Mar. 20th, 2017

Jennifer Ackerman's book reminds me of "The Sports Gene" quite a bit. Biology as destiny.
  • Among the published studies tumbling from scientific journals are some with titles that lift the brows: “Have we met before? Pigeons recognize familiar human faces”; “The syntax of gargles in the chickadee”; “Language discrimination by Java sparrows”; “Chicks like consonant music”; “Personality differences explain leadership in barnacle geese”; and “Pigeons on par with primates in numerical competence.”
  • the dawn chorus, that mysterious moment when birds sing with a thousand voices in “A Music numerous as space— / But neighboring as Noon,” as Emily Dickinson wrote.
  • a friend saw perched just above a nest of tent caterpillars: The cuckoo waited as the caterpillars climbed out of the nest to scale the tree, then plucked them off one at a time, like sushi from a conveyor belt.
  • Perhaps it’s because they’re so unlike people that it’s difficult for us to fully appreciate their mental capabilities. Birds are dinosaurs, descended from the lucky, flexible few that survived whatever cataclysm did in their cousins. We are mammals, related to the timid, diminutive shrewlike creatures that emerged from the dinosaurs’ shadows only after most of those beasts died off. While our mammal relatives were busy growing, birds, by the same process of natural selection, were busy shrinking.
  • More recently, genius has been defined as “nothing more nor less than doing well what anyone can do badly.”
  • We also share with birds similar ways of meeting nature’s challenges, which we’ve arrived at through very different evolutionary paths. It’s called convergent evolution... To meet the challenges of filter feeding, creatures as far apart on the tree of life as baleen whales and flamingos show striking parallels in behavior, body form (large tongues and hairy tissues known as lamellae), even body orientation during feeding.
  • startlingly similar gene activity in the brains of humans learning to speak and birds learning to sing, suggesting that there may be a kind of core pattern of gene expression for learning shared by birds and humans alike and arrived at through convergent evolution.
  • New Caledonia, a remote tropical finger of land in the southwest Pacific, halfway between Australia and Fiji. The Parc des Grandes Fougères is named for the giant tree ferns that grow to seven stories
  • For Darwin, even earthworms “show some degree of intelligence” in their manner of dragging pine needles and vegetable matter to plug up their burrows, protection from the proverbial “early bird.”
  • “Those who are in anthropodenial,” says de Waal, “try to build a brick wall to separate humans from the rest of the animal kingdom.”
  • I watched the whole shimmering sheet of them dark against the sky, wheeling, twisting, eddying in intricate movements with the cohesion of a single organism—
  • The great naturalist Edmund Selous, who loved birds passionately and observed them with scientific fervor, attributed this flocking phenomenon to telepathic thought transference from one bird to the next. “They circle; now dense like a polished roof, now disseminated like the meshes of some vast all-heaven-sweeping net, now darkening, now flashing out a million rays of light . . . a madness in the sky,”..  Instead, each bird is interacting with up to seven close neighbors, making individual movement decisions based on maintaining velocity and distance from fellow flock members and copying how sharply a neighbor turns, so that a group of, say, four hundred birds can veer in another direction in a little over half a second. What emerges is almost instantaneous ripples of movement in what appears to be one living curtain of bird.
  • Maybe a good way to measure bird cognition, Lefebvre thought, would be to look at these sorts of occurrences—birds doing unusual new things in the wild... Among the more inventive examples: bald eagles ice fishing in northern Arizona.
  • One of Lefebvre’s favorites was the report of vultures in Zimbabwe that perched on barbed-wire fences near minefields during the war of liberation, waiting for gazelles and other grazers to wander in and detonate the explosives. It gave the birds a ready-made meal already pulverized.
  • Chickadees are also possessed of a prodigious memory. They stash seeds and other food in thousands of different hiding places to eat later and can remember where they put a single food item for up to six months.
  • To meet the constraints of flight, nature has in fact considerably lightened a bird’s load with a skeleton that blends strength and airiness. Some bones have been fused or eliminated. A light beak made largely of keratin has replaced a heavier, toothy jaw. Other bones, such as wing bones, are pneumatic, almost hollow but reinforced with strutlike trabeculae to keep them from buckling. A bird’s bones are dense only where needed—even denser than the bones of their mammal counterparts—in the legs and in the deep solid breastbone that anchors the wings.
  • that birds possess more than twice as many genes for bone remodeling and resorption than mammals do. Most bird bones are hollow and thin walled, yet surprisingly stiff and strong. The paradoxical result sometimes boggles the mind: A frigate bird with a seven-foot wingspan has a skeleton that weighs less than its feathers.
  • A bird’s wild knot of a heart is four-chambered and double-barreled like our own, but tiny, with a beat far more rapid (between 500 and 1,000 times a minute for black-capped chickadees; 78 for humans). Its respiratory system is quite extraordinary, proportionately larger than in mammals (one fifth of its body volume, compared with one twentieth in mammals), but much more efficient. Its “flow-through” lung, encased in a rigid trunk, maintains a constant volume (in contrast with mammalian lungs, which expand and contract in a flexible body) and is connected to an intricate web of balloonlike sacs that store air outside the lungs.
  • The condensed genomes of birds may also be an adaptation to powered flight. Birds have the smallest genomes
  • Dinosaurs gave rise to chickadees and herons in part through a process of relentless shrinking, a kind of Alice in Wonderland phenomenon known as sustained miniaturization.
  • As it happens, we humans may have pulled just such a Peter Pan–like move. As adults, we share the big head, flat face, small jaw, and patchy body hair of baby primates. Paedomorphosis may have enabled us to develop bigger brains, just as it did in birds.
  • In other words, nest sitters end up with bigger brains than nest quitters.
  • “Overall, the parallels between mammalian and avian sleep raise the intriguing possibility that their independent evolution may be related to the function served by this pattern of sleep: the evolution of large, complex brains in both birds and mammals.”
  • MIGRATION IS ANOTHER TRADE-OFF. Birds that migrate have smaller brains than their sedentary relatives.
  • elephant brains have three times the number of neurons found in the human brain (257 billion to our average 86 billion). But 98 percent of them are in the elephant cerebellum, she says, where they may be involved in control of the trunk, a two-hundred-pound appendage with fine sensory and motor capabilities.
  • this suggests that what determines cognitive abilities is not the number of neurons in the whole brain but in the cerebral cortex—or its equivalent in birds.
  • Whereas the nerve cells in a mammal’s neocortex are stacked in six distinct layers like plywood, those in the bird’s cortexlike structure cluster like cloves in a garlic bulb. But the cells themselves are basically the same, capable of rapid and repetitive firing, and the way they function is equally sophisticated, flexible, and inventive.

Profile

fiefoe

July 2017

S M T W T F S
      1
2 3 45678
9 101112131415
16 171819202122
23242526272829
3031     

Page Summary

Style Credit

Expand Cut Tags

No cut tags
Page generated Jul. 25th, 2017 08:32 pm
Powered by Dreamwidth Studios