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Earth History

Terms in this set (34)

Fossil
The preserved remains or traces of an organism that lived in the past
Climate
The average weather conditions in an area over a long period of time
Catastrophe
a large-scale disaster, misfortune, or failure
Mold Fossil
forms when sediments bury an organism and the sediments change into rock; the organism decays leaving a cavity in the shape of the organism
Cast Fossil
forms when a mold is filled with sand or mud that hardens into the shape of the organism
Petrified (Permineralized) Fossil
forms when minerals soak into the buried remains, replacing the remains, and changing them into rock
Preserved Fossil
forms when entire organisms or parts of organisms are prevented from decaying by being trapped in rock, ice, tar, or amber
Carbonized Fossil
forms when organisms or parts, like leaves, stems, flowers, are pressed between layers of soft mud/clay that hardens, squeezing almost all of the decaying organism away leaning the carbon imprint in the rock
Trace Fossil
forms when the mud or sand hardens to stone where a footprint, trail, or burrow of an organism was left behind
Geologic Time Scale
A record of the geologic events and life forms in Earth's history.
Precambrian Era
Earth's first era that began 4.6 billion years ago that includes creation of the Sun, Earth, the atmosphere, oceans and life
Paleozoic Era
the part of geologic time 570-245 million years ago ; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant
Mesozoic Era
middle life (245-144 million years ago); rise of mammals and dinosaurs; the rise of birds; extinction of dinosaurs, rise of flowering plants
Cenozoic Era
era that began about 66 million years ago, known as the "Age of Mammals;" We live in this era
Trilobite
a marine arthropod, now extinct, that lived during the Paleozoic era
Ammonite
squid-like animal, now extinct, with coiled, chambered shell
Infer
to find out by reasoning; to arrive at a conclusion on the basis of thought; to hint, suggest, imply
Paleontologist
A scientist who studies fossils to learn about organisms that lived long ago
Fossil Record
Chronological collection of life's remains in sedimentary rock layers
Relative Age
The age of a rock or object compared to the ages of rock layers around it
Relative Dating
Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
Absolute Age
the numeric age of an object or event, often stated in years before the present, as established by an absolute-dating process, such as radiometric dating
Absolute Dating
A technique used to determine the actual age of a fossil
Radiometric Dating
method used to determine the age of rocks using the rate of decay of radioactive isotopes
Carbon-14 Dating
the use of carbon-14 in dating rocks and organic remains of relatively recent origin
Ice Core
a drill core of ice that can help tell the climates of the past
Sedimentary Rock
A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together
Law of Superposition
The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it.
Fault
A break in the earth's crust
Tectonic Plate
Sections of the Earth's crust that move due to convection currents.
dip-slip fault
Two pieces of land that change their vertical position compared to one another
strike-slip fault
a type of fault where rocks on either side move past each other sideways with little up or down motion
Igneous rock
a type of rock that forms from the cooling of molten rock at or below the surface
Igneous Intrusion
magma cutting through formed layers of sedimentary rock that then cools and hardens
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