Geological History
The oldest eon, when Earth first formed.
What is the Precambrian?
Fossils are usually found deeper in rock layers when they are this.
What is older?
The process by which organisms with beneficial traits survive and reproduce more.
What is natural selection?
Evolution caused by random changes in allele frequencies.
What is genetic drift?
Structures that share a common origin but may have different functions.
What are homologous structures?
The era is known as the “Age of Dinosaurs.”
What is the Mesozoic Era?
The event that caused a rapid increase in animal diversity about 540 million years ago.
What is the Cambrian Explosion?
A trait that increases an organism’s chance of survival or reproduction.
What is an adaptation?
Genetic drift caused by a sudden reduction in population size.
What is the bottleneck effect?
Reduced structures that no longer serve their original function.
What are vestigial structures?
This era is when mammals became dominant after dinosaurs went extinct.
What is the Cenozoic Era?
A fossil that lived for a short time but was widespread and helps date rock layers.
What is an index fossil?
Natural selection acts on this level, not on individuals.
What is a population?
When a small group starts a new population with limited genetic variation.
What is the founder effect?
Whales having femur bones is evidence for this concept.
What is common ancestry?
List the four eras from oldest to youngest.
What are Precambrian, Paleozoic, Mesozoic, and Cenozoic?
The mass extinction that ended the Paleozoic Era.
What is the Permian extinction?
Why long-necked tortoises were favored on certain Galápagos Islands.
What is access to food higher off the ground?
Two unrelated species evolving similar traits due to similar environments.
What is convergent evolution?
A diagram used to show evolutionary relationships among species.
What is a phylogenetic tree?
The geological time scale is based on evidence from these two records.
What are the fossil record and the geologic (rock) record?
One major cause of mass extinctions is seen in the fossil record.
What are climate change, volcanic eruptions, asteroid impacts, or sea-level change?
(Any one with an explanation earns full credit)
Explain how environmental change can lead to a change in a species over time.
What is natural selection favoring traits better suited to the new environment over generations?
The process by which one species splits into two or more new species.
What is speciation?
How DNA evidence supports evolution.
What is that closely related species have more similar DNA sequences?