Bell Work 10-19-15If you were to put the following

events in to a time sequence of first to last, how would you do it? What else would you add?

Go to school

Wake up

Eat lunch

Put clothes on

WHAT’S IN THE ROCKS!

State Performance Indicators SPI 0807.5.5 Compare fossils found in sedimentary rock to

determine their relative age Essential Learning: How do I compare fossils found in rock to

determine their relative age?

Objectives

Describe the process of relative dating to determine the age of rocks

Compare and Contrast different types of fossils in sedimentary rock to determine their relative age

TOC: Geologic History Notes

Sedimentary Rock

Sedimentary rocks cover 75% of the Earth’s land area.

Layer after layer of eroded earth is deposited on top of each. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Relative Dating

Scientists use different methods to determine the age of objects in sedimentary rocks.

One method, Relative dating, examines a fossil’s position within rock layers to estimate its age.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

The bottom layers of rock are usually the oldest, and the top layers are usually the youngest.

Scientists can use the order of rock layers to determine the relative age of objects within the layers.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Discuss with elbow partner which layer is the oldest in this rock column and which is the youngest.

Identify the type of rock in the oldest and youngest layers.

Which is the biggest fossil in the rock column? Is the fossil young or old relative to the other fossils in the rock column?

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

The Geologic ColumnTo make relative dating easier, geologists

combine data from all of the known rock sequences around the world.

From this information, geologists created the geologic column — an ideal sequence of rock layers that contains all of the known fossils and rock formations on Earth, arranging layers from oldest to youngest.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

PalaeontologyPalaeontology is the science

involved with the study of past life.

Scientists who study past life are called palaeontologists.

Palaeontologists collect data by studying fossils.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

The remains or physical evidence of an organism preserved by geologic processes is called a Fossil.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Fossils in rocks happen when organisms die, the fleshy parts decompose and are buried quickly in sedimentary rocks.

The hard parts are left to become fossils.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Fossils in Amber occurs when insects get stuck in tree sap that hardens quickly.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Petrification is the process in which minerals replace an organisms tissues.

One form of petrification is called permineralization, which is the process in which minerals fill in pore spaces of an organism’s tissues.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Frozen fossils occur when animals are frozen in ice and die. We find them 1000s of years later when it thaws.

Fossils in Asphalt occurs when animals are preserved in thick, sticky pools of asphalt.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

Trace fossils are any naturally preserved evidence of an animal’s activity.

Three types:

1.Track- footprint2.Burrows- shelters made by animals

3.Coprolites- preserved animal dung

elbow partner

discuss and analyze why tracks and coprolites are considered trace fossils?

Burrow

Coprolite

Some fossils do not contain any original material of the original organism. Molds form when sediments cover the organism, such as shell, and the hard part is alter removed by weathering or erosion.

A cast is an object that is created when sediment fills a mold and becomes rock.

History of Changing Organisms

Scientists study the relationships between fossils to interpret how life has changed over time.

Since the fossil record is incomplete, palaeontologists look for similarities between fossils over time to try to track change.

Using Fossils to Date Rocks

Scientists have found that particular types of fossils appear only in certain layers of rock.

By dating rock layers above and below these fossils, scientists can determine the time span in which the organism lived.

If the organism lived for a relatively short period of time, its fossils would show up in limited layers.

Index fossils are fossils of

organisms that lived for a

relatively short, well defined

geologic timespan.

Trilobites

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SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

 

SPI 0807.5.5 (Fossils)The diagram below shows three substrate layers with fossils.

1. Which statement is best supported by the diagram?a.A. The fossils in Layers 1 and 3 are from closely related organisms.b.B. The fossils in Layers 2 and 3 are from closely related organisms.c.C. The fossil in Layer 3 is older than the fossil in Layer 2.d.D. The fossil in Layer 1 is older than the fossil in Layer 2.

 SPI 0807.5.5 (Fossils)Two geologic columns are shown below. The columns are from areas about 1 kilometer apart

a.Layers 3 and 4 c.Layers 2 and 3b.Layers 2 and 6 d.Layers 1 and 4

2. Which layers were most likely deposited at the same time?

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

SPI 0807.5.5 (Fossils)

3. Scientists use a fossil’s position within rock layers to determine whether the fossil is older or younger than other fossils in a process called

a. the geologic column. c. half-life.b. relative dating. d. absolute dating.

SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age

SPI 0807.5.5 (Fossils)

4. A scientist was digging for fossils along a rocky cliff. The scientist discovered trilobite fossils in rocks at two different depths in the cliff. What can be determined about the fossils based on their locations?

a. the diet of the trilobites c. the relative age of the trilobite fossilsb. the size of trilobite population d. the number of trilobite predators

5. A cross section of rock layers is shown below.

Which fossil is found in the oldest layer?a.dinosaurb.shellc.leafd.fish

Bell Work 10-20-15 Compare the fossil layers shown below.

Which organisms are most likely to be the same approximate age?

a. 2 and 4

b. 5 and 6

c. 1 and 3

d. 3 and 5

Using Fossils to Interpret the PastFossils can reveal changes in the environment.

Scientists have found marine fossils on mountaintops (e.g. Yoho National Park)

The presence of these fossils means that rocks were once below the surface of an ocean.

Middle TN, specifically Murfreesboro, was once covered by a shallow sea.

Marine fossils found in the limestone tell scientists that.

FINDASAURUS ACTIVITY Scenario: A paleontologist from Tennessee went on vacation to

Montana where he discovered dinosaur bones in a particular layer of rock. He wondered if the same layer existed in Tennessee so he could find bones closer to home. If that particular rock appears on Earth’s surface, continuously, all the way from Montana to Tennessee he would be able to walk along the layer to follow it. That would be easy, but unfortunately, the easy way never seems to work. Erosion would make it impossible to follow the layer all the way from Montana to Tennessee. One of the most reliable ways to locate fossils is with other fossils. Index fossils can be used to track a layer from Montana to Tennessee, or from Montana to France. Relative dating places events in sequence within the rock layers while the process of determining if layers in different places are the same is called correlation.  

1.There are two stacks of rock layers, one in Montana and one in France. Your job is to determine: Which layers in Montana correlate with layers in France by matching the letters. Which layer in France contains the same dinosaur fossil as layer “d” in Montana.  

2.Draw the fossils in the layers shown on the chart. For example, index fossil #2 should be drawn only in layers c and i. Make your best effort at reproducing the drawing.  

3.Using colored pencils connect the borders of the rock layers in Montana with those in France.

2-minute journal reflection using accountable talk ( I hypothesize that ...) on which layer is correct and what you learned today.

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