The natural history of the hand

What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern?

-- from The Origin of Species by Charles Darwin, quoted by Carl Zimmer in a pleasant note about hands.

I am reminded of something from Jonathan Kingdon (2003) quoted in my forthcoming book:

When I watched possums expertly finger-drumming bark to locate larval burrows or maneuvering witchetty grubs out of holes and into mouths, I suspect I that was witness to some of the most ancient skills that distinguish not just possums but, maybe archaic mammals as a whole. Touching, gauging, gouging, probing hands and fingers are so closely coordinated with smelling, seeing, hearing, and tasting that their refinements have as much to do with serving senses and feeding appetites as with clambering through branches. If, as most evolutionary biologists would contend, human anatomical history is made up of successive increments, perhaps we need look no further than our hands to discover a legacy that could stretch back 140 million years.

Aye-aye

The limits of human senses

Our vision is limited to a tiny segment of the electromagnetic spectrum, where wave frequencies in their fullness range from gamma radiation at the upper end, downward to the ultralow frequency used in some specialized forms of communication. We see only a tiny bit in the middle of the whole, which we refer to as the “visual spectrum.” Our optical apparatus divides this accessible piece into the fuzzy divisions we call colors. Just beyond blue in frequency is ultraviolet, which insects can see but we cannot. Of the sound frequencies all around us we hear only a few. Bats orient with the echoes of ultrasound, at a frequency too high for our ears, and elephants communicate with grumbling at frequencies too low.

Tropical mormyrid fishes use electric pulses to orient and communicate in opaque murky water, having evolved to high efficiency a sensory modality entirely lacking in humans. Also, unfelt by us is Earth’s magnetic field, which is used by some kinds of migratory birds for orientation. Nor can we see the polarization of sunlight from patches of the sky that honeybees employ on cloudy days to guide them from their hives to flower beds and back.

Our greatest weakness, however, is our pitifully small sense of taste and smell. Over 99 percent of all living species, from microorganisms to animals, rely on chemical senses to find their way through the environment. They have also perfected the capacity to communicate with one another with special chemicals called pheromones. In contrast, human beings, along with monkeys, apes, and birds, are among the rare life forms that are primarily audiovisual, and correspondingly weak in taste and smell.

-- E O Wilson

Photo: Alistair Lee

Imagination and seeing

The term “imagination” in what I take to be its truest sense refers to a mental faculty that some people have used and thought about with the utmost seriousness. The sense of the verb “to imagine” contains the full richness of the verb “to see.” To imagine is to see most clearly, familiarly, and understandingly with the eyes, but also to see inwardly, with “the mind’s eye.” It is to see, not passively, but with a force of vision and even with visionary force. To take it seriously we must give up at once any notion that imagination is disconnected from reality or truth or knowledge. It has nothing to do either with clever imitation of appearances or with “dreaming up.” It does not depend upon one’s attitude or point of view, but grasps securely the qualities of things seen or envisioned.

I will say, from my own belief and experience, that imagination thrives on contact, on tangible connection. For humans to have a responsible relationship to the world, they must imagine their places in it. To have a place, to live and belong in a place, to live from a place without destroying it, we must imagine it. By imagination we see it illuminated by its own unique character and by our love for it. By imagination we recognize with sympathy the fellow members, human and nonhuman, with whom we share our place. By that local experience we see the need to grant a sort of preemptive sympathy to all the fellow members, the neighbors, with whom we share the world. As imagination enables sympathy, sympathy enables affection. And it is in affection that we find the possibility of a neighborly, kind, and conserving economy.

-- Wendell Berry

Gomphotheres of the Rambunctious Garden

At an event titled Human Nature? Man and the Environment at Canning House in London yesterday, Yadvinder Malhi, one of the four excellent speakers, invited his listeners to consider human impacts on the Amazon basin over a longer time frame than many of us are accustomed to do. 

Malhi described the sense of sense of awe he felt at seeing this continent-sized forest on his first visit in 1995. Contemplating the huge trees, he experienced nature in the Amazon as essentially benign. The feeling has remained with him. You do have to watch out for the odd snake, but essentially there's nothing [natural] to worry about. Even the insects aren't too bad.

His more recent experience in the West African rainforest, by contrast, was a completely different. Walking with a guide in forest in Gabon for the first time, he learned to stop every few steps and listen for forest elephants: cow-sized animals which look cute but are extremely dangerous.

The contrast led him to ask himself, why were there no elephants in the South American rainforest?The answer is that, of course, there were. Gomphotheres were common across much of the continent until about 12 to 10,000 years ago when, along with some fifty other large mammals including the Stegomastodon, the Toxodon, the Giant Ground Sloth and the Glyptodont, they became extinct.

Few dispute that humans played an important role in many of these extinctions, as well those on other continents beyond Africa from about 60,000 to 10,000 years ago. Rapid climate change may also have played a part. Quite likely it was a combination of the two pressures that did it. (In Africa animals had co-evolved with humans, and learned to be wary of them much earlier [although see this].)

What impact did the South American extinctions have on the forest? Elephants and other large mammals have significant impact on African ecosystems, and there is every reason to suppose that the same was true for their counterparts in South America. In Africa, tree cover is often more patchy where elephants are present in large numbers. On the other hand, the large seeds of some tree species may need large animals such as elephants to spread them around, and the same would have been true in the New World.

In addition, it may be that (over a very long time) big animals played a major role in the transport of nutrients flowing down the rivers to the poor soils beyond. The animals would eat vegetation on the river banks and often pooh elsewhere. Other animals would later eat the vegetation so fertilized and carry nutrients further inland. The Amazon ecosystem could still be responding to the loss of these animals-as-nutrient-transport-systems 10,000 years later.

The Amazon, said Malhi, has only really become a part of the global social-economic system since around 1950, his favoured date for the start of the Anthropocene, or at least its startling acceleration. Malhi suggested four scenarios/ways of thinking about the future Amazon:

• 'Breadbasket' (made possible by huge inputs of fertilizers and fuel)
• (Inter)national conservation park
• Lungs of the world
• Rambunctious garden

The last scenario, from a phrase coined or popularized by Emma Marris, would, he suggested, represent compromise between the preceding visions -- one that recognizes that Amazonia was and is a human-altered system.

I wonder: what about a project to introduce and monitor the impact of a small herd of elephants on a designated and contained area of South America forest or savannah?

P.S. 26 April:  following the four speakers, some discussion focused on Brazil's land use law.

Sick nature

Darla Rooks, a fisherwoman, told Al Jazeera that she is finding crabs “with holes in their shells, shells with all the points burned off so all the spikes on their shells and claws are gone, misshapen shells, and crabs that are dying from within … they are still alive, but you open them up and they smell like they’ve been dead for a week”...

...Along the Gulf there have been reports of collapsing fisheries, mutated shrimp, fish with oozing sores, underdeveloped blue crabs lacking claws, and eyeless crabs and shrimp...

-- from Sick Fish, Eyeless Shrimps and Dead Dophins

Death of coral reefs: exaggerated?

We demonstrate that important functional components of coral assemblages “sample” space differently at 132 sites separated by up to 1740 km, leading to complex latitudinal shifts in patterns of absolute and relative abundance. The flexibility in community composition that we document along latitudinal environmental gradients indicates that climate change is likely to result in a reassortment of coral reef taxa rather than wholesale loss of entire reef ecosystems.

-- from Assembly Rules of Reef Corals Are Flexible along a Steep Climatic Gradient by Terry P. Hughes et al.

XNA

Heredity and evolution, two hallmarks of life, are not limited to DNA and RNA but are likely to be emergent properties of polymers capable of information storage.

-- Synthetic Genetic Polymers Capable of Heredity and Evolution

"There is nothing Goldilocks about DNA and RNA," Holliger told Science. "There is no overwhelming functional imperative for genetic systems or biology to be based on these two nucleic acids.

-- DNA alternative created by scientists

The work heralds the era of synthetic genetics, with implications for exobiology, biotechnology, and understanding of life itself

-- Gerald Joyce

XNA analogues of nucleic acids

P.S. Good overview by Ed Yong

Animals of the Great Unconformity

A massive and toxic alkalisation of the oceans hundreds of millions of years ago was probably a spur to the evolution of complex animal life. More...

Cellular origins in a viral world

The discovery of an unusual hybrid virus living in one of the harshest environments on the planet suggests a solution to the conundrum of how RNA-based life 'updgraded' to DNA-based life. More

P.S. A good phrase: "It's a mythological beast of a virus, but it actually exists.”

Where be your quiddities now?

This is the heart of phenomenal experience: any one conscious experience is both highly differentiated from any other one but also unitary, holistic. The larger the phi, the richer the conscious experience of that system. Furthermore, the theory assigns any state of any network of causally interacting parts (these neurons are firing, those ones are quiet) to a shape in a high-dimensional space. The shape (think of it as a crystal in a fantastically high-dimensional space) accounts for the peculiar feel of any one conscious experience. If the network switches into a different state - you fantasise about sex rather than listen to a droning speaker - the crystalline shape changes as well.

This crystal is the system viewed from within. It is the voice in the head, the light inside the skull. It is everything you will ever know of the world. It is your only reality. It is the quiddity of experience. The dream of the lotus-eater, the mindfulness of the meditating monk, the agony of the cancer patient, all feel as they do because of the shape of the distinct crystals in a space of a trillion dimensions.

-- Christof Koch

Landscape of The Moon's Last Phase 1943 by Paul Nash

P.S. But is it the case that consciousness always only exists ultimately in relation to an external object? As Riccardo Manzotti tells Tim Parks, 'consciousness is spread between sunlight, raindrops, and visual cortex, creating a unique, transitory new whole, the rainbow experience.'

'Reverse panspermia'

Speculative, but fun:

A handful of rocks [from Earth] could even have made it to planets around other stars. Once such could be Gliese 581, a red dwarf 20 light years away with a super-Earth orbiting at the outer edge of its habitable zone, where water could be liquid. Hana and colleagues calculated that about 1000 rocks from the Chicxulub impact could have reached that far in about a million years, meaning any life that made it would have had 64 million years to develop - or die off.

-- from How Earthly life could populate space by panspermia.

Plankton dreams

A good short movie



Hat tip Grrlscientist.

Evidence that plankton numbers have declined steeply in recent decades is debated. But the evidence that they will fall in the future as the oceans warm is strong.

Plankton-related posts on this blog include: The power of plankton, Mobile marine reserves, Plankton Chronicles, Big World, Touching the world ocean, Dancing and The numberless goings-on of life...

Full of noises

When we were living closer to the natural world, we discovered links between the ways in which sounds were formed - what I call "biophonies". We then used this structure to learn to orchestrate and vocalise. That's how we got our music. It goes back to when humans first emerged from the forests and plains of Africa...

There are a couple of groups, like the Jivaro in South America and the BiAka tribe of pygmies in the Central African Republic. Because they live as part of the natural world, they still do this collective music. They use the natural world as a karaoke orchestra. There's nothing primitive about it - it is far more advanced than anything we are doing.

-- Bernie Krause

'The pillars of morality...

...are reciprocity (fairness) and empathy (compassion).'

There is little new in this presentation if you're already familiar with Frans de Waal's work but it's a nice introduction if you're not:

Men, in spite of all their morality, would never have been better than monsters, if nature had not given them pity to assist reason. Indeed, what is generosity, what clemency, what humanity, but pity applied to the weak, to the guilty, or to the human species in general?...It is this pity which hurries us without reflection to the assistance of those we see in distress; it is this pity which, in a state of nature, stands for laws, for manners, for virtue, with this advantage, that no one is tempted to disobey her sweet and gentle voice.

-- from On the Inequality of Man by Jean-Jacques Rousseau (and quoted by Timoth Pachirat in Every Twelve Seconds)

Eating songbirds

When the platters of songbirds arrived, everyone would start to chirp. Except for the birds, of course. They would be plucked bare, squeezed between bread and pork, tiny, with the useless stumps that used to be their wings looking like broken arms bent backwards. Mostly, you’d notice their big, empty eye sockets and their beaks.

The beaks were generally the subject of conversation once people started eating: are you or are you not one of those people who eats the beak? The birds were so small and fragile that the usual breast, thigh, drumstick division didn’t apply; people would just hold the beak between their manicured thumbs and forefingers and nosh their way through the entire bird, bones and all. They would say a little rhyme, “Anche la Regina Margherita mangia il pollo con le dita,” (even Queen Margaret ate chicken with her fingers), to excuse themselves before digging in.

-- Clare Mahon

Mighty worms

This sentiment from Gilbert White (Letter XXXV, 1771) is often quoted:

The most insignificant insects and reptiles are of much more consequence, and have much more influence in the economy of Nature than the incurious are aware of, and are mighty in their effect, from their minuteness, which renders them less an object of attention, and from their numbers and fecundity.

More remarkable is the continuation, in which White's intuition broadly anticipates Darwin's research 110 years later:

Earth−worms, though in appearance a small and despicable link in the chain of Nature, yet, if lost, would make a lamentable chasm. For, to say nothing of half the birds, and some quadrupeds, which are almost entirely supported by them, worms seem to be the great promoters of vegetation, which would proceed but lamely without them, by boring, perforating, and loosening the soil, and rendering it pervious to rains and the fibres of plants, by drawing straws and stalks of leaves and twigs into it, and, most of all, by throwing up such infinite numbers of lumps of earth called worm−casts, which, being their excrement, is a fine manure for grain and grass. Worms probably provide new soil for hills and slopes where the rain washes the earth away; and they affect slopes, probably to avoid being flooded. Gardeners and farmers express their detestation of worms; the former because they render their walks unsightly, and make them much work; and the latter because, as they think, worms eat their green corn. But these men would find that the earth without worms would soon become cold, hard−bound, and void of fermentation, and consequently sterile...