Science notes 1 Flashcards
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what is an unconformity?
a break or gap in the geologic RECORD where some layers have disapeared because of erosion
uniformitarianism-
states that the geologic process that happened in the past can be explained by the current geologic process
relative dating
Determining whether an object or event is older or younger than another object.
Superposition
The principle that states the younger rocks lie above older rocks if the layers have not been disturbed.
geologic column
an ordered arrangement of rock layers that is based on the relative ages of the rock with the oldest rock at the bottom column.
What is a fossil?
how do most fossils form
Most fossils are going to form by being buried by sediment
What are mold fossils? Cast? Trace? Carbon film?
Mold fossils are imprints or hollow areas in the sediment which shows the shape of an organism or a part of an organism. cast- a solid copy of a shape of an organism trace-gives us clues about activities of ancient organisms carbon film- thin coating on rock
what is evolution
A gradual change in living organisms over long periods of time
What’s the difference between relative and absolute dating of rocks?
Relative dating compares ages of rock to the age of other rocks absolute dating tells us exactly how old the rock is.
what is the law of superposition
In horizontal layers of sedimentary rocks each layer is older than the layer above it and younger than the layer below it
What are index fossils?
Remains of an organism that lived for a short period of time.
What are the eras of Earth’s history?
paleozoic , mesozoic, cenozoic eras
What is the geologic time scale of a record?
The life forms and geologic events in earth’s history
The Permian extinction ended which era?
Paleozoic era
What organisms were the first vertebrates?
jawless fish
What is our hypothesis for why the dinosaurs became extinct?
Asteroids hit earth and threw dust, dust blocked out the sun causing the climate to cool off and the dinos died.
What are the periods of the Paleozoic Era? Mesozoic? Cenozoic?
Paleozoic-Cambrian Ordovician Silurian Devonian carboniferous and Permian Mesozoic- Triassic Jurassic Cretaceous Cenozoic- Paleogene Neogene quaternary
What is the time called that begins Earth’s time?
Precambrian time
What era are we in?
Cenozoic era
What era is the “Age of the Reptiles”? “Age of Fish” “Age of Mammals”
reptiles - mesozoic era
Fish- paleozoic era
Mammals- cenozoic era
The climate-
describes the weather conditions in the area over a long period of time.
Scientists can drill down into ice caps to collect a long cylinder of ice called an ice core
