A Trip Through Geologic Time Hang on, we’re going to the past!

What are fossils? Examine your fossil with your hand lens. Write down the name of your fossil. Write how old it is. Write what it resembled Draw your fossil. Switch spots to the next fossil! Analysis: 1. Describe how these fossils were formed. 2. What information can fossils give us?

Bellwork Quiz What is a fossil? A.A rock that is made of hardened sediment B. A living organism C. Preserved remains or traces of living things. D. All of the above

Important concepts Fossils are preserved remains or traces of living things. Fossils are formed when organisms die and they are covered by sediment that eventually turns into rock. Soft parts are not preserved! Molds: Hollow part of sediment in the SHAPE of the organism. Cast: sediment/minerals gets into the mold and now there is a solid copy of the shape of the organism. Fossil record reveals change over time - Evolution

Make a Fossil! Follow the instructions given to you. Answer the analysis questions in your journal.

How can we find the age of rocks? Page 122.

Bellwork Quiz What is the relative age of a rock? A. Its age compared to the ages of other rocks. B. The number of years since the rock formed. C. It is a rock with a fossil in it. D. It is the age of the Earth.

Important Concepts Relative age compares a rock age with other rock ages and absolute age is the # of years since the rock formed. The law of superposition explains that the oldest rocks are on the bottom and each layer is younger than the layers below it. Index fossils help geologists date rocks. They are only from 1 time period and are wide spread.

How is the history of the Earth divided up? Look at the “Geologic Clock” – take notes. Divide up class into important eras. Create a poster for your important event. Human Geologic Time Scale (on the roof) Glue it to the rope and hang it up!

Bellwork Quiz What do we call the divisions that make up Earth’s history? A. Time periods, years B. Jurassic, Triassic C. Cambrian, Precambrian D. Eras and Periods

Important Concepts The geologic time scale is a record of the life forms and geologic events in Earth’s history. Scientists develop the time scale by studying rock layer and index fossils worldwide. Between pre-Cambrian and the present there are 3 eras. Each era is divided into periods.

What was early Earth like? “Welcome to the Early Earth” Flip Book. Page 1. The Atmosphere Page 2. The Oceans Page 3. The continents Page 4. Life Left side = How did this part of Earth get there? Right side = picture

Important Concepts Earth formed at the same time as the other planet and sun (4.6 billion years ago). Scientists used radioactive dating to find the age of the Earth. Earth went through a variety of phases until it got to the way it is today (temperatures, shapes, atmospheres) Bacteria were the first living organisms on the Earth (3.5 billion years ago!) Early bacteria made its own food with Oxygen as a waste product. This eventually allowed the diversity of organisms on the planet.

Bellwork Quiz How old is the Earth? A. One hundred thousand years old B. 1 million years old C. 1 billion years old D. 4 billion years old

Dinosaurs Magic School Bus Jurassic and Triassic Reading

Dinosaur Project What time period did it live? (Include years) What were the predators? What were the prey? What was the environment like? Why is this dinosaur extinct? Include Geologic Time Scale with your period highlighted

Picture 1 THE ATMOSPHERE The (second) atmosphere was formed when volcanoes released gases from Earth’s interior. Comets also brought gases to the Earth. All these gases stayed thanks to gravity!

Picture 2 THE OCEANS Comets carrying ice collided with the Earth for millions of years. The earth was SO hot it all turned to vapor. Once the Earth cooled the water condensed and formed rain. Eventually all the water accumulated to form the ocean!

Picture 3 THE CONTINENTS The Earth was SO hot it was like liquid magma. 500 million years after Earth’s formation, the temperature cooled and rocks became solid. These solid rocks formed continents.

PICTURE 4 LIFE Life began in the water 3.5 billion years ago! The earliest forms of life were single – celled bacteria. 1 billion years later (2.5 billion years ago) organisms began using photosynthesis and it added OXYGEN to the environment!

PICTURE 5 The law of Superposition In SEDIMENTARY rock layers the oldest layer is at the bottom and the youngest layer is on top. INTRUSIONS are always younger than all the rocks around it.

PICTURE 6 GEOLOGIC TIME SCALE The geologic time scale is divided into Eons, Eras and Periods. The PRECAMBRIAN EON was the LONGEST of all of them! The time scale is divided up according to major geologic events (it is NOT random!)

Vocabulary Concepts Fossil Mold Cast Evolution Extinction Intrusion Extrusion Period Relative age Absolute age Law of superposition Geologic time scale How the atmosphere formed How the oceans formed How the continents formed

Critical Thinking Questions Paleontologists find a trilobite fossil in a rock layer at the top of a hill in South America. They find the SAME kind of fossil in a rock layer at the bottom of a cliff in Africa. What could the paleontologists conclude about the two rock layers? Why were the dinosaurs able to grow so big? Which organism has a better chance of leaving a fossil: a jellyfish or a bony fish? Why? Is the Earth’s environment/climate/forms of life/ done changing? Why or why not?