Scientific Practices & Earth's Structure
What are the four main layers of Earth, from outside to inside?
Crust, mantle, outer core, inner core
What was the name of the ancient supercontinent proposed by Alfred Wegener?
Pangaea
What is magma called after it reaches Earth's surface?
Lava
According to the Law of Superposition, where are the oldest rocks usually found in undisturbed sedimentary layers?
At the bottom
What do we call the permanent disappearance of a species?
Extinction
In an experiment, what is the variable deliberately changed by the scientist called?
Independent variable
What type of plate boundary occurs when two plates move away from each other?
Divergent boundary
What is the point on Earth's surface directly above an earthquake's focus called?
The Epicenter
Is a dinosaur footprint a body fossil or a trace fossil?
Trace fossil
How many major mass extinction events are recognized in Earth's history?
5
A rock has a mass of 120 g and a volume of 40 cm³. What is its density?
3 g/cm³
Give two pieces of evidence Wegener used to support continental drift.
Any two: matching fossils, matching rocks/mountain ranges, matching continental shapes, ancient climate evidence
What major mountain range formed from the collision of the Indian Plate and Eurasian Plate?
Himalayas
Scientists discover coral fossils in rocks located far inland. What does this suggest about the area's past environment?
It was once underwater, likely in a warm/shallow marine environment.
Which of the Big Five was the largest mass extinction in Earth's history?
Permian–Triassic / End-Permian extinction
A student tests whether water temperature affects how quickly sugar dissolves. They use 100 mL of water in every trial but change the temperature. Identify the independent variable, dependent variable, and one controlled variable.
Independent Variable: water temperature; Dependent Variable: time/rate of dissolving; Control: amount of water (100 mL)
Scientists discover that ocean-floor rocks become progressively older as they move away from a mid-ocean ridge. What process does this provide evidence for?
Seafloor spreading
Two continental plates are moving toward each other. Neither easily sinks into the mantle. What happens to the crust, and what major landform can result?
The crust compresses, folds, thickens, and rises, forming mountains.
Four sedimentary layers formed in order A, B, C, D from bottom to top. A fault cuts through A, B, and C but not D. Did the fault form before or after Layer D?
Before Layer D
Scientists find a worldwide rock layer enriched in iridium and a huge impact crater dating to about 66 million years ago. Which mass extinction does this evidence relate to, and what likely caused it?
Cretaceous–Paleogene (End-Cretaceous); a massive asteroid impact.
Earth's inner core is hotter than the outer core, yet the inner core is solid while the outer core is liquid. Why?
The enormous pressure at Earth's center keeps the inner core solid despite its high temperature.
An oceanic plate collides with a continental plate. Predict what happens to the oceanic plate and name two geological features or events that may result.
Oceanic plate subducts beneath continental plate; examples: trench, volcanoes, mountains, earthquakes.
A region has a deep ocean trench, frequent earthquakes, and a chain of explosive volcanoes on a nearby continent. What type of plate interaction is occurring, and explain how it produces these three features.
Oceanic-continental convergence/subduction. The oceanic plate sinks, creating a trench; movement produces earthquakes; melting generates magma that feeds volcanoes.
Rock layers A, B, and C formed in that order. They were tilted and eroded. Later, horizontal Layers D and E formed on top. What feature separates C and D, and what does it represent?
An unconformity; a gap in the geologic record caused by erosion and/or non-deposition.
After a mass extinction, surviving groups sometimes rapidly diversify into many new species. Explain why removing so many species can create opportunities for survivors.
Extinction leaves ecological niches and resources available with less competition/predation, allowing surviving groups to spread, adapt, and diversify.