June 2nd

Discussion questions


Jun 2

1. What does Behe mean by a structure that is irreducible complex?

What Behe seems to be saying is that the cell is so complex and so specifically "designed" that if one piece of it were to be removed, and you were able to test it by removing a piece, then it would not be able to function.

2. Is the mammalian ear irreducibly complex? Why?

According to the text, there is debate about whether the workings of the inner ear is irreducibly complex or not, because the construct of the ear can be evolutionary explained rather than have just occurred. Further, before the parts were complete, they still functioned and served in certain ways. For instance, the lower jaw still functioned for chewing while still allowing the mammal to hear. This disregards the concepts of irreducibly complex because before the whole was complete, the parts still functioned.

3. Behe claims that the eukaryotic cilium as an irreducibly complex structure, arguing that the 9+2 pattern of microtubules is essential for the cilium to beat. Test this hypothesis scientifically.

Figure 5.2 shows that although the 9.2 standard is most common, it does not mean that other arrangements are nonfunctional. 3+0 flagellum is fully functional without the microtubules center, which is evident in the fly Monarthropalpus buxi. This proves that although the eukaryotic cilium is complex, it is not irreducibly complex without the central microtubules.

4. Explain how blood clotting evolved.

This is one system that Behe suggests is irreducibly complex because without one part the whole system would not work. In order to prevent blood loss, many mammals with a closed-circulatory system have clotting abilities: "clot-makers" (fibrinogen) makes up about three percent of protein in blood plasma. The clot-makers get sticky when clots form, and the Factor X steps are necessary to continue the process. This complex step suggests that it did not evolve.

May 10

Carnell and Price, in review

1. What hook does the author use to capture your attention?

Carnell and Price created a fun story that really intrigued me. My group and I are going to adapt the story idea in which the narrative follows kids in a museum that go through all the controversial aspects of T. Rex.

2. How could you adapt this hook in your own case study?

As mentioned above my group and I will be using a narrative with a museum theme. I think this will draw our audience in because it will be a comprehensible yet fun reading.

3. I completed Activity 2 Global Warming:
- For changes in average temperature, I added all the magnitudes of change of each of the ten cities listed, then divided that number by 10 (10 cities listed) to get the overall average temperature: 1.1 F
- Climate is the average, long-term weather of a particular region. For instance, deserts are known to be dry and hot.
-Weather is the day-to-day atmospheric activity of a place, such as rain to sunshine during a week in Seattle.
-Weather conditions that range from hot to cold throughout regions is considered Climate Variability.
-When climates throughout the globe change in temperature, such as cold regions becoming warm while hot regions decrease in temperature, this can be identified as Global Climate Change.
-Global cooling is the overall decrease in surface temperature of the Earth.
-On the other end, Global Warming is the overall increase in surface temperature of the Earth.

4. How is the case study a model for the one you are writing? What do you want to emulate? What do you want to change?

The case study is a significant model for my group because we want to do a story that travels through each chapter while staying interrelated. The challenge for us is what order we want to place the chapters, while maintaining that "hook." We do not need to make changes, thus far, because we have not yet formulated the story. We will have a meeting next week to discuss our narrative, etc.

Signor-Lipps Effect, Wednesday May 5

1. Ever ride the bus all the way to the end of the line? And have you noticed how the bus begins to empty out as you approach the final destination? And that sometimes, when you reach that final destination there’s still a gaggle (albeit a small gaggle) of people getting off? Use this metaphor to explain the Signor-Lipps Effect. As usual, your explanation should be good enough for anyone on campus to understand!

In effort to explain the Signor-Lipps Effect, the bus example on the lab handout provides a useful way to apply it. According to Signor-Lipps, mass extinction is immediate but it can look gradual in the fossil records. In regards to the bus trip, we can look at extinction as every person getting of the bus at each stop (species going extinct). On the final stop, the remaining people (species) exit the bus and no more people remain (catastrophic extinction). Though all the people remaining are gone, that does not mean people were not getting off the bus prior to the last stop. In reference to the fossil records, an animal may have gone extinct, but not in a catastrophic extinction (final bus stop). Species may have been going extinct throughout time (through several bus stops) before reaching a final extinction. Signor-Lipps present the challenge in being able to distinguish the difference in gradual extinction and catastrophic extinction in fossil records.

2. Dinosaurs went extinct at the Cretaceous-Tertiary boundary, but our earliest interpretations were that some groups went extinct well before then. Use the Signor-Lipps Effect to resolve this paradox.

Naturally species go extinct all the time. In regards to the Cretaceous-Tertiary period when animals went extinct, species were going extinct before that. In the Signor-Lipps explanation, diversity declined before the Cretaceous-Tertiary mass extinction but it can be difficult to compare the actual diversity from the apparent diversity. Gaps in fossil records suggests many things about the extinction process, and there are ways to test the hypotheses but it can often be biased (hence the title). However, environmental changes, climate changes, and natural selection are strong evidences that support species extinction before the Cretaceous-Tertiary mass extinction.


3. Write a detailed caption for the graph you made for the worksheet called “Figure 3”. Make sure you explain what each of the curves means, and why each curve has a different shape. You may want to refer to the captions in Signor and Lipps (1982) as a guide for the amount of detail I want.

The different lines in the graph represent diversity: apparent diversity, actual diversity. The blue curve represents apparent diversity which is what we see based on what is covered from the fossil record. The red and green curves represent the actual diversity in which extinction looks gradual. The green curve is the most constant looking line, but then all three curves show a severe drop-off when it reaches around 10 mya. Overall the graph is visually presenting the relationship of gradual diversity from catastrophic diversity before a mass extinction.
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4. Given the fact that we need to consider the S-L Effect, how can we distinguish between a catastrophic mass extinction and a gradual mass extinction in the fossil record?

To be able to distinguish gradual mass extinction from catastrophic mass extinction from the fossil record we would have to look at apparent diversity from actual diversity. It is difficult to be certain about the differences, however, because the curves can be altered. Some species, for instance, may not have a good record. Or a species may have been going extinct before the mass extinction, but the fossil range may not be consistent. This can make it difficult to put a date on when the fossilized species became extinct.

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.