Review Questions

1^st Lecture Test

Earth History and Global Change

GEOL-1122 Fall 2009

Section #1 - Introduction

1) Define Historical Geology. How does it differ from Physical Geology?

2) Name and describe different types of events that Historical Geology attempts to recognize and correlate. List and describe the geologic data that is used to recognize these events.

Section #2 ‑ Geologic Time

Readings ‑ Chapter 17 (Geologic Time: Concepts and Principles)

1) Name and describe the earliest types of time-keeping devices. Describe how the invention and use of these devices changed social behavior.

2) How do infants and most animals other than humans perceive time and the past? Define deep time. Give examples and explain why certain theories in biology and/or astronomy are dependent on the modern view of geologic time.

3) Why did early societies believe that time was cyclic and events were repeated? When and why was linear time proposed and accepted?

4) Describe how James Ussher determined that the earth was 6,000 years old. How did Lord Kelvin determine the age of the earth? Describe two other methods involving geologic processes that were used to determine an age for the earth. Why did these age estimates differ so much? How do these dates compare to Ussher's age?

5) Why is the currently proposed age for the earth based on moon-rocks and meteorites and not earth rocks? What is this age? Why does the moon's surface record a much older and different geologic history than the earth's surface if they are both similar in age?

6) Define stratigraphy. Describe the following principles of stratigraphy: lateral continuity, horizontality, superposition, cross‑cutting relationships, and law of inclusions. How are these principles used to decipher the geologic rock record? Which type of age data relative or absolute) can be obtained from the application of these principles.

7) What is seismic stratigraphy? Why is this technique commonly used in oceanic areas to study subsurface geology?

8) What is a key (marker) bed? Why are marker beds so useful in correlating and mapping rock units? Name a rock type that would make a good key or marker bed in a thick sequence of sandstone, shale and limestone. Name a rock type that would make a good key or marker bed in a sequence of lava flows and tuffs.

9) Name and describe the similarities and differences in the geologic histories of the three types of unconformities. Make a simple sketch of each type of unconformity.

10) What is the Law of Fossil Succession? Describe how biostratigraphy is used to determine relative rock ages.

11) What is a guide (index) fossil? What are the important characteristics of a guide fossil? Why are fossil assemblages more accurate than single guide fossils?

12) Describe how radioactive decay is used in radiometric dating. What are the important characteristics of radioactive decay that allow it be used as a geologic clock? Which rock types can be dated by radiometric techniques? Be able to calculate geologic ages based on isotopic abundance and/or percentages of parent and daughter material and reported half‑lives. (See your homework exercise for this question.)

13) Compare and contrast the following types of radioactive decay: alpha decay, beta decay, and electron capture.

14) What are the names and basis for the three major subdivisions of geologic time?

15) Define the following terms: relative and absolute ages, fossil, formation, isotope, Carbon-14, tree-ring dating, Precambrian, Paleozoic, Mesozoic, and Cenozoic.

Section #3 ‑ Evolution and the Fossil Record

Readings: Chapter 18 (Fossils and Evolution)

1) Describe the optimal conditions for fossilization. Describe the different types of information that can be derived from fossils. Why is preservation in anoxic sedimentary environments more common?

2) Why is the fossil record biased? Describe the biasing factors.

3) List the major groupings (taxonomic classifications) of life forms. How is a species recognized and defined?

4) What is Lamarckism? What was the proposed mechanism responsible for the change?

5) How did Darwin's study of finches on the Galapagos serve as evidence for evolution?

6) What is Natural Selection? Describe the observations on which this theory is based. Describe how the theory has been misinterpreted by certain political groups. Describe how Gregor Mendel's work provided a valid mechanism for natural selection. How does artificial selection differ from natural selection?

7) How are paleobiogeography studies used in support of evolution? Describe the other major lines of evidence in the fossil record support the idea of evolution?

8) Describe how both genetic recombination and mutations are the sources for variation within a population. What are some causes of increased mutation rates?

9) Compare and contrast convergent and divergent evolution. Give examples of both.

10) What is speciation? What are some possible isolating barriers that might cause speciation?

11) Compare and contrast gradualism and punctuated equilibrium. Which of these is best supported by the fossil record?

12) What is extinction? What are some of the possible causes?

13) Define the following terms: genetics, chromosomes, mutation, vestigial organ, cladogram, analogous structures, and mass extinction.

14) Describe why the different limbs shown below are considered homologous organs.