Signor-Lipps, ZImmer

Discussion questions


May 3

Lab handout

1. What is the main point of Signor and Lipps 1982?
How to look at and understand the difference between actual diversity and apparent diversity.
2. What have you learned from the title of this paper?
I have learned that samples from the gradual and catastrophic extinctions can look similar, so if researching for either there is a good chance of bias.
3. Explain what the vertical axes mean on all three graphs in Figure 2 of Signor and Lipps 1982. The vertical axes demonstrate the time and type of diversity.
4. What do you think Signor and Lipps mean when they question whether the fossil record is to “be accepted at face value” (291)? By this I believe they mean whether the evidence demonstrates the apparent divesity in the fossil record (gradual diversity).
5. What do Signor and Lipps mean by “random truncation of ranges” (292)? This means last time that a species can be preserved.

Zimmer 2010, Radiations and extinctions (excerpt)

1. What hook does the author use to capture your attention? Again, Zimmer uses good images that pertain to the subject. Figure 10.13 for instance, helps the reader to graphically see the dramatic differences in extinctions.


2. How could you adapt this hook in your own case study? We can utilize images that can illustrate what we are trying to explain to our audience, such as the physical structure of T. Rex's leg muscle that show why it was unlikely that the dino could not run fast.

3. When was the biggest mass extinction in the history of animals? What do we call this extinction event? What caused it?
According to the chart on page 231, the biggest mass extinction, also called Permian-Triassic extinctions, occurred 250 mya.
4. Which species seem to be most robust to extinction? Why? According to the article, it seems that birds would have been least vulnerable to extinction because they have the advantage of flying. They probably had better navigational an transportation abilities, likely to outrun sudden impacts in their environment.
5. What’s the difference between mass extinctions and background extinctions? Background extinctions occur as when a species goes extinct overtime. Mass extinction happens when species die out simultaneously along with the ecosystem.

6. Zimmer warns us that global climate change is one drastic consequence of increasing the amount of carbon dioxide in the atmosphere. What is the other? Humans. Humans have contributed to evolutionary forces such as deforestation, increases in carbon dioxide, and climate change that can lead to extinction.

7. How could you use Figure 10.15 as a hook for capturing the attention of your audience in the introduction of a case study? Images like this can have a greater effect on the viewer to comprehend the subject. In regards to T. Rex, we can use a visual aid like 10.15 that can show whether it was a scavenger or hunter. I don't how we can make it a graph but we can demonstrate the scavenger point of view from the hunter point of view and explain how each may be possible.