Transcript Change Over Time Geologic Evidence

End of Year Review
Geologic Evidence of
Change Over Time
Wake County
8th Grade
Science Curriculum
Change Over Time
Geologic 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
en.wikivisual.com
You can see the rings.
www.alaska.edu
Change Over Time
Geologic Evidence
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
Cake
mold
www.ammonoid.com
Change Over Time
Geologic Evidence
Cast: a solid copy of the shape of an
organism; made by filling in a mold with
minerals that later turn to rock.
esp.cr.usgs.gov
Mold
Cast
Change Over Time
Geologic Evidence
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
Change Over Time
Geologic Evidence
Trace fossil: evidence of activities of ancient
organisms; may be tracks, burrows, nest, or trail
igs.indiana.edu
Fossil burrow
Fossil tracks
Change Over Time
Geologic Evidence
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
Change Over Time
Geologic Evidence
Frozen remains: organisms caught in ice or
snow Adult mammoth
Frozen baby mammoth
flickr.com
www.cryptomundo.com
Change Over Time
Geologic Evidence
Fossil record: the complete body of fossils
that shows how species and ecosystems
change over time
www.rockandwater.com
anthropology.net
images.mooseyscountrygarden.com
Change Over Time
Geologic Evidence
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
Change Over Time
Geologic Evidence
Dating Rocks and Fossils
Relative 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 Time
Relative 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.
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.
Change Over Time
Relative Dating
The fossils in layer 3
are “relatively” the
same age.
Which layers are older than layer 3?
1 and 2
Which layers are younger than layer 3?
4,5,6,and 7
ESSENTIAL QUESTION #1
• 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.
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.
ESSENTIAL QUESTION #2
•How can an
unconformity be used
as evidence for
geologic evolution?
Change Over Time
Relative Dating
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?
Change Over Time
Relative Dating
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 weathering
B. Current climate
C.Amount of daily rainfall
D.Law of Superposition
Which does a scientist most
likely consider when studying
the relative ages of rock layers
in a canyon wall?
A. Chemical weathering
B. Current climate
C.Amount of daily rainfall
D.Law of Superposition
ESSENTIAL QUESTION #3
•How is the age of the
earth determined?
Change Over Time
Absolute Dating
• When magma or lava hardens, new rock is
formed.
• When new rock is formed, some elements’
isotopes are radioactive.
www.kilaueaadventure.com
Change Over Time
Absolute Dating
• 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)
Daughter isotope:
the stable isotope
that results from
radioactive decay
(Helium-3)
www.radiation-scott.org
Change Over Time
Absolute Dating
• 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)
Parent
isotope
Daughter
isotope
www.impcas.ac.cn
Change Over Time
Absolute Dating
• 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)
Change Over Time
Absolute Dating
www.kgs.ku.edu
Change Over Time
Absolute Dating
• All radioactive elements have a specific
half-life
library.thinkquest.org
Change Over Time
Absolute Dating
• 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.
Change Over Time
Absolute Dating
• 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
ESSENTIAL QUESTION #3
•How is the age of the
earth determined?
•Radioactive dating of
Earth and moon rocks
(4.6 billion years old).
ESSENTIAL QUESTION #4
•How has the geology of
the Earth changed over
time?
Continental Drift
Continental Drift Theory:
theory that states that the
gradual shifting of Earth’s
plates causes continents to
change their global
positions over time.
37
38
Plate Tectonics
•Correlation: the matching up of
rock layers from different locations
•Can use minerals in rock layers or
fossils
physics.uwstout.edu
www.answers.com
39
ESSENTIAL QUESTION #4
•How has the geology of
the Earth changed over
time?
•Continents have moved
because of the plates.
ESSENTIAL QUESTION #5
• How has the Earth been
impacted by major
geological events?
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.
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
Plate Tectonics
Plate tectonics is the
theory that explains how
large pieces of the Earth’s
outermost layer called
tectonic plates move and
change shape
44
Plate Tectonics
Cause of Plate Movements:
Heat from the
core sets up
convection
currents within
the mantle. As
the mantle
moves, it moves
the plates above.
mediatheek.thinkquest.nl
45
Plate Tectonics
All Over the World
cimss.ssec.wisc.edu
46
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?
ESSENTIAL QUESTION #6
• How have mechanical and
chemical weathering
impacted the earth?
Weathering
Mechanical weathering: is the erosion
of rocks and soil caused by wind, water,
or ice freezing inside rocks
WATER 
soilerosion.net
www.flickr.com
WIND 
www.kidsgeo.com
WATER
FREEZING 
49
Weathering
Chemical weathering: is the erosion of
rocks and soil caused by chemical
reactions
mail.colonial.net
edutel.musenet.org
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
50
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.
51
ESSENTIAL QUESTION #6
• How have mechanical and
chemical weathering
impacted the earth?
• Mountains and other land
features are worn down.
Which process best explains
how mountain ranges are
worn down over time?
A.Asteroid impacts
B.Volcanic eruptions
C.Mechanical and chemical
weathering
D.Continental drift and seafloor
spreading
53
Which process best explains
how mountain ranges are
worn down over time?
A.Asteroid impacts
B.Volcanic eruptions
C.Mechanical and chemical
weathering
D.Continental drift and seafloor
spreading
54
ESSENTIAL QUESTION #7
• How have technological
processes allowed us to
understand change over
time?
ESSENTIAL QUESTION #8
• How does remote sensing
help scientists make
predictions about land
use, urban sprawl, and/or
resource management ?
Remote Sensing
Using satellites to study changes in Earth
57
Remote Sensing
Satellite
pictures/maps
can be used
to monitor
land use,
urban sprawl
and resource
management.
58
ESSENTIAL QUESTION #8
• Why do scientists use
remote sensing when
monitoring the Earth?
• To see the change of
Earth’s surface over time
ESSENTIAL QUESTION #9
• How does the spectral
analysis of reflectance
curves help scientists
monitor the Earth?
Spectral Analysis
The Gulf
Stream can be
seen (red) in
this thermal
satellite image
www.emagazine.com
Spectral analysis uses bands of reflected light
to monitor changes in the Earth
61
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.
ESSENTIAL QUESTION #10
• How does ground truthing
help scientists make
predictions about land
use, urban sprawl, and/or
resource management?
Ground Truthing
When scientists study satellite
images, they sometimes must go
to the areas to see how the image
correlates with the actual
environment.
ian.umces.edu
www.oakparkjournal.com
64
ESSENTIAL QUESTION #10
• 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?
ESSENTIAL QUESTION #11
•What evidence is there
for climate change?
Global Change
Due 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
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?
www.worldwithoutwinter.com
ESSENTIAL QUESTION #11
• What evidence is there for
climate change?
• Melting icecaps, sea level rising,
slight global temperature
increases.
ESSENTIAL QUESTION
#12
•What does the Geologic
Time Scale tell us about
the Earth’s geologic history
and the evolution of life?
Geologic
Time Scale
• The standard
method used
to divide the
Earth’s long
natural history
into
manageable
parts
geomaps.wr.usgs.gov
73
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
74
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 multicelled organisms
• Paleozoic – Fish and arthropods
• Mesozoic – Reptiles
• Cenozoic – Mammals
ESSENTIAL QUESTION #13
• How has the distribution of
living things changed over
time?
Precambrian
• Longest time division
• 4.6 billion to 544 million. This is equal to a little
more than 4 billion years.
Early Earth: Geological Changes
Water condensed and formed oceans
Storms dominated the atmosphere
Atmosphere was methane, ammonia, and other
chemicals
No oxygen
Moon was closer so appeared larger
77
encarta.msn.com
78
Precambrian
Considered 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
79
Bacterial Colony
www.nd.edu
80
Volvox Colony
Cells work together to
move the entire
colony using
individual flagella
www.morning-earth.org
io.uwinnipeg.ca
• 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
81
End of the Precambrian
• Oxygen in the atmosphere
• Most life is single celled organisms
• All life exists in oceans
These are
stromatolites
formed by buildup of blue-green
algae
82
Paleozoic 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 America
Coral reefs develop
Continents collide creating the Appalachian
Mountains
Pangaea forms
83
Paleozoic Era
www.paleoportal.org

• As you can
see (), most
of the East
was under
water in early
Paleozoic
84
Paleozoic Era
www.paleoportal.org

• Continents
collide causing
the
Appalachian
Mountains to
form
• This causes
sea shell fossils
to be on the top
of mountains
85
Paleozoic Era
Pangaea
forms
www.canadiangeographic.ca
86
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
www.50bird
s.com
Megosaurus
www.answers.com
87
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.
88
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.
89
Paleozoic Era
Biological Changes
• Great “explosion” of new species of
invertebrates
www.sciencedaily.com
90
ESSENTIAL QUESTION #14
• How do index fossils help
us understand life forms in
the four major geologic
eras?
Paleozoic Era
Biological Changes
• 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.
92
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.
Paleozoic Era
Biological Changes
• First land
plants
appear
www.msu.edu
• First spiders
and insects
appear
www.treknature.com
bleedingeyeballs.com
94
Paleozoic Era
Biological Changes
• 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
95
Paleozoic Era
Biological Changes
• Simple amphibians then reptiles evolve
animals.howstuffworks.com
96
ESSENTIAL QUESTION #13
• How has the distribution of
living things changed over
time?
• Evolved from simple, singlecelled organisms to more
complex organism (amphibians
to reptiles)
Mesozoic Era
• 245 to 66 million years ago or about 180
million years
Geologic Changes:
Hot and dry climate
Pangaea splits into individual continents
Widespread volcanic activity due to the
continents moving
98
Mesozoic Era
Hot and dry climate
www.3drelax.com
99
Mesozoic Era
Pangaea splits
www.albury.net.au
100
Mesozoic Era
Biological Changes
• Species evolved quickly to take advantage of the land that
hadn’t been occupied by many species
• Dinosaurs appear and evolve quickly
101
www.kittymowmow.
Mesozoic Era
Biological Changes
First mammal appears as a small rat-like
animal
www.nmnaturalhistory.
org
102
ESSENTIAL QUESTION #15
• What types of catastrophic
events have occurred over
time?
Mesozoic Era
Biological Changes
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
104
Which most likely happened
to species that are found in
the fossil record but have no
living members?
They had offspring of a
different species.
B. They mutated to other
species.
C. They became extinct.
D. They never really existed.
A.
105
Which most likely happened
to species that are found in
the fossil record but have no
living members?
They had offspring of a
different species.
B. They mutated to other
species.
C. They became extinct.
D. They never really existed.
A.
106
Cenozoic Era
Age of Mammals
66 million years ago to present
Geologic Changes:
Rocky Mountains and Himalayas form
Ice ages periodically cover much of the land
Last ice age ends
107
Cenozoic Era
Continents
crashing into
each other
create new
mountain
ranges like the
Himalayas
108
Cenozoic Era
Periodic ice ages create glaciers that reach into most of
North America and other continents
geography.howstuffw
109
Cenozoic Era
Biological Changes
exurbanpedestrian.wordpress.com
dearkitty.blogsome
om
www.colemangallery.com
Mammals evolve to replace the niches
dinosaurs had occupied
110
Cenozoic Era
Biological Changes
First grasses and flowering plants appear for
the first time
ruralramblings.com
thoreaugrass.blogspot.com
111
Cenozoic Era
Biological Changes
Ice ages have caused mammals of the
Cenozoic Era to adapt to many strange
creatures.
news.bbc.co.uk/2/hi/science/nature
www.joevenusartist.com
houseofstaunton.com/.../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?
ESSENTIAL QUESTION #16
• How did the geological
theories of evolution assist
Darwin in his theory of
natural selection?
Change Over Time
Charles 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
Change Over Time
Charles Darwin
• He studied the Galapagos Island wild life and noticed
similarities between different species of finches, tortoises,
and iguana
www.mirrabac.com
photos.mongabay.com
Notice the differences
in the shells
Notice the
differences
in the
beaks
www.bbc.co.uk
Iguanas have evolved to eat
cactus for one species and sea
algae for another
Change Over Time
Charles Darwin
• 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.
ESSENTIAL QUESTION #17
• How are the biological
theories of Darwin and
Lamark similar and how
are they different?
Change Over Time
Evolution
Theory: an explanation that ties together
many hypothesis and observations
• Adaptation: a trait that increases the chances that
an organism will survive and reproduce
Can you see all four moths?
www.cals.ncsu.edu
Peppered
Moth
www.arn.org
ESSENTIAL QUESTION ##18
•How does the
extinction of a species
relate to evolution?
Change Over Time
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 Views
Jean-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
Artificial
Selection



Change Over Time
Evolution
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
Change Over Time
Evolution
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
Change Over Time
Evolution
• 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
ESSENTIAL QUESTION #18
• 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
Cenozoic Era
Biological Changes
First humans appear towards the end of the
Cenozoic Era
129
news.bbc.co.uk