08/22/14

Gut instincts


Ars TechnicaA story on Science Daily says research suggests our so-called “free will” may be less free than we ever imagined. We may, instead, be meat puppets ruled by the desires and cravings of the smallest symbiotes we carry: our gut bacteria.

The story opens:

It sounds like science fiction, but it seems that bacteria within us — which outnumber our own cells about 100-fold — may very well be affecting both our cravings and moods to get us to eat what they want, and often are driving us toward obesity… researchers from UC San Francisco, Arizona State University and University of New Mexico concluded from a review of the recent scientific literature that microbes influence human eating behavior and dietary choices to favor consumption of the particular nutrients they grow best on, rather than simply passively living off whatever nutrients we choose to send their way… the authors believe this diverse community of microbes, collectively known as the gut microbiome, may influence our decisions by releasing signaling molecules into our gut. Because the gut is linked to the immune system, the endocrine system and the nervous system, those signals could influence our physiologic and behavioral responses.

Actually this is not really surprising. It has long been known that human evolution has been affected by both viral and bacterial presence, as well as having our own DNA encoded with bits from them. And recently it was discovered bacteria can encode DNA from other animals – even dead ones – into their own.

The discovery of the recombinant DNA process should have alerted everyone to the wider possibility that there may be biological analogues already. After all, it only makes sense that in any symbiotic relationship, there must be some way for all parties to communicate with each other for mutual survival. The gut is a competitive environment with numerous species, so they also need a mechanism for cooperation and communication in ways that also help keep the host alive.

Most life on the planet has some form of symbiotic relationship and many are mutually beneficial like that with our gut flora, although there are also parasitic relationships as well.

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07/25/14

Gangs of Feathered T-Rex


Packs of tyrannosaurs
Imagine, if you will, an early morning scene in the late Cretaceous. The air is quiet as the day warms. At the edge of a large forest a plain of ferns ripples in the light breeze (grass would not evolve for another 20 or so million years). Under the canopy of the ancient beeches and maples, there is movement. Nothing fast, just a hint. A flash of mottled colour against the background. A glint of light off an eye. A soft snuffling. A feather falls silently to the forest floor.

Among the nearby ferns, a pack of ceratopsians grazes, adults watching the woods carefully, nervously, herding the young towards the safety of the pack’s centre with prods of their heads, honking to get the young ones’ attention. They eat the flowers that dot the plain among the ferns and cycads, chew the horsetails that grow at the edge of the ponds and streams. A youngster sees a tasty patch of moss and, unnoticed, slips out between the elders to get it.

Suddenly the forest explodes. Leaves scatter and branches snap as the muscular forms crash through the cover and converge on the young triceratops, separated from the horned protection of the pack. Two large adults, a teenager and two younger tyrannosaurs running a well-coordinated hunt as they have done many times int he past. Their speed makes them a blur against the trees.

The ceratopsians bellow in fear and rage, and quickly form a circle, heads out, protecting the oldest and youngest within the centre. The pack of tyrannosaurs’ charge sounds like thunder, and they screech in anticipation as they race to surround the doomed youngster. They circle rapidly, darting to avoid the feeble attempts at defence from the surrounded dinosaur.

The herd can’t save it, and they move away, quickly, the outer ring still shuffling backwards to keep their ferocious, horned heads facing the danger. The tyrannosaur pack ignores the herd as it feeds, tearing off chunks of the living flesh as the youngster’s screams get fainter.

Their hunger slaked for the moment, the pack would soon retire to the forest to look for another easy target that might venture close by.

Triceratops vs tyrannosaur

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