Rock Record and Dating
The Law of Superposition states that in an undisturbed sequence of rocks, the oldest layer is found here.
At the bottom
This is the study of ancient life through the examination of the fossil record.
Paleontology
According to the Geologic Time Scale, the Earth is approximately this many years old.
4.6 billion years
He is the scientist who proposed the theory of evolution by natural selection.
Charles Darwin
Using relative dating, the method of determining the age of a rock by its position in a stack is called this.
Relative Age/Dating
This term describes a gap in the rock record caused by erosion, where rock layers are missing.
Unconformity
Most common rock fossils are found in this specific type of rock.
Sedimentary rock
The Mesozoic Era is famously known by this nickname.
The Age of Reptiles (or Age of Dinosaurs)
This is the gradual process by which something changes into a different and usually more complex form.
Evolution
If an igneous "dike" (intrusion) cuts through several layers of sandstone, which is younger: the dike or the sandstone?
The dike (Principle of Cross-Cutting Relationships)
This principle states that geologic processes occurring today are the same as those that occurred in the past.
Uniformitarianism
Besides being buried in sediment, name one other way an organism can be fossilized.
Frozen in ice, trapped in amber, or stuck in a tar pit
We currently live in this era, which is also known as the Age of Mammals.
The Cenozoic Era
This is a random error in gene replication that leads to a change in an organism.
Mutation
This is the amount of time it takes for half of a radioactive sample to decay.
Half-life
Scientists use the predictable decay of these atoms to determine the "absolute age" of a rock.
Radioactive isotopes (or Radiometric dating)
This type of fossil is a footprint, trail, or burrow that shows the activity of an animal rather than its body.
Trace fossil
Geologic eras are primarily divided or broken up based on these major global events.
Mass extinctions or major climate changes (like ice ages)
When two or more species evolve from a single ancestral species, it is called this.
Speciation
To be used as an "Index Fossil" to date rock layers, a species must have lived for a short time but been found in this type of geographic area.
Sedimentary Rock
In a decay graph, the point where the parent isotope line and the daughter isotope line intersect represents this.
One half-life (50% parent, 50% daughter)
This is the general term for the preserved remains or traces of an organism that lived in the past.
A fossil
List the four major Earth History Eras in order from oldest to youngest.
Precambrian, Paleozoic, Mesozoic, Cenozoic
This term refers to the most recent individual from which all organisms in a group are directly descended.
Common Ancestor
True or False: Evolution is defined as a change in the genetic makeup of a population over time.
True