Unit 4 Section 3: Fossils

​Science Root of the Day:

DO NOW: Write what you think the example words mean in your lab manual.

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Unit 4 Section 3: Fossils

In 1990, a woman named Sue Hendrickson went looking for fossils in Faith, South Dakota. During her search, she found several bones which lead to the ​discovery of the largest and most complete Tyrannosaurus Rex skeleton ever found. The skeleton named for her now resides in the Chicago Field Museum.

Multiple Choice

Who is the person credited with developing the theory of continental drift?

• Harry Hess
• Galileo
• Alfred Wegener
• Newton

Multiple Choice

Massive pieces of land that are part of the Earth's crust and upper mantle

• Tectonic plates
• Trenches
• Divergent boundary
• Continental shelves

Multiple Choice

What are the three types of Evidence that supports Alfred Wegener's Theory?

• Fossils, Fish, and Land

• Sedimentary, Magma, and Climate

• Fossils, Land forms, and Climate

• Climate, Land forms, and Metamorphic rock

Multiple Choice

This is a picture of glacier scars found in Africa.  What are these evidence for?

• Africa has always been near the equator
• Africa was once in an area of the Earth that had a very cold climate
• The continents have not moved
• sea floor spreading

Multiple Choice

Why was Wegener's theory not accepted?

• He had no proof of how they were moving
• Pangea just didn't look right

• He was married
• He was not a Scientist

Multiple Choice

The OLDEST seafloor is located? 

• Closest to the mid-ocean ridge
• Farthest from the mid-ocean ridge

Multiple Choice

What happens when Subduction occurs?

• Parts of the crust fall into the mantle
• Parts of the crust fall into the core
• Parts of the crust fall into space
• Parts of the mantle rise up to the crust

Lesson Objectives

​

• Describe how Fossils form

• Differentiate between different kinds of fossils

• Discuss what Fossils tell us about organisms and environments of the past

​What are Fossils?

• Fossil: the preserved remains or traces of living things

  • Includes things like:

    • Bones

    • Teeth

    • Imprints

  ​

​How do Fossils Form?

• Most Fossils form when living things die and are buried by sediment

• Are found in or near still water where sediment builds up

  • After an organism dies, the soft tissue decays quickly or gets eaten

    • ​Usually, only hard tissues remain

  • Over time, sediment covers the organism in layers and hardens into sedimentary rock

​What are the different kinds of Fossils?

• ​Different kinds of of fossils include

  • Molds and Casts

  • Petrified Fossils

  • Carbon Films

  • Trace Fossils

  • Preserved Remains​

​Molds & Casts

• The most common types of fossils

  • Preserve the fine details of the organisms (Textures, shapes)

• Mold: a hollow area in sediment in the shape of an organism

  • Forms when the organism is buried in sediment

  • Just an imprint

• Cast: A solid copy of the shape of an organism​ where sediment fills in spaces

  • Shows all the fine details

​Petrified Fossils

• Petrified: turned to stone

• In petrified fossils, minerals replace all or part of an organism

  • water seeps into the cells, carrying minerals

  • Eventually water evaporates and the minerals are left behind, taking the form of the organism

• Are usually plants or bones​

​Carbon Films

• Carbon Film: An extremely thin layer of carbon is left behind of an organism

• While other sediment is removed, the carbon leaves a flat image behind

• Preserves the most delicate details of organisms

  • Shows the outer details of an organism

​Trace Fossils

• Show the activities of an organism

  • Footprints

  • Nests

  • Scat

• Can reveal what an organism did and ate

​Preserved Remains

• Preserve the entire organism

  • Freezin​g in ice

  • Trapped in amber

    • Amber: Hardened tree sap

  • Tar Pits

​Answering The Jurassic Park Question

• It isn't possible to retrieve DNA from remains in Amber

  • While some tissue remains, the DNA degrades over time

• Frozen Fossils do preserve some DNA, but it is extremely difficult to extract

  • DNA degrades as the fossil thaws

    • Wooly Mammoth DNA has been preserved

  • 2021:​ Scientists believe they may have successfully retrieved DNA from a frozen dinosaur

    • tests remain inconclusive as to whether it is true Dinosaur DNA

Multiple Choice

A __________ fossil can form when sediment buries the hard tissues of an organism.

• mold/cast

• Trace

• Carbon Film

• Petrified

Multiple Choice

A __________ fossil forms when minerals replace parts of an organism

• mold/cast

• Trace

• Carbon Film

• Petrified

Multiple Choice

Which of the following can you learn from a carbon film fossil?

• How an organism behaved

• What an organism ate

• Fine Details of an organisms body

• The bone structure of an organism

Multiple Choice

Which of the following substances is not able to preserve entire organisms?

• Tar

• Water

• Amber

• Ice

​What do Fossils show?

• Paleontologists: Scientists who study fossils

• Paleontologists gather information into the Fossil Record

  • Provides evidence about the history of life and past environments on Earth

    • Helps show how organisms have changed over time

​Fossils and Past Environments

• The types of fossils found in an area can tell what the area was like in the past

  • Can tell if a location was under water or on land

    • Can distinguish between fresh and salt water

  • Can show the previous climates of area

    • Antartica has coal deposits, which only form in warm climate

​Change and the Fossil Record

• Looking throughout the fossil record, changes in species can be seen

• Evolution: the change in living things over time

  • Organisms become more complicated in subsequent generations

  • Older rocks have simpler organisms while newer rock has more complex organisms

• ​Some fossils show organisms that no longer exist

  • Extinct: a type of organism no longer ​exists and will no longer reproduce on Earth

    • Can occur due to different factors like environmental changes

    • Fossils help scientists construct models of what extinct organisms could have looked like

Multiple Choice

This is the sort of scientist who studies fossils/

• Geologist

• Evolutionist

• Paleontologist

• Fossilist

Multiple Choice

_____________ is the gradual change in living things over long periods

• Evolution

• Petrification

• Fossilization

• Paleontology

Multiple Choice

An organism that no longer exists on Earth is called

• Decayed
• Evolved
• Extinct
• Preserved

Multiple Choice

Which type of rock are most fossils found in?

• sedimentary rock

• metamorphic rock

• igneous rock

• fossilatary