earth and life history

the rock cycle
the process of rock formation and recycling
nicholas Steno
In 1666, he realized that "tongue stones" were actually fossils of sharks teeth
sedimentary rock
weathering and erosion break down rocks into sediments that over time, layer and layer
metamorphic rock
with heat and pressure, it can become this
igneous rock
with heat, or hardened lava, it can form a rock
Alfred Wegener
theory that earth was once connected into Pangaea
Age of earth
4.6 billion years old
largest time scale
time scales
eons, eras, periods
geologic time scale is based on...
layer of rock
radiometric dating gives...
absolute dating
relative dating
a method of sequencing events in the order they happened
rock pieces found inside another rock
amount of time it takes for half of the unstable atoms in a sample to decay
absolute dating
scientists estimate the age of fossils by measuring the ratio of unstable to stable atoms in a rock from a fossil and comparing radioactive decay
plate tectonics
the movement of lithospheric plates
lithospheric plates
the outer layer of earth
65 mya- present
cenozoic Era - people and mammals
determined by dominant life forms present at the time
cenozoic means....
recent life
paleozoic means...
ancient life
542- 251 mya
Paleozoic era- early life developed
Mesozoic means...
Middle life
251-65 mya
Mesozoic Era
mass extinctions
large scale extinction (5(6 including now))
the understanding of volcanoes, dinos, earthquakes, rock cycles, and other earth systems and the process that act upon it
estimating the age of fossils and rock layers from the arrangement of sedimentary layers
people who uncover fossils in rock layers and conduct lab techniques
254 mya, all major continents were fused into a massive landmass
geologic time scale
the division of earth's history divided into eras and periods
using the present as keys to the past