Put this video on full screen and sit back and savor the under-appreciated weirdness found in our oceans.
(If I had to guess, it looks like a deep sea jellyfish to me.)
No, dinosaurs did not fart themselves to death. This is what happens when you get your information from Fox News.
Dinosaurs may have farted themselves to extinction, according to a new study from British scientists.
The researchers calculated that the prehistoric beasts pumped out more than 520 million tons (472 million tonnes) of methane a year — enough to warm the planet and hasten their own eventual demise.
Until now, an asteroid strike and volcanic activity around 65 million years ago had seemed the most likely cause of their extinction.
So I read the paper. The researchers didn’t say that at all. There is nothing about extinction in the paper; it would have been ridiculous and I was prepared to dismiss such a claim without even reading the paper (the Jurassic lasted 55 million years, the Cretaceous 80 million, with dinosaurs farting away throughout). But the paper makes no such claim, instead suggesting that the mass of herbivores during the Mesozoic would have made a substantial, but stable, contribution of greenhouse gases to the atmosphere that may have been partially responsible for the warmer, moister climate of the era and the greater primary production.
Take together, our calculations suggest that sauropod dinosaurs could potentially have played a significant role in influencing climate through their methane emissions. Even if our 520 Tg estimate is overstated by a factor of 2, it suggests that global methane emission from Mesozoic sauropods alone was capable of sustaining an atmospheric methane mixing ratio of 1 to 2 ppm. Equally, our estimate may be understated by a similar factor, (i.e. possibly supporting 4 ppm methane). In the warm wet Mesozoic world, wetlands, forest fires, and leaking gasfields may have added around another 4 ppm methane to the air. Thus, a Mesozoic methane mixing ratio of 6–8 ppm seems very plausible.
The Mesozoic trend to sauropod gigantism led to the evolution of immense microbial vats unequalled in modern land animals. Methane was probably important in Mesozoic greenhouse warming. Our simple proof-of-concept model suggests greenhouse warming by sauropod megaherbivores could have been significant in sustaining warm climates. Although dinosaurs are unique in the large body sizes they achieved, there may have been other occasions in the past where animal-produced methane contributed substantially to global environmental gas composition: for example, it has been speculated that the extinction of megafauna coincident with human colonisation of the Americas may be related to a reduction of atmospheric methane levels.
See? A reasonable conclusion, not Fox News sensationalism.
But here’s the information you really wanted to know: they estimate that a medium-sized sauropod would have farted out 2675 liters of gas a day. Happy now? Impressed?
Wilkinson DM, Nisbet EG, Ruxton GD (2012) Could methane produced by sauropod dinosaurs have helped drive Mesozoic climate warmth? Current Biology 22(9):292-293.
Vertebrates are modified segmented worms; that is, their body plan is made up of sequentially repeated units, most apparent in skeletal structures like the vertebrae.
Arthropods are also modified segmented worms. Look at a larval fly, for instance, and you can see they are made up of rings stacked together.
So here’s a simple and obvious question: can we infer that the last common ancestor of vertebrates and arthropods was also a segmented worm? That is, is segmentation a common ancestral trait, or did arthropods and vertebrates invent it independently? At first thought, you might assume they are: it’s a complex trait shared by two taxa, so the simplest assumption is that both groups inherited it from their common ancestor (making it a synapomorphy), but there are also substantial differences in the mechanism of segmentation, so it’s possible that this trait wasn’t present in the common ancestor (making it a homoplasy).
The Heartland Institute has begun a new ad campaign. I’ll put the billboard below the fold, but first you have to try and guess what direction they’ve taken. Facts to consider: it’s a right-wing think-tank committed to climate change denial. They’re pro-corporate and anti-science, and apparently they don’t know much about logic, either. And a final hint: it’s a place full of sleazy Republicans, and this campaign aims to outsleaze their presidential campaigning.
Before you read the rest, try to imagine what kind of wretched ratfuckery they could be up to.
I think I saw this tree in a Dr Seuss book once upon a time. Unfortunately, all the source says about is that it is “typical habitat of the Western Clawless Upside-down Fly, Nothoastia clausa.” That belongs in Dr Seuss, too.
(Also on Sb)
Salon has also picked up my Near death, rehashed article, which further abuses Mario Beauregard. Let’s see what New Agers come scuttling out of the woodwork again.
The latest Carnival of Evolution is at Evolving Thoughts, hosted by that guy Wilkins who usually covers the philosophical beat…but we’ll let him out of that cage this one time.
The Carnival of Evolution 48 will be held right here, on Pharyngula. You can submit entries via the carnival widget; get them in before 1 June, or I’ll ignore them and they’ll be passed on to the next carnival host, who doesn’t exist. And therefore doesn’t have a blog. Which means your carefully crafted science post will be shipped off to dev:null. So you might also consider volunteering for the hosting duties some time. The electrons you save might be your own.
(Also on Sb)
Cholera is an ugly little beast loaded with all kinds of nasty optimizations to kill human beings. Read this post for a nice summary of all the gory details, and then after explaining all the specific elements of the cholera toxin, asks this plangent question:
How would a Creationist or I.D. advocate explain all of this? They don’t believe that bacteria can develop significant new adaptations, so they’d have to attribute all these changes to recent surreptitious tinkering by an Intelligent Designer (who is presumably still tinkering with cholera bacteria to make it look like they’re evolving, of course). For the sake of argument, let’s assume for a minute that this unlikely explanation is true. If so, we could deduce at least three things about the Intelligent Designer (possibly more):
1) The Intelligent Designer does not like humans. (Why else would s/he/it design lethal pathogens?)
2) The Intelligent Designer is tricking us by surreptitiously intervening in a way that makes it look like bacteria are evolving in order to fool us.
3) The Intelligent Designer is not very smart. If you were an all-powerful Intelligent Designer that wanted to make bacteria that would kill lots of humans, you could do a much better job, because cholera bacteria don’t survive very well in highly acidic conditions. The vast majority of the cholera bacteria you ingest when you drink contaminated water will perish in your stomach acid. From an evolutionary perspective this makes perfect sense, because we know that cholera became a killer through a blind process of evolution by natural selection. From a Creationist or I.D. perspective, however, it makes no sense at all. Indeed, the only way a Creationist or I.D. advocate can explain cholera is to shrug and say that “God moves in mysterious ways”, which is just dodging the question altogether.
Some recognize the problem. I’ll recommend (!) Michael Behe’s book, The Edge of Evolution, which isn’t very good science but at least he comes right up to this problem of the parasites and nasty-man killing nature of Nature, and comes right out and says it: his Intelligent Designer had to have gone in to specifically engineer every brutal feature of every hostile microbe and protist. Further, his Designer is pursuing an ongoing project, and is intentionally introducing almost every significant set of mutations to make pathogens more lethal right now.
I’ve been amused to see the stunned and embarrassed silence of the creationist community to that book. They laud Behe still for Darwin’s Black Box, but The Edge of Evolution? Nah, let’s pretend that one didn’t happen.
