How earth has evolved
Theory of plate tectonics and continental drift
FCAT standard 9....SC.7.E.6.4
Explain and give examples of how physical evidence supports scientific theories that earth has evolved over geologic time due to natural processes. (Theory of plate tectonics, Wegener's hypothesis, etc.)
Physical evidence involving the theory that earth has evolved over geologic times due to natural processes
Scientists think that the earliest forms of life started on earth around 3.5 billion years ago. Since then, many organisms have lived on earth. Alfred Wegener proposed continental drift in the early 20th century. He said that the continents have all been joined together at one point, and over time have drifted apart.
How he came to this point
One key piece of evidence he used is fossils. He states that Pangea broke up into what is now the 7 continents. Archeologists discovered very similar fossils on two different coastlines that were once connected during Pangea.
Pangea
This is what Wegener believed Earth looked like before continental drift.
(source:http://eatrio.net/pangea-maps)
Earth
This is Earth now.
(source: PaleoEarth_now)
Alfred Wegener
Alfred Wegener was best known for advancing the theory of continental drift. He thought the different continents fit together like a puzzle.
(source: Photo from wikipedia)
Continental drift (plate tectonics)
Wegener found the rock strata on the margins of two separate continents which were very similar. It suggested that these rocks were formed in the same way, implying that they were joined initially. Plate tectonics caused the breaking of these continents, according to Wegener.
Vocabulary
Folding: When one or a stack of originally flat, level surfaces are bent or curved as a result of pressure and high temperature.
Faulting: A crack in the earth's crust caused by plate-tectonic forces.
Fossil records: Term used by paleontologists to refer to the total number of fossils that have been discovered.
Plate boundaries: This is where two or more plates meet up.
Absolute age dating: The process of determining an age on a specified time scale in archaeology or geology.
Relative age dating: The science of determining the relative order of past events.