in newer, more shallow layers. Scientists can tell the relative ages of fossils based on which rock layers they are found in.
Scientists can also use radiometric dating to figure out a fossil's age. Radiometric dating is a way to tell how old something is by studying its chemical properties.
All of the fossils that have been found on Earth make up the fossil record.(7 votes)