end of year review geologic evidence of change over time

End of Year ReviewGeologic Evidence of Change Over Time

8th Grade Science Curriculum

Change Over TimeGeologic 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

http://images.google.com/imgres?imgurl=http://farm1.static.flickr.com/194/485808703_cd391bf9bd.jpg%3Fv%3D0&imgrefurl=http://flickr.com/photos/manukalra/485808703/&usg=__t9yEbnvE8onS_4wCU-LOjWr_EHs=&h=491&w=500&sz=65&hl=en&start=5&um=1&tbnid=JuuJfBeXRFD9QM:&tbnh=128&tbnw=130&prev=/images%3Fq%3Dfrozen%2Bmammoth%26hl%3Den%26um%3D1


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 FossilsRelative Dating: uses information about rock

layers and the fossil record to determine the age relationships between rocks

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

ESSENTIAL QUESTION #1

•What is the Law of Superposition?

Change Over TimeRelative 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.

ESSENTIAL QUESTION #2• 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 TimeAbsolute 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?

•Class discussion.


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

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

37

Plate Tectonics•Correlation: the matching up of rock layers from different locations

•Can use minerals in rock layers or fossils

39

www.answers.com

physics.uwstout.edu


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

•Class discussion.


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

42

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.

43

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

44

Plate TectonicsCause of Plate Movements:

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

45

mediatheek.thinkquest.nl

Plate TectonicsAll Over the World

46cimss.ssec.wisc.edu

ESSENTIAL QUESTION #5• 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

49

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

50

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

51

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.

53

Which process best explains how mountain ranges are

worn down over time?A.Asteroid impacts

B.Volcanic eruptionsC.Mechanical and chemical

weatheringD.Continental drift and seafloor

spreading

54

Which process best explains how mountain ranges are

worn down over time?A.Asteroid impacts

B.Volcanic eruptionsC.Mechanical and chemical

weatheringD.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 Sensing

57

Using satellites to study changes in Earth

58

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


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

•Class discussion


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

Spectral Analysis

61

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

ESSENTIAL QUESTION #9• 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 Truthing

64

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 #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 ChangeDue to fossil fuel use and other pollutants, the amount of CO2

has been increasing 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

http://globalwarmingsiren.com/climategate-global-warming-hoax-exposed/

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?

http://www.worldwithoutwinter.com/about-world-without-winter.html


• What evidence is there for climate change?

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

ESSENTIAL QUESTION

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

• Class discussion

ESSENTIAL QUESTION

•How does the information gathered by these methods help scientists make predictions about change over time?

•Class discussion


•What does the Geologic Time Scale tell us about

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

75

Geologic Time Scale

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

geomaps.wr.usgs.gov

76

Geologic 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 #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?

79

Precambrian• 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

80encarta.msn.com

81

PrecambrianConsidered the Age of Algae

Biological 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

82

www.nd.edu

Bacterial Colony

83

Volvox ColonyCells work together to move the entire colony using individual 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

84

End of the Precambrian• Oxygen in the atmosphere• Most life is single celled organisms• All life exists in oceans

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

85

Paleozoic Era• 544 to 245 million years agoGeologic 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

86

Paleozoic Era

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

www.paleoportal.org

87

Paleozoic Era• Continents

collide causing the Appalachian Mountains to form

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

www.paleoportal.org

88

Paleozoic Era

Pangaea forms

www.canadiangeographic.ca

89

Paleozoic 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

Megosaurus www.answers.com

www.50birds.com

90

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.

91

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.

92

Paleozoic EraBiological Changes

• Great “explosion” of new species of invertebrates

www.sciencedaily.com


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

94


• 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.

ESSENTIAL QUESTION #14• 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.

96


• First land plants appear

• First spiders and insects appear

www.msu.edu

bleedingeyeballs.com

www.treknature.com

97


• 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.edu

98


• Simple amphibians then reptiles evolve

animals.howstuffworks.com


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

•Class discussion

100

Mesozoic 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

101

Mesozoic EraHot and dry climate

www.3drelax.com

102

Mesozoic EraPangaea splits

www.albury.net.au

103

Mesozoic EraBiological 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.com

104


First mammal appears as a small rat-like animal

www.nmnaturalhistory.org


•What types of catastrophic events have occurred over time?

106


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

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

107

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

living members?

A. They had offspring of a different species.

B. They mutated to other species.

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

108

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

living members?

A. They had offspring of a different species.

B. They mutated to other species.

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

109

Cenozoic EraAge of Mammals

66 million years ago to presentGeologic Changes:Rocky Mountains and Himalayas formIce ages periodically cover much of the landLast ice age ends

110

Cenozoic EraContinents

crashing into each other create new mountain ranges like the Himalayas

111

Cenozoic EraPeriodic ice ages create glaciers that reach into most of

North America and other continents

geography.howstuffworks.com

112

Cenozoic EraBiological Changes

Mammals evolve to replace the niches dinosaurs had occupied

exurbanpedestrian.wordpress.com

www.colemangallery.com

dearkitty.blogsome.com

113


First grasses and flowering plants appear for the first time

thoreaugrass.blogspot.com

ruralramblings.com

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

creatures.


www.joevenusartist.com news.bbc.co.uk/2/hi/science/nature

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

http://www.joevenusartist.com/

http://news.bbc.co.uk/2/hi/science/nature/7130014.stm

http://houseofstaunton.com/Store/product_name=The+Mammoth+Ivory+Collector+Series+Luxury+Chess+Set+-+4.4+inch+King/exact_match=exact/user-id=/password=

ESSENTIAL QUESTION #15• 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 TimeCharles 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

ESSENTIAL QUESTION #16• 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 TimeEvolution

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 ##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 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 #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 TimeEvolutionArtificial

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

131


First humans appear towards the end of the Cenozoic Era

news.bbc.co.uk

end of year review geologic evidence of change over time

Documents

layer of rock

rock layers

timegeologic evidencecast

timegeologic evidenceamber

timegeologic evidencemold

timegeologic evidencefrozen

timegeologic evidencehow

fewer fossils