The Alaskan nutrient cycle

Paul Klaver has an absolutely breathtaking short film revealing the nutrient cycle spawned (rimshot) by the salmon in Alaska. It’s gorgeous and I just don’t understand how he managed to get some of the shots. Watch it in fullscreen mode.

I have a fond (?) memory of growing up in Portland, Oregon and heading out to “Outdoor School” for a few days, where they attempted to inculcate a love of the outdoors in us city kids. We visited right after spawning season which meant the stream that ran through the camp was surrounded with decaying salmon carcasses, resulting in the entire place smelling of old fish. Lovely, no?

via Explore

Superorganisms = organism

People like to talk about ants as ‘superorganisms’. Of course, we’re all kind of superorganisms, built out of a structure of captured cells and using home-grown bacteria to function. But when we talk about ants, wasps, and termites, we mean something else. Each insect on its own seems to be an independent organism – though they can’t all survive away from the colony – but in reality, the colony is the organism.

In PNAS, Hou et al. apply the metabolic scaling law to eusocial insect colonies. Individual organisms have a metabolic rate that scales as the 3/4 power of body mass. Along with this are laws scaling reproductive organ mass, total biomass, and organism (colony) growth with metabolism. Individual ants do not follow this law: worker ants have almost no reproductive organs while the queen has tons of ’em.

The figure above shows the body mass vs. metabolic rate for some (non-ant/wasp/termite) insects and for various colonies as a whole. And the curves are the same! If you look at the other predictions, they all turn up exactly on the curve, too. So it is only when you consider the colony as a whole that eusocial insect act as a proper organism. Iain Couzin once mentioned to me that ants in a colony act analogously to neurons in a brain, though I can’t for the life of me remember how that was. But see, the individual ant is just like a lonely neuron: meaningless.

The cycle of the city of ants

E.O. Wilson has a story in the New Yorker! About ants! It’s not great as literature, per se, but it is quite interesting. Imagine ant fanfic: that’s basically what this is. Like a preening middle schooler, he tries to show off all the fun little things he knows about how ants live. That’s not meant as too much of a knock, because maybe that’s the point: the story’s not about immersing yourself in the characters so much as about conveying knowledge about the characters. Read it and learn.

[picture from]

Ecology of the canine subway

Here’s an interesting Financial Times article on the ecology of stray dogs in Moscow:

The dogs divide into four types, he says, which are determined by their character, how they forage for food, their level of socialisation to people and the ecological niche they inhabit.

Those that remain most comfortable with people Poyarkov calls “guard dogs”. Their territories tend to be garages, warehouses, hospitals and other fenced-in institutions, and they develop ties to the security guards from whom they receive food and whom they regard as masters. I’ve seen them in my neighbourhood near the front gate to the Central Clinical Hospital for Civil Aviation. When I pass on the other side with my dog they cross the street towards us, barking loudly.

“The second stage of becoming wild is where the dog is socialised to people in general, but not personally,” says Poyarkov. “These are the beggars and they are excellent psychologists.” He gives as an example a dog that appears to be dozing as throngs of people walk past, but who rears his head when an easy target comes into view: “The dog will come to a little old lady, start smiling and wagging his tail, and sure enough, he’ll get food.” These dogs not only smell who is carrying something tasty, but sense who will stop and feed them.

The beggars live in relatively small packs and are subordinate to leaders. If a dog is intelligent but occupies a low rank and does not get enough to eat, he will separate from the pack frequently to look for food. If he sees other dogs begging, he will watch and learn.

The third group comprises dogs that are somewhat socialised to people, but whose social interaction is directed almost exclusively towards other strays. Their main strategy for acquiring food is gathering scraps from the streets and the many open rubbish bins. During the Soviet period, the pickings were slim, which limited their population (as did a government policy of catching and killing them). But as Russia began to prosper in the post-Soviet years, official efforts to cull them fell away and, at the same time, many more choice offerings appeared in the bins. The strays flourished.

The last of Poyarkov’s groups are the wild dogs. “There are dogs living in the city that are not socialised to people. They know people, but view them as dangerous. Their range is extremely broad, and they are ­predators. They catch mice, rats and the occasional cat. They live in the city, but as a rule near industrial complexes, or in wooded parks. They are nocturnal and walk about when there are fewer people on the streets.”

It’s an interesting story of what happens when a domesticated animal is, in a sense, redomesticated, or undomesticated. These dogs have also learned how to use the subway system to get from place to place. Surely that is a novel behavior you wouldn’t expect from animal psychology? What’s interesting is that not all the dogs have learned how to do this but, presumably, are able to pass on the ability to other dogs who follow them. Do we have a little animal culture here?

Why old people shrink

Here’s why I’ll end up 5’2″ by the time I die:

Degeneration with age interferes with the normal process of regaining height, and by 60 a loss of two inches is not uncommon.

There are 23 jellylike intervertebral disks that act as shock absorbers between the spinal vertebrae, Dr. Härtl said. The disks, which are as much as 88 percent water, are compressed during the day as standing, moving and vibration squeeze out fluid. Then at night, when the body is flat and at rest, the disks reabsorb fluid like sponges.

As we get older, degenerative processes interfere with reabsorption, Dr. Härtl said. Blood supply and circulation diminish, and the disk material stiffens.

[picture from]

My brother the Dauphin

Dolphins are pretty smart. Their brain-to-body ratio is in fact second only to humans, and the cerebral folds that allow a more dense collection of grey matter are probably more wrinkly than a humans. It shouldn’t come as a particular surprise that dolphins even pass things on culturally (something that’s been discussed here before) –

In one recent case, a dolphin rescued from the wild was taught to tail-walk while recuperating for three weeks in a dolphinarium in Australia…After she was released, scientists were astonished to see the trick spreading among wild dolphins who had learnt it from the former captive…There are many similar examples, such as the way dolphins living off Western Australia learnt to hold sponges over their snouts to protect themselves when searching for spiny fish on the ocean floor.

Behavior is not just culturally expressed, it is both novel and conscious:

A dolphin’s ability to invent novel behaviours was put to the test in a famous experiment by the renowned dolphin expert Karen Pryor. Two rough-toothed dolphins were rewarded whenever they came up with a new behaviour. It took just a few trials for both dolphins to realise what was required. A similar trial was set up with humans. The humans took about as long to realise what they were being trained to do as did the dolphins. For both the dolphins and the humans, there was a period of frustration (even anger, in the humans) before they “caught on”. Once they figured it out, the humans expressed great relief, whereas the dolphins raced around the tank excitedly, displaying more and more novel behaviours.

Go watch some videos of them doing awesome things. Because awesome dolphins are awesome.

[Photo source]

Bugs in our gut

Stumbling along the cybernet, I came across this intriguing article about the extinction of our intestinal flora. The tag line here is:

Having evolved along with the human species, most of the miniscule beasties that live in and on us are actually helping to keep us healthy, just as our well-being promotes theirs. In fact, some researchers think of our bodies as superorganisms, rather than one organism teeming with hordes of subordinate invertebrates.

The human body has some 10 trillion human cells—but 10 times that number of microbial cells. So what happens when such an important part of our bodies goes missing?

It’s hard to appreciate just how symbiotic our relationship is. In fact, the flora has a collective metabolic activity equal to a virtual organ within an organ. Our body is well attuned to this fact: immunosensory cells can actually distinguish pathogenic bacteria from the helpful ones. So what are the functions of this virtual organ?

Well, they actually help us to break down some undigested carbohydrates; rodents raised in a sterile environment without gut flora need to eat 30% more calories. They are also able to repress pathogenic bacteria from colonizing the gut through a “barrier” effect. They help prevent allergies. They’re even able to help prevent cancers.

It’s interesting that we’ve been able to selectively allow bacteria to colonize our bodies – and it’s not just us mammals; certain ants have gut flora that allow them to obtain nutrition from honeydew. In fact, the reason that ants are able to be herbivores at all is due to their intestinal flora. Completely unrelated herbivorous ants have bacteria from the same order – as Myrmecos puts it, “The bacteria are not mere evolutionary hitchhikers passively tracking the genealogy. They show up in a highly non-random fashion in ants that have need of nitrogen.” But it gets even more interesting! Leafcutter ants not only employ antibiotics in their fungus gardens, they use colonies of the bacteria Klebsiella to capture atmospheric nitrogen and make it available to the fungus and the ants. I wonder how similar the evolutionary symbiosis of these bacteria is?

And now, here are a few of our friendly flora.

Why we’re exactly the same, most of the time

Here’s a video of Robert Sapolsky, who has excellent hair. He gives an excellent overview of what is unique and what is different about humanity versus the rest of the animal kingdom. You’ll learn a lot about primate culture. It really is worth the watch (though start 5 minutes in; I can’t seem to embed it with that set). Here’s some other, possibly unrelated, things I learned:

  • Menstruation cycle matching – the dominant, most social female leads in humans
  • Chess grandmasters burns ~6000-7000 calories a day thinking
  • Vampire bats live in large social groups and search for cows blood in order to feed their communal offspring. If you prevent one from feeding other babies but make the bat look like it has blood, the other bats won’t feed her babies…evidence of tit for tat behavior
  • Highest entropy tasks release the most dopamine…tasks with the same amount of entropy (ie, 25% vs. 75% probability decision tasks) lead to release of the same amount of dopamine (I should find this citation…)

Monkey talk

Those crafty scientists at the University of St Andrews have managed to decipher monkey language, it seems:

“Krak” is a call that warns of leopards in the vicinity. The monkeys gave it in response to real leopards and to model leopards or leopard growls broadcast by the researchers. The monkeys can vary the call by adding the suffix “-oo”: “krak-oo” seems to be a general word for predator, but one given in a special context — when monkeys hear but do not see a predator, or when they hear the alarm calls of another species known as the Diana monkey.

The “boom-boom” call invites other monkeys to come toward the male making the sound. Two booms can be combined with a series of “krak-oos,” with a meaning entirely different to that of either of its components. “Boom boom krak-oo krak-oo krak-oo” is the monkey’s version of “Timber!” — it warns of falling trees.

This seems to be based on this PLoS One paper from November. They basically correlated vocalizations with features of the environment (ok, they used a GLM). They then used these features, such as the presence of a jaguar, as templates and simulated their arrival in the environment to check their predictions. They were right. The important point isn’t that the monkeys have words, but rather that they string together words to modify meaning (ie, they use syntax). Here’s how they sum it up:

[I]t is still largely unclear whether non-human primates intentionally inform their audience about the event they have just experienced, or whether their vocal response is more directly driven by the psychological processes triggered by external events, the currently prevailing hypothesis. What our results show is that callers appear to make some judgements about the nature of the event (tree fall, group gathering to travel, conspecific intruder, eagle, leopard), and that this assessment determines whether or not affixation takes place. Equally important, male Campbell’s monkeys rarely produce single calls but almost always give sequences of different call types.

I just want to know when we can hold a conversation with them that contains more content than an interview Sarah Palin. Zing!

The Matrix: Population you

Remember how the robots in the matrix harvested people for energy? Well – why not do that ourselves? Apparently, turning our bodies into portable batteries isn’t that far-fetched of an idea:

[T]he bio-batteries closest to reality at this time, the yeast cell ones, have a major problem with waste products. That waste is created as those particular batteries involve microbial yeast-based fuel cells that steal “some of the electrons produced when the yeast metabolizes glucose” in order to create a small current. While the entire process works just fine, the yeast cells are at risk unless the waste products are removed. We can’t exactly let the waste be dumped into the blood stream, so until there’s a some kind of cleaning process, the batteries are trouble as they either they die off or poison your bloodstream while trying to survive.

People are already dreaming up gadgets that could, say, use your blood to power a digital tattoo. Who needs an iPhone when you’ve got a blood powered tattoo on your arm?

Anyway, this is from a cool blog I haven’t seen before – This Cyborg Life. Read up on people choosing to amputate in order to receive prosthetics (sometimes there’s a good reason).

The Lyrebird

The lyrebird mimics sounds it hears in the environment in order to attract mates, combining the sounds in intricate ways. But it copies any sound it hears – including such things as chainsaws and camera clicks and whirs. Watch the video, it’s pretty impressive.

Dance, sifaka, dance!

I learned today that there is a lemur, the Sifaka, that dances, only to then learn that that’s not true. Apparently they just can’t walk on the ground very well, so they hop around sideways in what looks like a ‘dance’. What a sad day. Watch some videos of Sifaka Dancing, or just be informed by the video above.

Plants: they work!

bee_on_flower

Here’s a good blog called Howplantswork that focuses on, well, how plants work. It’s only updated once a month or so, but going through old posts is fascinating. Some highlights:

  • Plant versus plant: some plants kill other plants using natural herbicides
  • Nervous plants? (part 2) [ie, do plants have a nervous system?
  • Flowers: what you see versus what the bees see ]
  • Plant “RAM”? – some plants could record environmental experiences for future reference by altering their DNA
  • The World-Wide-Web: Are plants inter-connected by a subterranean fungal network?
  • Monkey music has a whole new meaning

    I don’t have much to add to this:

    Previous experiments have shown that tamarin monkeys prefer silence to Mozart, and they don’t respond emotionally to human music the way people do. But when a psychologist and a musician collaborated to compose music based on the pitch, tone and tempo of tamarin calls, they discovered that the species-specific music significantly affected monkey behavior and emotional response….“If we play human music, we shouldn’t expect the monkeys to enjoy that, just like when we play the music that David composed, we don’t enjoy it too much.”

    Click the above link to listen to clips of the songs they played to the monkeys. ‘Song’ has been seen in birds, whales, and gibbons (and humans), but that’s it. If you read the original research article (in Biology Letters), they mention that cotton-top tamarins and marmosets prefer slow tempos but are indifferent to human music; the question that they tried to answer was why the monkeys would be responsive to tempos and not music. When are we going to create the academic field of ‘non-human culture’?