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End of Year Review Geologic Evidence of Change Over Time
Wake County 8th Grade Science Curriculum
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Change Over Time Geologic Evidence
Fossil: evidence of past life preserved in rock; Different kinds of fossils are: Petrified fossil: minerals replace all or part of an organism en.wikivisual.com You can see the rings.
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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
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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
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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
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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
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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
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Change Over Time Geologic Evidence
Frozen remains: organisms caught in ice or snow Adult mammoth Frozen baby mammoth flickr.com
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Change Over Time Geologic Evidence
Fossil record: the complete body of fossils that shows how species and ecosystems change over time anthropology.net images.mooseyscountrygarden.com
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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?
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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
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What is the Law of Superposition?
ESSENTIAL QUESTION #1 What is the Law of Superposition?
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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
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The top layer is older 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? The top layer is older than layers located farther down the cliff. The top layer is younger than layers located farther down the cliff. The top layer contains more fossils than layers located farther down the cliff. The top layer contains fewer fossils than layers located farther down the cliff.
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The top layer is older 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? The top layer is older than layers located farther down the cliff. The top layer is younger than layers located farther down the cliff. The top layer contains more fossils than layers located farther down the cliff. The top layer contains fewer fossils than layers located farther down the cliff.
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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
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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.
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Fossils give clues about the past climate patterns.
Based on the Law of Superposition, what can be concluded about fossils? Fossils give clues about the past climate patterns. Fossils form from the hard parts of organisms. The oldest fossils are found in the lowest rock layers. The most recent fossils were advanced organisms.
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Fossils give clues about the past climate patterns.
Based on the Law of Superposition, what can be concluded about fossils? Fossils give clues about the past climate patterns. Fossils form from the hard parts of organisms. The oldest fossils are found in the lowest rock layers. The most recent fossils were advanced organisms.
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How can an unconformity be used as evidence for geologic evolution?
ESSENTIAL QUESTION #2 How can an unconformity be used as evidence for geologic evolution?
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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?
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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.
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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.
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Amount of daily rainfall
Which does a scientist most likely consider when studying the relative ages of rock layers in a canyon wall? Chemical weathering Current climate Amount of daily rainfall Law of Superposition
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Amount of daily rainfall
Which does a scientist most likely consider when studying the relative ages of rock layers in a canyon wall? Chemical weathering Current climate Amount of daily rainfall Law of Superposition
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How is the age of the earth determined?
ESSENTIAL QUESTION #3 How is the age of the earth determined?
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Change Over Time Absolute Dating
When magma or lava hardens, new rock is formed. When new rock is formed, some elements’ isotopes are radioactive.
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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)
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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
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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)
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Change Over Time Absolute Dating
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Change Over Time Absolute Dating
All radioactive elements have a specific half-life library.thinkquest.org
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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.
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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
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How is the age of the earth determined?
ESSENTIAL QUESTION #3 How is the age of the earth determined? Radioactive dating of Earth and moon rocks (4.6 billion years old).
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How has the geology of the Earth changed over time?
ESSENTIAL QUESTION #4 How has the geology of the Earth changed over time?
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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.
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Plate Tectonics Correlation: the matching up of rock layers from different locations Can use minerals in rock layers or fossils physics.uwstout.edu
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How has the geology of the Earth changed over time?
ESSENTIAL QUESTION #4 How has the geology of the Earth changed over time? Continents have moved because of the plates.
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How has the Earth been impacted by major geological events?
ESSENTIAL QUESTION #5 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?
They have similar types of rocks and fossils. They are in the same stage of succession. They exist along the same line of latitude. They have the same climate.
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Which is the best evidence that two continents were once connected?
They have similar types of rocks and fossils. They are in the same stage of succession. They exist along the same line of latitude. They have the same climate.
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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
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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
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Plate Tectonics All Over the World
cimss.ssec.wisc.edu
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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?
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How have mechanical and chemical weathering impacted the earth?
ESSENTIAL QUESTION #6 How have mechanical and chemical weathering impacted the earth?
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Weathering Mechanical weathering: is the erosion of rocks and soil caused by wind, water, or ice freezing inside rocks WATER soilerosion.net WATER FREEZING WIND
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Weathering Chemical weathering: is the erosion of rocks and soil caused by chemical reactions mail.colonial.net edutel.musenet.org Pollutants causing acid rain that will react to minerals in natural rock or statues carved from rock Iron in rock combining with oxygen to form iron oxide (rust)
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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.
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How have mechanical and chemical weathering impacted the earth?
ESSENTIAL QUESTION #6 How have mechanical and chemical weathering impacted the earth? Mountains and other land features are worn down.
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Mechanical and chemical weathering
Which process best explains how mountain ranges are worn down over time? Asteroid impacts Volcanic eruptions Mechanical and chemical weathering Continental drift and seafloor spreading
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Mechanical and chemical weathering
Which process best explains how mountain ranges are worn down over time? Asteroid impacts Volcanic eruptions Mechanical and chemical weathering Continental drift and seafloor spreading
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ESSENTIAL QUESTION #7 How have technological processes allowed us to understand change over time?
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ESSENTIAL QUESTION #8 How does remote sensing help scientists make predictions about land use, urban sprawl, and/or resource management ?
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Remote Sensing Using satellites to study changes in Earth
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Remote Sensing Satellite pictures/maps can be used to monitor land use, urban sprawl and resource management.
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Why do scientists use remote sensing when monitoring the Earth?
ESSENTIAL QUESTION #8 Why do scientists use remote sensing when monitoring the Earth? To see the change of Earth’s surface over time
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ESSENTIAL QUESTION #9 How does the spectral analysis of reflectance curves help scientists monitor the Earth?
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Spectral Analysis 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
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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.
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ESSENTIAL QUESTION #10 How does ground truthing help scientists make predictions about land use, urban sprawl, and/or resource management?
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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
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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.
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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?
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What evidence is there for climate change?
ESSENTIAL QUESTION #11 What evidence is there for climate change?
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Global Change Due to fossil fuel use and other pollutants, the amount of CO2 has been increasing steadily. earthobservatory.nasa.gov
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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
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This is what Florida would look like if all ice on this planet melted.
South Florida is home to millions of people . . . 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?
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ESSENTIAL QUESTION #11 What evidence is there for climate change? Melting icecaps, sea level rising, slight global temperature increases.
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ESSENTIAL QUESTION #12 What does the Geologic Time Scale tell us about the Earth’s geologic history and the evolution of life?
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Geologic Time Scale The standard method used to divide the Earth’s long natural history into manageable parts geomaps.wr.usgs.gov
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Divisions are determined by the major life forms of the time
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
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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
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How has the distribution of living things changed over time?
ESSENTIAL QUESTION #13 How has the distribution of living things changed over time?
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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
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encarta.msn.com
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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
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Bacterial Colony
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Volvox Colony Cells work together to move the entire colony using individual flagella
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
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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
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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
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Paleozoic Era As you can see (), most of the East was under water in early Paleozoic
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Paleozoic Era Continents collide causing the Appalachian Mountains to form This causes sea shell fossils to be on the top of mountains
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Paleozoic Era Pangaea forms
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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
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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? The reptiles evolved in both South America and Africa. The continents of South America and Africa were once joined. Land bridges connected the continents of South America and Africa. 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? The reptiles evolved in both South America and Africa. The continents of South America and Africa were once joined. Land bridges connected the continents of South America and Africa. The reptiles could swim the distance between South America and Africa.
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Paleozoic Era Biological Changes
Great “explosion” of new species of invertebrates
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ESSENTIAL QUESTION #14 How do index fossils help us understand life forms in the four major geologic eras?
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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.
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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.
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Paleozoic Era Biological Changes
First land plants appear First spiders and insects appear bleedingeyeballs.com
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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
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Paleozoic Era Biological Changes
Simple amphibians then reptiles evolve animals.howstuffworks.com
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How has the distribution of living things changed over time?
ESSENTIAL QUESTION #13 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 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
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Mesozoic Era Hot and dry climate
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Mesozoic Era Pangaea splits
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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
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Mesozoic Era Biological Changes
First mammal appears as a small rat-like animal
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What types of catastrophic events have occurred over time?
ESSENTIAL QUESTION #15 What types of catastrophic events have occurred over time?
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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
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They had offspring of a different species.
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. They mutated to other species. They became extinct. They never really existed.
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They had offspring of a different species.
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. They mutated to other species. They became extinct. They never really existed.
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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
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Cenozoic Era Continents crashing into each other create new mountain ranges like the Himalayas
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Cenozoic Era Periodic ice ages create glaciers that reach into most of North America and other continents geography.howstuffworks.com
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Cenozoic Era Biological Changes
exurbanpedestrian.wordpress.com dearkitty.blogsome.com Mammals evolve to replace the niches dinosaurs had occupied
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Cenozoic Era Biological Changes
First grasses and flowering plants appear for the first time ruralramblings.com thoreaugrass.blogspot.com
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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 houseofstaunton.com/.../user-id=/password=
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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?
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ESSENTIAL QUESTION #16 How did the geological theories of evolution assist Darwin in his theory of natural selection?
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Change Over Time Charles Darwin
At the age of 21, Darwin sailed on board the HMS Beagle as science officer richarddawkins.net Voyage of the HMS Beagle
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Change Over Time Charles Darwin
He studied the Galapagos Island wild life and noticed similarities between different species of finches, tortoises, and iguana Iguanas have evolved to eat cactus for one species and sea algae for another Notice the differences in the shells photos.mongabay.com Notice the differences in the beaks
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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”
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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.
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ESSENTIAL QUESTION #17 How are the biological theories of Darwin and Lamark similar and how are they different?
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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? Peppered Moth
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How does the extinction of a species relate to evolution?
ESSENTIAL QUESTION ##18 How does the extinction of a species relate to evolution?
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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
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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.
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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
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Change Over Time Evolution
Artificial 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
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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
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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
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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
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Cenozoic Era Biological Changes
First humans appear towards the end of the Cenozoic Era news.bbc.co.uk
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