ASSIGNMENT 4 GEOL: Dodos, Dinos, and Deinococcus: The History of a Habitable Planet

CHAPTER 11: Questions

1) For those of us who live near or in the Rocky Mountains, the Late Paleozoic is an important and fascinating time.

Examine Figure 11.8 carefully. This is called a paleo-geographic reconstruction.

Both mountain uplifts and “evaporite-deposits” are found in what is now the Colorado region.

Do you think that the location of the mountains might have influenced the formation of evaporite deposits? Explain.

2) The erosion of the Ancestral Rockies produced rocks known as “arkose.”

Explain the use of the term “arkose.”

3) Use a web search to investigate the Fountain Formation. Please describe:

*What sort of rocks are present.

*Age of this unit.

*Location of Fountain Formation.

CHAPTER 12: Questions

Basically, there is ONE key event in the Paleozoic history of life—it’s called the Cambrian Explosion.

Learn about the Cambrian explosion on UCMP web page. (Links to an external site.)Links to an external site.

1) Predating the Cambrian Explosion are some curious multi-celled creatures called Ediacarans (or Vendians). Describe the following:

*When they lived.

*Where they have been found

*What they looked like (size, shape, etc.)

2) What makes the “Cambrian Explosion” so unique in the history of life on earth?

3) Describe the Burgess Shale. What is special about preservation of fossils in the Burgess Shale?

4) What does “phyla” mean in a taxonomic sense?

(Does it represent a broad category or a very narrowly defined category of animal?)

5) Judging by your impression of how evolution works, would you suspect there to be greater or less variety in animal phyla early in earth’s history compared to today?
No right or wrong answer, but you must explain your reasoning.

6) One common Cambrian animal was the trilobite. Google “image search”a picture of the Cambrian trilobite “phacops”.
It has little bumps on either side of its head. What do you think these might be?

CHAPTER 13: Questions

Perhaps not as revolutionary as the Cambrian Explosion, the Late Paleozoic is nevertheless marked by a very significant event—the arrival of life on land.

1) Yunnanozoon and Pikaia are some of the earliest of examples of what phylum?

How do we distinguish this phylum in the fossil record? In other words, what features define this taxonomic group?

2) The earliest fish lacked jaws. With time, they acquired jaws. How did this take place and how does this process exemplify one of the key features of evolution—remodeling and jury-rigging of pre-existing structures.

3) Fin-backed reptiles were part of a lineage leading to mammal-like reptiles (Therapsids)– e.g., Dimetrodon.
What function might these fins have served, and how does this relate to mammalian characteristics?

4) In order to reproduce on land, animals had to acquire a specific evolutionary “invention.” What was this new development?

5) If you hopped into a time machine and traveled back to a Pennsylvanian coal swamp, describe some of the flora and fauna that you might find.

(If you do not know what is meant by “flora” or “fauna”—look up those words!)

6) The end of the Paleozoic is marked by the most severe mass extinction of all time.

What is a mass extinction? And, what are potential causes for mass extinctions, and in particular what causes have been proposed for the “terminal Paleozoic” extinction?


The textbook is Historical Geology, Evolution of Earth and Life Through Time, 7th Edition, by Wicander and Monroe.

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