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tag: biology


A Dove In The Bell Jar

Next month at the Greenwich Gallery, my significant other Julia has a solo exhibition of her photomicrography practice. With a laboratory-grade microscope and digital SLR camera, she explores the hidden microworlds of cellular biology, crystallography, and more.

Alongside a whole series of aluminium-mounted prints, she will be in the gallery on Saturdays and Sundays with the microscope, projecting a live video feed of microscopic specimens onto a plasma display.

You want something teeny looking at? Bring it down.

A Dove In The Bell Jar
Greenwich Gallery
London, SE10 8RS
21 June 3 July 2013

For much more, check out the eponymous blog: A Dove In The Bell Jar

Emergence ch5: Aggregativity: Reductive Heuristics for Finding Emergence

in project: emergence-advent

William C Wimsatt - Aggregativity: Reductive Heuristics for Finding Emergence (1997)

Rather than focusing on seeking the essential characteristics of emergence, Wimsatt's paper takes the opposite approach and attempts to pin down the set of properties for a property to be definitively non-emergent. We saw earlier that it's not a straightforward process to distinguish between the two in any case, with certain "obviously" linear-additive properties being a little more complex on inspection, and vice versa. Wimsatt throws in another nice example of nonlinear composition, that of volume under dissolution: the volume of a salt-water solute is actually less than the volume of either of its constituents. Sometimes, more is less.

The key thesis is that emergence is a consequence of certain organisational properties, combined with context-sensitivity of the parts that constitute this organisation. Non-emergent systems properties are termed "aggregates" by Wimsatt. To be truly aggregative, a property must be functionally invariant when its parts are subjected to any of the following transformations:

  • intersubstitution (that is, rearranging or substituting parts for others)
  • size scaling (adding or subtracting parts)
  • decomposition and reaggregation (of parts)
  • linearity

For the macro-scale systems property to not vary under any of these transformations, it is pretty clear that it must be radically functionally homogeneous. Wimsatt observes that the only paradigmatic aggregative properties are those governed by major laws of conservation: mass, energy, momentum and charge.

Perhaps the most rewarding movement of this argument is where Wimsatt takes it in the final couple of pages. With a background in the philosophy of biology, he writes on the structures that underlie natural selection and the models that we, as scientists, impose to understand them. Here, he criticises the "nothing but X" language of radical reductionism, such as in the oft-touted "genes are the only units of selection". However, if we take the complex dynamical systems that comprise the natural world and attempt to reduce them to a model based on one underlying constituent unit (the gene, the agent, the neuron), we cannot then make claims to universality of our model: this is what Wimsatt terms the functional localisation fallacy. Such a decomposition is useful to study some aspects of a system, but it should be understood that it must be complemented by other such decompositions from different levels and angles.

Mosquito buzz harmonised in mating practices

K http://scienceblogs.com/.../...

mosquito Research from Cornell University, and published in this month's Science (requires subscription), indicates that there is purpose behind the mosquito's buzz besides keeping its human neighbours awake at night: male and female mosquitoes induce harmonic convergence within the frequency spectra of their hums as part of their mating practice. Contradicting earlier research which suggests that males have a highly limited hearing range whilst females are entirely deaf, both sexes were shown to modulate their buzzing frequencies to enter into harmonic love-making.

More info, and video, on Wired's Not Rocket Science.

The Evolution of Invasiveness in Garden Ants

ants.jpg

Fortify your gardens: BBC News reports (based upon this paper) that a novel ultra-invasive ant species, Lasius neglectus, is soon to strike the cold temperate climes of Northern Europe. This new strain is creating supercolonies that are orders of magnitude greater than existing colonies, based on the seemingly counter-evolutionary development of a flightless queen, alongside workers that are willing to mate within their colony rather than first taking flight to pastures new. Moreover, it's a relatively unaggressive form, constituted by "a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies".

As a consequence, it's exhibiting self-organization on a staggering (and somewhat frightening) scale, resulting in single vast populations that inexorably expand outwards. Courtesy of human transport to locations that lack natural parasites (cite, PDF), Lasius neglectus has begun to blanket central Europe over the course of just 25 years.

The authors conclude that:

"Our results show that invasive L. neglectus populations are a potential problem of global dimensions, and a particular threat for man-made ecosystems in the cold-temperate climate zones that have so far suffered very little from invasive ants."

I, for one, welcome our new insect overlords.

Starlings over Brighton's West Pier

Work is coming to a climax on the Fragmented Orchestra, with more sound transmission sites being installed around the UK on a daily basis. There are 24 sites in total, spread as far afield as Inverness, Belfast and Cornwall, so it's no small feat to co-ordinate and maintain; it's also vital that each site provides a reliable 24/7 audio stream to the central neuro-granulation server at the FACT gallery for the duration of the installation, a requirement which has thrown up a number of unexpected obstacles. One illuminating example is the site at the Kielder Observatory, Cumbria, which is not connected to the Internet and so is hooked up via an RF transceiver to the nearby village, at which point the radio transmission is encoded in real-time and streamed via the net to the neural server. This then relays the mixed-down stream to the web for (eventually) web clients to listen in to. Heavens.

Still, the infrastructure is now mostly in place. I accompanied Nick on Thursday's installation at Brighton's West Pier, which remains an icon of the city despite being rendered a skeletal hulk by a fire in early 2003. The soundbox itself is installed in the beach hut at the end of the pier, picking up an evocative mix of seagulls, waves and passers-by - and relaying the neuro-granulated stream through the resonant surface of its window.

As we were finishing laying the cables for the site, we were fortunate enough to witness what is apparently another iconic Brighton sight: the nesting of a staggeringly vast flock of starlings, who gather together each dusk to swoop around the pier before landing on it to rest. Never before have I seen flocking on such a remarkable scale.

Beach hut, Brighton West PierThrough the windowBroken glassFacing westwardsFlocking starlingsFlock divides in twoWest PierFlocking starlings #2