Monday, January 18, 2016

Hockomock After Snow

I made a brief foray into Hockomock Swamp along the old railway embankment a few weeks ago, and that put it into my mind to see it this morning (MLK Day) in a new white coat.  Instead of going in from the south, this time I used the powerline right-of-way that crosses the embankment.  I hadn't been this way since last winter.  It was bright, not too windy, and not far below freezing: ideal winter hiking weather.  

 Entering from MA rt138, where it is part of the Massachusetts Bay Circuit Trail.

 An improbable sight so far into the swamp: could there have been
an Infinite Improbability Drive* in operation somewhere close?

Turning down the old railway embankment, then looking back at the crossroads.

Off the embankment & right-of-way the terrain is wet, with frequent standing water and streams.

The embankment interrupts water flow through this part of the swamp,
so it was built with culverts beneath it.  I like watching and listening here.

 Whatever made these tracks crossed the bank and then turned parallel to and within inches of the water below.  Short-tailed weasel fits the bill, maybe.  (Peterson Flash Guide: Animal Tracks)

*High-tech** interstellar propulsion system able to generate infinitely improbable events on demand--such as your spacecraft's infinitely improbable arrival elsewhere in the universe without having crossed the intervening space.  The operation of the drive creates locally improbable events as a side-effect.  (Hitchhiker's Guide to the Universe by Douglas Adams)

**Since superseded by the even cooler Bistromathic Drive.  (see above source)

Friday, January 15, 2016

What the Snow Shows

 All plainly visible after snow as at no other time: a bit of lichen fallen from a branch,
some bark fragments, and a lot of tiny particles of what might be soil or dust.  (2/7/15)
I first notice last winter--the Winter of Endless Snow--how snow shows what's been in the air.  The high contrast shows up dust, dirt, tree bark, whatnot, which is normally lost on pavement, soil, or leaf litter.

I have been accumulating seeds for the native trees I plan to plant in spring; all except one: I had no paper birch seeds.  The few local trees I know of carry their branches too high for me to reach, but waiting to collect the seeds from the ground isn't practical, because they are so small and hard to see.  Mindful of the snow trick, I headed straight for the paper birch down the street today.  Even though the snow was days old and partly melted, I quickly spotted a few tan samaras.  They were very thinly scattered, so it took probably five minutes to collect a small pinch to bring home and try to sprout.  Passersby on the busy main road saw an old guy bent over, carefully picking up invisible objects--adding to the Lore of the Crazy Neighbor.  But, then, I'm used to it.  

Birch samaras are tiny things--no more than two or three millimeters wide.  
The two little wings help ensure that the young are dispersed so as not to 
grow up in the shade of their mother.  Bottom right in the second photo,
 looking a bit like a fleur de lis, is a scale from a "cone" of the same tree.

I cannot help thinking of the sausage-shaped fruits of birch as anything but "cones,"
since they are built a bit like pine cones.

Wednesday, January 6, 2016

And you thought the seasonal changes in sunrise, sunset and day length were simple?

Oh, no.  Although the shortest day/longest night for the northern hemisphere occurs at the December solstice, sunrise and sunset times don't fall so neatly into line!  It even depends where in the northern hemisphere you are!  EarthSky explains how and why better than I could.

Here in the Boston area, the sun has risen at about 7:12am eastern standard time every morning since the beginning of the year.  Sunsets, on the other hand, have been getting slowly later since before the middle of December, when they bottomed-out at about 4:12pm est.  Here's the NOAA site where you can see for yourself. 

Meanwhile, Earth made its closest approach to the sun on Jan 2!  (That three-million mile difference between closest (perihelion) and farthest (aphelion, July 5) amounts to about three percent of the 93-million-mile average distance--not enough of a difference to overwhelm seasons caused by earth's axial tilt.  I do wonder, though, if it eases our winters a bit, while worsening Australia's summers!)

From what EarthSky tells us, perihelion and aphelion will line up with the equinoxes in 6430.  With the greatest and least distance (and therefore light intensity) completely out of sync with the seasons, I wonder if those seasons will be a bit milder worldwide.  And, if so, what difference did these milder climates mean to the people of 2400 BCE???

Friday, January 1, 2016

Lyell, Darwin and Wallace (I)

This will NOT be my usual post of observations in suburban natural history.  But it IS a post I'm itching to write!  

Owing to my "discovery" of FREE electronic books after receiving an e-reader for my birthday, I have been immersed of late in the world of Charles Darwin.  I hadn't read his Origin of Species, and the journals of his round-the-world voyage since I was an undergrad, so I downloaded both and started in on the Journal.  I emerged a month later with a new appreciation for Darwin the Geologist (which is how he thought of himself) and quickly turned to Charles Lyell, the author of the three-volume Principles of Geology that came out around the time of Darwin's voyage and became both a major resource for Darwin, and a classic of the science in its own right.  (The Beagle's captain, Robert Fitz Roy, presented Darwin with the first volume* as a gift, and Darwin had the remaining volumes shipped to him during the five-year voyage.) 

I plowed through Principles of Geology over Christmas break, learning much about the state of science in the middle of the nineteenth century.  Lyell included a good deal of history and biology in his book, and--despite a scientific open-mindedness that sometimes surprised me--revealed some of the attitudes and biases of Victorians in his writing. 

Thinking about these two, their friendship, the encouragement Lyell gave Darwin on publishing his theory of species evolution, and yet Lyell's disbelief in Darwin's theory, I turned for the first time to the "other evolutionist": Alfred Russel Wallace.  Wallace is credited with arriving at very much the same theory as Darwin, and spurring Darwin to finally publish his "little book"--after decades of dithering--so that he wouldn't lose his priority of discovery.  In my scanty memory of science history, Wallace isn't credited with much else, but he certainly deserves to be. 

I will take these men in roughly chronological order, devoting this post to Charles Lyell.

<b>Charles Lyell</b>, British Geologist Photograph

Lyell was a lawyer, but also a man of means able to travel freely.  He was both a scientist** in his own right, and a great theorist and compiler of information.  His Principles is comprehensive, but is not a field manual.  (Darwin learned his rocks, strata, and the like as a college student--though almost entirely unofficially.)  The picture of 19th century science I get from reading Lyell ranges from science's attitudes toward religion, to white supremacist notions of Victorians, to the details of physical geography and stratigraphy. 

I will take the science first.  Lyell was a chief proponent of Uniformitarianism: the idea that the earth's surface was formed by ordinary processes that had occurred over long periods of time.  ("Deep time"--uncertain in extent, but probably measured in millions of years--was a break from the biblical timeline of 6000-odd years made popular by Bishop Usher.)  Uniformitarianism is often summarized: "the present is the key to the past."  The opposing camp believed that vast catastrophes had shaped the earth in olden times (often equated with biblical events such as Noah's flood), leaving us a landscape that could not be explained by present experience.  It was the consensus opinion that many species of ancient life were now extinct, and Lyell was one who believed extinction to be a normal part of earth history, rather than resulting from catastrophes.  Uniformitarianism was on the ascendancy, and modern geology traces its understandings mainly to it, though acknowledging that catastrophes DO sometimes happen: enormous volcanic eruptions and asteroid strikes, for example. 

Geologists, aware of the power of erosion to wear down the landscape, was very much concerned with understanding how there could still be mountains on an old earth.  At the same time, commonplace knowledge of strata bearing sea shells found high in the mountains begged explanation. Much of Lyell's second volume is reports of land that have risen or sunk in historical, or recent prehistorical, times.  Much of this work is very ingenious.  For example, a Greek ruin included pillars that showed evidence of damage by marine life, and historical reports of their being sometimes on dry land, other times in shallow water; Lyell interprets this as evidence that that landscape had fallen deep enough for the pillars to be completely submerged since they were built, and risen and fallen several times more recently.  He discusses many instances of coast that has sunk and been destroyed by the sea, including loss of whole villages in Great Britain.  He finds strata with marine fossils elevated above sea level, interpreting the age in which the land rose according to how many of the fossils matched creatures still living: the more that matched, the more recent the uplift.  (Geologists knew that lower rock strata in a series were older than higher strata, but had no way to know just how old any strata were.)  What causes the rising and falling of the earth's surface?  Lyell describes several hypotheses, some laughable until you realize that no one had any idea what lay below earth's surface beyond evidence that it was hot and molten in places.  He does not pretend an answer, but finds it pretty clear that earthquakes and volcanoes are somehow related to each other, and intermediate causes for some of the motion. (Not until just fifty years ago did we really begin forming a comprehensive picture, the theory of plate tectonics.)

Lyell's entire third volume is devoted to living species, what they are, their geographic distribution, and the question of their origin.  His understanding of ecology is very respectable.  He has clear notions of how species grow, decline and change their distribution in response to their physiological requirements, changes in conditions, and the influences of other species--whether competitors or predator/prey.  Except for terminology, Lyell could almost have taught the introductory ecology class I took in college.  He spends a good deal of time and ink first explaining Jean Baptiste Lamarck's evolutionary theory (now remembered as the first, but flawed, truly evolutionary theory) and then takes him apart with a very sharp scalpel.  He got my full attention when he turned his gaze on variation: the raw material of Darwin's Evolution by Natural Selection that would burst upon the world only a few years after this particular edition of Principles came off the presses.  Lyell showed evidence that variation was not the bottomless well Darwin needed, but had built-in limits.  He gave instance after instance of animals brought under domestication, bred in various direction, and then hitting a wall after they ran out of variation.  I wondered how Darwin would answer this.*** 

Of course, genetics was a black hole until the 20th century.  Many observations showed that offspring had characteristics of their parents and sometimes other ancestors, and that individuals varied.  But there was no clear mechanism to explain this.  (Gregor Mendel, hard at work crossing peas in his monastery garden, would publish in an obscure journal no one would read for decades.  He it was who discovered genes.)  So ideas like "inheritance of acquired characteristics" (Lamarck) were far from dead letters; Darwin entertained some unlikely theories of inheritance himself, and considered Lamarkian ideas possibly valid in late editions of his Origin.  

Science in Lyell's day was in the middle of a slow evolution.  Physics and chemistry had long since stopped invoking the "God hypothesis" to explain their observations.  The other natural sciences were following, but biology was lagging behind--in part because no one could come up with a plausible way to explain how living things could be so closely adapted to their situations without being designed so.  (Of course, even today there are those who can't accept it, but it's no longer a scientific problem, just one of human nature.)  Lyell himself looks hard for natural explanations for things, but still occasionally reaches for a teleological**** explanation.  "It seems, also, reasonable to conclude, that the power bestowed on the horse, the dog, the ox, the sheep, the cat, and many species of domesticated fowls, of supporting almost every climate, was given expressly to enable them to follow man throughout all parts of the globe, in order that we might obtain their services, and they our protection."  And the last few paragraphs of his Principles is a kind of credo.  "But in whatever direction we pursue our researches, whether in time or space, we discover everywhere the clear proofs of a Creative Intelligence, and of His foresight, wisdom, and power."  Not until the dawn of the 20th century would science finally refuse to settle for supernatural answers.  

The Victorian Lyell displays what I think a remarkable open-mindedness.  At one point he muses upon the future of humanity; he expects that humanity, as one among many species that have come and gone, will eventually become extinct as they have.  Later, in the realm of ecology, he points out that a natural landscape brought into cultivation--increasing its productivity for us--might very well be less productive for wildlife, making it at best a mixed blessing in the whole scheme of things.  "It admits of reasonable doubt whether, upon the whole, we fertilize or impoverish the lands we occupy," he writes.  Though he is aware of human-caused extinction, on the other hand, he seems to believe that it is our destiny--like that of many successful species before us-- to dominate and modify the face of nature.  (Of course, he could have little way of knowing what a hash we would make of it.)

I will leave discussion of Lyell's attitude toward imperialism and other races for another post, since it was one shared by other protagonists.

Description Sir Charles Lyell, 1st Bt.jpg

*This first volume was devoted to a history of geological ideas, going all the way back.  I suspected it would be a snoozefest.  It wasn't.

**Science at that time was not a profession; so most scientists had day jobs.  Many were clergyman, since the study of natural history was encouraged with the idea of learning about God from His creation.  Darwin came from a landed upper-middle-class family (at one point preparing for the ministry himself) and married his first cousin Emma Wedgewood (yes, that Wedgewood family), making him a man of leisure.  --though to his everlasting credit he worked very hard his whole adult life at his chosen vocation, making many discoveries which were eclipsed by his theory of evolution.

***Today we know that we inherit genes from our parents in the form of molecules of DNA that encode information, and that this DNA accumulates code variations randomly over time as chemical changes called mutations.  So although a particular population of domesticated animals really can "run out" of variation in the short term, mutation will continue to add more variation to the gene pool in the long term.

****Teleological explanations are about purpose; things are the way they are because they are means to some end.  For example, dogs have so much variation because that enables them to be bred to many different uses.  This is simply another way of saying it was "designed" that way.  (Lyell himself discusses a much more reasonable alternative hypothesis: that domestication didn't "work" on any animal that didn't start with enough variation to make useful breeds--such attempts were early abandoned and not recorded.)