Though I personally like the "hydrostatic equilibrium" phrase for defining a planet (which would leave the Sun with dozens if not hundreds of planets), it's not part of the definition. In practice, the "clear the neighbourhood" definition almost requires that the object is large enough to have been classically considered a planet. The edge cases are 1 Ceres and 4 Vesta - nearly spherical asteroids (whereas 2 Pallas, smaller than 4 Vesta, is considerably less spherical) but nowhere near having "cleared their neighbourhoods".
Because it is not a star itself (it isn't in thermal equilibrium between interior fusion and external heat loss), it is in orbit around a star, and there is nothing in it's orbit which could possibly eject it from the orbit around it's star (it is, in the words of the infamous "Pluto Killer" definition, it has gravitationally cleared it's orbit).
Where can I see one of these vehicle-sized reactors?
What's that Lassie? They don't exist except as vapourware? Gosh, I'm so surprised that I'm going to fall backwards into this Old Mine Shaffffffftttttttttt...
Not as far as I know. Since the introduction of streaming music services - what was it, 15 years ago? - I've changed the amount of music I listen to online from 0 hours per year to 0 hours per year. I've also changed the amount of locally-hosted music I listen to from about 5 hours per year to 2-3 hours per year.
If the music industry wants to increase the profitability of online services, then they need to increase their user base. That's probably going to mean producing music or other sounds that people want to listen to, which is something they haven't done for a generation now.
VR porn where you are the girl as the poster requested...
That sounds kinky,
Let me guess : you're a guy, and you've never acknowledged the "feminine side of your nature".
I'm a guy, who knows by experience that I prefer poking women to poking men, and I don't get anything from "anal play" myself. I find the idea of "be the girl VR porn" interesting. For one thing, it'll completely change the extremely stereotyped mainstream porn industry. It might actually open a whole new market of porn for women which actually involves women enjoying themselves. Ground-breaking potential indeed.
While I think the OP was speaking shite, this point is fair. Venus is probably much more easily terraformable than Mars. And if you don't feel the need to terraform, but simply to make lebensraum in whatever form is most suitable for a particular planet, then it is much more achievable.
Building airships is a known technology. Biotechnology could, relatively easily, mine the CO2 atmosphere of Venus for carbon compounds for structural materials (carbon fibre plus the necessary epoxy (or other) resins to bind the carbon fibre - most commentators forget that utterly essential component). How to support the biotech - using gas bags and pans, or making composites like Portuguese Men o' War which can support themselves in the atmosphere - is an open question. If you want land, then you'll need to dump most of the atmosphere onto the ground - another task for biotech that excretes thermally stable carbon compounds which will precipitate out to ground level. you may need to add water - gigatonnes - which would be better added at the start of the project rather than the end, because the delivery process would be quite disturbing to floating infrastructure.
No need for Unobtanium.
By contrast, all terraforming proposals I've seen for Mars ignore the need to add water, and then continually add more water to keep the atmosphere habitable.
Long term habitation (gigayear plus) of Venus would require some attention to the brightening sun, but that's easily doable if you're already committed to the massive engineering of terraforming.
Is to possible to manually decide when the vehicle changes speed, like on a manual gearbox?
Well, normally I change speed using the accelerator (errr, "gas pedal") and brake - I suspect you mean changing gear selection, rather than changing speed.
As long as the vehicle has actual gears (i.e.: a car with an internal combustion engine) the car will have, in addition to the fully automatic mode ("D" on the gear shift) also have a "sequential gearbox"-mode ("+" and "-" on the gear shift).
'D' for drive ; 'P' for park ; '1' for ultra-low speed (pedestrian-designated areas), '2' for low speed (traffic jams), and 'R' for reversing, as I recall. I don't recall ever seeing a "+" or "-" on the mode selector. And it's little more than a year since the last time I was in an automatic (though not driving). Oh, hang on, I'm not sure if that was an IC engine or an electric - I didn't have any reason to ask.
Depending on the model, you either tap the stick side ways, or you move the stick to a different position (sometimes called "M") and tap up and down.
No, I don't recall seeing that sort of motion as a possibility. You've got to press a button on the side of the mode selector before you can change modes - "tapping" it anywhere is prevented by an interlock in the selector. I remember having to figure that out first time I found myself with the keys to an automatic. (Also, the mode selector is where a normal gear selector is - not on the steering column, as I see in the movies.
Depending on your driving style, that might come handy when driving in the mountain.
Precisely. In towns as well - there's no shortage of -in-4 and 1-in-5 hills in many towns too. The machines don't seem to know when to drop down a gear in order to increase engine revs and power. Totally gutless response in consequence. Which may be why automatics have such a poor reputation over here.
We do the joke about the tourist doing a weeks driving in first gear too.
if the car companies hadn't killed the spare tire.
What? Killed is a bit strong - it's probably less than 1/3 of cars that are supplied with a "space saver" or "inflation pack" alternative to a spare tyre. Which is hardly "killed".
Though, to be honest, I do choose a vehicle with a full-size spare wheel and tyre over one with a "space saver" or alternative. Even when hiring vehicles.
I wonder if vehicles supplied with "space savers" can actually accommodate a full-size spare. I'll ask, next time the question comes up. Because AFAICS, a "space saver" only really saves on breadth of the tyre/wheel combo.
I take it that you never learned to parallel park? Tough shit on you - it's been a compulsory part of the driving test here for around a decade, which was in turn about a decade after I taught myself how to do it. It's not as if it's a difficult skill.
If your motor skills and spatial comprehension are so poor that you really can't parallel park, then you really should be asking yourself if you're safe to drive at all.
If you can't drive a stick shift, the odds are good you are a 'non-driver'.
As someone who was taught to drive with a manual gearbox and passed my test with one, I'm also licensed to drive an automatic, though they're so rare over here that I' think I've only done it 4 or 5 times in nearly 30 years. However, if I'd passed my test in an automatic, I wouldn't be licensed to drive a manual vehicle. So basically, the UK's DVLA agrees with you.
Knowing very little about automatics, could you answer a question? Is it possible to drive an automatic like a manual gearbox? I know that, with practice and care, you can drive a manual gearbox with a broken clutch (though starting and stopping is a real bitch) ; is it possible to do something similar with an automatic.
At that time the dinosaur-bird link was a hugely controversial theory.
When was Jurassic Pork? (I've still not seen it) 1993.
The birds are dinosaurs theory was first put forward in any detail in the 1890s (about the time Archaeopteryx #3 was found) and by the 1950s there were about 7 Archaeopteryxes in the record and no other serious contenders for the origin of the birds on the table. By the 1960s, the outstanding questions such as the homologies between the bird "hand" and the stereotypical vertebrate pentadactyl manus had been solved by combinations of gold pellets and dyes injected into developing chick embryos, so the remaining uncertainties about the birds being dinosaurs were dug up, decapitated, mouth stuffed with garlic, put back into the coffin with Holy Water and finally a stake driven through the heart. Just to make sure that the dead uncertainties were really dead. (This doesn't stop the Creationist cretins trying to resurrect them.)
Come the 1970s and people were actually identifying the genes and signaling chemicals at work, controlling the development of chicks into chicks (instead of more stereotypical vertebrates). (Chicks are great to work on - reliable, cheap, and you can cut the shell away to watch the fuckers grow. Try doing that with a human embryo and someone is bound to complain.) Still no doubt about the fact that birds are dinosaurs, but just for safety's sake the vamipre of uncertainty was dug up, chopped up, stuffed with garlic, another stake and a winchester of Papally-blessed dihydrogen monoxide. Still a dead idea. So the Creationists dug it up again the next day and tried to wave it around.
Well, you can see where this is going. Every few years, science would find out something more that re-confirmed the "birds are dinosaurs" theory. Often this would be as a side effect of using those really useful chick developmental models to do things like studying drugs that can affect the growth of bones and nerves and muscles. And more and more wooden stakes and triply-resublimated Papally blessed holy water and all sorts of odouriferous relatives of the onion would get hammered into the tattered corpse of "the controversy of whether birds are dinosaurs"... and still the fucking Creationists would drag the corpse of the controversy out of the ground and wave it around as if it were a threat to anything.
Is that the controversy you were talking about being live in 1993?
Much though I like the idea of this increasingly dead controversy getting another battering, can we move on? It is an ex-controversy. It has ceased to be. It has shuffled of this mortal coil, gone to join the Choir Immortal (of controversies). It has ceased to be a controversy. Except among the fucking Creationists.
We still cannot agree on whether dinosaurs were cold or hot blooded (the birds threw a spanner in the wrench too)
For theropod dinosaurs (birds included), the bone histology is reckoned pretty conclusively to indicate hot-blooded. [Also, in at least one T. rex specimen, they've found bone with a distinctive structure and location homologous to the bone that chickens build up then re-absorb to store/ release/ buffer calcium minerals for eggshell production.] For the rest of the dinosaurs, I think there is still room for uncertainty. However, by the time that anything weighs several tonnes, the basal metabolism of that flesh (ably assisted by the square-cube relation between volume and surface area) means that they are effectively isothermic (constant body temperature) regardless of whether they are endothermic (generate heat internally for homeostasis ; "hot blooded") or ectothermic (get heat from the environment for homeostasis ; "cold blooded").
Intermediate-sized dinosaurs are where it gets sticky. Which is why the paper published a couple of months ago about a titanosaur chick was so intere
Well, I'm getting good confirmation of my understanding - which you share to some degree - that there was a hange in grass abundance in the not-too-distant past. From http://www.ucmp.berkeley.edu/t...
The Miocene Epoch, 23.03 to 5.3 million years ago,* was a time of warmer global climates than those in the preceeding Oligocene or the following Pliocene and it's notable in that two major ecosystems made their first appearances: kelp forests and grasslands. The expansion of grasslands is correlated to a drying of continental interiors as the global climate first warmed and then cooled.
That's just a bit confusing - is it a "first appearance" of grasslands, an "expansion of grasslands, or possibly an appearance followed by an expansion. Also note that they're careful to talk of the ecosystem "grassland" rather than specific grass species.
A book on palaeopedology (the science of studying ancient soil deposits ; do I need to point out that changing from (say) open forest to grassland will affect soil structure in ways that will be detectable?) talks on the changes in spore abundance, with diagrams. See particularly fig 20.3 on p.303.
The rapid ecological expansion of grasses with C4 photosynthesis at the end of the Neogene (8-2 Ma) is well documented in the fossil record of stable carbon isotopes. As one of the most profound vegetation changes to occur in recent geologic time, it paved the way for modern tropical grassland ecosystems.
This was a major change. There was discussion a couple of years ago about using genetic engineering to copy the C4 carbon fixation path from grasses into other crop plants for IIRC a 20% improvement in efficiency. Worth considering, but a lot of work, and not popular with the Greens.
... this broadly synchronous change, long after the evolutionary origin of the C4 pathway in grasses. To date, these hypotheses have suffered from a lack of direct evidence for floral composition and structure during this important transition.
And the paper I'm quoting then provides evidence of the change. The paper is open access, so you cn sweat it as much as you like, but the clearest indicator of change I can see is a decline in tree cover in their study area through the time interval - fig 4-A
The increase in abundance of grasslands in the Miocene is well established, even if the actual families of grasses evolved much earlier. Which does rather raise the question of why it took so long between evolution of the grasses and the development and increase of the grassland ecoystems of the world. That's a good question.
I'm not sure about the FA (first appearance) of grasses - or phytoliths which would certainly show up more regularly in microfossil samples than recognisable "grass" fossils. However grasses did undergo a considerable differentiation and spread around the Early Miocene, and the change in vegetation led to a change in animal populations. The diversification of horses (before their more recent catastrophic decline) paralelled the spread of grasses.
Prior to 2005, fossil findings indicated that grasses evolved around 55 million years ago. Recent findings of grass-like phytoliths in Cretaceous dinosaur coprolites have pushed this date back to 66 million years ago.[1][9] In 2011, revised dating of the origins of the rice tribe Oryzeae suggested a date as early as 107 to 129 Mya.
Hmmm, that's news to me.
On the other hand, first appearances (FA) are not the same as acmes (peak occurrence of the taxon in question) or indeed last appearances. So a FA for grasses as far back as the Mid-Cretaceous - Early Cretaceous even - remains compatible with a large expansion of the grasses (or of grassland - I'd forgotten that bamboos were grasses) in the mid-Tertiary.
I have never noticed if ACs can be moderated. I'll look next time I have points to dispense.
Though on general principles, I probably wouldn't moderate an AC. What would be the point?
We have so few body fossils from early mammals that it is very had to tell when the modern groups evolved. Most of the dates you've given are based on molecular clocks, which are probably right in sequence of splits, but unless you an pin some of the branching points with fossil evidence, thee absolute ages are much more suspect.
A seriously high proportion of mammal fossils are isolated teeth, or short sections of mandible/ dentary, because the teeth are both hard and tough. Unfortunately, while teeth tell you lots about diet, they don't tell you much about reproductive biology.
Oxygen levels have certainly varied. Unfortunately for your thesis, both dinosaurs and mammals evolved in a relatively low oxygen period (along with the rest of the radiation of the "reptiles" from the amphibians, pelycosaurs and "mammal like reptiles" - this is another evolutionary radiation the details of which are simply not clear from the fossil record) ; both existed through a gradual rise in oxygen levels until a peak in the Early Cretaceous, then through a decline in the Middle and Late Cretaceous. And their relative diversities didn't change in a concerted manner through that (as best we can tell through the filter of the fossil record).
In short, modest changes in oxygen levels (between about 12 and 25% v/v) do not correlate with changes in populations of animals. Since the Carboniferous, the atmospheric oxygen level hasn't gone outside that range.
The old debate about "decimate" is boring. Yes, it's meaning has drifted from its original. These things happen.
The author is not a very good writer. I believe the word he was looking for is annihilated.
What English actually lacks is a word which unambiguously means "a very large but not complete loss." "Annihilate" does not work because it means "to kill every last one of [group]". In this context : "at the K-Pg boundary event, the ichthyosaurs were annihilated, but a mere 90% of mammals and dinosaurs were killed off".
That's the popular meaning of "decimate", but because "decimate" does have this original other meaning of a "large but not crippling loss" it's not a word I'd use, because of the ambiguity.
It's a definite lack, and it comes up every time extinction events get discussed. How does "nonimate" sound - for killing 9 in 10 of [group].
"Hecatomb" - "a hundred oxen" for a very large sacrifice is in the right direction meaning-wise, but I still don't find it satisfying.
Does anyone have an appropriate word in their native tongues? After having at least one 30% death event in their history, I wouldn't be surprised if Icelandic had a suitable word. And I like "jokullhlaup," and work it into the conversation at every possible opportunity. Rei can have his rant about Unicode now - there should be at least one umlaut in "jokulhlaup."
There is a ha-ha-but-serious joke that you could fit the entire first hundred million years of the mammal's fossil record into a shoe box - and they'd almost all be teeth. That's probably not been true or a couple of decades now. You'd probably need a fairly large rucksack. But the collection is still overwhelmingly teeth.
And then, as plantlife recovered, there were these massive ecosystem niches ready to be taken advantage off - and no big creatures in the way,
... apart from the birds. There were birds around in very much the same size range as the mammals, and they too underwent a major evolutionary radiation in the early Palaeogene. If you came back 2 million years after the KPg boundary event, you'd have been hard put to decide if the most successful group were the birds or the mammals.
If you count species today, it is still a toss-up : there are about 11000 bird species to a mere 7000 odd mammals. If you count biomass, then the individual mass of humans, pigs, sheep and cattle considerably outweighs chickens and the wild birds.
Keep in mind also that plants themselves were different. Shrubs and ferns mostly. Large landcoverers didnt exist. Hell grass only evolved about 15 to 20 million years ago
The angiosperms evolved in the latest Jurassic or early Cretaceous (they live on land ; this is not good for being fossiised). You're more likely to know "angiosperms" as the "flowering plants" - the group includes the grasses, which have very small and boring flowers.
Most things you'd call a "shrub" are also angiosperms. Perhaps you mean "cycads", not "shrubs"?
The Komodo Dragon is a varanid (a.k.a. monitor) lizard, a squamate. It is classified in with the American Gila monster, the British "Slow Worm" and any chameleon you are to mention. Net closest group is any snake you care to mention (the "Slow Worm" is not a snake).
The precise relations of the squamates + tuataras, turtles, pterosaurs (Pterodactylus is a genus, not a higher-level group), mosasaurs, ichthyosaurs and pleisosaurs to the clade of birds + crocodilians are still a matter of disagreement. Since we've only got fossil evidence for a number of those groups.
As for relevance, a global flood would be another form of extinction event.
There's no shortage of work been done on the sedimentology and taphonomy of flood deposits. They can be locally important.
Global flood - hasn't happened since the last time the oceans got boiled down by a major asteroid impact. The was probably 4 billion plus years ago, and even then there probably were deepest ocean basins that didn't lose all their water, and small (a few percent, maybe) of land underlain by SIAL-ic (low density) crust by that point. There had to have been to give the isotope compositions in some of the overgrowth layers in the Jack Hills zircons.
Sorry - bringing evidence to a theological gum-flapping exercise. Next thing you know, I'll be shitting on the carpet and propositioning the vicar's daughter.
Slashdot Mirror
Though I personally like the "hydrostatic equilibrium" phrase for defining a planet (which would leave the Sun with dozens if not hundreds of planets), it's not part of the definition. In practice, the "clear the neighbourhood" definition almost requires that the object is large enough to have been classically considered a planet. The edge cases are 1 Ceres and 4 Vesta - nearly spherical asteroids (whereas 2 Pallas, smaller than 4 Vesta, is considerably less spherical) but nowhere near having "cleared their neighbourhoods".
You asked a question and you got an answer.
Did they notice the previous seven missions?
What's that Lassie? They don't exist except as vapourware? Gosh, I'm so surprised that I'm going to fall backwards into this Old Mine Shaffffffftttttttttt ...
If the music industry wants to increase the profitability of online services, then they need to increase their user base. That's probably going to mean producing music or other sounds that people want to listen to, which is something they haven't done for a generation now.
Let me guess : you're a guy, and you've never acknowledged the "feminine side of your nature".
I'm a guy, who knows by experience that I prefer poking women to poking men, and I don't get anything from "anal play" myself. I find the idea of "be the girl VR porn" interesting. For one thing, it'll completely change the extremely stereotyped mainstream porn industry. It might actually open a whole new market of porn for women which actually involves women enjoying themselves. Ground-breaking potential indeed.
Building airships is a known technology. Biotechnology could, relatively easily, mine the CO2 atmosphere of Venus for carbon compounds for structural materials (carbon fibre plus the necessary epoxy (or other) resins to bind the carbon fibre - most commentators forget that utterly essential component). How to support the biotech - using gas bags and pans, or making composites like Portuguese Men o' War which can support themselves in the atmosphere - is an open question. If you want land, then you'll need to dump most of the atmosphere onto the ground - another task for biotech that excretes thermally stable carbon compounds which will precipitate out to ground level. you may need to add water - gigatonnes - which would be better added at the start of the project rather than the end, because the delivery process would be quite disturbing to floating infrastructure.
No need for Unobtanium.
By contrast, all terraforming proposals I've seen for Mars ignore the need to add water, and then continually add more water to keep the atmosphere habitable.
Long term habitation (gigayear plus) of Venus would require some attention to the brightening sun, but that's easily doable if you're already committed to the massive engineering of terraforming.
Well, normally I change speed using the accelerator (errr, "gas pedal") and brake - I suspect you mean changing gear selection, rather than changing speed.
'D' for drive ; 'P' for park ; '1' for ultra-low speed (pedestrian-designated areas), '2' for low speed (traffic jams), and 'R' for reversing, as I recall. I don't recall ever seeing a "+" or "-" on the mode selector. And it's little more than a year since the last time I was in an automatic (though not driving). Oh, hang on, I'm not sure if that was an IC engine or an electric - I didn't have any reason to ask.
No, I don't recall seeing that sort of motion as a possibility. You've got to press a button on the side of the mode selector before you can change modes - "tapping" it anywhere is prevented by an interlock in the selector. I remember having to figure that out first time I found myself with the keys to an automatic. (Also, the mode selector is where a normal gear selector is - not on the steering column, as I see in the movies.
Precisely. In towns as well - there's no shortage of -in-4 and 1-in-5 hills in many towns too. The machines don't seem to know when to drop down a gear in order to increase engine revs and power. Totally gutless response in consequence. Which may be why automatics have such a poor reputation over here.
We do the joke about the tourist doing a weeks driving in first gear too.
What is worthwhile about any effort to be "cool"?
Amazon - the thrusting company for Millennials who want to work for 1950s ideas. Their (Amazon, not Belgium's) death must be nigh.
What? Killed is a bit strong - it's probably less than 1/3 of cars that are supplied with a "space saver" or "inflation pack" alternative to a spare tyre. Which is hardly "killed".
Though, to be honest, I do choose a vehicle with a full-size spare wheel and tyre over one with a "space saver" or alternative. Even when hiring vehicles.
I wonder if vehicles supplied with "space savers" can actually accommodate a full-size spare. I'll ask, next time the question comes up. Because AFAICS, a "space saver" only really saves on breadth of the tyre/wheel combo.
If your motor skills and spatial comprehension are so poor that you really can't parallel park, then you really should be asking yourself if you're safe to drive at all.
As someone who was taught to drive with a manual gearbox and passed my test with one, I'm also licensed to drive an automatic, though they're so rare over here that I' think I've only done it 4 or 5 times in nearly 30 years. However, if I'd passed my test in an automatic, I wouldn't be licensed to drive a manual vehicle. So basically, the UK's DVLA agrees with you.
Knowing very little about automatics, could you answer a question? Is it possible to drive an automatic like a manual gearbox? I know that, with practice and care, you can drive a manual gearbox with a broken clutch (though starting and stopping is a real bitch) ; is it possible to do something similar with an automatic.
You don't know some of the vicars daughter's I know. Two girls, one cup.
When was Jurassic Pork? (I've still not seen it) 1993.
The birds are dinosaurs theory was first put forward in any detail in the 1890s (about the time Archaeopteryx #3 was found) and by the 1950s there were about 7 Archaeopteryxes in the record and no other serious contenders for the origin of the birds on the table. By the 1960s, the outstanding questions such as the homologies between the bird "hand" and the stereotypical vertebrate pentadactyl manus had been solved by combinations of gold pellets and dyes injected into developing chick embryos, so the remaining uncertainties about the birds being dinosaurs were dug up, decapitated, mouth stuffed with garlic, put back into the coffin with Holy Water and finally a stake driven through the heart. Just to make sure that the dead uncertainties were really dead. (This doesn't stop the Creationist cretins trying to resurrect them.)
Come the 1970s and people were actually identifying the genes and signaling chemicals at work, controlling the development of chicks into chicks (instead of more stereotypical vertebrates). (Chicks are great to work on - reliable, cheap, and you can cut the shell away to watch the fuckers grow. Try doing that with a human embryo and someone is bound to complain.) Still no doubt about the fact that birds are dinosaurs, but just for safety's sake the vamipre of uncertainty was dug up, chopped up, stuffed with garlic, another stake and a winchester of Papally-blessed dihydrogen monoxide. Still a dead idea. So the Creationists dug it up again the next day and tried to wave it around.
Well, you can see where this is going. Every few years, science would find out something more that re-confirmed the "birds are dinosaurs" theory. Often this would be as a side effect of using those really useful chick developmental models to do things like studying drugs that can affect the growth of bones and nerves and muscles. And more and more wooden stakes and triply-resublimated Papally blessed holy water and all sorts of odouriferous relatives of the onion would get hammered into the tattered corpse of "the controversy of whether birds are dinosaurs" ... and still the fucking Creationists would drag the corpse of the controversy out of the ground and wave it around as if it were a threat to anything.
Is that the controversy you were talking about being live in 1993?
Much though I like the idea of this increasingly dead controversy getting another battering, can we move on? It is an ex-controversy. It has ceased to be. It has shuffled of this mortal coil, gone to join the Choir Immortal (of controversies). It has ceased to be a controversy. Except among the fucking Creationists.
For theropod dinosaurs (birds included), the bone histology is reckoned pretty conclusively to indicate hot-blooded. [Also, in at least one T. rex specimen, they've found bone with a distinctive structure and location homologous to the bone that chickens build up then re-absorb to store/ release/ buffer calcium minerals for eggshell production.] For the rest of the dinosaurs, I think there is still room for uncertainty. However, by the time that anything weighs several tonnes, the basal metabolism of that flesh (ably assisted by the square-cube relation between volume and surface area) means that they are effectively isothermic (constant body temperature) regardless of whether they are endothermic (generate heat internally for homeostasis ; "hot blooded") or ectothermic (get heat from the environment for homeostasis ; "cold blooded").
Intermediate-sized dinosaurs are where it gets sticky. Which is why the paper published a couple of months ago about a titanosaur chick was so intere
That's just a bit confusing - is it a "first appearance" of grasslands, an "expansion of grasslands, or possibly an appearance followed by an expansion. Also note that they're careful to talk of the ecosystem "grassland" rather than specific grass species.
A book on palaeopedology (the science of studying ancient soil deposits ; do I need to point out that changing from (say) open forest to grassland will affect soil structure in ways that will be detectable?) talks on the changes in spore abundance, with diagrams. See particularly fig 20.3 on p.303.
Ah, I'd forgotten about that. C3 versus C4 plants. The Neogene transition from C3 to C4 grasslands in North America: assemblage analysis of fossil phytoliths I'd forgotten bout the C3-C4 transition. (I'm not a plants or fossils person - more high grade metamorphics for me. Plus shit-bagging for pay.)
This was a major change. There was discussion a couple of years ago about using genetic engineering to copy the C4 carbon fixation path from grasses into other crop plants for IIRC a 20% improvement in efficiency. Worth considering, but a lot of work, and not popular with the Greens.
And the paper I'm quoting then provides evidence of the change. The paper is open access, so you cn sweat it as much as you like, but the clearest indicator of change I can see is a decline in tree cover in their study area through the time interval - fig 4-A
The increase in abundance of grasslands in the Miocene is well established, even if the actual families of grasses evolved much earlier. Which does rather raise the question of why it took so long between evolution of the grasses and the development and increase of the grassland ecoystems of the world. That's a good question.
Hmmm, that's news to me.
On the other hand, first appearances (FA) are not the same as acmes (peak occurrence of the taxon in question) or indeed last appearances. So a FA for grasses as far back as the Mid-Cretaceous - Early Cretaceous even - remains compatible with a large expansion of the grasses (or of grassland - I'd forgotten that bamboos were grasses) in the mid-Tertiary.
I'll have to do some more research on this.
I have never noticed if ACs can be moderated. I'll look next time I have points to dispense. Though on general principles, I probably wouldn't moderate an AC. What would be the point?
A seriously high proportion of mammal fossils are isolated teeth, or short sections of mandible/ dentary, because the teeth are both hard and tough. Unfortunately, while teeth tell you lots about diet, they don't tell you much about reproductive biology.
People are looking for more fossils.
In short, modest changes in oxygen levels (between about 12 and 25% v/v) do not correlate with changes in populations of animals. Since the Carboniferous, the atmospheric oxygen level hasn't gone outside that range.
What English actually lacks is a word which unambiguously means "a very large but not complete loss." "Annihilate" does not work because it means "to kill every last one of [group]". In this context : "at the K-Pg boundary event, the ichthyosaurs were annihilated, but a mere 90% of mammals and dinosaurs were killed off".
That's the popular meaning of "decimate", but because "decimate" does have this original other meaning of a "large but not crippling loss" it's not a word I'd use, because of the ambiguity.
It's a definite lack, and it comes up every time extinction events get discussed. How does "nonimate" sound - for killing 9 in 10 of [group].
"Hecatomb" - "a hundred oxen" for a very large sacrifice is in the right direction meaning-wise, but I still don't find it satisfying.
Does anyone have an appropriate word in their native tongues? After having at least one 30% death event in their history, I wouldn't be surprised if Icelandic had a suitable word. And I like "jokullhlaup," and work it into the conversation at every possible opportunity. Rei can have his rant about Unicode now - there should be at least one umlaut in "jokulhlaup."
... apart from the birds. There were birds around in very much the same size range as the mammals, and they too underwent a major evolutionary radiation in the early Palaeogene. If you came back 2 million years after the KPg boundary event, you'd have been hard put to decide if the most successful group were the birds or the mammals.
If you count species today, it is still a toss-up : there are about 11000 bird species to a mere 7000 odd mammals. If you count biomass, then the individual mass of humans, pigs, sheep and cattle considerably outweighs chickens and the wild birds.
The angiosperms evolved in the latest Jurassic or early Cretaceous (they live on land ; this is not good for being fossiised). You're more likely to know "angiosperms" as the "flowering plants" - the group includes the grasses, which have very small and boring flowers.
Most things you'd call a "shrub" are also angiosperms. Perhaps you mean "cycads", not "shrubs"?
The Komodo Dragon is a varanid (a.k.a. monitor) lizard, a squamate. It is classified in with the American Gila monster, the British "Slow Worm" and any chameleon you are to mention. Net closest group is any snake you care to mention (the "Slow Worm" is not a snake).
The precise relations of the squamates + tuataras, turtles, pterosaurs (Pterodactylus is a genus, not a higher-level group), mosasaurs, ichthyosaurs and pleisosaurs to the clade of birds + crocodilians are still a matter of disagreement. Since we've only got fossil evidence for a number of those groups.
There's no shortage of work been done on the sedimentology and taphonomy of flood deposits. They can be locally important.
Global flood - hasn't happened since the last time the oceans got boiled down by a major asteroid impact. The was probably 4 billion plus years ago, and even then there probably were deepest ocean basins that didn't lose all their water, and small (a few percent, maybe) of land underlain by SIAL-ic (low density) crust by that point. There had to have been to give the isotope compositions in some of the overgrowth layers in the Jack Hills zircons.
Sorry - bringing evidence to a theological gum-flapping exercise. Next thing you know, I'll be shitting on the carpet and propositioning the vicar's daughter.