Fossils & Fossil Formation
These fossils form when only the carbon outline of an organism remains.
What is carbonization?
This method determines whether a rock layer is older or younger than the layers around it.
What is relative-age dating?
The ship Darwin traveled on during his famous voyage.
What is the HMS Beagle?
An inherited trait that increases an organism’s chance of survival.
What is an adaptation?
Structures similar in structure but different in function, like human arms and bat wings.
What are homologous structures?
A fossil copy of an organism that forms when sediment fills in a mold.
What is a cast?
Scientists rely on this type of rock to determine the absolute age using radioactive decay.
What is igneous rock?
Darwin noticed tortoises differed between islands mainly because of differences in these two environmental factors.
What are food sources and habitat?
A mountain range forming due to tectonic plate movement is an example of this type of environmental change.
What is gradual change?
Body parts like whale pelvic bones that have lost their original function.
What are vestigial structures?
Footprints, tracks, and burrows are all examples of this type of fossil.
What are trace fossils?
Radioactive isotopes decay into these kinds of isotopes over time.
What are stable isotopes?
A slight difference in an inherited trait among individuals of a species.
What is a variation?
A harmless species resembling a dangerous one is an example of this adaptation.
What is mimicry?
The stage of development studied by embryologists.
What is a zygote to birth?
This fossil-forming process replaces an organism’s original material with minerals from water.
What is mineralization?
This chart divides Earth’s history into eons, eras, periods, and epochs.
What is the geologic time scale?
The process where organisms with helpful traits survive and produce more offspring.
What is natural selection?
Why might a species go extinct after a major environmental change?
It cannot find necessary resources to survive.
DNA and protein comparisons between species come from this field.
What is molecular biology?
Name two conditions that make the preservation of soft tissues possible.
What are freezing, amber, or rare sediment conditions?
Why do scientists date igneous layers above and below sedimentary rocks instead of dating the sedimentary rock directly?
Because sedimentary rocks form from older rock pieces, which makes them impossible to date directly.
Darwin concluded the Galápagos tortoises shared this because of their similarities.
What is a common ancestor?
The movement of Earth’s plates can isolate populations. What long-term effect can this isolation cause?
Extinction or the formation of new species.
Structures that perform the same job but differ in structure, like bird wings and insect wings.
What are analogous structures?