Questions and Thoughts for John Alroy
Add your questions and/or thoughts as a comment to this post...Remember to have them up by Monday so there is time for all of us (and John) to look over them before class on Wednesday.
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Jason Lau
Defaunation & Biological Annihilation
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* From what I gathered, the paper focused on the herbivorous large mammals. How does this play into the extinction of the carnivorous ones?
ReplyDelete* How important do you think the mentioned, but not tested, concept of disease introduction is?
* Can this model be applied to other Megafaunal extinctions or just that in the Americas?
* It's widely assumed by most (all?) parties that the extinction of dire wolves, short faced bears, sabre toothed cats, American lions, American cheetahs, assorted large carnivorous birds, etc. resulted from a cascade extinction, so there's little to explain.
ReplyDelete* I think the disease idea is nuts. See my 1999 book chapter (not available online and I don't have a PDF, sorry). Among other things, disease doesn't explain body size selectivity or the lack of similar extinctions over the previous 65 million years of mammal evolution despite at least a couple hundred successful immigration events.
* It could certainly be applied to the other extinctions (at least one paper tried to do so for Australia). The problem is that the other researchers almost always develop super-simplified models that leave out the two key features, i.e., multiple prey species and variation in reproductive parameters tied to body mass (these two things combine led to the apparent competition that caused the mass extinction). Also, most other people have a pet theory they are pushing, so they do what they must to get what they want!
Hi! I really enjoyed your paper. I found it a very informative and easy read (compared to most other papers I have read.) I am an undergrad…so I am going to warn you…my questions may seem very trivial.
ReplyDelete- What exactly do you mean by “moderate” hunting?
- Were you pleased with the results that you found in your simulation? How long did this paper take you to compile?
Thank you for your time,
Ana-Marie Mollo
Hi,
ReplyDeleteI had a couple thoughts:
1. It would be nice to have seen a list of the species that were used, and which are extinct now and which are extant. I am not sure if one was included; if so I missed it.
2. I was wondering if you could explain what some of the hunting methods the people during the Pleistocene used. Many of the other students in my class probably have some idea, but I don't have that background. It would be interesting to see the tools that were able to drive so many species to extinction, and whether some were species specific. Humans probably had to adapt their weapons to the species that were in their area. I was wondering if this is true, and if this (their efficiency) was factored into your simulation at all.
Thanks!!!!
- As the large herbivorous mammals became extinct, did other animals take over the empty ecological niches?
ReplyDelete- Is there a way to tell if humans at the time of the mass extinctions had a favorite prey species? This seems like it would be based not only on rate of extinction, but population numbers and availability among other factors.
Mike
I don't know if folks looked at the supplemental material for this article - it can be found here: www.sciencemag.org/cgi/
ReplyDeletecontent/full/292/5523/1893/DC1
It contains some useful info, including the list of species (@pjhogan1).
John, I was thinking about how most simulations had human population sizes crash somewhat. One of the points often cited by proponents of the meteorite hypothesis is that Clovis spear points disappeared after the Younger Dryas cooling. They suggest this was due to a meteorite strike. Could there have been a population crash caused by extinction of prey species that resulted in abandonment of Clovis technology?
Well, I would have to agree with Mason's comments on the paper. I had a few questions on the methodology of the analysis pertaining to the species distribution modeling and modeling of human population size that were answered in the supplemental materials. One question I do have is whether there was any evidence of human mediated declines on mammal species with smaller body sizes.
ReplyDelete