Fossil Identification Greenish-Brown Sedimentary Rock Sample What type of organism is fossilized in this rock sample? This rock sample was found on top of a mountain in Center County PA near Penn State. Use the geologic map to determine the age range of rock in Centre County? (Note: Centre County is in the center of PA) It has been determined that these fossils came from organisms that lived in the ocean, what does this tell you about the environment of Centre County, PA when the fossil was alive? How could these marine fossils get on top of a mountain in PA? Coal (Black Sedimentary Rock) Sample What type of organism is fossilized in this rock sample? The rock type is coal. What type of environment did this organism once live in? Choices: (desert tropical arctic) Using the Geologic Map, which county in PA could these fossils have been found in? Choices: (Montgomery Schuylkill Erie) How old would the fossils be if they were from this county?
Interpreting Fossil Prints When paleontologists study fossils they must often make inferences (educated guesses) about the events that produced the fossils they are studying. At this station you will work with sketches of a set of fossil footprints made by animals more than 100 million years ago. 1-5. Make FOUR observations (facts) about the fossilized footprints. Consider such factors as size, shape, and position of the footprints. 6-10. Make FOUR inferences (educated guess) about the prints that reconstruct the events that could have caused this pattern. There is more than one possible answer.
Transitional Species • Also called common ancestors or missing links, transitional species are searched for in the fossil record to show the evolutionary connection between species & how they change over time. • (#1-4) Write the name of the transitional species by matching its description with the numbered picture. • For each species, provide an adaptation that proves it is an “in-between” form of two animal groups (use either the text or the pictures on the 2 additional papers) CHOICES for 1 to 4: Archaeopteryx (dinosaur to birds) Thrinaxodon (reptiles to mammals) Tiktaalik (fish to amphibians) A. afarensis (ape to human) 1. 2. 4. 3.
Fish to Amphibians What adaptation(s) does Tiktaalik have that makes it a transitional species? Reptiles to Mammals What adaptation(s) does Thrinanodon have that makes it a transitional species?
Reptiles to Birds What adaptation(s) does Archaeopteryx have that makes it a transitional species? Primates to Bipedal Primates What adaptation(s) does A. afarensis have that makes it a transitional species?
Match the transitional species of horse ancestor (below) with the correct fossil slides (A – E). (1) Horse Evolution (2) (3) (4) (5)
Fossil Set B Fossil Set A Fossil Set C Fossil Set D Fossil Set E
Relative Age Dating Answer the following questions using the diagram above. • Which letter represents the oldest rock layer? • What law explains your answer? • Provide TWO organisms that would be a good index fossil? • Briefly explain why they are good index fossils. • Which species would be the worst example of an index fossil? • Which of the following fossils is the oldest? dinosaur bird mammal • Between Site 1 & 2 certain rock layers match, such as, layers F & Y and C & X. What could explain why there is no yellow sedimentary rock layer at site 2 that matches with layer “D” at site 1? • What type of rock is E, C, X & V? (igneous; sedimentary; metamorphic)
Unconformities Matching • Descriptions: • Layers are folded with no unconformity • New sediments are deposited on top of an erosion unconformity • Surface shows an erosion unconformity • Fault line unconformity cuts through an erosion unconformity • Horizontal sedimentary rock layers with no unconformity • Igneous intrusion unconformity and an erosion unconformity 2. 1. 3. 4. 6. 5.
Relative Age & Unconformity Brain Teaser ***List the rock layers and unconformities in order from youngest to oldest. NOTE: All the rock layers are sedimentary rocks except the igneous intrusions A and E and the fault line H
Absolute Age Dating 1. Carbon-14 has a half-life of 5,730 years. You begin with 600 grams of Carbon-14 in a sample of bone. At the end of the first half-life, how many grams of Carbon-14 is still in the bone? 2. After 3 half-lives, how many grams of Carbon-14 are still in the bone? • If a radioactive rock has a half-life of 10,000 years and the sample that is being measured is only 12.5% radioactive (87.5% of the rock is stable) how old is the radioactive rock? U Pb Pb Pb Pb Pb Pb U U U U U Pb Pb U U U U Pb Pb C N N C N N C N N N C N N N N N N N C N N N N C