end of year review geologic evidence of change over time wake county 8 th grade science curriculum

End of Year ReviewEnd of Year ReviewGeologic Evidence of Geologic Evidence of Change Over TimeChange Over Time

Wake County Wake County

88thth Grade Grade

Science CurriculumScience Curriculum

Change Over TimeChange Over TimeGeologic EvidenceGeologic Evidence

Fossil: evidence of past life preserved in rock; Different kinds of fossils are:

1. Petrified fossil: minerals replace all or part of an organism

www.alaska.edu

You can see the rings.

en.wikivisual.com


Mold: a hollow area in sediment in the shape of an organism or part of an organism; formed when the organism makes an indentation that turns to rock over time

www.ammonoid.com

Cake mold


Cast: a solid copy of the shape of an organism; made by filling in a mold with minerals that later turn to rock.

Mold Cast

esp.cr.usgs.gov


Carbon film: an extremely thin coating of carbon on rock; made when an organism is squeezed by rock until only carbon remains

www.geology.ohio-state.edu


Trace fossil: evidence of activities of ancient organisms; may be tracks, burrows, nest, or trail

Fossil burrow Fossil tracks

igs.indiana.edu


Amber: a hardened resin, or sap, of evergreen trees; organisms that get trapped in the sticky substance becomes part of the rock

pixdaus.com

www.ambermine.com


Frozen remains: organisms caught in ice or snow Adult mammoth

flickr.com

Frozen baby mammoth

www.cryptomundo.com


Fossil record: the complete body of fossils that shows how species and ecosystems change over time

www.rockandwater.com

images.mooseyscountrygarden.com

anthropology.net


How do fossils give us the age of organisms that lived in the past?

Is this fish fossil a few thousand years old or a few billion years old?

www.treasure-hunting-team.com


Dating Rocks and FossilsDating Rocks and Fossils

Relative Dating: uses information about rock Relative Dating: uses information about rock layers and the fossil record to determine the layers and the fossil record to determine the age relationships between rocksage relationships between rocks

Absolute Dating: any method of measuring the Absolute Dating: any method of measuring the age of an event or object in yearsage of an event or object in years

ESSENTIAL QUESTION #1ESSENTIAL QUESTION #1

•What is the Law of Superposition?

Change Over TimeChange Over TimeRelative DatingRelative Dating

Law of Superposition: states that the oldest rocks lie on the bottom and the youngest rocks are on top of any undisturbed sequence of sedimentary rocks.

media-2.web.britannica.com

Which can most likely be concluded about the top layer of rock seen in an

undisturbed cliff wall?

A. The top layer is older than layers located farther down the cliff.

B. The top layer is younger than layers located farther down the cliff.

C. The top layer contains more fossils than layers located farther down the

cliff.D. The top layer contains fewer fossils

than layers located farther down the cliff.


The fossils in layer 3 are “relatively” the same age.

Which layers are older than layer 3?

Which layers are younger than layer 3?

1 and 2

4,5,6,and 7


• What is the Law of Superposition?

• Law of Superposition: states that the oldest rocks lie on the bottom and the youngest rocks are on top of any undisturbed sequence of sedimentary rocks.

Based on the Law of Superposition, what can be concluded about

fossils?

A. Fossils give clues about the past climate patterns.

B. Fossils form from the hard parts of organisms.

C.The oldest fossils are found in the lowest rock layers.

D.The most recent fossils were advanced organisms.


•How can an unconformity be used as evidence for geologic evolution?


Since the top of layer 5 and layer 6 are at the same level, are these two layers the same age? Why or why not?


No, they are not the same age. Layer 5 is older than layer 6.

Unconformity: gaps in the rock record created when older rock is worn away then new rock is layered over it.

You can see that parts of the older layers are missing.


• How can an unconformity be used as evidence for geologic evolution?

• An unconformity can be used to determine relative age of rock layers.

Which does a scientist most likely consider when studying the relative ages of rock layers

in a canyon wall?

A. Chemical weatheringB. Current climate

C.Amount of daily rainfallD.Law of Superposition


•How is the age of the earth determined?

Change Over TimeChange Over TimeAbsolute DatingAbsolute Dating

• When magma or lava hardens, new rock is formed.

• When new rock is formed, some elements’ isotopes are radioactive.

www.kilaueaadventure.com


• Isotope: an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (thus a different atomic mass)

• Parent isotope: an atomic nucleus that is undergoing decay (Tritium H-3)

www.radiation-scott.org

Daughter isotope: the stable isotope that results from radioactive decay (Helium-3)


• Tritium is radioactive. • It “decays” by losing an electron from one of the

neutrons. • Radioactive decay: the process in which a radioactive

isotope tends to break down into a stable isotope of the same element or another element.

• The neutron becomes a proton increasing the atomic number from one (Hydrogen) to two (Helium)

www.impcas.ac.cn

Parent isotope

Daughter isotope


• Half-life: the time needed for half of a sample of radioactive substance to undergo radioactive decay (Tritium has a half-life of 12.5 years)


www.kgs.ku.edu


• All radioactive elements have a specific half-life

library.thinkquest.org


• After measuring the amount of parent isotopes and daughter isotopes in a rock, scientists use mathematical calculations to determine the rock’s age.

• These calculations are based on the half-life of the isotopes.

• When the rock is dated, we can know exactly how long ago the organism was alive.


• Radioactive Dating: the process by which the age of a rock is determined by measuring the amount of radioactive isotopes present in the rock or rock sample

eapbiofield.wikispaces.com


•How is the age of the earth determined?

•Radioactive dating of Earth and moon rocks (4.6 billion years old).


•How has the geology of the Earth changed over time?

Continental DriftContinental DriftContinental Drift Theory: theory that states that the gradual shifting of Earth’s plates causes continents to change their global positions over time.

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Plate TectonicsPlate Tectonics•Correlation: the matching up of rock layers from different locations•Can use minerals in rock layers or fossils

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www.answers.comwww.answers.com

physics.uwstout.edu


•How has the geology of the Earth changed over time?

•Continents have moved because of the plates.


• How has the Earth been impacted by major geological events?

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Which is the best evidence that two continents were

once connected?A.They have similar types of

rocks and fossils.B.They are in the same stage

of succession.C.They exist along the same

line of latitude.D.They have the same climate.

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Which is the best evidence that two continents were

once connected?A.They have similar types of

rocks and fossils.B.They are in the same stage

of succession.C.They exist along the same

line of latitude.D.They have the same climate.

Plate TectonicsPlate TectonicsPlate tectonics is the theory that explains how large pieces of the Earth’s outermost layer called tectonic plates move and change shape

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Plate TectonicsPlate TectonicsCause of Plate Movements:

Heat from the core sets up convection currents within the mantle. As the mantle moves, it moves the plates above.

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mediatheek.thinkquest.nl

Plate TectonicsPlate TectonicsAll Over the WorldAll Over the World

4646cimss.ssec.wisc.edu


• How has the Earth been impacted by major geological events?

• Plate tectonics has caused continents to move to different climates.

• Movement of plates cause mountains to build, earthquakes, and volcanoes.

• What other major geological events can you think of?


• How have mechanical and chemical weathering impacted the earth?

Weathering Weathering

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Mechanical weathering: is the erosion of rocks and soil caused by wind, water, or ice freezing inside rocks

www.kidsgeo.comwww.flickr.com

soilerosion.net

WIND

WATER

WATER FREEZING

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Weathering Weathering Chemical weathering: is the erosion of rocks and soil caused by chemical reactions

Iron in rock combining with oxygen to form iron oxide (rust)

Pollutants causing acid rain that will react to minerals in natural rock or statues carved from rock

edutel.musenet.org

mail.colonial.net

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Weathering Weathering •Mountains formed by plate tectonics are constantly being worn down by mechanical and chemical weathering.•The Himalayas are the largest mountains on Earth.•The Appalachian Mountains used to be as large as the Himalayas.•The Appalachians are now just the worn remnants of a once immense mountain range.


• How have mechanical and chemical weathering impacted the earth?

• Mountains and other land features are worn down.

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Which process best explains how mountain ranges are

worn down over time?

A.Asteroid impactsB.Volcanic eruptions

C.Mechanical and chemical weathering

D.Continental drift and seafloor spreading

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Which process best explains how mountain ranges are

worn down over time?

A.Asteroid impactsB.Volcanic eruptions

C.Mechanical and chemical weathering

D.Continental drift and seafloor spreading


• How have technological processes allowed us to understand change over time?


• How does remote sensing help scientists make predictions about land use, urban sprawl, and/or resource management ?

Remote SensingRemote Sensing

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Using satellites to study changes in Earth

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Remote SensingRemote Sensing

Satellite pictures/maps can be used to monitor land use, urban sprawl and resource management.


• Why do scientists use remote sensing when monitoring the Earth?

• To see the change of Earth’s surface over time


• How does the spectral analysis of reflectance curves help scientists monitor the Earth?

Spectral AnalysisSpectral Analysis

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The Gulf Stream can be seen (red) in this thermal satellite image

Spectral analysis uses bands of reflected light to monitor changes in the Earth

www.emagazine.com


• How does the spectral analysis of reflectance curves help scientists monitor the Earth?

• It aids scientists by helping them get a visual picture of the atmosphere and surface that couldn’t be viewed otherwise.


• How does ground truthing help scientists make predictions about land use, urban sprawl, and/or resource management?

Ground TruthingGround Truthing

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When scientists study satellite images, they sometimes must go to the areas to see how the image correlates with the actual environment.

www.oakparkjournal.com

ian.umces.edu


• How does ground truthing help scientists make predictions about land use, urban sprawl, and/or resource management?

• This process lets them observe up close, what satellites have shown them.

ESSENTIAL QUESTION #7ESSENTIAL QUESTION #7• How have technological processes

allowed us to understand change over time?

• Satellite imagery has made it easier to observe plate tectonics.

• Machines can dig deeper to study rock layers.

• Can you think of others?


•What evidence is there for climate change?

Global ChangeGlobal ChangeDue to fossil fuel use Due to fossil fuel use and other pollutants, and other pollutants, the amount of COthe amount of CO22

has been increasing has been increasing steadily.steadily.

earthobservatory.nasa.gov

Global Change•Even though we have not experienced huge increases in temperatures, evidence of global warming is the melting of the polar ice caps.

globalwarmingsiren.com

South Florida is home to millions of people . . .

www.worldwithoutwinter.com

This is what Florida would look like if all ice on this planet melted. What would happen to the temperature if all ice on the planet were gone?


• What evidence is there for climate change?

• Melting icecaps, sea level rising, slight global temperature increases.

ESSENTIAL QUESTION ESSENTIAL QUESTION #12#12

•What does the Geologic What does the Geologic Time Scale tell us about Time Scale tell us about

the Earth’s geologic history the Earth’s geologic history and the evolution of life? and the evolution of life?

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Geologic Geologic Time ScaleTime Scale

• The standard method used to divide the Earth’s long natural history into manageable parts

geomaps.wr.usgs.govgeomaps.wr.usgs.gov

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Geologic Time ScaleGeologic Time Scale• Eon: largest division of geologic time• Era: A unit of geologic time that includes

two or more periods• Period: a subdivision of the eras in

geologic time• Epoch: A subdivision of a geologic period

Divisions are determined by the major life forms of the time

ESSENTIAL QUESTION #12ESSENTIAL QUESTION #12• What does the Geologic Time Scale tell us

about the Earth’s geologic history and the evolution of life?

• The four eras of the geologic time scale were set up based on the life of the era.

• Precambrian – Bacteria and small multi-celled organisms

• Paleozoic – Fish and arthropods

• Mesozoic – Reptiles

• Cenozoic – Mammals


• How has the distribution of living things changed over time?

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PrecambrianPrecambrian

• Longest time division• 4.6 billion to 544 million. This is equal to a little

more than 4 billion years.

Early Earth: Geological ChangesWater condensed and formed oceansStorms dominated the atmosphereAtmosphere was methane, ammonia, and other

chemicalsNo oxygenMoon was closer so appeared larger

7878encarta.msn.com

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PrecambrianPrecambrianConsidered the Age of AlgaeConsidered the Age of Algae

Biological ChangesBiological Changes• Simple single celled bacteria evolve in the

oceans.• Some bacteria adapt to photosynthesize and

evolve into algae• The atmosphere began to build up oxygen• Some bacteria adapt to use oxygen in

respiration• Some cells form simple colonies• Colonies of cells begin to evolve into small

invertebrates

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www.nd.eduwww.nd.edu

Bacterial ColonyBacterial Colony

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Volvox ColonyVolvox ColonyCells work together to Cells work together to move the entire move the entire colony using colony using individual flagellaindividual flagella

• Individual cells are connected like a primitive life form

• Small colonies form inside and become individual colonies when the large one dies and breaks open

www.morning-earth.org

io.uwinnipeg.ca

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End of the PrecambrianEnd of the Precambrian• Oxygen in the atmosphere

• Most life is single celled organisms

• All life exists in oceans

These are These are stromatolites stromatolites formed by build-formed by build-up of blue-green up of blue-green algaealgae

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Paleozoic EraPaleozoic Era• 544 to 245 million years ago

Geologic Changes:Life is still found mostly in the oceans but some

moves to the land.Shallow seas cover most of the land including

North AmericaCoral reefs developContinents collide creating the Appalachian

MountainsPangaea forms

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Paleozoic EraPaleozoic Era

• As you can see (), most of the East was under water in early Paleozoic

www.paleoportal.orgwww.paleoportal.org

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Paleozoic EraPaleozoic Era• Continents

collide causing the Appalachian Mountains to form

• This causes sea shell fossils to be on the top of mountains

www.paleoportal.orgwww.paleoportal.org

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Paleozoic EraPaleozoic Era

PangaeaPangaea

formsforms

www.canadiangeographic.cawww.canadiangeographic.ca

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Paleozoic EraPaleozoic Era• Mesosaurus was a species that lived on Pangaea.• Fossils of the reptile and other species were made.• When Pangaea broke up, the fossils could still be found on the

different continents proving they were once connected

MegosaurusMegosaurus www.answers.comwww.answers.com

www.50birdwww.50birds.coms.com

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Which best explains why fossils of the same species of a reptile were discovered in South America and in western Africa?

A. The reptiles evolved in both South America and Africa.

B. The continents of South America and Africa were once joined.

C. Land bridges connected the continents of South America and Africa.

D. The reptiles could swim the distance between South America and Africa.

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Which best explains why fossils of the same species of a reptile were discovered in South America and in western Africa?

A. The reptiles evolved in both South America and Africa.

B. The continents of South America and Africa were once joined.

C. Land bridges connected the continents of South America and Africa.

D. The reptiles could swim the distance between South America and Africa.

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Paleozoic EraPaleozoic EraBiological ChangesBiological Changes

• Great “explosion” of new species of invertebrates

www.sciencedaily.comwww.sciencedaily.com


• How do index fossils help us understand life forms in the four major geologic eras?

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• Trilobites appear at the beginning of this era…

• …then disappear at the end making them an index fossil for the Paleozoic Era

• Index fossil is found in a narrow time range but widely distributed around the earth; used to date rock layers in any era.


• How do index fossils help us understand life forms in the four major geologic eras?

• Index fossils, if found in a rock layer with other fossils, can help us determine the relative age of that layer and the other fossils in it.

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• First land plants appear

• First spiders and insects appear

www.msu.eduwww.msu.edu

bleedingeyeballs.combleedingeyeballs.com

www.treknature.comwww.treknature.com

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• Considered the “Age of Fish” due to the evolution of fish from a worm-like creature to a fish with a jaw

www.life.umd.eduwww.life.umd.edu

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• Simple amphibians then reptiles evolve

animals.howstuffworks.comanimals.howstuffworks.com


• How has the distribution of living things changed over time?

• Evolved from simple, single-celled organisms to more complex organism (amphibians to reptiles)

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Mesozoic EraMesozoic Era• 245 to 66 million years ago or about 180

million years

Geologic Changes:Hot and dry climatePangaea splits into individual continentsWidespread volcanic activity due to the

continents moving

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Mesozoic EraMesozoic Era

Hot and dry climate

www.3drelax.com

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Mesozoic EraMesozoic EraPangaea splits

www.albury.net.au

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Mesozoic EraMesozoic EraBiological ChangesBiological Changes

• Species evolved quickly to take advantage of the land that hadn’t been occupied by many species

• Dinosaurs appear and evolve quickly

www.kittymowmow.www.kittymowmow.comcom

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First mammal appears as a small rat-like First mammal appears as a small rat-like animalanimal

www.nmnaturalhistory.www.nmnaturalhistory.orgorg


• What types of catastrophic events have occurred over time?

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End of the Mesozoic Era ends with the sudden End of the Mesozoic Era ends with the sudden extinction of all dinosaursextinction of all dinosaurs

One theory is that a comet hit the earth causing One theory is that a comet hit the earth causing a cloud to cover the earth for yearsa cloud to cover the earth for years

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Which Which most likelymost likely happened happened to species that are found in to species that are found in the fossil record but have no the fossil record but have no

living members?living members?

A.A. They had offspring of a They had offspring of a different species.different species.

B.B. They mutated to other They mutated to other species.species.

C.C. They became extinct.They became extinct.D.D. They never really existed.They never really existed.

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Which Which most likelymost likely happened happened to species that are found in to species that are found in the fossil record but have no the fossil record but have no

living members?living members?

A.A. They had offspring of a They had offspring of a different species.different species.

B.B. They mutated to other They mutated to other species.species.

C.C. They became extinct.They became extinct.D.D. They never really existed.They never really existed.

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Cenozoic EraCenozoic EraAge of MammalsAge of Mammals

66 million years ago to present

Geologic Changes:Rocky Mountains and Himalayas formIce ages periodically cover much of the landLast ice age ends

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Cenozoic EraCenozoic Era

Continents crashing into each other create new mountain ranges like the Himalayas

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Cenozoic EraCenozoic EraPeriodic ice ages create glaciers that reach into most of

North America and other continents

geography.howstuffwgeography.howstuffworks.comorks.com

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Cenozoic EraCenozoic EraBiological ChangesBiological Changes

Mammals evolve to replace the niches dinosaurs had occupied

exurbanpedestrian.wordpress.comexurbanpedestrian.wordpress.com

www.colemangallery.comwww.colemangallery.com

dearkitty.blogsome.cdearkitty.blogsome.comom

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First grasses and flowering plants appear for the first time

thoreaugrass.blogspot.com

ruralramblings.comruralramblings.com

Ice ages have caused mammals of the Ice ages have caused mammals of the Cenozoic Era to adapt to many strange Cenozoic Era to adapt to many strange

creatures.creatures.


www.joevenusartist.comnews.bbc.co.uk/2/hi/science/nature

houseofstaunton.com/.../user-id=/password=


• What types of catastrophic events have occurred over time?

• Comets and meteors have struck the planet causing global change.

• Many ice ages have occurred causing specie extinctions.

• Can you thing of others?


• How did the geological theories of evolution assist Darwin in his theory of natural selection?

Change Over TimeChange Over TimeCharles DarwinCharles Darwin

• At the age of 21, Darwin sailed on board the HMS Beagle as science officer

richarddawkins.net

www.genghisthedog.com

Voyage of the HMS Beagle


• He studied the Galapagos Island wild life and noticed similarities between different species of finches, tortoises, and iguana

photos.mongabay.com

Notice the differences in the shells

Notice the differences in the beaks

www.bbc.co.uk

www.mirrabac.com Iguanas have evolved to eat cactus for one species and sea algae for another


• Based on these similarities, Darwin came to the conclusion that species evolved over time to adapt to different environments

• He called this adaptation natural selection or “survival of the fittest”

www.thisviewoflife.org


• How did the geological theories of evolution assist Darwin in his theory of natural selection?

• He studied the different islands of the Galapagos

• He found that the islands had different climates and food sources therefore the animals had adapted to fit those environments.

• He also found that fossils in different parts of the world supported his theory.


• How are the biological theories of Darwin and Lamark similar and how are they different?

Change Over TimeChange Over TimeEvolutionEvolution

Theory: an explanation that ties together many hypothesis and observations

• Adaptation: a trait that increases the chances that an organism will survive and reproduce

Peppered Moth

www.cals.ncsu.edu

Can you see all four moths?

www.arn.org

ESSENTIAL QUESTION ##18ESSENTIAL QUESTION ##18

•How does the extinction of a species relate to evolution?


Natural Selection: survival of the fittest organisms that are the best adapted to their environment and the ones that will live long enough to reproduce and pass on their favorable adaptations

Lamark’s ViewsLamark’s ViewsJean-Baptiste Lamarck • 1 August 1744 – 18 December 1829

• Contributed his evolution theory before Darwin

• His theory included the idea that organisms developed traits because they needed them

• Example: A giraffe’s neck became longer because the giraffe would stretch it to reach food

• Although incorrect, his ideas began research into organisms changing over time.

ESSENTIAL QUESTION #17ESSENTIAL QUESTION #17• How are the biological theories of

Darwin and Lamark similar and how are they different?

• Both thought organisms had changed over time.

• Darwin supported natural selection.

• Lamark thought that organisms changed due to environmental stresses on them

Change Over TimeChange Over TimeEvolutionEvolutionArtificial

Selection the breeding of

plants and animals with desired traits to attempt to produce offspring with these same traits

all domesticated animals and plants were developed using this process

also known as selective breeding

www.harunyahya.com


Speciation: the process of natural selection producing a new species out of existing species over thousands or millions of years

Species: a group of organisms that can breed and produce fertile offspring; most specific classification of living things

Extinction: The evolutionary termination of a species caused by the failure to reproduce and the death of all remaining members of the species; the natural failure to adapt to environmental change


• Evolution: the change in population of a species over time; caused by differences in variation or successful mutations that allow individuals to survive and pass on their genes

• Mutation: a random change to a gene that results in a new trait

• Biological Evolution: the change over time of living organisms


• How does the extinction of a species relate to evolution?

• If a species becomes extinct, they were not able to adapt to the changing environment.

• Only those able to adapt (change) will survive

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First humans appear towards the end of the Cenozoic Era

news.bbc.co.uknews.bbc.co.uk

end of year review geologic evidence of change over time wake county 8 th grade science curriculum

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