The History of Life Flashcards
(35 cards)
Earth was a molten body when it formed…
4.6 billion years ago.
Fossil is…
Any preserved evidence an organism.
The surface was rich in…
Lighter elements
There was no……… In earths atmosphere
Oxygen
Trace fossil is…
Any indirect evidence left by an organism. Footprints, feces.
Molds and casts are…
An impression of an organism. Cast… Mold filled with sediment.
Replacement is…
The original material of an organism is replaced with mineral crystals that can leave detailed replicas of hard or soft parts.
Petrified or permineralized is…
Empty pore spaces are filled in by minerals, such as petrified wood.
Amber is…
Preserved tree sap traps an entire organism. It hardens into Amber and preserves it.
Original material is…
Mummification our freezing preserves original organisms.
Fossils are formed in..
Sedimentary rock
Paleontologist studies…
Fossils
Relative Dating is…
A method used to determine the age of rocks by comparing them with those in other layer]s.
Law of Superposition is…
A law that states that younger layers of rocks are positioned on top of the older ones.
Radiometric dating is…
Use the decay of radioactive isotopes to measure the age of a rock.
Half-life is…
The medium time.
Radiometric dating is used only on…
Ingenious and Metamorphic rocks.
Geologic Time Scale is…
A record of Earth’s history.
Epochs last…
Several million years. Are the smallest unit of geologic time.
Periods last…
Tens of millions of years. Consist of two or more epochs.
Eras last…
Hundreds of millions of years. Two or more periods.
Eons last…
Billions of years. Longest unit of geologic time.
Precambrian Era
Cells appear.
Paleozoic Era
Cambrian explosion. First animals appear. Insects appeared.
