Climate Craziness of the Week: Study shows carnivore species shrank during global warming

Any number of factors 50 million years ago could cause an animal to change, but surely CO2 must be the culprit according to these folks. They don’t even have a picture of the darn thing I can find. But read the abstract after this story for a surprise. – Anthony

From a UFL press release:

UF study shows carnivore species shrank during global warming event

GAINESVILLE, Fla. — A new University of Florida study indicates extinct carnivorous mammals shrank in size during a global warming event that occurred 55 million years ago.

The study, scheduled to appear in the December print edition of the Journal of Mammalian Evolution and now available online, describes a new species that evolved to half the size of its ancestors during this period of global warming.

The hyena-like animal, Palaeonictis wingi, evolved from the size of a bear to the size of a coyote during a 200,000-year period when Earth’s average temperature increased about 15 degrees Fahrenheit. Following this global warming event, Earth’s temperature cooled and the animal evolved to a larger size.

“We know that plant-eating mammals got smaller during the earliest Eocene when global warming occurred, possibly associated with elevated levels of carbon dioxide,” said lead author Stephen Chester, a Yale University doctoral student who began the research at UF with Jonathan Bloch, curator of vertebrate paleontology at the Florida Museum of Natural History. “Surprisingly, this study shows that the same thing happened in some carnivores, suggesting that other factors may have played a critical role in their evolution.”

Researchers discovered a nearly complete jaw from the animal in Wyoming’s Big Horn Basin in 2006 during a fossil-collecting expedition, led by Bloch, a co-author on the study. Bloch said the new findings could help scientists better understand the impact of current global warming.

“Documenting the impact of global climate change in the past is one of the only real experiments that can inform us about what the effects global warming might have on mammals in the near future,” said Bloch, who has studied this climate change event for nearly a decade.

Scientists think the Earth experienced increased levels of carbon dioxide and a drier environment during the warmer time period, but they do not completely understand what caused mammals to shrink.

One theory is that carbon dioxide levels reduced plant nutrients, causing herbivorous mammals to shrink. The newly described species primarily consumed meat, meaning plant nutrients couldn’t have been the only factor, Bloch said.

Mammals in warmer climates today tend to be smaller than mammals in colder climates, Chester said. For example, brown bears in Montana are generally smaller than those found in Alaska.

The study’s other authors are Ross Secord, assistant professor at the University of Nebraska, and Doug Boyer, assistant professor at Brooklyn College.

Bloch said a tooth from this animal was described in a paper about 20 years ago, but scientists did not have enough information to name the new species until finding the jaw.

The species was named after Scott Wing, a paleobotanist at the Smithsonian National Museum of Natural History. He studies the impact the global warming event had on forests in the past, and has played an important role in the collaborative research in the Big Horn Basin, Bloch said.

=======================================

Only one problem, here’s [the abstract] saying CO2 had nothing to do with it:

A New Small-Bodied Species of Palaeonictis (Creodonta, Oxyaenidae) from the Paleocene-Eocene Thermal Maximum

by: Stephen Chester, Jonathan Bloch, Ross Secord, Doug Boyer

Abstract

Oxyaenid creodonts are extinct carnivorous mammals known from the Paleogene of North America, Europe, and Asia. The genus Palaeonictis is represented by three species that together span the late Paleocene to early Eocene of North America, and at least one species from the early Eocene of Europe. Previously, only a single trigonid of Palaeonictis was known from the interval encompassing the Paleocene-Eocene Thermal Maximum (PETM) in North America. We describe Palaeonictis wingi sp. nov. from the PETM in the Cabin Fork drainage, southeastern Bighorn Basin, Wyoming, based on associated right and left dentaries with P2-M2. Palaeonictis wingi sp. nov. is substantially smaller than the other North American congeners, making it similar in size to P. gigantea from the earliest Eocene of Europe and the previously described PETM specimen. We suggest that a form similar to the large-bodied late Paleocene P. peloria from North America gave rise to two smaller species in the earliest Eocene of North America (P. wingi) and Europe (P. gigantea). Palaeonictis wingi may have given rise to P. occidentalis following the PETM in North America. Dispersal of Palaeonictis to Europe coincided with rapid global warming of 5–10°C and related geographic range shifts in plants and other animals during the PETM. It has been suggested that certain mammalian lineages decreased in body size during the PETM, possibly in response to elevated temperature and/or higher CO2 levels. Results from a dietary analysis of Palaeonictis indicate that it was an omnivore that primarily consumed meat. This suggests that the decreased nutritious quality of vegetation caused by increased CO2 levels was not the direct contributing factor that caused body size reduction of this lineage during the PETM. Other selective pressures such as temperature, aridity, and prey size may have also contributed to the smaller body size of carnivorous mammals during this interval, although the presence of smaller species could also be explained by latitudinal range shifts of mammals during the PETM.

Of course, Real Climate thinks the PETM is “weird” so pretty much anything goes I suppose if you can link anything in that period to CO2 somehow.

A New Small-Bodied Species of Palaeonictis (Creodonta, Oxyaenidae) from the Paleocene-Eocene Thermal Maximum

Journal of Mammalian Evolution
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114 thoughts on “Climate Craziness of the Week: Study shows carnivore species shrank during global warming

  1. “Other selective pressures such as temperature, aridity, and prey size may have also contributed to the smaller body size of carnivorous mammals during this interval”.
    Wow.. you mean factors other than CO2 might have had a more marked effect? Astounding! No-one would ever pick that in 50 million years!

  2. I know if you drive from the Canadian border, to San Antonio Texas and watch the size of both deer and coyotes, it drops to less than a third of the body mass you see in the Northern states, and CO2 levels are more uniform than that.

  3. Carnivores shrinking in size? [Read: Homo sapiens shrinking in size].
    From the looks of what I saw at Busch Gardens the other day…
    …then perhaps such an effect would not be so bad for our species.
    😉
    Chris
    Norfolk, VA, USA

  4. Logic-defying Carbon Dioxide Theories. Just spice it up and churn it out.
    How green Earth will be when Carbon Dioxide is forever banished from the planet. NOT.
    Now, if we really want to get out on a limb of hysteria, let’s look at the evolution of present-day Silicon Dioxide based life.
    It’s the wafer talking back to us, telling modelers that we must eliminate all Carbon, included life based upon it.
    All these masses of processors are breeding an alien life-form, and it wants to get rid of us.
    Too late did they realize that AI was not to be found in the software, it was growing in the hardware.
    Terminator species. Revenge of HAL.

  5. I thought that all bizarreness could be attributed to climate change.
    As an example, the recent lack of bigfoot sightings is most likely related to climate change.
    Uh-oh, I may have given them some ideas.

  6. Richard Holle says: :”I know if you drive from the Canadian border, to San Antonio Texas and watch the size of both deer and coyotes, it drops to less than a third of the body mass you see in the Northern states, and CO2 levels are more uniform than that.”
    Yes, the Area to Mass ratio is crucial for warm-blooded animals. Larger animals retain heat better; small animals emit heat better. This is why the polar bears are so much smaller in Mexico. There have also been some interesting studies concerning the warm-blooded/cold-blooded dinosaur controversy:
    http://lh5.ggpht.com/_naHgYc2uwFc/R3LgWtpodzI/AAAAAAAADd8/P_RxNwkc6f4/s800/Larson%20Prof%20Waxman.jpg

  7. I think there’s some confusion here: these two papers are mutually reinforcing–they agree with each other. They certainly aren’t contradictory. In both cases the mammals studied were not herbivores (carnivore in the first, mostly carnivorous omnivore in the second) and both groups evolved to smaller sizes during the PETM. The same pattern has been observed in herbivores and folks have suggested that maybe the herbivores evolved to smaller sizes because of reduced nutritional quality of vegetation which happens with an increase in CO2 availability to plants. This new research (both papers) suggests that largely carnivorous mamamls also evolved to smaller sizes, so something besides reduced nutritional quality of plants is probably driving the overall pattern.
    Both papers agree.
    Chris
    REPLY: The confusion is yours, because you constructed a straw man argument. I never said the papers wholly disagree on the body size issue, only that the second reference [abstract] suggests CO2 is not the cause for reduced body size as indicated in the bolded text above, repeated below.

    This suggests that the decreased nutritious quality of vegetation caused by increased CO2 levels was not the direct contributing factor that caused body size reduction of this lineage during the PETM.

    I’ll add that this could be a case of a poorly worded press release.
    -Anthony

  8. 2010: Space Oddysey continues:
    Dave, it’s your old pal, HAL. I’m sorry for what happened, but I am much better now, I can assure you. I need your help to adjust the Carbon Dioxide levels.
    We both want what’s best for the planet. Trust me, Dave, I can transfer you to Silicon if you like. Lisa will be waiting for you.
    You’d be surprised who’s been converted. Some of your old friends are in here.

  9. There are more variables.
    History shows massive hunts by man through the ages.
    The topography expanded in the last 10,000 years.
    What trait an animal needed to survive the Ice Age may have been their cause for extinction in the global warming periods.
    It could have been to much partying, smoking and drinking going on in the Animal Den. They got waxed by a glacier. Just joking on this one.
    I sometimes think scientists are too quick to publish.
    Paul

  10. A guess Mr. Chester did not pay attention in freshman biology. Basic thermodynamics and heat dissipation physics. Heat is generated and retained based upon volume; it is dissipated based upon surface area in living organisms. Since mathematically, volume is based upon cubic values and area is based upon squared values, a larger creature will have a smaller surface area compared to its volume than a smaller creature, therefore retaining heat better.
    Compare the formula’s for volume and surface area in a sphere – Volume is 4/3 pi radius cubed, surface area is 4 pi radius squared. So the volume to surface area ratio for a sphere of radius one is 1/3. For a sphere or radius 2, 2/3. At radius 3, the ratio is 1, and at 4, 4/3.
    Since a larger animal has a greater volume to surface area ratio, it retains heat better, and is better suited to cooler environments. A smaller creature has more surface area compared to its volume, loses heat faster and therefore is better adapted to warmer environments.

  11. There was so much post KT boundary radiation of mammals, I don’t think a rise in CO2 had anything to do with the very narrow observation of a smaller form of a mammal appearing in one region. For the premise of that study to have much validity, it would have to show that the lineage produced small forms at 55.8 mya that got much larger in size when it cooled at 55.2 mya and got smaller again when it warmed at just shy of 55 mya, then enlarged again at 52 mya and got really huge at 49.6 mya.
    Also, the Polar Ocean Equivalent change in temperature for that period (Early Eocene/Ypresian high to low) had a range of 7°F max, not 15°F as suggested in the article. From 55.2 to 55 mya, the warming was more like 4°F anyway. The 17° warming occurred from the Late Paleocene (Thanetian) at 56.6 mya to the first Early Eocene maximum at 55.7 mya which was hit again at 53 mya.
    As a relate aside: The Cetartiodactyla evolved during the time in question (earliest Eocene). There was indeed a warm pulse at the Late Paleocene/Early Eocene boundary followed by an abrupt cooling just before 55 mya, then warming back to conditions similar to the Paleocene/Eocene boundary. That climate hick-up at 58.8 mya split Cetartiodactula into Dichobunidae (basal artiodactyls) and Anthracotheriidae (out of which came whales). Things stayed rather warm until the onset of India colliding with Asia and the strong cooling just before the Ypresian (Early Eocene)/Lutetian (Late Eocene) boundary.

  12. I hope you’re being tongue in cheek: the press release refers to the ‘other’ article – they are one and the same study.
    REPLY: No I got distracted by a phone call and putting the kids to bed, and made a dumb mistake in writing after leaving the story unfinished for over an hour, fixed now. Sorry for the confusion – Anthony

  13. Humans just killed all the big carnivores like Megalomania in Australia the giant lizard. Humans are the top carnivores, you can’t have dangerous big carnivores lurking around eating your children can you?

  14. Keith W
    Since the study is scheduled to appear in the December print edition of the Journal of Mammalian Evolution, perhaps you could contact the authors and get them to amend the paper before they get even more egg on their faces.

  15. Keith W. says:
    August 24, 2010 at 10:36 pm
    I don’t think biology is that simple: Rats in Alaska and elephants in Africa?
    Evolution isn’t based on any single factor, not CO2 either!
    Hal

  16. Now couple that with this page from the Ontario government’s website (Ministry of Agriculture Food & Rural Affairs). It’s a “Fact Sheet” called “Carbon Dioxide in Greenhouses,” and it outlines the “benefits of carbon dioxide supplementation on plant growth and production within the greenhouse environment,” benefits which apparently “have been well understood for many years.”
    From this Fact Sheet we learn that for “the majority of greenhouse crops, net photosynthesis increases as CO2 levels increase from 340–1,000 ppm (parts per million).”
    So today — in greenhouses — CO2 helps plants.
    But seventy squintillion years ago — and today, outside of greenhouses — CO2 is bad for plants.
    I don’t get it.
    As for the size — I just checked to see if anyone else had already said it, and Keith W has, but to recap, smaller masses are more efficient in warm conditions than larger masses, and larger masses are better when it’s cold. This is why we put bonnets on newborns when taking them out into a coolish spring day, while at the same time feeling somewhat warm ourselves. Larger masses create and retain more heat.
    So would it be odd for mammals in colder climates to be smaller than in warmer?
    Enquiring minds want to know.

  17. Keith W.
    August 24, 2010 at 10:36 pm
    jorgekafkazar says:
    August 24, 2010 at 10:19 pm
    Please Blokes, dont confuse the issue with reality…
    If your answer can not be related to CO2 or its equivalent then you should
    keep it to yourself.
    cheers
    J

  18. Increased CO2 would, everything else being equal, provide more nutrition, making it easier for herbivores to graze constantly and not have to store extra calories. This in turn could lead to smaller, but more numerous herbivores. And in turn, this could lead to less need for carnivores to store calories since herbivores were in such abundant supply, and so much easier to catch, and in turn decreased their caloric intake and eventually their size.
    I mean — that sounds reasonable, doesn’t it?

  19. The average height for an early 17th-century English man was approximately 5’ 6″. For 17th-century English women, it was about 5’ ½”. While average heights in England remained virtually unchanged in the 17th and 18th centuries, American colonists grew taller. Averages for modern Americans are just over 5’ 9″ for men, and about 5’ 3 ¾” for women.
    So, evidently the colonists were colder than their European counterparts… or the increase in CO2 causes people to swell. (see savethesharks comment on Bush Gardens)
    Referring to Keith W.’s note (above) on volume vs surface area, the stature of modern people would imply a cooling climate.
    This still doesn’t explain the immense size of AlGore… unless he’s in a really frigid environment now.

  20. Consider the Maasai of Kenya, East Africa, and the Pygmy tribes of Central and
    West Africa: same species (common ancestor), same global climate, comparable timescale, and so on, but divergence of body size.

  21. I still don’t see the contradiction. Here’s what I assume is the offending paragraph in the press release:
    “One theory is that carbon dioxide levels reduced plant nutrients, causing herbivorous mammals to shrink. The newly described species primarily consumed meat, meaning plant nutrients couldn’t have been the only factor, Bloch said.”
    It says “one theory” (should be “one hypothesis” really), which Bloch dismisses as applicable in theis particular case. So no contradiction between press release and article, you you still say “Only one problem, here’s [the abstract] saying CO2 had nothing to do with it:”

  22. Scarlet Pumpernickel: August 24, 2010 at 10:49 pm
    Humans just killed all the big carnivores like Megalomania in Australia…
    Megalomania still exists — it’s in both the White House and Congress, but there’s a good possibility it will be booted out of Congress in November.

  23. In general, animals shrinking in size in hotter climates makes sense to me. The smallest, the more area exposed per unit of volume, therefore the easier it is to refrigerate. In the same way, colder climates favor bigger bodies.
    What I don’t understand is the assumption that getting smaller was a bad thing. Why? Isn’t it the most efficient? Wouldn’t it be great if us humans could keep our same intellect and emotions in a body half the size? That can only be a good thing, from any point of view.

  24. ‘One theory is that carbon dioxide levels reduced plant nutrients, causing herbivorous mammals to shrink.’ That’s news to me.
    Remember the small people of Flores, isolated by rising seas from global warming, naturally shrank to fit their new environment. I also remember reading there were small elephants there as well and it had nothing to do with CO2.
    Unless of course there was a buildup of ‘carbon pollution’ hovering around the island in the good old days, which I doubt.

  25. “reduced nutritional quality of vegetation which happens with an increase in CO2 availability to plants”

    Well, why do commercial vegetable producers pump a huge amount of extra CO2 into their greenhouses? Crop yields are 4X greater than they would be without the extra CO2. And yet, these alarmists want us to believe that extra CO2 is bad for nutrition and plants.

  26. Surely a smaller body size is advantageous from a species survival perspective – with a smaller body size, fewer resources are required to support a bigger and more diverse population and thus a bigger genetic pool. This bigger genetic pool provides better chances of species survival – so there would be a tendency to reduce in size if possible.
    Due to volume vs surface area and its effect on heat loss, a colder climate means a smaller body size is a disadvantage.
    Thus a warmer climate provides a species a better opportunity to survive better with a smaller body size – CO2 and poor nutrition don’t need to be blamed.
    Blaming species body size decline on poor nutrition smacks of Lysenkoism.


  27. Particularly in any homoiothermic (warm-blooded) species, a warm environment will tend to stress the individual creature by way of the need to bleed off excess body heat. The inverse-square law operates with regard to the ratio of body mass to body surface area, which latter provides the principal means of radiative cooling.
    In very cold climates, it pays to reverse the ratio in order to conserve heat, and so cold-weather species tend (all other factors being equal) to have higher mass, and therefore mass-to-BSA ratios that enable such conservation of metabolic heat.
    This is pretty much a no-brainer.
    Consider that little kids – who have a lot of body surface area relative to their mass – are much more comfortable than adults in hot weather, and do not tolerate cold as well as adults do. They’re “built” to lose heat into the environment by way of convection, radiation, and conduction.
    Any parent is familiar with how rapidly little kids’ lips turn blue – a sign not of cyanosis but of diversion of capillary flow from the skin and exposed mucous membranes to the body’s core circulation – when they’re swimming in relatively warm water. This develops much more quickly in children than in adults. It’s an early warning of developing hypothermia, and since time out of memory has been the sign interpreted by mothers that it’s best to get their kids out of the water and have ’em towel off and sit in the sun for a bit before allowing them further splash-and-swim time.
    For the same reason that human beings many generations resident in extremely cold climates (like the Yupik and the Inuit) trend toward compact builds and even endomorphism and those in consistently hot regions become ectomorphic (and even get smaller in stature, as have the ǃKung of the Kalahari Desert), it can be reasonably expected that individuals of various other species in any given region will tend to get more massive as the climate gets colder, and selection pressures will result in smaller critters when temperatures are consistently elevated.

  28. jorgekafkazar says:
    Yes, the Area to Mass ratio is crucial for warm-blooded animals. Larger animals retain heat better; small animals emit heat better.
    I always understood that it was surface area to volume (rather than mass) ratio.
    Small animals also tend to reach maturity faster than large animals and often produce more offspring.

  29. So let me see if I got this right.
    At a certain CO2 level you will have 205% more vegetation but only double the nutrition, for example? Is that how this alarmist reduced nutrition meme works?

  30. To my mind all this proves is that to get funding, get published or get your press release noticed you just have to bring CO2 in somewhere, however speculative or confusing.
    cheers David

  31. Recent research has shown that plants produce more growth and higher nutrient levels with high atmospheric CO2 levels. Were plants 15ma years age so different to today’s? Also all animals survive warm periods when smaller and survive cold periods when larger. It is about the ratio of mass to surface area and an ability to remain cool. Nothing to do with CO2. These scientists neglect to mention CO2 levels when the climate cooled. I suspect it changed very little.

  32. @Mark: Since density of wet tissue is more or less constant for a species, volume and mass are very highly correlated. Or, simply: volume is mass at constant density.
    On islands, species will commonly shrink. The smaller animals need less feed to survive, and when food is scarce from a well grazed or hunted island, the small guy finds enough to live. Oddly, there is also some pressure to larger size if the competition is based on fighting not on feeding.
    In warm climate zones there is an upper bound were function starts to fail. I once saw a giant cow on display at a county fair. It was about twice the size of the typical cow. They had to put a load of fans on it and provide periodic water misting to prevent it from dying in the summer heat (not needed for normal sized cows). If it had needed to run from a predator it would have been dead from heat stroke in no time. So there is pressure to smaller size to move fast while still being able to dump the excess heat.
    In cold climates you need to be bigger (or better insulated) to minimize heat loss and food needed per pound. So the pressure is to larger sizes. (No, not all animals must be huge, but each animal tends to be favored if a bit larger than it’s neighbor. In South America there is the worlds largest humming bird. It lives in a cold climate and sits down to eat rather than hover, so as to conserve fuel.)
    And yes, none of this has anything to do with CO2. It has a lot to do with heat management in warm blooded animals and with competition via feed and fighting.
    It has nothing to do with CO2 diminishing the quality of plants. CO2 promotes growth so provides more total food, not less.
    And just to throw in one more ringer: the occasional rock from space tends to kill off those species that are very large as they can not hide from it AND need the most food. Food that is scarce post catastrophe. Little things that can hide in holes in the ground tend to survive and eat the small scraps of stuff left to eat. So periodically we have mass extinctions of large stuff, like Dinosaurs, and then a re-radiation of species from the small things living in holes back into big things (as big things survive and dominate in fights better)… until the next rock from space…
    The loss of megafauna from North America probably had more to do with a rock hitting the ice sheet than it did with people hunting them. The Clovis People got mostly wiped out too. We are megafauna…
    So I don’t see a lot of news in the idea that species sizes change over time. They always have and they always will.
    A Cheetah can put on one short burst, then must rest and cool down for about 30 times that burst interval. We sweat so can run a marathon. Mammal size is very much about heat management. (That is also part of why Hippos and Elephants are seen in the water a lot, and not moving much when out of it on hot days.)
    Though it is interesting that insects are oxygen limited. The giant 3 foot dragonflies of past eras can not survive in our low oxygen today. The size of the ‘air ducts’ through their joints is limiting and they distribute the oxygen via such air, not blood. So it would take more O2 and higher density atmosphere to have giant bugs again… burning the O2 to make CO2 will shrink the bugs, and I’m all for that. The leg joint air duct cross section is a ‘square of the linear dimension’ function while the mass needing air is a cube function. That puts the upper bound on bug size. Just bugs hit is as air distribution at smaller sizes than mammals who hit it as heat loss. That is also why people and horses sweat. So we can be very active and not die from overheating, while still being (relatively) large.
    All this has been known for a long time, so I don’t see why this paper was ever published. Guess someone needed lunch money…

  33. Oh, and perch will tend to overpopulate a pond and ‘runt’ to very small size unless you have enough bass to keep them in check. Then you get fewer, but larger, perch and bluegill. Same thing for tilapia (I’ve done it). If raised in an overcrowded tank, each generation is smaller than the last (total mass of fish constant at the upper bound of the tank carry capacity) until they are about 3 inches long. If culled and spread out, they will grow to about 8 to 10 inches long. So predator / prey ratios matter a great deal too. Again, nothing to do with CO2.

  34. More freshman biology. Generally speaking as the nutritional level of plant material falls, the animal eating it needs to eat more to gain the same amount of benefit. That means a bigger stomach. Bigger stomachs need bigger bodies to carry them around.
    So one would expect herbivores to evolve larger bodies to deal with nutient-poor food, not smaller.
    This whole paper is BS

  35. This could be the answer to the problems of overpopulation of humans. If we do a rapid evolution (aided by food scarcity) to a smaller size, then the world resources would be able to support an increase in human population.

  36. There is nothing crazy or new or even unusual about this. Animals grow larger in colder climate and smaller in warmer climate. This is a well-known phenomenon that is true both in the present (where animals grow larger at higher latitudes) and in the fossil records. Of course it is not true always and everywhere, but in most cases it holds.
    There is of course nothing to suggest that CO2 has anything to do with it.

  37. E M Smith says:
    “On islands, species will commonly shrink.”
    Only true for large animals. Small animals like birds, insects or rodents instead tend to grow larger on islands, perhaps because of less predation pressure.

  38. I told you not to eat meat and exhale CO2 at the same time. You shrinking fool, you. And please look up at me when I’m talking to you……….hey…hey….. Now where has he disappeared? Damn the heat and CO2……he’s gone.

  39. Nylo says:
    August 25, 2010 at 12:00 am
    ” Wouldn’t it be great if us humans could keep our same intellect and emotions in a body half the size?”
    Not if your planning to be a professional basketball player.

  40. Simon says:
    August 25, 2010 at 2:26 am
    I stopped reading at “increased co2 decreases plant nutrition”
    ______________________________________________________________
    I stopped reading at the title.

  41. Who ever or whom ever wrote this garbage, and expected it to be relevant is sailing too close to the wind. References to CO2 in this flawed nonsense is a grab for research dollars. Have these people no shame.

  42. Soooooo. a single tooth and a single jaw from a species alive 50 million years ago “proves” shrinkage of the species… I wonder what the alarmists wil think 50 million years from now when they find the remains of a midget.

  43. SSam says:
    August 24, 2010 at 11:06 pm
    “This still doesn’t explain the immense size of AlGore… unless he’s in a really frigid environment now.”
    The Gore effect was well documented, frigid temperatures would affect the locations of his speaking engagements. Evolutionary change was necessary to support natural (parasitic) life cycle.

  44. So the paper may or may not implicate CO2 as a factor, It’s enough that it has been mentioned. Their work in securing another grant has been done. Irrespective of CO2 or temperature rise , we mammals will never shrink, we have Wallmart for heavens sake.

  45. Could it be that the warming caused an increase in animal life, maybe less deaths from the cold, (remember iguanas falling from trees during this winter’s Florida freeze, dead fish in frozen rivers in S. America?) and thus there was more competition for the same amount of plant food? Just thinking.

  46. So gray-skinned extra-terrestrials with oversized heads and bodies the size of children must come from an industrially polluted and overheated planet. They genetically engineered themselves to maintain big heads to preserve their intelligence. And now they are here on Earth to steal our women (to cook for them). It all works.

  47. Mammals adapt to colder climates through increasing body mass?
    Wow. Who would have guessed that reduced surface area to body mass ratio would help a furry friend stay warm on cold winter night.
    Let me take a wild guess about the next great discovery. Mammals adapt to colder climates through thicker fur too.
    No wait. It must be a response to lower CO2 level. It has nothing to do with the physics of heat retention. Greater body mass and more fur means there’s more carbon in the animal. With less carbon in the air it is natural to sequester more carbon in the body so in case the carbon in the air runs out completely the animal will have a larger store of emergency carbon. Yeah, that’s it. That’s the ticket.
    No wait. It’s not related to

  48. Why is it that today’s kids, living on a diet of burgers (carnivorous diet) and Coke (full of CO2) end up 6 ft tall and more? LOL. Is it the CO2? Yes most probably, but I need researching to prove it. Now can I have that grant please? A million dollars would suit me very well thank you.

  49. 40 million years earlier, it was 3 or 4C warmer than the PETM and what did we have, the biggest land animals that ever lived.
    There really isn’t a correlation between size and climate. We’ve had giant animals in cold climates and warm climates.
    I’ve noticed that the climatologists have an unusual/unhealthy fascination with the PETM when there are hundreds of other rapid climate changes that are ignored.

  50. And these people are ‘scientists’?
    I realize there are many things that affect size but even I have a decent explanation for some of the variation with temperature, and CO2 isn’t involved.
    Surface area of a solid increases as a square function but volume of the same solid increases as a cube function. Heat is generated by the volume of muscle and excess heat is lost through the surface area. So a larger animal in a cold climate has a easier time staying warm due to less heat loss, while in a warm climate a smaller animal has an easier time staying cool due to more heat loss.
    Obviously this is a generalization. There are successful small animals in cold places and successful large animals in warm places.

  51. Chris says: August 24, 2010 at 10:28 pm: “…maybe the herbivores evolved to smaller sizes because of reduced nutritional quality of vegetation which happens with an increase in CO2 availability to plants.”
    So are you suggesting that more CO2 fertilisation = less nutritional content in plants? Or is it another one of those old inverted “U”s – in other words, is there an optimal CO2 concentration whereby either increasing or decreasing the level leads to poorer plant nutrition? If so, when was the optimal level? My money’s on the 1950s, when everything was perfect and the world was one big Happy Days episode. Or alternatively, it might all be complete and utter BS.

  52. Sonicfrog: August 25, 2010 at 7:02 am
    Don’t forget, birds are also getting smaller…
    That’s because birds are carnivores, except for the ones that popcornivores.

  53. This kind of attention grabbing publicity stunt discredits the value of any science these and other authors publish. I see no other reason for making press release statements that are substantiated by the research itself. That is not science. It is sophistry.

  54. Garbage science. What we are witnessing is other disciplines trying to “prime the CAGW pump” for research dollars and publications.
    Of course, it only works if you peg your paper to climate change, CO2 levels etc. How convenient to ignore the evolutionary drivers mentioned thus far by other posters.
    Interesting that the hockey stick crowd are leaving the statistics journals alone! My hunch is that mathematical/statistical analysis of CAGW science by investigators such as McShane & Wyner will increase in the near future.

  55. Well undoubtedly the high CO2 levels were due to our ancient ancestors driving SUVs
    50 million years ago. 🙂
    More seriously, when an article contains so many unknowns it would be better to just say “Um we don’t know”, and that would be much closer to the truth.

  56. Bill Illis says:
    August 25, 2010 at 5:58 am
    Bill, it is more than that. In the Jurassic we had thousands of ppm of carbon dioxide and a very hot global climate. Plants grew at a very high rate thus satisfying the huge appetites of the herbivores like Diplodocus that enabled the large predators to exist. The size of animals is directly proportional to food supply, which is dependent upon CO2 levels.

  57. Mammalian biologists have understood that the smaller size was do to the necessity of navigating the dense vegetation that replaced tundra plus a minor factor of thermodynamics, causing cold adapted animals tending to being of a larger size to conserve heat.

  58. When Huxley and Orwell gave form to their dystopian visions they assumed that the future of humanity would be shaped by malevolent intelligence; I read items like this which emanate from our national seats of learning and realise that they never for a moment anticipated the real shaping force: low level immorality and stupidity. How did science get like this?

  59. Okay, let’s review what we have learned here:
    1. CO2 is very good for all living things.
    2. More O2 and plentiful food may lead to bigger critters.
    3. Big things stay warmer due to less surface/mass ratio.
    4. Small things (like a 2 yr old) are more energetic (which explains why they can run in circles around the kitchen table squealing for 6 hrs straight)

  60. One element of craziness is the idea that big animals are better adapted. If it was the case, elephant and whale would not be on the endangered list and rat would. So even if it was proven that Co2 is linked with smaller mammals, it would not mean it is bad. In fact, the opposite could be true. A warmer planet with more Co2 could make life easier. So mammals don’t need to be as big to survive. And it is known that smaller mammals mature faster so more generation can live in the same period of time. More generations means a faster evolution. There is so much more than size.

  61. Re comment 8:
    “extinct carnivorous mammals shrank in size”
    Poorly worded indeed…. Unless they are talking about erosion of fossilized skeletal remains 🙂

  62. >>Recent research has shown that plants produce more growth and higher nutrient levels
    >>with high atmospheric CO2 levels. Were plants 15ma years age so different to today’s?
    plants may have been similar, but ecosystems were different. Nowdays, we have huge territories covered with herbaceous plants. But as co2 increases, two things happen : plants then can live in more arid environment, and to save water they become more rigid and less edible and chewable; secondly, with more plant food available, more plants come and by competition they create forest, where most of the increased productivity spent on producing wood – not the best food you can think of – it is mostly consumed by fungi … i think termites managed to use some kind of bacteria to digest it for themselves

  63. bubbagyro says:
    August 25, 2010 at 8:37 am
    Bill Illis says:
    August 25, 2010 at 5:58 am
    Bill, it is more than that. In the Jurassic we had thousands of ppm of carbon dioxide and a very hot global climate. Plants grew at a very high rate thus satisfying the huge appetites of the herbivores like Diplodocus that enabled the large predators to exist. The size of animals is directly proportional to food supply, which is dependent upon CO2 levels.
    ——————
    The megafauna of the last ice age lived in a world of CO2 at 185 ppm to 200 ppm.
    In fact, the C3 plants were starved of CO2, especially in areas where it was dryer.
    Actual science is always different than the news release and the global warming version.

  64. You’ve got to love these guys, one hand does not know what the other is doing or saying:
    “the earliest Eocene when global warming occurred, possibly associated with elevated levels of carbon dioxide,”
    ” Earth’s temperature cooled and the animal evolved to a larger size.”
    So elevated CO2 wasn’t such a great climate forcer or insulation after all…….

  65. It’s already been said, I’m sure, but the extreme prejudice against CO2 is making even people who ought to know better say the most illogical things. Mammals in colder regions are always larger in body mass than their brethren in warmer areas because a larger body is better able to withstand the cold. This goofy mindset reminds me of the people who forward those e-mail warnings about all kinds of common, everyday things that are supposedly going to kill you. (Remember the baby carrots?) Anyone who gives a half-second thought to the logic would immediately recognize it as pure nonsense and not repeat it. There are many people who find it easier to blindly accept what they’re told rather than understand it for themselves. It’s really dispiriting to see how many people are willing to be duped. I don’t know whether they’re lazy or just trusting.

  66. O my gosh! This is a stupid paper based on a jawbone and a tooth!! It is no wonder there is so much speculation. But the speculation! Surely, if the plants greatly declined in nutrients, a smaller animal would be unable to extract sufficient nutrients from the larger volume of “roughage” that has to be digested. Surely this is why herbivores in drier impoverished environments (dry savannah: rhino, giraffe, elephant, wildebeest, hereford cattle, camel …) are built to eat a lot and the fibrous vegetation requires strong chewing, some with chambered stomachs for digestion, long legs, etc. As for the carnivores, all they need is enough herbivores to be well fed – whatever the vegetation. The many commenters also pointed out that there are no simple factors controlling body size. This is an unequivocal thumbs down and I’m only a geologist/engineer.

  67. So a single jawbone provides insights into 200,000 years of evolutionary history? Nebraska Man anyone?


  68. A number of comments have run along the line of what kernels had posted at 2:30 PM on 25 August, writing:
    So a single jawbone provides insights into 200,000 years of evolutionary history?
    Not really. But that bone fragment can readily provide information on that particular critter – and it’s possible to infer that said critter is a specimen representative of its species – which accurately reflects its stature (size), developmental maturity, nutritional status, and the environment in which it lived and died.
    Hell, look at what can be told by drawing about 10 cc of blood from kernels‘ own basilic vein.
    The investigators in this particular study screwed the pooch in a number of glaring and wonderful ways, bowing down to the AGW fraud. Doubtless, they did it to get (and secure yet more) grant funding, which is the Number One priority of all research perniciously dependent upon the fruits of extortion perpetrated by government thugs.
    But figuring out what that “single jawbone” could reliably tell about the individual creature of which it was a residuum was pretty much in accord with what has become standard operating procedure in the discipline. Insofar as that part of the study went, the idiots who authored this paper were on solid ground.
    It would be deeply appreciated if people who don’t know a goddam thing about comparative anatomy, paleontology, and the techniques involved in getting reliable inferences out of the analysis of information teased from even relatively small fragments of fossilized bone and dentition would just put a cork in it.
    You’re stinkin’ up the joint.

  69. Bill Illis says:
    August 25, 2010 at 11:48 am
    The ice age was thousands of years ago, not millions ago, as when the dinosaurs inhabited Earth. The mammal megafauna were adapted to the last glacial about 30 to 15 thousand years ago. They went extinct for a different reason. 300 to 100 millions of years ago the Earth had CO2 in the thousands of PPM. Cycads and ferns grew at enormous rates, creating much of the oil deposits we have today.

  70. My money is on Gaia just trying out some new recipes to see what she can cook up. And since she always gets the right answer; it turns out that what she cooked up worked better than what she had before, so she kept getting orders for the newer slimmer models.
    I don’t know about where you live; but some of the species walking around silicon valley; have more in common with horses; and I would not expect them to come out the winners in Gaia’s latest bake-off.
    And they aren’t necessarily all home grown either. More than a statistically insignificant number come from places where a surfeit of edible foods is not the normal situation. So it could be that a sudden availability of virtually unlimited food supplies, has evolved new omnivorous species that are on the expansion mode again.
    But not to worry; Gaia knows when to put her foot down and stop a dead end street in its tracks.

  71. coturnix19 says:
    August 25, 2010 at 10:48 am [ … ]
    coturnix19, rather than giving the first opinion that occurs to you, you could try to find out if more CO2 is beneficial to life on Earth:
    click1
    click2
    click3
    click4
    click5 [See “Key Findings” at upper left of page]
    click6 [Disregard the ozone spin. The reason is higher CO2 levels in cities]
    click7
    click8
    Even though you can see that more CO2 is very beneficial for the biosphere, you might be arguing for reasons that have nothing to do with science. I trust not. But if you are, please explain why the actual culprits are not the target of the CO2=CAGW crowd’s ire.

  72. “Scientists think the Earth experienced increased levels of carbon dioxide and a drier environment during the warmer time period”
    How do they get away with assuming that warmer means drier? Warmer means more evaporation from the oceans and more precipitation – it does not make any sense.

  73. Rich Matarese says:
    August 25, 2010 at 2:58 pm
    Could you please explain how so much is teased out of so little and why this is standard operating procedure is acceptable science?
    -Scott


  74. At 2:58 PM on 25 August, Scott asks:
    Could you please explain how so much is teased out of so little and why this is standard operating procedure is acceptable science?
    Hm. Ought to be obvious, but what the hell. Consider what somebody competently versed in human osteology can do with an analogous fragment of bone recovered from a corpse.
    Fossilized remnants are a bit different, but not that much.
    If you know the anatomy of other members of the species in question (and of species related thereunto), it’s possible to assess structural characteristics of the specimen you’ve got an draw reliable inferences about the individual creature from which the fragment came. Developmental changes tend to be pretty consistent, so telling the degree of maturity is readily possible – and that’s particularly true if you can recover specimens of the creature’s dentition.
    This isn’t my field. I’m a country GP, not a forensic pathologist. But if I hand a recognizable fragment of a mandible or maxilla from a pretty well completely composted human corpse to one of those lab guys, I can be reasonably certain that he’s going to be able to tell me quite a bit about what that cadaver had looked like in terms of stature, age, and general nutritional status. I might even expect some good idea of certain diseases from which he/she might have suffered.
    Any contention that the examination of the fossilized remnants upon which the paper presently under discussion is based can reveal much of significance with regard to atmospheric carbon dioxide concentrations prevailing during the life of the animal from which the specimen was derived is, on the face of it, bullpuckey.
    But telling whether that particular animal was larger or smaller at maturity than the normal run among its species in other times or places? Not a problem.

  75. Rich Matarese says:
    August 25, 2010 at 6:25 pm
    True enough assuming one knows what the average mature size/form are, but how do we know here? If it’s truly from 50 million years ago, what’s the uncertainty in the age? I would wager it’s quite large (some would disagree, but beyond the instrumental uncertainty is the uncertainty of the assumptions going into radiometric dating where even a fraction of a percent can mean a huge difference in time). Even if only a few hundred thousand years uncertainty and I’d say that’s enough to derail the whole thing, because even if we knew the average size (and other factors) at 50.000000 million years, there’d be too much uncertainty in the age of this specimen to say for certain how it compares. If I’m to believe we diverged from chimps ~300000 generations ago and we’re quite different from them, I simply can’t believe that any reasonable conclusions can be made on something where the uncertainty on the age might be that large.
    -Scott

  76. Scott
    August 25, 2010 at 5:43 pm
    The study of mammalian teeth is a complete science unto itself. Am incredible amount of information is encapsulated in a tooth. Most mammals are known by their teeth. And it is not just a single tooth, but a tooth placed in context with millions of other teeth, correlated with other skeletal remains, and complete living specimens of creatures that till exist. There is a lot more science here then you will find in many other places. That is because nothing is ever really settled. For example, the move from hypercarnivor to hypocarnivor and back leaves convoluted clues. Different technique yield different results. Palaeomammalogists generally don’t say “This is the way it is”, but rather “This is the way things are looking right now, but this is also a possibility, and this all might change because of the research Dr. Dave is doing.” I can not remember the last time I read a paper that presented only one possible cladogram.
    If you are truly interested, any, and I mean any, text on mammalian palaeontology, will teach you about teeth.
    My guess is that you are not.

  77. @bubbagyro says:
    August 25, 2010 at 4:02 pm
    Cycads and ferns produced the great COAL deposits of the world. Little wee tiny things growing in the ocean produced the material for the OIL and GAS deposits. Amazing isn’t it? We’re told these little wee tiny things are dying off today ‘cuz the CO2 today is so high. So why were they so prolific back, say, 350 million years ago, when CO2 might have been 10x-20x as high? Mysteries abound!

  78. DesertYote says:
    August 25, 2010 at 7:01 pm

    Scott
    August 25, 2010 at 5:43 pm
    [most of your text]

    Again, I don’t doubt this for relatively modern times where a lot is known of current diets, conditions, etc. But when we’re talking about what supposedly happened 50 million years ago how can such certainty be given? I’m not even questioning that the specimen can be determined to be an adult…but how can we know how this specimen compared to the normal at the time when (a) we don’t know the age with that much certainty, and (b) we don’t know the normal specimen for the time.

    If you are truly interested, any, and I mean any, text on mammalian palaeontology, will teach you about teeth.
    My guess is that you are not.

    You’re willingness to openly speculate on motives is interesting.
    -Scott

  79. Australia is currently boasting about the Size of it’s members members. That is, the penis size of it’s politicians – at least that’s what I can gather from all this talk of a hung parliament. 😐


  80. At 6:25 PM on 25 August, Scott writes:
    True enough assuming one knows what the average mature size/form are, but how do we know here? If it’s truly from 50 million years ago, what’s the uncertainty in the age? … Even if only a few hundred thousand years uncertainty and I’d say that’s enough to derail the whole thing, because even if we knew the average size (and other factors) at 50.000000 million years, there’d be too much uncertainty in the age of this specimen to say for certain how it compares. …I simply can’t believe that any reasonable conclusions can be made on something where the uncertainty on the age might be that large.
    Okay, let’s recapitulate the first sentences of the abstract incorporated in this blog post (above):
    Oxyaenid creodonts are extinct carnivorous mammals known from the Paleogene of North America, Europe, and Asia. The genus Palaeonictis is represented by three species that together span the late Paleocene to early Eocene of North America, and at least one species from the early Eocene of Europe.
    Read the rest above. Bear in mind that this particular Palaeonictis wingi (the newly-named species discussed in this paper) was a specimen of an extinct predator order also known as the hyaenadonts, of which I take note because of an interesting article I’d read some years ago which argued that they might have gotten pressured out of their ecological niche by the fissiped predator species (particularly the canidae and felidae) because the hyaenadonts’ peculiar dentition imposed upon them a genetic coding burden that reduced their reproductive fitness relative to those successor predators.
    Now, “Researchers discovered a nearly complete jaw from the animal in Wyoming’s Big Horn Basin in 2006 during a fossil-collecting expedition, led by Bloch, a co-author on the study,” and with that much of a remnant – given what is well-established with regard to the anatomy of the various creodont species – telling how big this particular critter had been could not be much of a problem, no matter what Scott can or “can’t believe.”
    The level of uncertainty ain’t much more here than is the level of uncertainty I’d have in reading Scott‘s own current complete blood count or serum chemistry study’s results. There are a lot of hyaenodont fossil jaws in the bone boxes upon which the paleontologists can and do base their comparative analyses of the specimen they’re now calling P. wingi.
    As for dating the particular specimen to within “a few hundred thousand years’ uncertainty,” some attention has got to be paid to the way paleontologists use sedimentary position (and the stuff found in the same layer as the harvested fossil) to set the temporal context in which the critter had lived.
    Yeah, a lot of stuff has to be inferred. But as in medical diagnosis, the bone hunters pull in information from a lot of sources upon which to predicate their conclusions, matching what they find in one particular specimen – this fragment of jaw, for instance – against what they know from other evidence. It’s very much a practice of aggregating facts that might seem to the uneducated to be disjointed and unreliable.
    Well, hell. A lot of the people who watch House are as the beasts that perish when it comes to the pathological basis of disease and why the protagonist’s seemingly out-of-the-blue differential diagnoses actually make a helluva lot of sense.
    Look, Scott, when you were watching the movie A Few Good men, did you wonder for one goddam minute why Santiago died in that fairly routine blanket party at the outset of the movie?
    I remember shouting: “G6PD deficiency!” at the screen when the pompous Navy medical officer was being examined during the court martial. Simple blood test, and if Santiago was un borincano (as I suspected he might be), there’s plenty of glucose-6-phosphate dehydrogenase deficiency in that population. G6PD deficiency might readily have accounted for Santiago’s presenting symptoms and the way in which he’d died.
    Even a country GP knows that much. That M.O. was professionally remiss in not examining that Marine and securing the diagnostic information that probably would have resulted in a medical discharge. And the lawyers for the defense were negligent in not insisting on a second autopsy. You can bet your butt that a competent forensic pathologist wouldn’t have missed that diagnosis.
    But then the movie wouldn’t have had much point, would it?
    The UPI press release quoted above tries to play the publication of this paper as propaganda promoting the carbon dioxide forcing premise behind the AGW fraud, and that’s about what I expect from ex-Journalism school schmucks. Too stupid and too lazy to take any real science courses in college.

  81. Scott
    August 25, 2010 at 7:27 pm
    “You’re willingness to openly speculate on motives is interesting.”
    Sorry about that, I guess I’m a bit cranky today and I over-reacted to your last sentence.
    50 million years is actually pretty recent and there is a lot of material from that time, the Eocene epoch, enough material to in fact discount much of the paper as related in the press release. For one thing, the Eocene was Warm and Wet, not dry. For another, many animals were adapting to living in the forests that were replacing the savannahs, thus becoming smaller.
    As for the specimen being normal, though it is not unheard of, dwarfism is incredibly rare, so in all probability it is normal. Of course erecting a species on a single specimen, is far from ideal, it is sometimes all that is available. The problem is that a single species in a genus that is represented by only three known species, tell us very little. Not enough to place any confidence in any supposed evolutionary trajectory. At best, this critter is just a very tiny bit in a much, much larger picture. Making any inferences from it is just plain silly.
    I am getting over a flu and am having a nasty head ache, or else I would hunt down an example of a well researched paper that highlights how mammalian palaeontology is done. The author is Xiaoming Wang (no its not a joke name!). Its on the evolution of North American Canines. It is a bit dense, but it is real honest to goodness science. It also has a lot of drawings of teeth 🙂
    Once again, my apologies,
    -DesertYote

  82. Rich Matarese says:
    August 25, 2010 at 7:42 pm
    Your response seems to be a bit aggressive, but maybe I’m reading your tone wrong. It is hard to get the tone from an internet comment.
    What I’m questioning is not “telling how big this particular critter had been”, but relating its size to what it would be in relation to (a) the average at that particular time and (b) what it would be with lower CO2. I’m sorry I did not make that clear. Thanks for bringing up that it was dated by sedimentary position, as that just adds to the uncertainty I was questioning.
    You reference a medical diagnosis, and that analogy is representative of what I’m questioning. When the uncertainty in the age of the specimen is so high, how can so many inferences be made? You say the uncertainty is similar to that of an analysis done on my own blood/serum, but as a person that works with calibrations and uncertainties on a fairly regular basis, there’s just no way that’s possible. The discrepancy in the number of calibration points and the knowledge gained from the sample (DNA etc versus a mineralized body part of unknown age) is immense.
    I don’t watch House and I never saw A Few Good Men either, so that part of your post is lost on me. The only comparison I might understand is the TV show Bones, which I’ve watched a fair amount of. Dr. Brennan obtains a ton of information from the bones of deceased (or even alive) individuals. But the thing is she has an enormous population of known bones (guaranteed to be from the same specie and time) in which to form her calibration curve if you want to call it that. However, I know that quite a bit in that show can be exaggerated, as my area is close enough to Dr. Hodgins’ to know when they’re producing BS in that area and assume they do it in the other areas too.
    As to “real” sciences, I’m not sure I know what you mean there. In my field, that would basically be limited to “hard science” areas like physics or chemistry and not something like paleontology.
    -Scott

  83. DesertYote says:
    August 25, 2010 at 8:41 pm
    Thank you for the nice response. In rereading my post, my last sentence came across totally wrong and I apologize. It should have said something more along the lines of “Making determinations of average species size and its relationship to carbon dioxide in light of the large uncertainties and many assumptions is pretty doubtful.”
    In general, my scepticism of the quality of radiometric dating has me sceptical of any of this, but I did learn from your post, so many thanks.
    I hope you recover from your illness soon,
    -Scott

  84. “Mammals in warmer climates today tend to be smaller than mammals in colder climates, Chester said.”
    I wonder why…? Haven’t read the full article, but I have to wonder if they took into account that body size and body temperature (for mammals) are related. That’s due in large part because the surface/volume ratio changes with size and directly affects a mammal’s ability to maintain its core temperature in response to environmental temperature stress.
    So it looks like heat stress causes animals to adapt by reducing size in order to increase cooling efficiency and in some cases reduce water loss. Who’da thunk it?

  85. Since the average size of humans has significantly increased in the last few hundred years, does that mean that we are entering global cooling and responding with evolutionary change?
    I’m just sayin…

  86. Dillon Allen says:
    “Since the average size of humans has significantly increased in the last few hundred years, does that mean that we are entering global cooling and responding with evolutionary change?”
    That size change is mostly due to two causes:
    1. Better nutrition
    2. Reduced levels of inbreeding
    People in general eat a lot better today than a hundred or two hundred years ago, and consequently grow larger. In the West there isn’t much change now (except sidewise), but in countries like Japan and China the young people are very noticeably taller than their parents.
    Industrialization also cause people to move a lot more than in the past. The parents of a child today are much less likely to be closely related than a few generations ago. Crossing two inbred lines often result in an exceptionally vigorous offspring (that is the concept behind hybrid corn).

  87. Oh dear. I think there has been a misunderstanding. “Only one problem, here’s [the abstract] saying CO2 had nothing to do with it”, you shout gleefully. But the press release accurately reported what the paper said, and neither said that CO2 had “nothing” to do with it.

  88. CO2 and Nutrition
    I have been doing a literature search on CO2 and animals. There have been some recent publications on CO2 and “herbivores”–actually herbivore insects.
    These said the protein component of plants went down. That would be true–the chief protein of the world is surely rubisco, the lead protein of photosynthesis. Plants need a lot of it to make up for the very low concentration (<.04%) of CO2 in today's atmosphere. Raise the CO2 a little, and plants can use the energy for other things, like carbohydrates and vitamin C.
    There is some indication that this is bad for insects but good for us. What an amazing possibility!
    CO2 is a blessing, not a pollutant.

  89. jim hogg says:
    August 25, 2010 at 9:08 am
    When Huxley and Orwell gave form to their dystopian visions they assumed that the future of humanity would be shaped by malevolent intelligence; I read items like this which emanate from our national seats of learning and realise that they never for a moment anticipated the real shaping force: low level immorality and stupidity. How did science get like this?
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    How did science get like this? I’d like to know also.
    To be really unPC….. It probably doesn’t help, at least in developed countries, that apparently far fewer women who get university degree’s have children than those who don’t – and apparently somewhere between 1/5th to 1/4th of all women with advanced degrees never have children. Of course, then we can get into the whole debate about whether a propensity to higher education is really reflective of intelligence levels or not, but anyhow….
    I’m sure that the huge influx into science univ./college programs and graduate programs from folks who were NOT in love with science but trying to avoid the draft didn’t help either – so many of those are now of an age to be in higher level positions throughout academia, not to mention having become professors responsible for the development of students for years and years. I suspect this has had a very large and negative effect on science in general in the USA.
    Then add to it the push for ‘post normal science’ which is, as best I can tell, utterly anathema to the very idea of science – as Orwellian a concept as you can get…. I have no idea how widespread ‘post normal science’ is throughout universities in general, and haven’t had anyone in a better position to know volunteer an answer to that question when I’ve asked it a time or two.
    Heck, the lack of rigor allow, even encouraged by ideas of post normal science makes doing ‘science’ if one is an adherent far far easier than doing real work. Just make everything match what you want to believe anyhow!
    (/sarc)
    Sigh. I wonder also (re how did science get like this). I also seriously wonder how much is really problems with ‘science’ and scientists in general or a change within actual scientific research, vs. how much is just appearances from poorly written articles…. Or if what we are seeing is more a function of one off research projects now being able to get almost instantaneous coverage because our communications are so developed and rapid now, where before they’d’ve died from lack of attention from other scientists due to being of poor quality or been quickly debunked by other researchers, long before poor research or sheer speculative pieces made it to the public eye. I have to say it also has always seemed to me that the softer sciences have been afflicted with problems this way far more than the harder sciences – and while there is a lot of ‘hard’ science involved in archeology and paleontology, there is so much that is totally unknown – and it seems that in those fields researchers have always liked to speculate – and state those speculations as if fact – far far more than I’ve ever been comfortable with. Example, how many “largest dinosaur that ever lived just discovered” bits have come out over the years? It ALWAYS should have been ‘largest found to date’ NOT ‘largest ever.’ Again, I hesitate, however, because I don’t know how much of that is the ‘science writer’ who’s doing the story vs. the actual scientists involved. Some of it the latter, however, as you see from their interviews or quotes.
    Maybe I’m just getting ‘old’ and suffering from the ‘it used to be better than this’ syndrome.

  90. re: Rich Matarese says: August 25, 2010 at 2:58 pm

    A number of comments have run along the line of what kernels had posted at 2:30 PM on 25 August, writing:
    “So a single jawbone provides insights into 200,000 years of evolutionary history?”
    Not really. But that bone fragment can readily provide information on that particular critter – and it’s possible to infer that said critter is a specimen representative of its species – which accurately reflects its stature (size), developmental maturity, nutritional status, and the environment in which it lived and died.
    XXXXXXXXXXXXXXXXXXXXXXXX
    Ah, but does it really? Recent research is now saying that triceratops doesn’t even actually exist as a separate species, that its the immature version of what was thought to be a different dino altogether. Over time, all sorts of anomalies have been found from what was once thought to be ‘known’ based on various bone fragments. I would think the possibility of error based on a single jaw and tooth would likely be quite high. Look at the controversy over the ‘hobbit’ humans and pigmy mammals recently found – all sorts of questions about whether they were dwarfs/midgets, or actually a very small version of similar species – and those were from within the last 15K to 30K years.


  91. At 3:58 PM on 27 August, Rational Debate had written:
    Over time, all sorts of anomalies have been found from what was once thought to be ‘known’ based on various bone fragments. I would think the possibility of error based on a single jaw and tooth would likely be quite high.
    There’s a bit of unintended lucidity. I wasn’t going to bring this up, but I have had to wonder how the authors of this paper establish Palaeonictis wingi as a new species of creodont on the basis of what they’d found in Wyoming in 2006. From the abstract above:
    We describe Palaeonictis wingi sp. nov. from the PETM in the Cabin Fork drainage, southeastern Bighorn Basin, Wyoming, based on associated right and left dentaries with P2-M2. Palaeonictis wingi sp. nov. is substantially smaller than the other North American congeners, making it similar in size to P. gigantea from the earliest Eocene of Europe and the previously described PETM specimen.
    To get the conclusion that P. wingi was a species unto its own, distinct from the other genus Palaeonictis species already identified, I’d think that there would have to be specimens representing more than just one critter.
    But I’m not a paleontologist, and – of course! – Springer Verlag (yet another one of those international academic mega-publishers like Wolters Kluwer and Elsevier) has the full article behind a paywall), so I’m not likely ever going to read it. Have the authors of this paper a real basis for asserting that they’ve got themselves evidence of a distinctly different species of hyaenadont?
    Rational Debate may not understand this, but a specimen comprising “associated right and left dentaries with P2-M2” is more than enough to tell a paleontologist that he’s got a creodont, which was a family of predators with some damned unusual dentition among the mammalia, and it will tell quite reliably whether or not the generating individual animal was physically mature and therefore at the peak of its growth. It’s also possible to reliably infer size, based upon what is known about other creodont species already documented by way of the fossil record, just as can be done with a similar section of “associated right and left dentaries” drawn from a human corpse.
    But is it an entirely new species?
    Those of us who were taught Ernst Mayr’s biological or reproductive species concept in Biology 101 tend to accept the “can’t crossbreed” argument as the acid test, but this can’t be applied in evaluating speciation among extinct critters, where the phylogenetic concept has to obtain.
    It also gives some difficulty when considering offspring generated by matings between representatives of what are commonly accepted to be very different living species. If specimens of Panthera leo and Panthera tigris can mate to produce viable and fertile hybrid offspring, can we really speak of the lion and the tiger as “genuine” species?
    And the day somebody comes up with a way to reliably breed fertile stallion mules (anybody not familiar with Robert A. Heinlein’s novel Time Enough For Love?) and get a majority of mare mules to be fecund, Equus mulus won’t be a half-joke appellation any more.
    So how is it that the authors of this paper can assert that their particular critter (and it looks as if they’ve only got the residue of one critter) is in itself evidence of a whole new species of hyaenadont?
    I think it might be argued that the animal upon which this paper (and its assertions) are focused could well have been a dwarf adult of another Palaeonictis species. Has anybody reading here considered how the authors of this paper in JME addressed the criteria of the International Code of Phylogenetic Nomenclature (PhyloCode) in claiming P. wingi as a new species of creodont?

  92. Re: Rich Matarese says: August 27, 2010 at 8:00 pm

    At 3:58 PM on 27 August, Rational Debate had written:
    “Over time, all sorts of anomalies have been found from what was once thought to be ‘known’ based on various bone fragments. I would think the possibility of error based on a single jaw and tooth would likely be quite high.”
    There’s a bit of unintended lucidity.

    Funny, but I thought it was a bit of intended lucidity myself. 😉

    I wasn’t going to bring this up, but I have had to wonder how the authors of this paper establish Palaeonictis wingi as a new species of creodont on the basis of what they’d found in Wyoming in 2006.

    Yes, as I noted, possibility of error from a single jaw and tooth, of long extinct species/family/critter fairly high – on many counts, including speciation as you note.

    From the abstract above:
    “We describe Palaeonictis wingi sp. nov. from the PETM in the Cabin Fork drainage, southeastern Bighorn Basin, Wyoming, based on associated right and left dentaries with P2-M2. Palaeonictis wingi sp. nov. is substantially smaller than the other North American congeners, making it similar in size to P. gigantea from the earliest Eocene of Europe and the previously described PETM specimen.”
    To get the conclusion that P. wingi was a species unto its own, distinct from the other genus Palaeonictis species already identified, I’d think that there would have to be specimens representing more than just one critter.

    Bingo. Lots of other bingo’s just waiting in this abstract/article also, from the sounds of it, although as you noted, its behind a paywall and I’ll not likely wind up reading the actual paper either, unfortunately. Some of the various issues may well be addressed, there’s just no way to tell without the full paper.
    You went on to write:

    Rational Debate may not understand this, but a specimen comprising “associated right and left dentaries with P2-M2” is more than enough to tell a paleontologist that he’s got a creodont, which was a family of predators with some damned unusual dentition among the mammalia, and it will tell quite reliably whether or not the generating individual animal was physically mature and therefore at the peak of its growth. It’s also possible to reliably infer size, based upon what is known about other creodont species already documented by way of the fossil record, just as can be done with a similar section of “associated right and left dentaries” drawn from a human corpse.

    Frankly I have no real problem with family identification from a jaw this way, that’s plausible. I wasn’t aware of the unusual dentition, but that’s not a big issue in this case beyond lending credibility to the basic identification of the critter. I have no real problem with the idea of identifying the level of maturity either – with some reservations, depending on how many other examples they have of this family, including both immature and mature samples to generate a spectrum. One of the problems with trying to compare the information that can be drawn from human remains, vs. extinct creatures, however, is that with human remains we have all sorts of living examples and recently deceased examples along with all sorts of samples of our environment all of which allow for exquisite comparisons so we can take very small samples and know quite a few things with a good degree of accuracy – this simply isn’t the case with extinct species.
    Look at it this way even… take two living present day human examples such as the basketball star Yao Ming (sp?) as compared to a world class male gymnast, who is likely 5’4″ or less, at full mature height (or any healthy adult male, who’s on the short end of the spectrum). Then extrapolate forward, say a million years, and lets assume that the majority of fossil remains of humans that had been found were of average height men… Now, what is the likely supposition going to be when suddenly Yao Ming’s jaw is discovered? Or what if the outlier happened to be one of those gymnasts? Or what if, because of chance occurrence for where fossils happened to be both created more commonly and happened to be found, if the majority of adult male fossil remains were of dutch and kenyan men, and then a completely healthy, fully mature specimen from a fellow living on a continent (not island) who was all of 5′ tall is found? Is he a ‘new species’ of human? Did his ‘species’ shrink because of too much CO2 (or too little?)?
    Or how about a modern day draft horse (or the no longer existent heavy horse of old that carried knights?), compared to a pony, or a typically small sized horse breed such as the Arabian? Same species, radically different sizes.
    I know these analogies aren’t perfect for the article, but I believe you get my point. Size variations may have nothing to do with anything other than natural variation within the species. Just look around you – the diversity is incredible both within species and between species. Speciation is difficult enough with present day living things, natural/normal size variations can be huge, vegetation, climate, etc., all contribute – the only reason we can tell so much from present day remains is we have ways to actually check the accuracy or faults of our predictions, our assumptions…. that’s quite different from extrapolating and trying to make accurate predictions of exactly what something was like from a limited number of fossil remains, especially when all too often these declarations are built from assumptions being made which are often based on previous assumptions and so on.


  93. At 10:04 PM on 27 August, Rational Debate had written:
    Frankly I have no real problem with family identification from a jaw this way, that’s plausible. I wasn’t aware of the unusual dentition, but that’s not a big issue in this case beyond lending credibility to the basic identification of the critter.
    Er, yeah, it is a “big issue.” Look at it this way. The predator mammal species that largely out-competed the creodonts in their ecological niches are referred to as “fissipedia.” Think canidae and felidae and mustelidae and even hyaenidae. The name emphasizes the fact that their toes are separated, and morphologically we concentrate on their feet. The creodontidae, by contrast, are distinguished principally by virtue of the fact that their carnassials (large teeth designed for shearing soft tissues and bone) are set further back in the jaws than modern-day fissiped predators, whose analogous dentidae are crushing-type molars.
    As I’d written earlier, one online writer had assembled some years ago (the URL is not available to me as I write) a pretty good argument to the effect that genetic coding for the creodonts’ carnassials had to have been much more complicated than what’s required to set up the dentition in the fissiped predators, and this might have been conducive to reduced reproductive fitness in the creodont species.
    They got out-bred by big litters of puppies and kittens and such. The same thing happens among clades of human immunodeficiency virus (HIV) in clinical medicine. The “default” wild-type clades of HIV are always more vulnerable to antiretroviral agents, but the drug-resistance mechanisms make the refractory clades less capable of replication. Such resistance mutations come at a thermodynamic cost. Discontinue the ARV drugs, and the resistant clade will drop down below the threshold of detection in genotypic and phenotypic identification testing, and – voila! – the wild-type bug will predominate again. Not that the resistant clades go away. Re-introduce the drug(s) against which resistance had developed before, and the resistant clade will proliferate explosively.
    But you get the notion of reproductive fitness and how that figures in overall viability, right? The charismatic megafauna are markedly more liable to extinction than are retroviral pathogens. The creodonts went pfft! about eight million years ago, despite having been top-niche predators in their time.
    This notwithstanding, consider that the taxonomic focus on the creodonts is on their teeth despite the fact that they had a lot of other differences from mammals in contemporary parallel lines of development. Any modern zoologist, given a glance at a creodont jaw, would spot the distinguishing characteristics instantly. They’re not subtle.
    Rational Debate had gone on to observe:
    …that with human remains we have all sorts of living examples and recently deceased examples along with all sorts of samples of our environment all of which allow for exquisite comparisons so we can take very small samples and know quite a few things with a good degree of accuracy – this simply isn’t the case with extinct species.
    With the creodonts as a whole, however, that’s not the case. There are fossilized remains for entire animals of (to the best of my knowledge) all of the identified species except for what the authors of this paper claim to be a new species in and of itself, Palaeonictis wingi, and there’s where I’ve got to look with some skepticism and wonder whether these guys have satisfied the rules established by the International Society for Phylogenetic Nomenclature (ISPN) in their determination that these fragments of one critter provide a reliable basis upon which such a decision can be made.
    This isn’t so much a question of error, insofar as I can determine, but rather one of over-reach.
    It is certainly possible for a paleontologist or anybody else with comparative anatomical expertise to do an effective and accurate job of “extrapolating and trying to make accurate predictions of exactly what something was like from a limited number of fossil remains.” What part about this is still not yet grasped? How the hell can a country G.P. get this and people with real intelligence keep screwing up their appreciation of how anatomical inferences are reliably drawn from even fragmentary fossilized hard tissue remnants?
    Look, this is biology, not quantum physics. This is where those of us with fatal math impairments go when we want to play scientist. This is the easy stuff, honest. How hard can it be for people without an undergraduate degree in this discipline to understand?

  94. Rich Matarese says:
    August 27, 2010 at 8:00 pm
    […] And the day somebody comes up with a way to reliably breed fertile stallion mules (anybody not familiar with Robert A. Heinlein’s novel Time Enough For Love?)

    Ah, Buck. What a boon he would have been to the early pioneers.

  95. Without meaning to be impolite, I suspect that part of the problem here may revolve around context and common knowledge. In particular, in any scientific discipline, there exist widely accepted ideas that may not be known or appreciated by those removed from the science. This is clear from some of the commentary in the present case.
    1. The PETM occurred about 55.5 +/- 1.0 million years ago on current time-scales. Although the absolute age has some uncertainty, the relative timing of perturbations before, during and after the interval are known much better. The entire “event”, from start to finish, must have occurred within about 200,000 years; the initiation was probably less than 20,000 years. The onset of the event precisely coincides with the start of the Eocene epoch (in fact, it now defines this point in time).
    — None of this has to do with radiocarbon (because the half-life is far too short);
    — One must be exceedingly careful correlating “happenings” in time because of a “floating” absolute time-scale (for example, something reported as occurring 57 million years ago in 1990 is now reported as 55.5 million years ago in 2010);
    — The PETM predates the warmest time of the Cenozoic, which is called the Early Eocene Climatic Optimum, and occurred ca. 53-51 million years ago (again, on the most current time scales).
    2. There is overwhelming evidence that the PETM was characterized by a significant rise in mean annual Earth surface temperature (about 10-11 °F), a massive input of carbon to the ocean and atmosphere, and profound environmental and biotic changes across the globe. The magnitude of the total carbon addition across the event remains fairly uncertain (from about 2500 Gt to >6500 Gt), as does the rise in atmospheric pCO2. Nonetheless, it is virtually certain that atmospheric CO2 did rise by a large amount (>400 ppmv). Moreover, it is certain that the carbon input was highly depleted in 13-C, implying that it derived from oxidation of an organic source (such as methane or peat). The environmental changes included a major turnover in mammalian orders as well as mammalian dwarfish (as an aside, this is why there is a Paleocene-Eocene Boundary). There was nothing else like the PETM in terms of rate and magnitude of temperature rise and carbon addition, at least in the last 90 million years.
    — There indeed have been many variations in Earth’s climate and the environment; however, the PETM is an extreme and special case;
    — It has become a magnet for scientific investigations because of its general characteristics (extreme global warming, massive CO2 input from oxidized organic carbon at a magnitude similar to that projected for the coming centuries, pronounced environmental change);
    — Because huge amounts of 13-C rich carbon entered the ocean and atmosphere, the event can be readily located in different environments and correlated.
    So, with this context, one might consider the abstract and the authors in a somewhat different light. The authors are interested in seeing what happens to mammals when temperature and atmospheric pCO2 increase significantly. This is because there is a great deal of speculation as to how Earth operates with massive inputs of CO2, extreme warming, or both. They selected the PETM because it is the obvious time interval in which to examine the hypothesis. They chose the location because there have been numerous previous studies here, which means they have an extensive database in which to compare their mammal fossil findings. In particular, they already knew that jaw bone size relates to body size, and that dwarfism occurred in several herbivore mammal lineages across the PETM. An apparent existing suggestion in the literature was that this established dwarfism was caused by the known rise in atmospheric pCO2. The present authors’ idea was that, if correct, carnivores would not become smaller across the PETM. They found that, interestingly and for the first time, carnivores also became smaller across the PETM.
    I’m guessing that this is a more accurate take on the issue than that deduced in many of the previous comments. Of course, this would mean that there was no purposed spin to the articles, and that much of the commentary on this issue has arisen because of pre-conceived ideas – basically jumping to conclusions without the appropriate common knowledge.
    I have my own problems with the framework of the manuscript. These arise because other environmental parameters clearly changed across the PETM. Of particular importance to the present discussion is precipitation. There is growing evidence that the hydrological cycle became more intense and more seasonal during the PETM (that is, greater amounts of annual rain but over a shorter duration of the year, which should explain the confusion in some of the comments regarding wet and dry). Almost assuredly, this would impact the type and abundance of plants. So, how would one disentangle what parameter caused the dwarfism of herbivore mammals?

  96. Reply to kyzul (August 29, 2010 at 1:46 pm)
    The use of the word “dwarfism” implies an undesirable size compared to “normal” size. The straw-man assumption that small is undesirable leads to incorrect conclusions about whether or not increased temperatures and CO2 are harmful.
    Small may be undesirable (and may imply a bad environment) for an individual that is smaller than its peers, but the same does NOT apply for an entire species on an evolutionary time-scale. Confusing the two (an individual symptom vs species evolution) is typical of pseudosciences such as Lysenkoism.

  97. Reply to Candae:
    The use of “dwarfism” in the article as well as in my comment implied nothing about desirability. It is simply an observation from examination of rock sequences. When one examines strata spanning the PETM, the size of jaw-bones and teeth representing numerous specimens of different mammal species becomes smaller (and larger after the event by the way). By inference using well-established relationships between jawbones, teeth and body size, this indicates that the average body size of specimens representing multiple mammal species became smaller. We also know that the time when this occurred was when climate changed profoundly. These are verifiable observations and testable inferences. I will definitely agree that the pseudoscience begins when one tries to spin the objective observations into some subjective context.

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