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the latest on dolphin language

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dolphins

I wrote, or semi-podcasted, on the brain of the dolphin a while back, and much of my focus was on language, often described as the sine qua non of cerebral complexity and intelligence. In that piece, posted about eight months ago, I reported that there there was little clear evidence of any complex language in dolphins, but there had been some interesting research. Allow me to quote myself:

Dolphins do sometimes mimic the whistles of other dolphins too, particularly those of their closest relatives, but signature whistles as a form of recognition and differentiation, are a long way from anything like language. After all, many species can recognise their own mates or kin from the distinctive sounds they make, or from their specific odour, or from visual cues. However, a clever experiment carried out more recently, which synthesised these whistles through a computer, so that the whistle pattern was divorced from its distinctive sound, found that the dolphins responded to these patterns even when produced via a different sound. It seemed that they were recognising names. It’s undoubtedly intriguing, but clearly a lot more research is required.

So it was with some interest that I heard, on a recent SGU podcast, an account of what seemed an elaboration of the experiments conducted above, further confirming that dolphins recognised names. Or were they just reporting the same experiments? Having re-listened to the SGU segment, I find that they didn’t give any details of who did the study they were talking about, the only mention was to a news article. So I’ll just report on anything I can find, because it’s such a cool subject.

There’s a nice TED talk, from February 2013, on dolphin language and intelligence here, which is about researches over many years in the Bahamas with Atlantic spotted dolphins. As always, I suggest you listen to the talk and do the ‘research on the research’ yourself, as I’m not a scientist and I’m only doing this to educate myself, but hopefully I can also engage your interest.

Dolphins have a brain- to-body ratio (a rough but not entirely reliable guide to intelligence) second only to humans, they pass the mirror self-awareness test (another standard for intelligence that’s been questioned recently), they can be made to understand very basic artificial human language tests, and they’re at least rudimentary tool users. But the real interest lies in their own, obviously complex, vocal communication systems.

I probably misrepresented the information on signature whistles before: they’re only what we humans have been able to isolate from all the ‘noise’ dolphins make, because they’re recognisable and interpretable to us. Denise Herzing, in her TED talk, refers to ‘cracking the code’ of dolphins’ communication systems. She and her team have been working with the dolphins over the summer months for 28 years. They work with underwater cameras and hydrophones to correlate the sounds and behaviours of their subjects. This particular species is born without spots, but is fully black-and-white spotted by age 15. They go through distinct developmental phases making them easy to track over the years (dolphins live into their early 50s). The distinctive spotted patterns make them easy to track individually. Females are sexually mature by about age 9, males at around 15. Dolphins are very sexually active with multiple partners, so paternity is not always easy to determine, so this is worked out by collecting fecal matter and analysing its DNA. So, over 28 years, three generations have been tracked.

What really interests me about the dolphin communication question is their relation to sound and their use of sound compared to ours. Herzing describes them as ‘natural acousticians’ who make and hear sounds ten times as high as humans do. They also have highly developed vision, so they communicate via bodily signals, and they have taste and touch. Sound is of course a wave or vibration which can be felt in water, the acoustic impedance of tissue in water being much the same as on land. Tickling, of a kind, does occur.

Signature whistles are the most studied dolphin sounds, as the most easily measured. They’re used as names, in connecting mothers and calves for example.  But there are many other vocalisations, such as echo-location clicks (sonar), used in hunting and feeding, and also socially, in tightly-packed sound formations – buzzes, which can be felt in the water. They’re used regularly by males courting females. Burst-pulse sounds are used in times of conflict, and they are the least studied, most hard to measure of dolphin sounds.

Interestingly, Herzing notes that there’s a lot of interaction and co-operation in the Bahamas between spotted and bottle-nose dolphins, including baby-sitting each others’ calves, and combining to chase away sharks, but little mention is made, in this talk at least, of any vocal communication between the two species. When she goes on to talk about synchrony, I think she’s only talking about within-species rather than between species. Synchrony is a mechanism whereby the dolphins co-ordinate sounds and body postures to create a larger, stronger social unit.

As I’ve mentioned, dolphins make plenty of sounds beyond the range of human hearing. Underwater equipment is used to collect these ultrasonic sounds, but we’ve barely begun to analyse them. Whistle complexity has been analysed through information theory, and is highly rated even in relation to human languages, but virtually nothing is known about burst-pulse sounds, which, on a spectrogram, bear a remarkable similarity to human phonemes. Still, we have no Rosetta Stone for interpreting them, so researchers have developed a two-way interface, with underwater keyboards, with both visual and audible components. In developing communication, they’ve exploited the dolphins’ natural curiosity and playfulness. Dolphins, for example, are fond of mimicking the postures and vocalisations of humans, and invite the researchers into their play. Researchers have developed artificial whistles to refer to dolphins’ favourite toys, including sargassum, a kind of seaweed, and ropes and scarves, so that they can request them via the keyboard interface. These whistles were outside the dolphins’ normal repertoire, but easily mimicked by them. The experiment has been successful, but of course it isn’t known how much they understand, or what’s going through their minds with all this. What is clear, however, is that the dolphins are extremely interested in and focused on this type of activity, which sometimes goes on for hours.

This research group has lately been using an underwater wearable computer, known as CHAT (cetacean hearing and telemetry), which focuses on acoustic communication. Sounds are created via a forearm keyboard and an underwater speaker for real-time Q and A. This is still at the prototype stage, but it uses the same game-playing activity, seeking to empower dolphins to request toys, as well as human game-players, through signature whistles. It’s hoped that the technology will be utilisable for other species too in the future.

All of this is kind of by way of background to the research reported on recently. This was really about dolphin memory rather than language – or perhaps more accurately, memory triggered by language. Dolphins recognise the sounds of each others’ signature whistles, but would they recognise the whistle of a dolphin they’d not been in contact with for years. And for how many years? Researcher Jason Bruck tested this by collecting whistles of dolphins in captive facilities throughout the US. Dolphins are moved around a lot, and lose contact with friends and family. Sounds a bit like the foster-care system. Bruck found that when dolphins heard the signature whistles of old companions played to them through an underwater speaker, they responded with great attention and interest. One dolphin was able to recognise the whistle of a friend from whom he was separated at age two, after twenty years’ separation. As biologist Janet Mann put it, this is a big breakthrough but not so surprising, as dolphins are highly social animals whose lives, like ours, are criss-crossed by profound connections with others, with effects positive, negative and equivocal.  It’s important, too, for what it suggests – the capacity to remember so much more, in the  same coded way. in other words, a complex language, perhaps on a level with ours. Will we ever get to crack this code? Why not. Hopefully we won’t stop trying.

Written by stewart henderson

August 24, 2013 at 3:55 pm

stress and resilience: what rats are telling us

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rat-on-sequencer-color-798010

I recently read that when you go to the dentist, an almost archetypal stressful experience, your stress will be massively diminished if the dentist tells you, before picking up the drill and attacking your enamel, exactly what he or she plans to do and why. It’s a finding that can surely be safely extrapolated to many other experiences in life, and, perhaps obscurely, it reminds me of the famous story by Franz Kafka, The Trial. K is arrested one fine morning, and he doesn’t know why and he never finds out despite his best efforts, and then he’s executed (excuse the spoiler). A classic literary exploitation of the horror of stress. It reminds me also of how our co-op was treated by its government regulating body, but more of that in later posts.

Kelly Lambert, a veteran stress researcher and rat-lover, describes our growing understanding of the impact of stress and how it might be avoided and treated as one of the most important developments in modern medical and health science. In The lab rat chronicles Lambert displays a pragmatic and down to earth view of stress and depression, with an emphasis on prevention and action rather than ‘treatment’ and medicalisation, which I heartily endorse, while always recognising that there are complex psychological factors that can weigh against individuals taking charge of their lives.

Lambert’s intriguing rat stories serve multiple purposes, of which altering the common view of rats (as pigeons sans wings) is not the least. She teaches us, I think, that we can and have learned a great deal from experiments with animals, and especially rats, but we need to treat them with respect – and can ultimately learn a lot more from them if we do. Among the things they can teach us about are resilience, endurance, reciprocity, social capital, healthy living and self-reliance, and no kidding. But it’s the subject of stress, and building up a resistance to it, that most concerns me here.

Our stress responses are of course necessary and valuable. They motivate us to save ourselves when under attack, or to perform the unpleasant task we must do as part of our job (the prospect of being sacked concentrates the mind wonderfully). Yet the negative physiological effects of stress are the same, whether you’re facing a charging elephant or an angry supervisor. So how do we maximise the motivating force of the stress response, while minimising the negative impact? How do we make ourselves more resilient?

My account here will be abridged – stress is a very complex subject, and I most certainly won’t be giving a full account of it. The first thing is to be aware of stressful situations, of the type I described at the top of this post.

Interestingly, the term stress as applied to humans, other animals and plants, is of very recent coinage, and it’s actually a misapplication from engineering. According to Lambert, in the 1940s, a famous researcher, Hans Selye, began injecting rats with a hormone extract to observe their responses. He noted a heap of immediate negative reactions including swollen adrenal glands, shrivelled thymus glands and stomach ulcers, and was keen to write them all up, but felt he needed more baseline data, so he tried the same experiment, this time using a saline solution to inject the rats with – a placebo, effectively. What he found was the same heap of negative responses. How could this be? It eventually dawned on him that his rough handling of the rats in order to inject them, as well as chasing the scared rats around the cage and dropping them from a height as they squirmed to get out of his hands – all of this was the cause of the adverse reactions. Selye was so intrigued by this that he ditched the hormone extracts and began running experiments to test the rats’ physiological responses to adverse events, deprivation, novel scenarios and the like. This was such a new direction in research that Selye had to find terminology from another discipline to describe the state of mind of the rats as evidenced by their physiological and hormonal responses. He found what he thought he needed in the literature of engineering, with its twin terms stress and strain, but, being a Hungarian reading in English, he appears to have misunderstood that the term stress was applied in engineering to the causal factors operating on, say, a bridge, while strain was a description of the effects of those factors on the strength and durability of the bridge. In any case, psychology had been gifted a new term, one which has been a major feature of psychology and mental and physical health research ever since.

As the evidence mounted for serious negative effects on subjects exposed to events now deemed ‘stressful’, more consideration was given to variation within the findings, so as to better understand resilience in the face of stress. Work done with rats exposed to novel scenarios has shown that the responses vary on a spectrum from neophilic at one extreme to neophobic at the other. That’s to say, when placed in a new environment, the neophilic rats will be happy to explore it, while the neophobic ones will exhibit avoidance and a degree of inertness. Another way to categorise them is ‘bold’ and ‘shy’, and whereas bold and risk-taking creatures (it’s almost inevitable to think of teenage male humans) can create their own physiological problems, such as broken limbs or death by misadventure, the evidence in rats is that they live longer, on average, than their risk-averse fellows. The research also indicates that having the right temperament, or somehow building it into our natures, is key to coping with the day to day stresses that can accumulate in affecting our health in a host of ways.

So how do we enhance boldness or neophilia – in just the right measure – to cope with the slings and arrows? And why is it that some rats and people are more neophilic than others? Not sure that I can provide clear answers to these questions, but let’s come back to them after looking at the rat studies.

 

First, we’ve all heard of homeostasis, right? It has something to do with maintaining your body temperature and internal environment within certain parameters regardless of what’s going on outside. Fine, but studies of stress and responses have added a new, related term, allostasis, to the physiological lexicon. Allostasis is not so much about stability as about appropriate bodily change in response to external stimuli. For example, if you suddenly consume a heap of chocolate, as I’ve been wont to do, you’ll be hoping that your body’s insulin-producing response is timely and appropriate. Neuroscientist Bruce McEwen, adapting another engineering term, introduced the concept of allostatic load, a reference to the strain on the body when it fails to adequately cope with a stressful experience, whether it be heavy lifting or the deaths of loved ones. Both the general concept of stress and the concept of allostatic load were developed by researchers observing the responses of rats.

 

McEwen injected rats with the stress hormone corticosterone for 3 weeks, and then looked for changes in the hippocampus, an area which contains many glucocorticoid receptors, implicated in stress-related responses. The hippocampus is a region essential for spatial learning and memory; it would stand to reason that stressors and memory need to be associated for effective response. The added corticosterone had the effect of reducing the connections and size of the neurons in the region. How did this downsizing affect memory and learning?

McEwen first tried to replicate this effect on the hippocampal neurons by means of stress. So instead of corticosterone injections, he placed the rats in a ‘Plexiglas restraint tube’ for a couple of hours a day for 3 weeks. The physiological changes were similar to those induced by the hormone injections.

 

Another stress experiment was tried by Lambert to see how quickly the brain could be affected. Rats were housed in cages with adjoining running wheels, and their food schedule was restricted to one hour of feeding a day. The rats responded by becoming more, rather than less, energetic, running frenetically and showing all the signs of stress first noted by Hans Selye – swollen or shrivelled glands and stomach ulcers – and shrinking of neurons in the hippocampus. But the shrinking of neurons in all these experiments was reversible, and Lambert considers that this shrinking is probably an energy-saving manoeuvre of the brain. Brains take up a lot of energy, and may react to increased hormone production by downsizing to prevent overload.

 

Returning to the temperamentally bold and shy rats, I’ve noted that the shy ones have shorter lives – 20% shorter on average. Not surprisingly, the bold rats’ hormones returned to base levels more quickly after stress than their shy kin (and often they were actual kin). Clearly, having a more exploratory nature, within limits, is more adaptive than being exploration-averse. Freezing and worrying over novel scenarios isn’t a healthy option.

 

Lambert and her students became interested in pig studies in which piglets, held on their backs for a brief period, reacted either by struggling to escape or by holding still. The struggling piglets were labelled proactive and the apparently passive ones were labelled reactive, but a second test showed that some of the piglets changed tactics. Lambert’s group tried the experiment with rats. They found that some rats were extremely active, some extremely passive, and some switched tactics from one test to another. The last group was labelled as variable or flexible copers. The question was, had this group learned something between the first and second test which had made them change their behaviour?

 

After the tests, the rats were put through an activity-stress program in which they were given a restricted feeding schedule and then were given a choice between running on a wheel or resting. The proactives and the flexible copers ran more than the reactives. The levels of stress hormone were measured in each group. The proactives had more elevated stress levels than the reactives, but, quite surprisingly, the flexible copers had considerably lower stress levels than both the other groups.

 

In another simple test with the same rats, clips were placed on the rats’ tails to see how long they would persist in trying to remove them. The flexible copers persisted longest, and generally interacted more with novel stimuli.

 

The rats were then tested for how they coped with more chronic and unpredictable stress, of the kind that might be compared with serious economic downturns as experienced in the US recently, not to mention Greece, Ireland and other countries. The rat equivalents were strobe lighting, tilted cages, vinegar in their water, and predator odours. What was found with these and other tests was that the flexible copers’ brains produced higher levels of neuropeptide Y (NPY), a neurochemical associated with resilience (special forces soldiers produce a lot of it). The flexible copers also had the highest levels of corticosterone, which assisted them in maintaining a constant state of readiness to meet changing challenges.

 

So, how to turn rats – and people – into more resilient, flexible copers? Perhaps a bit of training might be required. An experiment was conducted in which the profiled rats were assigned to two groups, a ‘contingent training’ group, in which reward was contingent on effort, and a control ‘noncontingent training’ group, the trust fund rats. It was expected, or hoped, that the passive and more stressfully active rats in the contingent training group would, feeling an enhanced sense of control over their environment, increase their NPY levels and generally behave in more resilient ways. The contingently-trained rats, regardless of their coping profiles, all performed better at trying to get rewards (froot loops!) out from inside a cat toy (the task was impossible, but they were being tested on persistence). So far so good. Next, the rats were asked to perform a swim test, which I won’t describe here, but the results were excellent for the flexible copers, who improved their performances even more (and had higher levels of the hormone DHEA, associated with resilience), but the other two profile groups didn’t improve. A disappointing but not entirely surprising result.

A more interesting result came out of the control group. The flexible copers in that group, after a regime of easy benefits, reduced their willingness to make an effort when confronted with the need to do so to gain rewards in subsequent tests. I’ll quote Lambert here at some length:

Instead of having no effect on the coping responses, the trust fund condition erased the advantage typically shown by the flexible copers. The lack of a predictable contingency formula accompanying the presentation of life’s sweetest rewards reset the behavioural computations underlying the rats’ motivation to work for their rewards. They were now characterised by less flexibility in their responses and a shorter tolerance for work that didn’t immediately produce a reward. Had we systematically spoiled our rats? Once again, animals that were more sensitive to associations between effort and consequences would likely be even more affected by the trust fund noncontingency condition; after the fact, it all made so much sense.

So what can we take from these complex but often striking findings? Of course it goes without saying that we’re not rats, but I also like to think it goes without saying that these findings are highly relevant to humans, and all other mammals. Above all we find that removing us from a state in which we have to strive for rewards tends to make us slothful, intolerant and complacent – ‘spoiled’. A term which now has added resonance. How we build in that resilience in the first place is another question – it might be that very early experiences in which we’ve made positive connections between effort and reward, strongly reinforced from time to time, make for a kind of ‘natural’ resilience which we wrongly consider innate. This has always been my suspicion, that the earliest experiences, even in the womb, can set a strong pattern, which is what we’re talking about when we note that a baby seems to have already a set character, whether timid or ebullient, from birth. That character, when it is ‘resilient’, can be spoiled, so that’s something to watch out for. And as to how a set character which is non-resilient can be transformed into a flexible coper, that’s a tougher problem, as you’d expect.

What I like about Lambert’s approach is that she’s always looking for how we can improve our well-being without resort to medications, ways of positively altering our hormone regulation system through behavioural change, rather than through resort to pills. As she points, the use of anti-depressant medications has sky-rocketed since the mid-nineties, as have diagnoses of depression and related disorders. Something’s definitely wrong here. You’re not likely to increase resilience with pills. The good thing is that more and more researchers are coming to realize this, and looking to behavioural change, from exercise to social interaction to the creation of challenges and rewards, for the answers.

 

 

Written by stewart henderson

June 30, 2013 at 8:21 pm

how to debate William Lane Craig, or not – part 7, objective moral values and duties

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ceci n'est pas Jesus

ceci n’est pas Jesus

Dr Craig’s sixth claim, that his god is the best explanation for objective moral values, is one I want to dwell on at some length, so please sit back in your electrified chairs and enjoy my reflections if you can. But please note that I dwell on the subject for my own interest’s sake, not because I find Dr Craig’s views require much work to overcome – far from it.

I suppose it’s fair to say that when it comes to moral issues, unlike with matters scientific, we all like to consider ourselves experts, and we’re all a little more committed and vociferous, because – it’s personal. So I’ll begin with some personal stuff. From earliest childhood I’ve always felt very emotional about issues of cruelty and injustice. I was often in tears on witnessing kids in my class being bullied – more often than not by teachers. When I was a little boy I read the Hans Andersen story, ‘the little match girl’, a simple but devastating story about a young girl out in the cold snow, trying to sell matches for her impoverished family, afraid to go home without having sold any. She finally dies, out in the cold, on the last night of the year. This tale of unfairness and cruelty and indifference, had me awash with tears at the time, and literally haunted my childhood. I think it’s fair to say that a sense of empathy was well developed in me from an early age. Needless to say, ethical ideas based on the harm principle, such as those articulated by the liberal philosopher John Stuart Mill, held great appeal for me, but further than this, active moral programs to protect and support individual human beings, such as those enshrined in the universal declaration of human rights and in the many conventions and protocols that have followed from that declaration, are programs that I hold dear.

The point I’m making here is that the starting point for my own moral values was an emotional one, a visceral one, if you like, and not something derived from any ‘higher consciousness’ or reflectivity or rationality.  And I suspect that’s quite a common experience. We don’t generally choose to cry over or be haunted by an injustice. So where do these deep emotional feelings come from? I have absolutely no reason to associate them with a non-material being who has, as far as I’m aware, never communicated anything to me. Nor was I, during my childhood, convinced that everyone would feel the same way as I did if exposed to the story of the little match girl. Some would, I was sure, but others would be cruelly indifferent, and there would be a whole variety of responses along the spectrum. In short, my observations of life, even from an early age, told me that people valued things and experiences very differently from me, and very differently from each other, to a rather bewildering and unpredictable degree.

So, from the fore-going I hope it won’t come as a surprise to you that I don’t believe in objective moral values, but that I’m far from believing that this entails some kind of moral nihilism or amorality. In Dr Craig’s presentation of this argument, he suggests that those who don’t subscribe to objective moral values, by which he means, values that come from a male supernatural being, don’t see anything ‘really’ wrong with the massacre of schoolchildren. Let me put that in another way. He argues that my own deeply felt disgust, shock, anger and pain, when I hear about, and see, played out on my tv screen, those sorts of crimes, is not really real, because it isn’t connected to a non-material creator-protector god, which is how he defines objective morality. I find this a ridiculous argument, as well as an offensive one.

Firstly, Dr Craig’s version of morality is a sham because it exists nowhere. Dr Craig will not be able to give you a single instance of a command from his favoured deity. The decalogue, the ten commandments, were written by men, and though some of them may seem uncontroversial – don’t lie, steal, don’t kill – even these aren’t absolute. A starving person, in my view, would be justified in taking food belonging to another person, who had an abundance of such food, if the alternate was death. I have no difficulty with that. Some people would, as they have the view that private property is sacrosanct. And I could make similar arguments to justify lying, and even killing, under certain special circumstances. To me, there are no absolutes. Other commandments, such as keeping the sabbath day holy, I don’t take at all seriously, because I don’t believe a supernatural being made the world in seven days, though had I lived several thousand years ago, I might well have believed that. And so my morality would have been different then, just as my morality would be different if I were born, on the same day that I actually was born, but in the city of Basra, to a devout Moslem family. My morality, that I hold so dear, and which gives my life so much meaning, is the result of my particular upbringing, my peculiar variety of experiences and influences, the culture that I was born into, my genetic inheritance, and I’m sure there are other factors that I’ve left out. One thing I’m happy to leave out, though, is the command of a deity. I’ve never experienced such a command, and I have no reason to believe anyone else has either.

Now, there are atheists I know who argue for an objective morality, but obviously not grounded in a deity. Personally I find such rational arguments a bit weird, and I’ll say no more about them here, except to make the obvious point that being an atheist doesn’t commit you to any specific moral position, as it’s simply an absence of belief in a deity. That’s all.

What I do want to focus on is the claim that morality without a deity is merely subjective and not really real. That’s to say, without a deity we can do whatever we like and call it morality. Well, that’s not how I feel about morality, and it’s not how morality, and laws relating to morality (and most laws have some sort of moral reasoning behind them) have developed in our increasingly secular society. The Universal Declaration of Human Rights is entirely secular, and I think it’s a grand step forward in global human interaction. And it’s more of an effect than a cause, it’s symptomatic of a gradual shift in our attitude to other cultures, in our attitude to race, whether the concept is a valid one or not. In the attitude of men to women, in the attitude of heterosexuals to homosexuals, in our attitude to and respect for children, and in our attitude to and respect for other species on this planet. All of these attitudes have changed drastically in the past 150 years or so. Living in an eternal present as we often do, we can easily overlook how thoroughly transformational these essentially moral developments have been, and they’ve owed nothing whatever to religion, which has generally dragged its heels at the rear. Look, for example, at the Catholic Church.

I’m an avid reader of history, and as such I’ve noted the social changes, particularly in western Europe, that occurred over the past 400 years or so. What has always struck me, in reading about the Thirty Years’ war or the English revolution of the 17th century, or the early slave trade, is how often and regularly God (the Judeo-Christian one) is invoked in the primary documents of those times. God appears on every page, often several times on every page, of every legal document. I’ve described the 17th century, and the centuries before, as a ‘god-besotted age’. And yet the everyday brutality, the callous inhumanity, the cruelty, the viciousness, the inequity, the impoverishment of basic human values of those times, were everywhere on display. If you think you’ve got problems now, transport yourself back to pre-Enlightenment Europe for a wake-up call. Arbitrary rulers, upstart priests, popular revolutionaries, all invoked the divine in order to invest themselves with authority, as still happens today. Think of the divine right of kings, and papal infallibility, and the dear leader and great leaders of North Korea, who promoted themselves as divine. In the past, monarchs regularly passed laws in the name of the god whom they represented. Nowadays, elected politicians pass laws in the name of the people who elected them. It seems to have been a great improvement.

Our morality and our laws are grounded, it seems to me, in our common, but changing, evolving human nature. This is not mere subjectivity. In fact it’s all we have to go on. We don’t make up our own morality as individuals because we’re essentially social beings who rely on each other for our survival and our thriving. We’re empathic because we see ourselves in others and others in ourselves. And we’ve evolved that empathic capacity to embrace species other than our own, which I think is a great step forward.

The theist has no ground for objective moral values because no single moral value, claiming to be objective, has ever been shown to come from a deity. I have no doubt that they’ve all come from human beings.

Written by stewart henderson

March 22, 2013 at 9:55 am

worms!

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worms

Nobody loves me, everybody hates me, thank I’ll go and eat worms

Long ones short ones fat ones skinny ones

Worms that squiggle and squirm

That’s called a kids’ song, or a campfire song, and in some versions the words are different, but that’s how I learned it in the wolf cubs as an eight-year-old, and the words often come back to me when, as quite often happens, I find that nobody loves me and everybody hates me. This is the case at present so I was heartened by watching a doco this morning on worms, and I thought I’d cheer myself by writing about them rather than eating them.

I’m talking earthworms here, just to narrow things down. The longest worm that we know of (not an earthworm) is the bootlace worm, Lineus longissimus, of the phylum Nemertea, specimens of which grow as long as 55 metres – though they’re stretchy, so that might be cheating. As for earthworms, Australia’s regarded as a hotspot of wormy diversity, according to wormologists, with the giant Gippsland earthworm, Megascolides australis, coming in as one of the biggest at up to 3 metres, and over an inch in diameter. You could base more than a couple of hefty meals on a critter that size, but sadly they’re a threatened species, another casualty of human encroachment on habitat. In fact, a great many of Australia’s 1000 or so known native earthworm species are in the same position, but for obvious reasons they don’t get the same attention as bilbies and potoroos.

As every gardener knows, worms are much valued for the way they transform the soil, providing new opportunities for the growth and development of plants. They also aerate the soil – letting in air, releasing carbon dioxide – with their burrowing activities. They don’t simply become two if they’re cut in half, though they can regenerate a chopped-off tail. They’re delicate and can be easily broken if pulled at, and in fact they have tiny gripping hairs, called setae, all over their bodies which makes them especially hard to pull out of the ground, as if you’d want to. Like me, they’re hermaphrodites (I think that’s why everybody hates me) and they breed by stretching alongside each other and exchanging sperm, a process that often lasts for many hours.

Okay, I’m not a hermaphrodite, but I may as well be, and a two-headed one at that.

Worms make great food for birds, platypuses and the occasional intrepid toddler, and their excreta, aka castings, the end-product of incessant organic digestion, is taken up by plants, and is full of such goodies as phosphorus, nitrogen, calcium and magnesium. They like and need moisture, and in fact the giant earthworm can be detected by the underground squelching and gurgling created by their activities.

The basic worm anatomical structure, whether you’re talking land or sea, has been around a very long time, and obviously has proved very effective and enduring. It’s believed that the first-ever vertebrate creature (according to current knowledge), the ocean-living chordate Pikaia gracilens, incorporated the beginnings of a backbone into its worm-like body some 500 million years ago. That makes worm-eating a form of cannibalism. In fact, eating itself is a form of cannibalism and we really should stop.

Let’s look at how earthworms get around. The direction of their movement is a response to light and to soil chemistry as it impacts on skin cells. They move by expanding and contracting their muscles, anchoring themselves as they go with their setae, which they put out and retract as they go. Skin secretions help to bind the soil around them, easing their burrowing passage. Like us, they move a lot more sluggishly (probably not a good choice of words) in the cold weather.

So, that’s it for worms, for now. I’ve opened a few cans of them in my time, but I’ve always been reluctant to examine the contents. See how I’ve changed.

a dish of mopane worms - a fave from Zimbabwe

a dish of mopane worms – a fave from Zimbabwe

Written by stewart henderson

January 30, 2013 at 10:09 am

on thinking like them to learn how they think

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An interesting conundrum from Clive Wynne’s book Do Animals Think?

First, imagine you are given four cards and told to test the rule that a card with a vowel on one side must have an even number on the other side. Let’s say the cards in front of you show an E, a K, a 7 and a 4. Which would you turn over? Most people find this a very difficult problem. Most turn over the E and some also turn over the 4. And yet the 4 can tell you nothing: Who cares what’s on the other side of an even number? The rule being tested does not say that the flip-side of an even-numbered card can not be a consonant, only that the flip-side of a card with a vowel cannot be an odd number. So you would learn nothing by turning over the 4. The correct answer is to turn over the E [see if the vowel has an even number on its reverse] and the 7 [check that there’s no vowel there]. Only about 5% even of the college-educated population give the right answer to this one. It’s a tough logical nut to crack.

Now consider this problem. Imagine that you are shown four people and told to test the rule that a person must be over the age of twenty-one to drink beer. One person is drinking Coke, one is drinking beer, the third is twenty-three years old, and the fourth, fifteen. Whom must you check [what they are drinking or what age they are] to ensure that the rule is being followed? Here nobody has any trouble. We don’t care what the twenty-three-year-old drinks, nor what age the Coke drinker is, but we do need to check the age of the beer drinker and the beverage of the fifteen-year-old. Nothing could be simpler. Hardly anybody gets this one wrong.

And yet logically these are absolutely identical  problems. There is no difference in the type of reasoning required to solve these two puzzles. Why the big difference in performance?

Wynne, a psychologist with a strong interest in, and a wide knowledge of, research in other-species reasoning, is making a very important point with application to the testing of other animals and their ability to solve problems. It’s hopefully obvious that the reason we do so much better with the second problem is that it’s a recognizable real-world problem about obeying the rules and not cheating or doing the ‘wrong thing’. We’re much more motivated to come to a quick and accurate solution than with the much more abstract first problem. So when we set problems for other species to solve, we need to understand that what motivates them to solve a problem might be very different to what motivates humans.

Wynne’s book, which I was motivated to read as further background to, and an extension of, my animals r us post, makes for excellent reading, as he’s healthily sceptical of, and pokes some holes in, research claims about other-species reasoning and mental processes, such as they are. He also provides some fascinating information, scientific and historical, about, inter alia, bats, bees and pigeons. My only quibble, perhaps a minor one, is that, both in the title of his book and throughout the writing, he refers to animals as though we’re not one of them. Not that he has any truck with the ‘we’re special and the proper end of evolution’ view. In fact I really don’t know why he writes of animals in this way – it’s as if he’s half-convinced that our development of language and our complex ‘theories of mind’ have really taken us to some level beyond the mammalian. They haven’t. We’ll never stop being mammals, though we’ll continue to amaze ourselves with what we can do with the difference between ourselves and other mammals.

Written by stewart henderson

September 14, 2012 at 8:33 am

is there life on enceladus?

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a cool place – and note the tiger stripe

The Curiosity landing has been fabulously successful, and it’ll certainly be worth keeping tabs on the rover’s findings. I posted recently on the possibility of life on Mars, not a couple of billion years ago, as many Mars experts think probable, but right now. The Curiosity rover, as we know, will be investigating this possibility further, but meanwhile there are other possibilities of finding extra-terrestrial life in this solar system, and one of the best places to look, I’m reliably informed, is Enceladus, a tiny moon of Saturn.

Enceladus is only about 500 kilometres in diameter, but its surface has intrigued astronomers ever since Voyager 2revealed detailed features in the early eighties, indicating a wide range of terrains of varying ages. Data from the Cassini spacecraft that performed fly-bys in 2005 showed a geologically active surface, with the most spectacular feature being a large volume of material, mostly water vapour, issuing from the southern polar region. This indicated the existence of ice volcanoes, or cryovolcanoes, which have also been observed elsewhere, and were in fact first observed by Voyager 2 on Triton, Neptune’s largest moon. However, on Enceladus what we have are more like geysers spewing out material from an area known by observers as ‘the tiger stripes’, a series of prominent, geologically active ridges. This material is now known to account for much of the outermost E ring of Saturn, within which Enceladus has its orbit, though a certain amount falls back onto the moon as snow.

Finding water on any object in the solar system obviously excites the souls of astrobiologists. A report from a May 2011 conference on Enceladus stated that this moon “is emerging as the most habitable spot beyond Earth in the Solar System for life as we know it”. However, there are plenty of sceptics, or I should say cautious questioners. First, the existence of water vapour spumes doesn’t necessarily entail liquid water below the surface – for, in spite of the thrill of detecting snow in large quantities on the surface, liquid water is generally regarded as essential to finding life. And even if we assume liquid water…

Some analysts argue that the spumes may be a result of sublimation – a change from a solid, icy state to a vapour, missing out on the liquid phase – or of the decomposition of clathrate deposits. A clathrate is a type of ice lattice that traps gas [methane clathrates are found at the polar regions of Earth]. However, the recent discovery of salt in these plumes has made these possibilities less plausible. Salt is more likely to be associated with liquid water, but hydrogen cyanide, also recently found, would have been expected to react with liquid water to form other compounds, not found as yet. In short, the jury is still out on the presence of liquid water.

And assuming there is liquid water, how could we test for life within it? With great difficulty, obviously. Analysts would be searching for biomarkers, ‘chemicals that appear to have biological rather than geophysical origins’ [Cosmos 44, p78]. Photosynthetic production wouldn’t be an option, so other systems are being hypothesised, including a methanogenic system in which methane is synthesised from carbon dioxide, or a system of metabolizing acetylene, which occurs on Earth. Traces of acetylene have been found on Enceladus. Other biomarkers include amino acids with the right chirality – that’s to say a strong chiral preference, one way [as found on Earth] or its opposite. Amino acids with no chiral preference are likely to be abiotic.

To test for such biomarkers would require new instrumentation and another visit to this intriguing moon. Something else to look forward to. What would we do without anticipation?

Written by stewart henderson

August 29, 2012 at 7:07 pm

is there life on mars?

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good question, Davie

Back in 1975, NASA sent two space probes to Mars. Their landers touched down on the Martian surface less than a year later. The Viking 1 lander remained operational for more than six years, Viking 2 for three and a half. During this time, biological experiments were conducted upon Martian soil. As far as the general public is concerned, the results of these tests were negative, though for those in the know, it wasn’t quite that simple. Not that there was any great conspiracy or cover-up; the consensus amongst the cognoscenti was that the evidence tilted much more towards no-life than towards life, for the minute samples examined.

It seems, though, that exobiologists have long been intrigued by some of the findings in a particular batch of experiments, known as the Labelled Release experiments. As this Wikipedia article describes, these experiments involved a soil sample being inoculated with a weak aqueous nutrient solution. The nutrients were of the type produced in the famous Miller-Urey experiments of the fifties. Evidence was sought for metabolisation of these nutrients by micro-organisms in the soil, if any, and the first trial of these experiments produced surprisingly positive results. In fact, both the Viking probes produced initially positive results from different soil samples, one with a sample of surface soil exposed to sunlight, the other with a sample from beneath a rock. However, when the tests were repeated later, they produced negative results. Many other different types of biological tests were carried out during this mission, all of them yielding negative results. So it was all very inconclusive and mysterious.

Fast forward to April 2012, when a report was released by an international team of scientists suggesting that, after thorough analysis of the Labelled Release data, ‘extant microbial life on Mars’ may have been detected.

Researchers long ago abandoned the idea of multicellular life currently existing on Mars. Conditions for the maintenance of such life forms may have existed there billions of years ago – the Viking orbiters found evidence of erosion and the possible remains of river valleys – but those conditions have changed, though some have argued that the soil coloration and recent detection of silicate minerals indicates more recent signs of water, vegetation and microbial activity. All of this is highly contentious, but all good fun, and indicates that more research is required.

In 2008, a robotic spacecraft landed on Mars, in the polar region, and remained operational for about six months. The Phoenix lander had two principal objectives, to test for any history of water in the region, and to search for anything organic in the surrounding regolith [the surface layer of broken rock and soil affected by wind or water]. Preliminary data revealed perchlorate, an acid-derived salt, in the soil, which wasn’t a good sign. Perchlorate can act as an ‘anti-freeze’, lowering the freezing point of water. Generally, though, the pH levels of the tested soil, and its salinity, were benign from a biological perspective. CO2 and bound water were also detected.

We’ve only minutely scratched a few surface points of a huge beast, you might say. What we’ve found isn’t too promising, but it’s enough to keep us wanting to investigate further, just to make sure, or to know more. After all, there’s still plenty to learn about the surface of our own planet. Recently, for example, we learned how perchlorates can be formed from soils with highly concentrated salts, in the presence of UV and sun light. Chloride is converted to perchlorate in the process, which has been reproduced in the lab. Only in 2010, soils with high concentrations of perchlorate were discovered over a large section of Antarctica.

Between August 6 and August 20, that’s to say in two or three weeks time, the Mars Science Laboratory [MSL, also known as ‘Curiosity’] will land on Mars and look for further signs, past or present, of biological activity. It’s likely that whatever is discovered, not just in terms of life itself, but in terms of conditions for life, will be hotly debated. This Wikipedia article, covering the whole life-on-Mars search and debate, includes this intriguing para:

The best life detection experiment proposed is the examination on Earth of a soil sample from Mars. However, the difficulty of providing and maintaining life support over the months of transit from Mars to Earth remains to be solved. Providing for still unknown environmental and nutritional requirements is daunting. Should dead organisms be found in a sample, it would be difficult to conclude that those organisms were alive when obtained.

True enough, but even if dead, what a revelation it would be. Extra-terrestrial death means extra-terrestrial life, and so very very close to home in the great vastness of the universe. Another blow to our uniqueness, what terrible fun.

Written by stewart henderson

July 25, 2012 at 7:08 pm

animals r us

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I felt a bit disheartened a while back when a teenage lass I know and love declared to me that she ‘hated animals’. Worse, one of her aunties chimed in enthusiastically with, ‘yeah, I hate them too’. I wasn’t sure about taking these assertions seriously, especially the fifteen-year-old’s, but my suppressed response, apart from WTF???, might’ve been, uhh but you do know that you’re animals, right?

In fact I didn’t respond at all, being too taken aback, but I’m sure they knew they were animals, and yet…

Us and them thinking is commonplace. It’s a feature of any species of living thing that they’re concerned with other members of their species, both positively and negatively. We compete with members of our own species for resources, and we also share resources with our own species. We mate, and fight, with our own species. We try to impress our own, either by our scariness or our attractiveness, depending on circumstances. Other species just don’t matter so much to us, except insofar as we need them, or need to avoid them, for our survival.

I’m speaking for species in general here, but humans have learned something about other species that should make a big difference to us, and that is that all species are more or less related. We even have techniques which can tell us just how related we are. We know that we’re a bit more closely related to chimps than we are to gorillas, and that we’re a bit more related to gorillas than we are to gibbons, and that we share a much more common ancestor with tree shrews than we do with lungfish, but the important point is that we know that we’re related to every other organism in the biosphere, without which not, as they say. So to hate animals, if you really mean it, is to be self-defeating in a big way.

And hatred, or dismissiveness, towards other animals, surely comes from an unthinking us-and-them position, a position that needs to be continually questioned and challenged.

I recently read the excellent Shadows of forgotten ancestors by Carl Sagan and Ann Druyan. Much of it, especially the second half, is devoted to demolishing claims to human specialness, our separateness from ‘animals’. They do so mainly by examining the lives and behaviour of other primates. Much of the following will derive from their book. I will start with the most general claim, and then look at some specific ones

Humans are different from all other animals, not just in degree, but in kind.

This ultimate us-versus-them claim is questionable in many respects. It usually comes with particular examples: we are the only ones who have x, or can do x, therefore…

But are we the only ones with property x, and if we are, where does this property come from? Humans, we know, are primates. We share a common ancestor with chimps and bonobos going back six million years. Are we different in kind from that common ancestor? If, for argument’s sake, we say that we are, at what point did that qualitative, rather than quantitative, difference emerge? We are still unable to clearly trace our descent back to that common ancestor, but we have plenty of example of earlier hominids to chose from – this site offers some 20 distinct species that might have been along the line of descent. Which one, if any, represented a qualitative transformation? Or do incremental quantitative changes somehow amount to a qualitative transformation? If so, how many changes, and, again, when exactly did the quantitative become qualitative? I don’t think these are fruitful questions, and the more we learn about other species, the more these questions dissolve away.

We share the properties of other animals in many ways, but I’ll pick on sex as one of the clearer examples. Humans long ago realized that the castrating of war captives rendered them less aggressive – though they would’ve had little idea why. They did of course know why such a practise rendered then incapable of producing offspring, another signal benefit. The removal of the testes, whether in humans, cats, dogs, sparrows or quails, has much the same effect; aggression is reduced, as are various other male traits governing behaviour towards females and towards other males. The reason is that the testicles produce most of the androgens – that’s to say the steroids or sex hormones, such as testosterone. The action of testosterone and other sex hormones is strikingly similar across all animal species. Experimenters have added or removed the hormones with increasingly predictable results, not only in mammals and birds, but lizards and fish as well. This isn’t to say, though, that the males of all these species, when their sex hormones aren’t interfered with, are always the more aggressive or dominant gender, for that depends on how much, and what types, of the sex hormones are naturally produced or released. Male and female wolves, gibbons and tree squirrels are about equally aggressive. Species have, over time, developed the ‘right’ hormone levels for their kind – that’s to say, the most adaptive. Give certain birds too much sex hormone, and the males sometimes end up killing each other, and overall numbers fall. In all of this humans are no different.

Of course patterns of sexual behaviour vary among mammals. Most mammals only mate when the female is ‘in heat’, during a particular phase of the estrous cycle, the estrus phase, which precedes ovulation. Menstruating females, though – the menstrual cycle is a subset of the estrous cycle, in which endometrial material is shed during menstruation – including a number of primate species, are not confined in their sexual activity to a particular period [so, no, we’re not the only ones with that ‘freedom’]. Interestingly, though, human societies often have prohibitions against sex during the menstrual period, whereas in other primates, sexual activity actually increases at this time. One of the wonders of human culture.

Humans are the only creatures that make tools

We only need one solid counter-example to demolish these general claims, and in this case we have several to choose from, but I’ll opt here for a very well-attested one; the use of reeds, straws or vine branches by chimps to catch termites. Not all chimps are able to do this, and few are able to do it really well (we tend to forget, with other species, apart from the domestic ones we deal with every day, that they have their bright sparks and their half-wits just as humans do), but it’s a highly developed skill which human researchers haven’t been able to develop. What’s more, it’s a skill that takes years to develop, and older chimps teach it to the young. What chimps have to do is find just the right kind of tool for the job – that is, to be manipulated down a termite hole and retrieved from the hole with as many termites clinging to it as possible, to serve as a dish worthy of the effort and expertise. This requires matching the tool to the termite burrow, which means knowing the characteristics of the various mounds in the neighbourhood, and then having the dexterity, not only to get the tool into the hole with the minimum of disturbance to the termites but, more importantly, to be able to twist it and move it to attract termites to the ‘intruder’, and then withdraw it without knocking all the termites off. If chimps can’t find the right shape and size of tool, they can and do modify it to suit the job, which is no different in kind from early humans modifying stones for cutting and for use as weapons. Such stones are our first well-attested tools, though only, of course, because stone outlasts other materials. This activity is far from simply opportunistic. It requires planning and foresight, and it’s certainly not the only example of tool use in chimps or in other animals, including birds.

Humans are the only self-aware animals

We have to be careful, of course, not to define ‘self-awareness’ and other related concepts in such a way that they can only apply to humans. Similarly, I can think of ways of defining the term which would make it inclusive of a great many species. Because of the great difficulty of accurate definition here, it’s quite useful, as a first approximation, to use a crude, behaviourist approach to the problem, such as the well-known mirror test – first applied, though in a non-rigorous way, by Charles Darwin. All of the great apes can pass this test, as can elephants, some cetaceans, and, probably most surprisingly, European magpies. They all fail the mirror test initially, but soon learn that they’re looking at their own reflection. Humans don’t pass the mirror test before the age of eighteen months, on average – though there are some problems with the reliability of that measure because of possible flaws with the classic mirror test which I won’t go into here. Suffice to say that learning to use mirrors for grooming, etc, is pretty solid evidence of self-awareness in other species.

Humans are the only species able to conceptualize

‘It would be senseless to attribute to an animal a memory that distinguished the order of events in the past, and it would be senseless to attribute to it an expectation of an order of events in the future. It does not have the concepts of order, or any concepts at all.’ [Stuart Hampshire, philosopher]

The above sort of observation, though it wasn’t actually an observation, was commonplace in philosophy well into the 20th century, but research into ‘comparative cognition’ has largely blown this bias away, as you might expect, with a bit of thought. After all where does conceptualisation come from if it isn’t an evolutionary development over time and species? Of course the concept of concepts is a bit murky, but researchers have been able to distinguish three types of concept learning – perceptual, associative and relational – and a more sophisticated type of concept-formation called analogical reasoning. A 2008 survey of the research found that many non-human species were capable of the first three types, with only the higher primates showing evidence of the fourth.

Humans are the only species with language

‘Language is our Rubicon, and no brute will dare to cross it.’ [Max Muller, 19th century linguist]

There has long been a great debate about this one, and much research and effort put in to trying to teach the rudiments of language to chimps and bonobos. Sagan & Druyan dwell at length on this work, though well-known linguists such as Charles Hockett and Steven Pinker suggest that there is a bigger divide than sometimes admitted between other primates and humans in this area. Again, this depends on how tight, loose or technical your definition of language is. Still, no matter how language is defined to exclude non-humans – such as arbitrariness between sound and meaning, and discreteness in the construction of terms – researchers manage to find evidence of it in other creatures. Nobody denies that language  has reached a pinnacle of sophistication with humans, but again there are many traces of complex communication in many other species, and it’s of no value to us to try to reduce their import. The Muller quote above indicates how our preoccupation with our own superiority can lead to a hostile attitude to any knowledge that dares to threaten it.

Humans are the only creatures who know they will die.

We know from an early age that we will die largely because of our sophisticated communications. We learn of the history of our culture, peopled with dead contributors, we see monuments to the dead everywhere, the disappearance of aged pets and relatives is patiently explained to us. Other animals, without these communications, may still feel it in their bones as the time approaches. There’s certainly evidence for mourning in elephants, chimps and many other animals.

Humans are the only ethical animals.

Ethics and social living are an almost essential pairing. The Biblical commandments that still make sense to us are all about making society more predictable and therefore more bearable to us as individuals, which is why they’re common to most religions and cultures. Whilst it may be argued that humans are more consciously and explicitly ethical than other social animals, some recent research has cast doubt on our freedom to choose our ethics. We appear to be driven, genetically, to preserve ourselves and our own, and to rationalise an ethical system around that drive. Other creatures have evolved the same drives and act in similar ways to ourselves.

Humans are the only animals that possess culture

If you think of culture as a process, rather than working back from cultural products, it would be hard to deny that this process exists in many other species. I’ve already pointed out that simple tool-making is passed down from adult chimps to children. This is cultural transmission, and is a basic factor in all culture. Basic tool-making and teaching were presumably the first forms of cultural transmission in humans.

Humans are the only creatures who explore their own origins, and the origins of all else

This may well be the last bastion, but again it doesn’t represent a difference in kind – even supposing that such explorations don’t occur to non-human minds. These types of explorations are the culmination of increasingly sophisticated concept-formation, meme-transmission and theoretical and technological development. With all this, knowledge, ideas and speculations are converging on us at an ever-increasing pace. It’s no surprise, therefore, that the idea of a ‘singularity’ has captured our imagination, tenuous though the idea might be. Interestingly, the idea of the singularity is another instance of quantity building up to a sudden ‘flip’, a qualitative transformation. Another self-serving and self-congratulatory idea perhaps?

We humans are quite fascinating, the more so the more we examine ourselves, but we are learning that what we’re made up of is the same stuff that other life forms are made of, and the similarities are every bit as instructive as the differences. We’re a distinct species, no doubt, but it is counter-productive to think of ourselves as a species apart.

 

Written by stewart henderson

July 22, 2012 at 9:12 pm

bonobo genome sequenced, but nothing jumps out

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I’ve long had an interest in bonobos, and now I read [via 3QD] that they’ve had their DNA sequenced, and researchers are trying to find clues in their genome as to their relatively placid and highly sexual behaviours. So we can now compare what the sequencing tells us with what has been learned in the field.

I’ve dealt a little with bonobos before in one of my experiments with podcasting here, where I told the story of how they were separated from chimps physically by the Congo River, maybe a couple of million years ago. The sequencing shows that this separation was radical and permanent, with modern bonobos showing no closer genetic affinity with their chimp neighbours across the river than with chimp populations much further away. It looks like it’s going to take some time, though, to identify in genetic terms the particular changes that have occurred since the split. In fact, it appears easier to identify environmental factors to explain bonobos’ more relaxed and non-aggressive behaviour when compared to chimps. North of the river the chimps compete for territory and food with gorillas, whereas south of the river the bonobos face relatively little competition.

The sequencing of one particular, possibly ‘atypical’ bonobo doesn’t necessarily provide all the answers, any more than it does with humans or any other species. In this case the specimen was an 18-year-old-female, Ulindi, who displayed quite a bit of aggression to one of the research team. In any case, there’s a lot of variation in bonobo behaviour, and to pick out one individual as ‘typical’ for sampling is as questionable as assuming that any one human is typical. The bonobo is the last of the ‘great apes’ to have its genome sequenced, following the chimp, the gorilla and the orang-outang, but some if not all of these species have sub-species, and there’s enough genetic variation within species to make it vital that we sequence more than one, and even more than a few, individuals of each species. As it is, preliminary findings from Ulindi’s genome indicate that we have a long way to go:

As a start, Prüfer’s team identified regions of the bonobo genome that differ from those of chimps and that may have evolved in bonobos since the split. Many of these regions contain no genes, while the genomic region that seems to have evolved the fastest in bonobos encodes a microRNA molecule that probably regulates the activity of as-yet unidentified genes.

So the story is complex and will take time and a lot more research to tease out. Some 1.6% of our genome is more closely related to that of bonobos than to that of chimps. The significance of this connection will also take time to establish. Mapping our genome to our closest relatives in this way will help us to determine how exactly we are different, to home in on that subsection of our genome that is unique to us. We’re still not clear on that, and then we have to try to work out what emerges from that subsection, in terms of physiology, behaviour and so forth.

Written by stewart henderson

June 21, 2012 at 8:32 pm

Posted in evolution, other life, primates, science

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returning to cephalopods

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A while back I wrote about the extraordinary spawning grounds of the Giant Australian Cuttlefish in Spencer Gulf, not so far from here. Though I’d heard of this habitat a while ago, courtesy of the controversy around the placement of a desalination plant nearby, it took a fascinating TV doco to really spur my interest. Another recent documentary on the intelligence of octopuses, together with some bad news about those spawning grounds, has prompted me to return to the subject of this fascinating class of molluscs.

I’m particularly interested in the sub-class of cephalopods which includes cuttlefish, squid and octopuses [fisherfolk cluster them together as inkfish, for obvious reasons], a sub-class which, it seems to me, has become flavour of the month, or year, or decade, for marine biologists of late.

This season, the numbers of cuttlefish coming in to breed and spawn at Point Lowly in Spencer Gulf have been disastrously low. Those that have come are generally smaller than usual. They normally congregate in mid to late June. No clear cut reason for this drop is on offer [the desal plant is still at the proposal stage – maybe they heard about it on the seagrape vine?], and we’ll have to wait and see if they return next year. Of course we also don’t know if they’ve relocated, or if this would be a normal thing to do – for example we don’t know for how long they’ve been breeding at Point Lowly. It appears that nobody is responsible for monitoring cuttlefish numbers, and presumably nobody is responsible for monitoring temperature, salinity and other variables there either.  The comments on the news article linked to above present various conspiracy theories, not too seriously I hope. BHP did it, to get rid of the cuttlefish as an environmental issue. The Greens did it, to highlight the sensitivity of cuttlefish to even rumours of environmental degradation. Others are arguing that the environment there has already been massively degraded recently, but they offer no suggestions as to what caused this, if it’s true. Hopefully some serious investigations can be made.

Meanwhile, research continues into the intelligence and learning abilities of octopuses. The documentary ‘Aliens of the Deep Sea’, which I saw a couple of nights ago, provided exciting proof of these abilities in a few simple but effective experiments. The most exciting of these involved a newly captured octopus being placed in a tank, where it tended to hide in a corner behind some rocks. A transparent container containing a crab, and with a hole on one side just large enough for the octopus to enter [octopuses are able to squeeze through the narrowest of openings, through distortions of their invertebrate bodies] was placed inside the tank. The octopus didn’t respond to the unfamiliar container. Then another tank was placed alongside it, containing an octopus of the same species. This octopus had been in captivity for some time, and had learned or been taught how to enter the opening to get at the tasty crab. So the experiment was repeated with the experienced octopus, and the inexperienced octopus literally rushed to the edge of its tank to get a ringside view of how the experienced octopus did it. I don’t know if there was any tricksy editing in this scene, but I do know that the sight of this eager spectating had me almost falling off the edge of my seat. And sure enough, when the experiment with the crab was repeated with the inexperienced octopus, it got the idea straight away, and was able to find the hole and get at the crab in no time at all. A number of similar experiments were shown [including the opening of a screw cap], and it became clear that the learning capabilities of these creatures were truly outstanding. It doesn’t seem to matter which species are chosen for these experiments, so it seems evident that such intelligence exists over the range of octopus species [there are presently around 300 recognized species], though more research might have to be done to confirm this.

All this raises tantalizing questions. How do they learn? Octopuses have short lifetimes [some as little as six months] and they learn virtually nothing from their parents, with whom they have almost no contact [females live only long enough to see their eggs hatch, and males die shortly after mating]. Also, how long have they been behaving in such an ‘evolved’ way? Cephalopoda date back some 500 million years, and a rare example of a fossilized octopus has been found, dating back 95 million years. This fossil appears to be remarkably similar to modern species – it appears that little evolving has taken place in the interim. So this kind of cleverness existed on the planet long before homo sapiens arrived on the scene. Indeed the first primates appeared only about 60 million years ago, according to current evidence. What we have here is a fascinating example of how highly intelligent life forms can evolve along completely different pathways from ourselves. Some researchers and atheists are keen to find extra-terrestrial life, especially of a highly evolved type, to demolish any notion that we are special, the uniquely privileged end-game of a supernatural designer. Yet we don’t have to look elsewhere for intelligence, it has been right under our noses throughout the lifetime of our species. We’ve just been too blind, too arrogantly bound up in our ‘specialness’, to really notice.

Written by stewart henderson

August 30, 2011 at 1:02 pm

Posted in other life