Fossils Flashcards
Fossils
preserved remains or traces of living things, formed when living things die, buried by sediments.
Fossilization is common, T or F?
false
paleontologist
scientists who study, collect and classify fossils
Fossilization
processes that produce fossils.
Impression Fossil
contain prints, or impressions, of plants or animals from long ago
Mold
hollow area in the sediment, shows the shape of an organism or a part. Impression Fossil
Cast
solid 3D copy of the shape of an organism. Impression Fossil
Replacement Fossil
replicas of things that were once alive, such as trees or sea creatures.
Petrified Fossil
fossils in which minerals replace all/part of an organism. plant or animal- (permineralization). Replacement fossils.
Trace Fossil
provide evidence of the activities of ancient organisms animals behavior/what they ate.
Carbon Film
extremely thin coating of carbon on rock left after the organisms has decayed away. Trace fossils
True Form Fossils
Some processes preserve the remains of organisms with little/no change (become trapped in tar, ice or amber).
Fossil Record
Information gathered by paleontologists
What are the things fossil record provide evidence of?
history of life on Earth
groups of organisms changing over long periods of time
Earth’s past climate
past environments and changes in Earth’s surface
The fossil record provides evidence to support the theory of evolution, what’s evolution?
gradual change in living things over long periods of time
2 ways determining the age of a fossil by finding the age of the rock it was found in.
relative age
absolute age
absolute age
number of years since the rock formed
relative age
age compared with ages of other rocks
Law of Superposition
in horizontal sedimentary rock layers
the oldest layer is at the bottom
higher layer is younger layer
Index fossils
commonly found, widely distributed fossils that existed a short time
What affects the relative age of rocks?
Intrusions and extrusions, faults, or unconformities .
fault
break in Earth’s crust which is always younger than the rock it cuts through
unconformity
gap in the geological record where some rock layers have been lost because of erosion
Igneous-extrusion
Lava that hardens on the surface An extrusion is always younger than the rocks below it.
Igneous-intrusion
Lava that cools and hardens below the surface .An intrusion is always younger than the rock layers that surround it.
Cross-Cutting Principle
something cuts across a body of rock, that “something” is younger than the rock it cuts across.
Absolute (Radioactive) Dating
They use radioactive minerals in rocks as geological clocks.
Absolute Dating Pros:
It can teach us about the past.
Tell us the numerical age or range of fossil is if there’s any in the rock.
Absolute Dating Cons:
Radioactive dating can only be used to date fossils older than approximately 50,000 years old.
