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Getting sufficient oxygen is a key limiting factor in metabolism. The more oxygen an animal can get, the bigger an animal can afford to get. And it's not just

by jjk166 5y ago

Getting sufficient oxygen is a key limiting factor in metabolism. The more oxygen an animal can get, the bigger an animal can afford to get. And it's not just insects. For example, the ancestors of dinosaurs evolved a highly efficient respiratory system towards the end of the permian period when oxygen concentrations were low, which likely helped them survive the deadliest mass extinction ever. Afterwards, oxygen levels skyrocketed up, and the dinosaurs, who still had their efficient lungs, could take advantage of it and became the giants we know and love. This same system is also key to the ability of modern birds to fly. Insects and other arthropods breathe through their skin, so the amount of oxygen they can get is limited by their surface area, whereas the amount of oxygen they need is determined by volume. Thus for any given oxygen concentration, there is some maximum surface area to volume ratio for insects, and in turn a size limit for any given body plan. This is why, for example, the largest species of tarantulas across multiple continents, despite evolving separately, are all the same size - being big has a lot of perks, but if they got any bigger they'd suffocate.

eloff 5y ago
That's a fascinating angle on dinosaurs and birds I've never heard of before, thanks for sharing!
willmadden 5y ago
Oil is mostly a renewable resource. New oil is made from magma heating the basement rocks of the Earth’s crust. As the rocks heat methane gas is distilled. This combines with carbonates and carbon 14 to form oil. This is why oil wells in Saudi Arabia, Russia, and elsewhere mysteriously refill after being depleted.
- btilly 5y ago
  Citation needed. Given how much your claim flies in the face of established and widely accepted scientific claims, preferably citations to peer reviewed research. Doubly so for the howler about C14. Oil is notable for its conspicuous LACK of C14, not an abundance of it.
  - willmadden 5y ago
    How do these "established and widely accepted scientific claims" explain why oil wells are filling back up? "Established and widely accepted scientific claims" are often nothing more than political propaganda, in this case propaganda originating with Standard Oil, the Rockefellers, and the even older money that backed that empire. Oil being non-renewable justifies overregulation by governments and price gouging by producers. I'll leave you to do your own research.
    - eloff 5y ago
      > How do these "established and widely accepted scientific claims" explain why oil wells are filling back up? Rocks are variably porous. It wouldn't surprise me at all to exploit a well until production is low, wait a period of time, and find there's small amounts of newly accessible oil there. Oil could maybe get squeezed out of the surrounding rock by the pressure differential crated by removing the oil in the first place. I don't know if that's true though, it's just a theory of mine. The success of fracking lends some credence to it.
      - dredmorbius 5y ago
        Note that hydrofracking literally works by using high-pressure water to expande cracks in the oil-bearing rock layer, then wedging bits of sand into the cracks to hold them open. Wellhead pressure (or lack thereof) is another major aspect of drilling and well production. Early "gushers" would spout 100s of feet (30--60m) into the air, spewing thousands of barrels of oil a day. Pressures could be ... immense (I've lost track of a cite I had for maximum recorded, though it was large). Mature or less-prolific wells have far less reservoir pressure and rely on slow seepage through what's actually mostly-solid rock. "Stripper" wells operated by pump-jacks may return only 10--15 barrels of oil per day. As the price of oil (or electricity necessary to run the pumps) rises and falls, these wells are literally turned on and off due to being only marginally economically profitable. Fracked petroleum wells have an operational life of ~10 years, possibly less. There are traditional wells still pumping strong after 80+ years. The First Oil Well, Bahrain, has been supplying oil since 1931, 90 years: https://en.wikipedia.org/wiki/First_Oil_Well,_Bahrain https://en.wikipedia.org/wiki/First_Oil_Well,_Bahrain
- vkou 5y ago
  Abiogenic petroleum is a fringe crackpot theory, not seriously considered by geologists. There are two possibilities, here. 1. You are an experienced geologist, and know far more on the subject of geology than I, or anyone else posting in this subthread. In that case, surely you would be able to preface your claims with a big fat disclaimer that most experts disagree with you, and that there are incredibly serious hurdles that your claims need to overcome. 2. You are, like me, a layman with little actual knowledge in the subject. In this case, you need to defer to expert consensus. Given your other response in this subthread, I think we'll have to go with the latter. Human knowledge doesn't advance because someone who is very smart, but understands nothing about a subject tells people that wet streets cause rain, and that they need to wake up and do their own research. Human knowledge advances when someone who deeply understands a subject posits a claim that can withstand cross-examination by people who know what they are talking about. https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin
  - IG_Semmelweiss 5y ago
    I don't disagree with your point. However, i disagree with your tone, particularly using "fringe crackpot theory". He's not advocating that green men put oil underground. He's promoting a theory that most (majority? some?) of oil has non biotic origins. Wikipedia itself says there are deposits worldwide that are abiotic, and also refers to this abiotic origin thesis as unlikely. He isn't arguing "wet streets cause rain". We are far from "fringe crackpot theory". https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin When the dispute is around the question of quantity "how much" vs whether it is physically possible at all, and the question currently is settled in terms of probability (95%~) vs replicable experiment proof (99.99% reliable), we should refrain from using wording that ridicules the other side.
- dredmorbius 5y ago
  False. Jeffrey S. Dukes, "Burning Buried Sunshine" (2003) Marine sediments produced the majority (about 86%) of the world’s petroleum, while deltaic and lacustrine sediments yielded smaller amounts (about 11% and 3%, respectively) (Demaison, 1993). The organic matter in carbon-rich marine sediments is primarily composed of the remains of phytoplankton. The percentage of annually fixed organic carbon that accumulates in sediment (the PF) is difficult to estimate because it can vary over several orders of magnitude, depending on the length of time that organic matter experiences oxic conditions, and on other factors (Bralower and Thierstein, 1987; Bordenave, 1993; Canfield, 1994; Gélinas et al., 2001). Two types of marine settings are thought to have been the major environments for the formation of petroleum source rocks: silled basins with oxygen-deficient waters, and highly productive upwelling zones (which generated 78% and 8% of world petroleum stocks, respectively; Demaison, 1993). https://www-legacy.dge.carnegiescience.edu/DGE/Dukes/Dukes_ClimChange1.pdf https://www-legacy.dge.carnegiescience.edu/DGE/Dukes/Dukes_C... Duke's paper goes on to estimate that the fossil fuels (coal and natural gas in addition to petroleum) consumed in 1997 represent over 400 times the current net primary production (plant growth) on Earth, and the petroleum consumed that year represents five million years of accumulated ancient biomass. (The reason for the difference is that whilst conversion from biomass to fossil fuels gives the first value, the additional geological losses in forming and preserving petroleum over hundreds of millions of years give rise to the five-million-fold factor. Fossil fuels are a very lossy battery.)

by jjk166 5y ago

eloff 5y ago

That's a fascinating angle on dinosaurs and birds I've never heard of before, thanks for sharing!

willmadden 5y ago

Oil is mostly a renewable resource. New oil is made from magma heating the basement rocks of the Earth’s crust. As the rocks heat methane gas is distilled. This combines with carbonates and carbon 14 to form oil. This is why oil wells in Saudi Arabia, Russia, and elsewhere mysteriously refill after being depleted.

btilly 5y ago
Citation needed. Given how much your claim flies in the face of established and widely accepted scientific claims, preferably citations to peer reviewed research. Doubly so for the howler about C14. Oil is notable for its conspicuous LACK of C14, not an abundance of it.
- willmadden 5y ago
  How do these "established and widely accepted scientific claims" explain why oil wells are filling back up? "Established and widely accepted scientific claims" are often nothing more than political propaganda, in this case propaganda originating with Standard Oil, the Rockefellers, and the even older money that backed that empire. Oil being non-renewable justifies overregulation by governments and price gouging by producers. I'll leave you to do your own research.
  - eloff 5y ago
    > How do these "established and widely accepted scientific claims" explain why oil wells are filling back up? Rocks are variably porous. It wouldn't surprise me at all to exploit a well until production is low, wait a period of time, and find there's small amounts of newly accessible oil there. Oil could maybe get squeezed out of the surrounding rock by the pressure differential crated by removing the oil in the first place. I don't know if that's true though, it's just a theory of mine. The success of fracking lends some credence to it.
    - dredmorbius 5y ago
      Note that hydrofracking literally works by using high-pressure water to expande cracks in the oil-bearing rock layer, then wedging bits of sand into the cracks to hold them open. Wellhead pressure (or lack thereof) is another major aspect of drilling and well production. Early "gushers" would spout 100s of feet (30--60m) into the air, spewing thousands of barrels of oil a day. Pressures could be ... immense (I've lost track of a cite I had for maximum recorded, though it was large). Mature or less-prolific wells have far less reservoir pressure and rely on slow seepage through what's actually mostly-solid rock. "Stripper" wells operated by pump-jacks may return only 10--15 barrels of oil per day. As the price of oil (or electricity necessary to run the pumps) rises and falls, these wells are literally turned on and off due to being only marginally economically profitable. Fracked petroleum wells have an operational life of ~10 years, possibly less. There are traditional wells still pumping strong after 80+ years. The First Oil Well, Bahrain, has been supplying oil since 1931, 90 years: https://en.wikipedia.org/wiki/First_Oil_Well,_Bahrain https://en.wikipedia.org/wiki/First_Oil_Well,_Bahrain
vkou 5y ago
Abiogenic petroleum is a fringe crackpot theory, not seriously considered by geologists. There are two possibilities, here. 1. You are an experienced geologist, and know far more on the subject of geology than I, or anyone else posting in this subthread. In that case, surely you would be able to preface your claims with a big fat disclaimer that most experts disagree with you, and that there are incredibly serious hurdles that your claims need to overcome. 2. You are, like me, a layman with little actual knowledge in the subject. In this case, you need to defer to expert consensus. Given your other response in this subthread, I think we'll have to go with the latter. Human knowledge doesn't advance because someone who is very smart, but understands nothing about a subject tells people that wet streets cause rain, and that they need to wake up and do their own research. Human knowledge advances when someone who deeply understands a subject posits a claim that can withstand cross-examination by people who know what they are talking about. https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin
- IG_Semmelweiss 5y ago
  I don't disagree with your point. However, i disagree with your tone, particularly using "fringe crackpot theory". He's not advocating that green men put oil underground. He's promoting a theory that most (majority? some?) of oil has non biotic origins. Wikipedia itself says there are deposits worldwide that are abiotic, and also refers to this abiotic origin thesis as unlikely. He isn't arguing "wet streets cause rain". We are far from "fringe crackpot theory". https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin When the dispute is around the question of quantity "how much" vs whether it is physically possible at all, and the question currently is settled in terms of probability (95%~) vs replicable experiment proof (99.99% reliable), we should refrain from using wording that ridicules the other side.
dredmorbius 5y ago
False. Jeffrey S. Dukes, "Burning Buried Sunshine" (2003) Marine sediments produced the majority (about 86%) of the world’s petroleum, while deltaic and lacustrine sediments yielded smaller amounts (about 11% and 3%, respectively) (Demaison, 1993). The organic matter in carbon-rich marine sediments is primarily composed of the remains of phytoplankton. The percentage of annually fixed organic carbon that accumulates in sediment (the PF) is difficult to estimate because it can vary over several orders of magnitude, depending on the length of time that organic matter experiences oxic conditions, and on other factors (Bralower and Thierstein, 1987; Bordenave, 1993; Canfield, 1994; Gélinas et al., 2001). Two types of marine settings are thought to have been the major environments for the formation of petroleum source rocks: silled basins with oxygen-deficient waters, and highly productive upwelling zones (which generated 78% and 8% of world petroleum stocks, respectively; Demaison, 1993). https://www-legacy.dge.carnegiescience.edu/DGE/Dukes/Dukes_ClimChange1.pdf https://www-legacy.dge.carnegiescience.edu/DGE/Dukes/Dukes_C... Duke's paper goes on to estimate that the fossil fuels (coal and natural gas in addition to petroleum) consumed in 1997 represent over 400 times the current net primary production (plant growth) on Earth, and the petroleum consumed that year represents five million years of accumulated ancient biomass. (The reason for the difference is that whilst conversion from biomass to fossil fuels gives the first value, the additional geological losses in forming and preserving petroleum over hundreds of millions of years give rise to the five-million-fold factor. Fossil fuels are a very lossy battery.)