The Fossil Record
What are the remains or evidence of once-living organisms?
fossils
What is the preserved evidence of the activity of an organism?
trace fossil
What kind of rocks form from volcanic magma?
extrusive igneous rocks
What is a chart that divides Earth’s history into different time units?
geologic time scale
What occurs when the last individual organism of a species dies?
the species becomes extinct
The fossil record is enormous, but is still_________.
incomplete
What is a fossil copy of an organism in a rock?
A petrified fossil
In a undisturbed rock formation, they know that the bottom layers are _______ and the top layer are _______.
generally the oldest
What are the longest time units?
Eons
What is an example of how environments can change slowly?
climate change
What is made up of all the fossils ever discovered on Earth?
the Fossil record
What is the impression of an organism in a rock?
mold or cast
What is a natural clocklike process in rocks, to learn a rock’s absolute age, or its age in years?
radioactive decay
What provide an easy way to mark time?
Index fossils, also known as guide fossils
What can occur when environments change suddenly or slowly?
species may struggle to adapt, potentially leading to reduced biodiversity and even extinction
What provides evidence that species have changed over time?
fossils, comparative anatomy, comparative embryology, molecular biology, biogeography, and direct observations of evolution in action.
In what process does a fossil forms when a dead organism is compressed over time and pressure drives off the organism’s liquids and gases?
carbonization
____________ helps scientists determine the relative order in which species have appeared on earth over time.
The fossil record
Some times entire collections of fossils are found in ___________. (Five words)
sedimentary rock layers
Who developed a theory about how species evolve from one another?
Charles Darwin and Alfred Russel Wallace
What stays the same from day to day?
The order of fossilization and the relative age of sedimentary layers generally stay the same from day to day in the fossil record.
What is the process called in which after an organism dies, its body could be buried under mud, sand, or other sediments in a stream or river. If minerals in the water replace the organism’s original material and harden into rock, a fossil forms?
permineralization
What is it called when a scientist determines the relative order in which rock layers were deposited?
relative dating
It seemed as if whole communities of _________ had suddenly disappeared.
Organisms
What is the change over time in populations of related organisms?
evolution, specifically population evolution