EEB 245
Problem Set #1
1. A paleontologist is working at an excavated quarry site in Greenland that has yielded a wealth of new
fossils. She is aware of the diverse suite of dating methods available to her, each of which has the potential
to provide important information as to the time of formation of the fossils. The fossils were extracted from
sedimentary rocks embedded in granite outcroppings (a type of igneous rock).
a) With this knowledge in hand, how might the paleontologist go about dating fossils found at this site?
Briefly explain the difference between relative & absolute dating in your explanation (7 pts.)
b) There are two additional sites, one in Scotland, and one in Australia, where there is a diverse fauna
of fossil trilobites dated to the same age as the fossils from the Greenland site. What could the
trilobite fossils from Greenland lead the paleontologist to conclude about trilobite evolution on a
global scale at this time? (Hint: Why is it useful to compare fossils from different sites?)(3 pts.)
2.
a) It is clear that some organisms, and the circumstances in which they lived (and/or died!), are more
likely to result in the formation of fossils containing a wealth of preserved external morphological
detail, than others. Describe the “ideal” organism for the formation of fossils with useful
morphological information. Be sure to provide details about its external morphology, habitat,
lifestyle, etc. to support your argument. It can be a species in existence, or you can make up a
hypothetical organism that typifies the ideal suite of characteristics.(5 pts.)
b) Provide two examples of organisms whose absence from the fossil record is likely to be a result of
the fact that for one or more reasons they are terribly unsuitable for fossilization. In each case,
describe why the organism you have chosen is an unlikely candidate for fossilization. (Hint:
Remember Dr. Caira’s lament about tapeworm fossils, or the lack there of). (5 pts.)
3. Lynn Margulis put forth the endosymbiotic theory in 1970 in her important work, “The Origin of
Eukaryotic Cells”, providing a plausible explanation for the existence of organelles in eukaryotic cells.
a) Provide two examples of endosymbiotic events and describe the evidence that supports the validity
of the occurrence of each.(5 pts.)
b) What basic advantages does this type of mutualistic association provide for each of the partners
involved? (5 pts.)
4. The history of life on earth dates back to 4.6 billion years ago. In order to place the major evolutionary
events that have occurred over that time into perspective, we can translate the occurrence of major
evolutionary events into a more familiar time frame, such as a 24 hour day, a year, or the innings of a
baseball game. However, many other equally appropriate and informative analogies are possible. Design
an analogy of your own (i.e. other than a day, week, month, year, or baseball game) to provide a framework
for the major evolutionary events that have occurred in the last 4.6 billion years. Be certain to provide
sufficient information to allow your TA to evaluate the accuracy of your scenario (i.e. there are 9 innings in
a baseball game etc.). You will be awarded 5 bonus points if you develop a scenario that is unique among
those presented by your classmates in answer to this question.
5. The Cambrian explosion marked a conspicuous increase in food web complexity.
a) What was the primary feeding strategy of the organisms that dominated the earth prior to the
Cambrian explosion? (3 pts.)
b) Describe a change that occurred that increased food web complexity over the course of the
Cambrian explosion? (3 pts.)
c) Provide an example that demonstrates the implications of (b) on morphological diversity after the
Cambrian explosion. (4 pts.)
6. What were some of the challenges plants faced before they could become terrestrial and in what Period
did the first non-vascular plant appear? What about the first vascular plant?
7. During the Cambrian Explosion, it is thought that the variety of “Bauplane” (German for “body plans”)
that appeared relatively rapidly comprised the majority of the 35 or so extant phyla that we recognize
today, along with tens of additional phyla that are now extinct.
a) Describe how the terms disparity and diversity apply to the appearance of animal phyla during the
Cambrian explosion, as well as to the changes that occur throughout the Paleozoic including the
Permian extinction. (10 pts.)
8. A major habitat transition occurred when organisms evolved innovations to allow them to colonize
terrestrial environments. (5 pts.)
a) Provide an example of an innovation in each of the following taxa: a vertebrate, an invertebrate, and
a plant. For each example describe the structure and/or behavior that allowed or facilitated this
transition; also describe its novel function, and the attributes of the new environment the new
feature helped the organism overcome. (Note: we mostly talked about plants and vertebrates in
class but, you can apply these same concepts to invertebrates if you think about the differences
between modern day terrestrial invertebrates, such as insects, and their marine counterparts such as
lobsters and shrimp.)
b) For each of your examples, identify the geological time period in which the innovations evolved. (5
pts.)
9. The apparent lack of intermediate forms in the fossil record is one line of reasoning that is often used to
dispute the validity of the origin of higher groups of taxa over time. In this line of thinking, many people
interpret Archaeopteryx as a fossil bird, not an intermediate form. Explain why this is not a valid argument,
giving explicit examples from your knowledge of the fossil record to back up your claims. (10 pts.)
10. On an airplane trip to visit warmer parts of the world over spring break, you bring along your Evolution
textbook to get ahead in the assigned reading. The curious person sitting next to you happens to look over
your shoulder to see what you are reading. Their discovery prompts them to share their thoughts on human
evolution:
a) First, they indicate that they don’t believe “humans came from chimps” as they believe there is no
convincing evidence to suggest that they did. How would you accurately describe the
evolutionary relationship between humans and chimps to your “traveling companion”? (Hint: Is it
correct to say that humans “came” from chimps?) (4 pts.)
b) How can we use the fossil record of hominin skulls, in comparison to extant chimp skulls, to support
the relationship between humans and chimps? Provide three examples with explanations to
support your argument. (6 pts.)
11. During the Pleistocene Epoch, North America experienced at least four major glaciation events causing
areas such as New England to be covered by glaciers as high as 2 kilometers. Describe two affects these
glacial episodes had on the distribution and abundance of North American flora and fauna. (10 pts.)