Warm Up Match the type of evidence with what scientists could learn about it. Type of Evidence: 1)Tree rings 2) trace fossils 3) mold fossils 4) petrified wood What can be learned: A) ancient trees B) shape of organisms C)footprints D) recent weather patterns Homework : Vocab Set 3, Day 1

Vocab Set 3 When you are done, copy next vocab 1.Uniformitarianism 2.Geologic Time Scale 3.Evolution 4.Charles Darwin 5.Overproduction 6.Adaptation 7.Variation 8.Natural Selection 9.Isolation 10.Speciation 11.Independent Variable 12.Dependent Variable 13.Control 14.Qualitative 15.Quantitative

5.01 Interpret ways in which rocks, fossils, and ice cores record Earth's geologic history and the evolution of life including: – Geologic Time Scale. – Index Fossils. – Law of Superposition. – Unconformity. – Evidence for climate change. – Extinction of species. – Catastrophic events.

Dating Rock Layers Notes Re lative Age: rock’s age when compared to the ages of other rocks. Layers of rock that are younger will be deposited on top of layers of rocks that are older. Index Fossil: a fossil that is widely distributed and represents a type of organism that existed only briefly

Law of Superposition: in horizontal sedimentary rock layers, the oldest is on the bottom and each higher layer is younger than the layer underneath it Stack three layers of clay (lightly), draw it into the superposition area of your notes, label youngest and oldest layer

Overturning: Horizontal rock layers tilt or fold due to movement of tectonic plates. Using the layers created previously, gently fold your layers in half (like a taco). Draw it into the overturning section of your notes. Label the youngest and oldest layers.

oldest middle youngest

Unconformity: a gap in the geologic record showing where some rock layers have been lost because of weathering and erosion. Mechanical weathering: wind, water examples Chemical weathering: acid rain examples Biological – tree roots Carefully unfold your rock layers. Gently remove the top layer. “Erode” (remove) part of the middle layer Replace the top layer Draw this into the unconformity section of your notes. Label the part of your diagram that is the unconformity.

Chemical weathering (acid rain most common)

Mechanical Weathering (wind, water, gravity, ice wedging)

Biological Weathering

Unconformity

Fault: a break in earth’s crust. When examining rock layers, the fault will have occurred after the layers it cuts across and before the continuous horizontal layers above it.

Happened: Sixth Fifth Fourth Third Second First

Intrusion: lava can cut/melt through rock layers. It cools and hardens into igneous rock on the surface. It is younger than the sedimentary layers it cuts through and may be older than the sedimentary layers above it. Carefully layer the three clay colors again Insert your pencil through the bottom two layers, make sure you can see it Draw the clay model into the intrusion/extrusion section of your notes Label the youngest and oldest layer, label the intrusion.

Intrustion

Absolute Age: the number of years since rock has formed. (IGNEOUS ROCK – “pure”) Radioactive Dating: Gives the absolute age of rock by using the unique half-life of an element. Half-Life: the length of time it takes for half the atoms in a sample to change from one form to another form. Radioactive elements with long half-lives are better for determining the absolute age of rocks.

You cannot use radioactive dating on sedimentary rocks because…… THEY ARE MADE FROM BITS AND PIECES OF OTHER ROCKS. (not “pure”…muts ) You can use radioactive dating from igneous rocks/intrusions