When things go bye bye!

Lab handout
1. What is the main point of Signor and Lipps 1982?
Both Signor and Lipps set out to research and explain how several taxa populations disappeared before the hypothesized catastrophic extinction event. Signor and Lipps reviewed the fossil record for specific information regarding the time periods in which these taxa began to decline and found that the mass extinction did not occur until later. The scientists are trying to pull apart the evidence that discusses the hypotheses of a catastrophic extinction and whether or not the theory of such a hypothesis is relevant.
2. What have you learned from the title of this paper?
The title is basically saying that Signor and Lipps’ are trying to find out whether bias in the fossil record research was a critical piece in the arrival of a catastrophic extinction event hypothesis; and whether or not the gradual extinction of several taxa points to another suggestion of a hypothesis about the mass extinction.
3. Explain what the vertical axes mean on all three graphs in Figure 2 of Signor and Lipps 1982.
Figure 2a’s vertical axis is the actual diversity of animals in a certain location. The graph depicts what would occur to the diversity in the population if a catastrophic extinction were to happen. Figure 2b-(ask professor). Figure 2c-(ask professor)
4. What do you think Signor and Lipps mean when they question whether the fossil record is to “be accepted at face value” (291)?
They are implying the fact that if we would like to go on thinking that there was a catastrophic extinction event instead of trudging through the actual evidence and fossil records to prove scientifically that there was actually that sort of event, then we are giving up to easily and there should be more research done in this area.
5. What do Signor and Lipps mean by “random truncation of ranges” (292)?
They explain that a sampling method such as a “random truncation of ranges” is likely to show a trend of gradual extinction because not every event of biotic extinction is recorded in the fossil record, so scientists must use a truncation of ranges to explore the patterns of the specific taxa extinction and they must use the last known record of that taxa to connect the two patterns. The randomness comes along if the last known records are in different sections of time and are random and not in a specific order.

Zimmer 2010, Radiations and extinctions (excerpt)
1. What hook does the author use to capture your attention?
The author uses the hook of the biggest extinction event in history that destroyed over half of the genera on the Earth. This is a good shock factor to get the audience’s attention.
2. How could you adapt this hook in your own case study?
I could adapt this hook by using it similarly in the opening statements of my case study by explaining the shock factor of the PT extinction.
3. When was the biggest mass extinction in the history of animals? What do we call this extinction event? What caused it?
When: 250 million years ago. Named: KT extinction Cause: Meteor
4. Which species seem to be most robust to extinction? Why?
Marine invertebrates seem most robust to extinction due to the fact that the ocean is so expansive that they would most likely survive a catastrophic event in a smaller range of area.
5. What’s the difference between mass extinctions and background extinctions?
Mass extinctions normally include a lot of genera and are more easily noticed when a large range of fossils are found from the same time period. Background extinctions tend to be smaller scale and usually include less number of genera and records are a bit more difficult to pinpoint the cause of these extinctions.
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?
Destroying the world’s rain forests.
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?
I could use this figure that depicts the rate of extinctions across several million years to explain the shocking evidence that we are potentially headed into another period of mass extinction and the fact that we can learn from our history of these events and try to prevent another catastrophic extinction event from occurring.