My Research!

[Xiphactinus]

I love reading intellectual debates like this. Professional, polite, and profound. One of the reasons I come to this forum.

Carry on.....

[AgrilusHunter]

Read! How dare you make me want to learn, much easier to spout without facts!

I would ask though, is it truly a speceis/area relationship, or is it a species/niche relationship? The old ecological study where two speceis of flour beetles are placed into two separate containers of flour. One of the containers has glass and flour in it, the other only flour. The first container will support only one beetle species, the second two. The difference being that the second container allows partioning of resources through the formation of a niche around the broken glass. (I assume beetle one larvae are hard bodied, allowing contact with the glass, while species 2 is soft bodied and gets eviscerated when bumping up against the shards.).

In the case of islands, I think the speceis number is limited because the number of niches is limited, not necessarily due to size, but due to lack of diversity at the abiotic and even the biotic level.

Brent Ashcraft

Ha! In that case I recomend Siri, I understand she can read them to you.

The number of species an island can support is hypothesized as the intersection between the extinction and immigration curves for that island. These curves are functions of the size of the island and the distance of that island from a mainland species source. This is MacArthur and Wilson's theory of island biogeography, and it has shaped the field ever since they first introduced it. What is so special about this theory? It is a simple, logic based, testable hypothesis. The hypothesis has been empirically tested dozens of times in many different systems by many different researchers and has always proven true. It is about as close as you can get to a scientific theory in ecology. For the visual learners I reference this figure.

Image source

Edited December 14, 2012 by AgrilusHunter

[ashcraft]

Thank you for all the compliments, I too like a good discussion particularly among equals and betters. I don't know that hard facts are passed this way, but concepts certainly are.

It would be intersting to see how their theory would apply to islands that are not islands. Things like hydrothermal vents, desert oasis, and coral reefs. I suspect that the "size" criteria would be found to be a constant based on the abiotic factors. One acre in a desert is going to support only so many species, while one acre in rainforest will support so many more speceis, regardless of location.

Viable breeding population size also would have an effect on species, but not necessarily guild. Komodo is too small to hold a breeding population of tigers, but can have a breeding population of large predatory lizards filling the same guild.

Brent Ashcraft

Edited December 14, 2012 by ashcraft

[Ordovician_Odyssey]

I predict that we'll be hearing good things from Shamus for a long time. He's got an excellent attitude and a ton of promise for someone his age.

Thank you very much Don!

Sorry it took so long to get back, I have been continuing my research! I am starting to look at a bunch of material from Anticosti Island, which is the official Ordovician-Silurian boundary. I'm also starting to look at world maps of bentonite distributions throughout the late Ordovician.

Right now I'm treating my conclusion similarly to a hypothesis, I'd like to keep adding to my research.

Thank you all for your feedback!

Cheers!

-Shamus

[Ludwigia]

I am starting to look at a bunch of material from Anticosti Island, which is the official Ordovician-Silurian boundary.

Hi Shamus. You probably already have this, but just in case...

http://cjes.geoscienceworld.org/content/38/2/153.full.pdf

[Ordovician_Odyssey]

Hi Roger,

Thank you very much for the paper! I haven't yet seen it, Paul Copper is one of the leading researchers on the Ordo-Silurian extinction event.

Cheers,

Shamus

[Ordovician_Odyssey]

Also, Don, touching on your point that gull river is not the latest Ordovician formation in the area, I had originally chosen it for accessibility and the fact it was far more fossiliferous then the Billings, Carlsebad or Queenston
But now I see the upper Gull River formation is based around the mid-late Caradocian age, which in the case could have housed something that began triggering long term effects.

Just a thought.. but I would also really enjoy looking at some Billings and Queenston and possibly Anticosti material.

Cheers,

Shamus

[FossilDAWG]

Welcome back, Shamus. It's been a long time.

Do you have actual access to material from Anticosti? I always wanted to go there, but access is difficult.

I'm reading a book by Peter Ward, called "Under a Green Sky", that has to do with mass extinctions. You would probably find it quite interesting.

What is clear is that these mass extinction studies require careful bed-by-bed collecting of fossils and rock specimens, and the rocks have to be carefully analyzed for all kinds of biomarkers that indicate the kind of bacterial communities that were present, carbon12/carbon13 ratios in shells or bone, iridium/buckyballs/helium3 as indicators of asteroid/comet impacts, etc. It's meticulous and expensive work. What is truly remarkable is the power to discern just what was happening in terms of temperature, atmospheric composition, ocean circulation, and other things at the time of the extinction event. It seems impact-related causes for mass extinctions were relatively rare, maybe only the end-Cretaceous event; all the others that have been studied in detail have involved home-grown factors, primarily related (directly or indirectly) to greenhouse warming events.

Don

[Ordovician_Odyssey]

Thank you Don,

I'll look for that book, it sounds interesting. Yes I have access, I have something of a minor internship job with the national type collection with NRCAN, helping them with loans and such.. I'm sure I would be able to see Anticosti material. I would also love the opportunity to visit the island, however I'm not sure if the sites are protected, or if I could collect?

Yes it really does require the tiniest attention to all details, right now I'm seeing if I can take a look at core samples from various late[r] Ordovician formations from around the Ottawa area.. as for the chemical traces I have no idea where they still run that type analysis, but I am going to try and look at possible universities if they have the equipment to do so..

Cheers,

Shamus

Edited August 15, 2013 by Ordovician_Odyssey