Life Changes Over Time - Middle School Life Science
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What is a fossil in the context of evidence for past life on Earth?
What is a fossil in the context of evidence for past life on Earth?
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Preserved remains, impressions, or traces of ancient organisms. Physical evidence of organisms that lived long ago.
Preserved remains, impressions, or traces of ancient organisms. Physical evidence of organisms that lived long ago.
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What is the fossil record?
What is the fossil record?
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All fossils and their positions in rock layers over time. Complete history of life preserved in Earth's rocks.
All fossils and their positions in rock layers over time. Complete history of life preserved in Earth's rocks.
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What does the law of superposition state about undisturbed sedimentary rock layers?
What does the law of superposition state about undisturbed sedimentary rock layers?
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Lower layers are older than layers above them. Unless disturbed, sediments settle chronologically.
Lower layers are older than layers above them. Unless disturbed, sediments settle chronologically.
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Which type of rock most commonly contains fossils: igneous, sedimentary, or metamorphic?
Which type of rock most commonly contains fossils: igneous, sedimentary, or metamorphic?
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Sedimentary rock. Forms from layers of sediment that preserve organisms.
Sedimentary rock. Forms from layers of sediment that preserve organisms.
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What is an index fossil?
What is an index fossil?
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A widespread fossil from a short time span used to date layers. Existed globally but only briefly, making it a time marker.
A widespread fossil from a short time span used to date layers. Existed globally but only briefly, making it a time marker.
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Identify the best use of index fossils when comparing two distant rock layers.
Identify the best use of index fossils when comparing two distant rock layers.
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To correlate layers and infer they are the same relative age. Same index fossils indicate simultaneous formation.
To correlate layers and infer they are the same relative age. Same index fossils indicate simultaneous formation.
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What is relative dating in geology and paleontology?
What is relative dating in geology and paleontology?
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Determining which rocks or fossils are older or younger. Compares ages without specific time measurements.
Determining which rocks or fossils are older or younger. Compares ages without specific time measurements.
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What is absolute dating?
What is absolute dating?
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Determining an actual age in years, often using radiometric methods. Provides specific numerical ages for rocks and fossils.
Determining an actual age in years, often using radiometric methods. Provides specific numerical ages for rocks and fossils.
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Which dating method uses radioactive decay to estimate the age of rocks: relative or absolute dating?
Which dating method uses radioactive decay to estimate the age of rocks: relative or absolute dating?
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Absolute dating. Measures isotope decay rates to calculate precise ages.
Absolute dating. Measures isotope decay rates to calculate precise ages.
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What is a trace fossil?
What is a trace fossil?
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Evidence of activity, such as footprints, burrows, or coprolites. Shows behavior and movement, not body structure.
Evidence of activity, such as footprints, burrows, or coprolites. Shows behavior and movement, not body structure.
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What is a mold fossil?
What is a mold fossil?
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A hollow impression of an organism left in rock. Forms when organism decays, leaving its shape in rock.
A hollow impression of an organism left in rock. Forms when organism decays, leaving its shape in rock.
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What is a cast fossil?
What is a cast fossil?
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A solid copy formed when a mold fills with minerals or sediment. Creates a 3D replica of the original organism.
A solid copy formed when a mold fills with minerals or sediment. Creates a 3D replica of the original organism.
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Which conclusion is best supported if a fossil species stops appearing above a certain layer?
Which conclusion is best supported if a fossil species stops appearing above a certain layer?
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That species became extinct by the time higher layers formed. Absence in newer layers indicates disappearance.
That species became extinct by the time higher layers formed. Absence in newer layers indicates disappearance.
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Identify the correct relative-age conclusion: Fossil A is in a lower layer than Fossil B in undisturbed rock.
Identify the correct relative-age conclusion: Fossil A is in a lower layer than Fossil B in undisturbed rock.
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Fossil A is older than Fossil B. Law of superposition: lower means earlier in time.
Fossil A is older than Fossil B. Law of superposition: lower means earlier in time.
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Which statement best links fossils to evolution: fossils show organisms are identical over time, or they change over time?
Which statement best links fossils to evolution: fossils show organisms are identical over time, or they change over time?
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Fossils show organisms change over time. Different species in different layers prove evolution.
Fossils show organisms change over time. Different species in different layers prove evolution.
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Which evidence best supports common ancestry: similar fossils in the same layer, or transitional fossils connecting groups?
Which evidence best supports common ancestry: similar fossils in the same layer, or transitional fossils connecting groups?
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Transitional fossils connecting groups. Shows evolutionary relationships between species.
Transitional fossils connecting groups. Shows evolutionary relationships between species.
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What does a mass extinction refer to in the fossil record?
What does a mass extinction refer to in the fossil record?
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A short interval when many species disappear worldwide. Global catastrophe eliminates numerous species rapidly.
A short interval when many species disappear worldwide. Global catastrophe eliminates numerous species rapidly.
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Identify the best fossil-based conclusion if many new species appear soon after a mass extinction layer.
Identify the best fossil-based conclusion if many new species appear soon after a mass extinction layer.
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Biodiversity rebounded through rapid diversification of survivors. Surviving species evolved to fill empty ecological niches.
Biodiversity rebounded through rapid diversification of survivors. Surviving species evolved to fill empty ecological niches.
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What is a mold fossil?
What is a mold fossil?
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A hollow impression of an organism left in rock. Forms when organism decays, leaving its shape.
A hollow impression of an organism left in rock. Forms when organism decays, leaving its shape.
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What is permineralization in fossil formation?
What is permineralization in fossil formation?
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Minerals fill pores of remains, turning them to stone. Most common fossilization process for bones and wood.
Minerals fill pores of remains, turning them to stone. Most common fossilization process for bones and wood.
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Which fossil type is a preserved bone or shell: body fossil or trace fossil?
Which fossil type is a preserved bone or shell: body fossil or trace fossil?
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Body fossil. Actual organism parts that became fossilized.
Body fossil. Actual organism parts that became fossilized.
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Which fossil type is a footprint or burrow: body fossil or trace fossil?
Which fossil type is a footprint or burrow: body fossil or trace fossil?
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Trace fossil. Shows evidence of behavior, not body parts.
Trace fossil. Shows evidence of behavior, not body parts.
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Which dating method determines an actual age in years: relative dating or radiometric dating?
Which dating method determines an actual age in years: relative dating or radiometric dating?
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Radiometric dating. Uses radioactive decay to calculate precise ages.
Radiometric dating. Uses radioactive decay to calculate precise ages.
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What does the law of superposition state about undisturbed rock layers?
What does the law of superposition state about undisturbed rock layers?
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Lower layers are older; higher layers are younger. Based on sediment deposition order over time.
Lower layers are older; higher layers are younger. Based on sediment deposition order over time.
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What is relative dating in geology?
What is relative dating in geology?
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Determining which rocks or fossils are older or younger. Uses position in rock layers, not actual years.
Determining which rocks or fossils are older or younger. Uses position in rock layers, not actual years.
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