Fossils what they show about evolution
Today you will be introduced to the job of a Paleontologist What is a Paleontologist? What is a Paleontologist? Why is this an important job? Why is this an important job? Someone who studies fossils Someone who studies fossils Their findings tell about the organisms that have lived on Earth and how they have changed over time. Their findings tell about the organisms that have lived on Earth and how they have changed over time.
What is a fossil? Remains or traces of organisms that lived in the past Remains or traces of organisms that lived in the past Comes from the Latin word fossilis, which means “dug up” Comes from the Latin word fossilis, which means “dug up”
Types of Fossils Sediment Sediment Mold Mold Cast Cast
Sediment Fossils Organisms die and become buried in mud and bits of rock Organisms die and become buried in mud and bits of rock
Mold Dead organism decays and leaves an empty space in rock. Dead organism decays and leaves an empty space in rock. Think of an ice tray – the “mold” is similar to the ice tray Think of an ice tray – the “mold” is similar to the ice tray
Cast Formed when a mold in rock is filled with minerals that have hardened. Formed when a mold in rock is filled with minerals that have hardened. Think of an ice tray – the “cast” is the ice cube Think of an ice tray – the “cast” is the ice cube
Where can you find fossils? Rocks, tree sap, ice and other materials Rocks, tree sap, ice and other materials All over the world All over the world
Time Frames Fossil Record: created by paleontologists to show the history of life on Earth based on fossils that have been discovered. Fossil Record: created by paleontologists to show the history of life on Earth based on fossils that have been discovered. Geologic Time Scale: created by paleontologists, this chart divides the Earth’s history into time periods. Geologic Time Scale: created by paleontologists, this chart divides the Earth’s history into time periods.
Who do Geologists like to date? ROCKS!
How they do it… Half-life: amount of time for one-half of a sample of radioactive minerals to change into another substance. Half-life: amount of time for one-half of a sample of radioactive minerals to change into another substance. Half-life of uranium-238 to change to lead is 4.5 billion years Half-life of uranium-238 to change to lead is 4.5 billion years Paleontologists compare the amount of uranium-238 to lead to age a fossil Paleontologists compare the amount of uranium-238 to lead to age a fossil
Why do we care? This information helps to discover the relationships among different groups of organisms. This information helps to discover the relationships among different groups of organisms. Show how certain organisms have evolved into others (some fishes into amphibians) Show how certain organisms have evolved into others (some fishes into amphibians) Through DNA sampling, scientist can piece together the history of life on Earth. Through DNA sampling, scientist can piece together the history of life on Earth.
QUIZ What are fossils? What are fossils? Name two kinds of fossils? Name two kinds of fossils? What does the fossil record show about the evolution of organisms? What does the fossil record show about the evolution of organisms? What is radioactive dating? What is radioactive dating?
Resources Link to careers in paleontology: Link to fossils: Link to careers in paleontology: Link to fossils: