In June birds are in full abundance. They are on the ground, in the trees and flying here and there. But why in the air? Why do birds fly at all? One good reason is that they escape ground-dwelling predators. Another is that the air is filled with nutritious insects. Here is a whole new environment available to whomever can enter it. Over time any slight hereditary modification in a bird ancestor, which at first enables soaring from a tree or a brief taleoff while running, when further enhanced leads to flight.
What about insects, most of which fly? What advantages does an aerial capability confer upon them? One great advantage is faster locomotion. It would take a fly a long time to walk from Saratoga Springs to Ballston Spa, but in flight it could be done in 20 minutes. The great advantage of fast flight is the ability to disperse over large areas which in turn means a greater chance of surviving abrupt environmental changes. In the fossil record wings first appear in insects as a double pair and many existing kinds of insects still have four wings (beetles, bees, butterflies). Some insects have lost a pair of wings and now have only two (flies) and a few kinds of insects have lost flying wings altogether (fleas, bedbugs). There is a hitch in flight as a way of escaping predators. Some birds have evolved as predators (hawks) and among their prey are their fellow birds. The same thing occurred among insects. Dragonflies feed upon many kinds of insects.
The only other truly flying animals are bats and they serve us well by eating enormous numbers of night-flying insects, especially mosquitoes. All those other animals described as flying (flying squirrels, flying fish) do not truly fly, they soar and glide. If we sometimes imagine how delightful it might be to fly lke a bird, we should keep in mind to look over our shoulder for the flying predator always lurking nearby.
Monday, May 30, 2011
Wednesday, May 4, 2011
Miniessay for May 2011
In May with leaves emerging, we think of that vast amount of leaf surface accomplishing photosynthesis, making food for those leaf-producing plants. We also know that the process is valuable in that it helps reduce carbon dioxide in the atmosphere and supplies oxygen. It is much less well known that photosynthesis occurs in the oceans as well, though not so much the shoreside seaweeds or those in the Sargasso Sea. Instead, there are minute photosynthetic bacteria (cyanobacteria) in the oceans that produce as much as 20% of the oxygen we breathe, but this was not known until the late 1980's. The discovery was made by a Skidmore College Biology Department graduate, Sally (Penny) Chisholm, and others, working at the Woods Hole Oceanographic Institute and MIT.
Of such small size that it would take 1000 to line up across the head of a pin, there might be a million of these oxygen-producing bacteria in a thimbleful of seawater. It is hard to believe that such important organisms were unknown for so long, but in fact the whole world of tiny creatures drifting in the oceans (and in lakes and ponds) was not known until 1828 and was not called plankton until 1887. When creatures are large, we easily recognize differences (an elephant is roughly 100 times longer than a mouse), but we tend to think of tiny organisms as pretty much alike and sommetimes group them under the same name, microbe. In this Lilliputian world, however, slowly opened up to us in the 1600's by the microscope, there are great differences in structure, size, chemical composition and function. Some bacteria are 150 times larger than others. Bacteria in our gut synthesize vitamin K, others cause disease, bacteria in the oceans help degrade oil from oil spills and now we know that other ocean bacteria make a sizeable portion of the oxygen we breathe.
How much there is that we would not know except for the instruments of modern day science. Pure science and technology are a productively matched pair.
Of such small size that it would take 1000 to line up across the head of a pin, there might be a million of these oxygen-producing bacteria in a thimbleful of seawater. It is hard to believe that such important organisms were unknown for so long, but in fact the whole world of tiny creatures drifting in the oceans (and in lakes and ponds) was not known until 1828 and was not called plankton until 1887. When creatures are large, we easily recognize differences (an elephant is roughly 100 times longer than a mouse), but we tend to think of tiny organisms as pretty much alike and sommetimes group them under the same name, microbe. In this Lilliputian world, however, slowly opened up to us in the 1600's by the microscope, there are great differences in structure, size, chemical composition and function. Some bacteria are 150 times larger than others. Bacteria in our gut synthesize vitamin K, others cause disease, bacteria in the oceans help degrade oil from oil spills and now we know that other ocean bacteria make a sizeable portion of the oxygen we breathe.
How much there is that we would not know except for the instruments of modern day science. Pure science and technology are a productively matched pair.
Wednesday, March 30, 2011
Seasonal Essay for April
April showers give us a chance once again to ponder the cycle of water as it moves from sky to earth and back to sky again, but through such a tortuous route! Surplus rain, collected in numerous streams, Kayaderosseras, Bog Meadow, Spring Run, pours into lakes Lonely and Saratoga. From here Fish Creek takes water to the Hudson which wends its way to the sea. Evaporation from the sea returns water to the sky once again, a cycle repeated over and over through many millions of years. Particles, eroded from the land and transported in our rivers have a different fate. Some, reaching the mouth of the Hudson, may be carried out to sea, slowly falling to the bottom as the current slows and over the course of many centuries a thick carpet of sediments piles up on the ocean floor reaching as far as 200 miles from shore. Dissolved solids carried in streams don't settle out directly, each kind having a different fate. Silica, upon reaching the sea, may be taken up by minute photosynthetic cells called diatoms and used to build glassy shells within which they live. When these cells die, their houses rain down upon the ocean floor and over great spans of time some deposits of these may be raised above sea level where we can mine them. The resulting fine abrasive is used in silver polish and even toothpaste. When we watch raindrops falling, we can think of their different fates. Some will soak into the earth and be taken up into the tallest trees where they will participate in the making of leaves. Others will evaporate back into the air to fall somewhere else. Still others will be embarking on that long journey to the sea.
Monday, February 28, 2011
Seasonal Essay for March
Some years ago I descended Spuce Mountain with windblown sleet splattering my back. The trail was wide and open making movement easy, freeing my mind and senses for other occupations. At a turn, a valley extended to one side and through it came wind which, added to that already blowing, set the trees into violent swaying, even the larger trunks moving almost to ground level. And the noise! The big trunks creaked and groaned. On top of them the smaller branches, hitting against each other cracked and rattled, and above it all the rushing sound of the wind provided the continuo.
It was too compellintg a scene to leave, so I pulled my square of insulated pad from my shoulder bag and sitting on it, leaned my back against a tree. Dark branches against a uniformly grey sky had their own fast beat, but in addition, each tree crown swayed as an entity, each tree size having its own resonant frequency. The effect was that of rows of dancers, arms upraised, each row bending first right andf then left, but in a direction opposite to that of the rows in front of and behind it, each tree-dancer having not two arms but many. I watched until a lull in the wind signaled intermission and as darkness fell I plodded homeward to offer a review of the performance.
It was too compellintg a scene to leave, so I pulled my square of insulated pad from my shoulder bag and sitting on it, leaned my back against a tree. Dark branches against a uniformly grey sky had their own fast beat, but in addition, each tree crown swayed as an entity, each tree size having its own resonant frequency. The effect was that of rows of dancers, arms upraised, each row bending first right andf then left, but in a direction opposite to that of the rows in front of and behind it, each tree-dancer having not two arms but many. I watched until a lull in the wind signaled intermission and as darkness fell I plodded homeward to offer a review of the performance.
Saturday, January 29, 2011
February Seasonal Essay
Winter offers us a chance to note again that among living organisms, each act of creation has its destructive counterpart. each great tree, rising out of the forest floor, finds many of its building materials among the ruins of former plants and animals. In addition, each forest creature throughout its life, sheds its used and worn-out parts onto the ground to be broken into its chemical constituents and recycled once again. We are fully aware of this in the fall when the great mass of leaves, generated through spring and early summer, having fulfilled their task of food manufacture, are cast free. But we are not so aware that this process of shedding continues in some degree throughout the year. In winter we see this especially clearly.
However pure the white new-fallen snows of February may be, in the woods they quickly lose their virginity. Soon they become littered with myriad dark fragments, some formless, others with clear and recognizable form repeated again and again. The last-remaining portions of birch catkins litter the snow and open cones of hemlocks and pines, shaken by the wind, shed the last of their more tenacious seeds. Strong wind loosens some of the last remaining leaves of oaks and beeches. A pile of wood chips at the base of a tree is readily explained by looking upward at the squared hole made by a Pileated Woodpecker. Masses of tiny black specks in snow hollows are jumping! They are insect-like springtails. And everywhere are fragments of bark, loosened by growth in girth of trees. The whiteness of snow gives the perfect background on which to display the products of the never-ending process of shedding, of life and death.
However pure the white new-fallen snows of February may be, in the woods they quickly lose their virginity. Soon they become littered with myriad dark fragments, some formless, others with clear and recognizable form repeated again and again. The last-remaining portions of birch catkins litter the snow and open cones of hemlocks and pines, shaken by the wind, shed the last of their more tenacious seeds. Strong wind loosens some of the last remaining leaves of oaks and beeches. A pile of wood chips at the base of a tree is readily explained by looking upward at the squared hole made by a Pileated Woodpecker. Masses of tiny black specks in snow hollows are jumping! They are insect-like springtails. And everywhere are fragments of bark, loosened by growth in girth of trees. The whiteness of snow gives the perfect background on which to display the products of the never-ending process of shedding, of life and death.
Monday, December 27, 2010
January Seasonal Essay
It is a great pleasure to walk in snowy woods, but if the snow is deep it is hard work. The answer? More flotation, walk on top of the snow the way snowshoe hares do, get a pair of snowshoes and poles. Snowshoeing has become a popular winter activity. Even 15 years ago there were over 600,000 people involved in it in the USA. Snowshoes were in use by Native Americans when Europeans first arrived and were quickly adopted by them. These ingenious snow-walking implements may well have come from Siberia as the first people to inhabit the Americas crossed Bering Straight, and probably were invented in Asia many thousands of years ago.
There are several sizes and shapes of snowshoes and if you are thinking about getting into this activity, in order to choose wisely I suggest that you look at any of the several books on the subject in the Saratoga Springs Public Library. Search nonfiction call number 796.92 which is where I obtained the information above. This will help you to match the snowshoes you buy to the kind of snowshoeing you contemplate: flat ground on trails, racing, or taking off into the woods. You could also rent a pair for the day and see how it goes.
There are some fine areas around Saratoga Springs for this recreation. You could begin hiking in the State Park or at the Saratoga Battlefield. In many trailless areas snow travel is much easier than going through summer woods littered with a tangle of brush and fallen branches. If you can navigate with map and compass, try the plateau that lies west of us, its slopes are not steep. Start at Lake Desolation and head northward to Spruce Mountain, descending the trail to the parking lot which requires someone to pick you up there. I have snowshoed on the Tongue Mountain penninsula where there are beautiful views of Lake George. A good way to do this is to have two people or groups of people, one group starting at one end of the trek and the other at the opposite end. They pass each other somewhere near the middle of the roughly four-hour hike and then drive home in each other's cars.
It is especially rewarding to walk in the woods in new fallen snow, untroddden by anyone before us. The silence is complete and that white covering is the very image of purity. One time, while snowshoeing in January, with snow falling steadily in windless deep woods, I came to a thin branch across my path on which snowflakes were accumulating. With hand raised to push it aside, I stopped, suddenly aware that in this thin line of snow perhaps an inch or so high, each flake was intact, its six sculptured arms unbroken. The whole was a naturally formed vitrine of cut glass.
There are several sizes and shapes of snowshoes and if you are thinking about getting into this activity, in order to choose wisely I suggest that you look at any of the several books on the subject in the Saratoga Springs Public Library. Search nonfiction call number 796.92 which is where I obtained the information above. This will help you to match the snowshoes you buy to the kind of snowshoeing you contemplate: flat ground on trails, racing, or taking off into the woods. You could also rent a pair for the day and see how it goes.
There are some fine areas around Saratoga Springs for this recreation. You could begin hiking in the State Park or at the Saratoga Battlefield. In many trailless areas snow travel is much easier than going through summer woods littered with a tangle of brush and fallen branches. If you can navigate with map and compass, try the plateau that lies west of us, its slopes are not steep. Start at Lake Desolation and head northward to Spruce Mountain, descending the trail to the parking lot which requires someone to pick you up there. I have snowshoed on the Tongue Mountain penninsula where there are beautiful views of Lake George. A good way to do this is to have two people or groups of people, one group starting at one end of the trek and the other at the opposite end. They pass each other somewhere near the middle of the roughly four-hour hike and then drive home in each other's cars.
It is especially rewarding to walk in the woods in new fallen snow, untroddden by anyone before us. The silence is complete and that white covering is the very image of purity. One time, while snowshoeing in January, with snow falling steadily in windless deep woods, I came to a thin branch across my path on which snowflakes were accumulating. With hand raised to push it aside, I stopped, suddenly aware that in this thin line of snow perhaps an inch or so high, each flake was intact, its six sculptured arms unbroken. The whole was a naturally formed vitrine of cut glass.
Monday, November 29, 2010
Seasonal Essay for December
For us, this is the month of our shortest day. Our tilted earth in its yearly passage around the sun is at the place where the North Pole is furthest from the sun and where we, looking up at that sun, see it at its southmost point. It therefore takes less time for those of us north of the equator on our rotating earth to pass by it. While we're having shorter days of winter, our neighbors south of the equator are having their long days of summer.
Day length has its effects on both plants and animals. Increasing day length brings about enlargement of the gonads in birds in preparation for the breeding season, and decreasing day length is a cue for migratory northern birds to head south. Some plants exhibit short day flowering while others are long day plants.
Dark days can have dark effects on our psyche and so it is the season of festivals, of ways to lighten the spirit. Peoples of antiquity in regions of Romania saw the bright side of the darkest day and called it, "the birthday of the invincible sun," the beginning of longer days.
No wonder ancient people worshipped the sun and struggled to plot its varying paths through the sky. It gives us warmth and that wonderful light that makes possible this chromatic world in which we live.
Day length has its effects on both plants and animals. Increasing day length brings about enlargement of the gonads in birds in preparation for the breeding season, and decreasing day length is a cue for migratory northern birds to head south. Some plants exhibit short day flowering while others are long day plants.
Dark days can have dark effects on our psyche and so it is the season of festivals, of ways to lighten the spirit. Peoples of antiquity in regions of Romania saw the bright side of the darkest day and called it, "the birthday of the invincible sun," the beginning of longer days.
No wonder ancient people worshipped the sun and struggled to plot its varying paths through the sky. It gives us warmth and that wonderful light that makes possible this chromatic world in which we live.
Friday, October 29, 2010
Essay for November
By November, trees have once again finished the cycle of leaf growth and shedding, leaving them stark again, to display their skeletal branches against winter skies. There can be as many as 200,000 leaves (two tons) lost from a large maple tree, but there is still living tissue remaining after they have fallen. Between the bark and the wood, a persistent thin elongate branching cone of delicate tissue provides growth in diameter. That is why bark and wood are fairly easily separated. In addition, inner bark and outer wood are also composed of living tissue.
But much of the total mass of a tree, the inner wood and the outer bark, is material that once was living, but now is dead. This forms the skeleton of the tree which supports its own weight and flexibly resists the enormous force of the wind which in summer especially presses upon the considerable surface area of its leaves and branches.
Trees, by their enormous size in comparison with ourselves, inspire awe and in former times, worship. Many kinds of trees live longer than we do, a few for many centuries. Some individual trees, known by our grandparents, will be known by our grandchildren. They survive defoliation by insects, fungal and viral infections, fire, and they heal after physical injury. Trees serve us as fuel, as building material, as the raw material of paper, and they give us fruit and nuts to eat. Several of our medications came initially from trees, though some now are synthesized (aspirin from willows, a cancer drug from yews).
When a forest tree dies and falls to the ground, it is food and shelter for a long succession of creatures until finally there remains only a barely detectable elongate mound on the forest floor.
But much of the total mass of a tree, the inner wood and the outer bark, is material that once was living, but now is dead. This forms the skeleton of the tree which supports its own weight and flexibly resists the enormous force of the wind which in summer especially presses upon the considerable surface area of its leaves and branches.
Trees, by their enormous size in comparison with ourselves, inspire awe and in former times, worship. Many kinds of trees live longer than we do, a few for many centuries. Some individual trees, known by our grandparents, will be known by our grandchildren. They survive defoliation by insects, fungal and viral infections, fire, and they heal after physical injury. Trees serve us as fuel, as building material, as the raw material of paper, and they give us fruit and nuts to eat. Several of our medications came initially from trees, though some now are synthesized (aspirin from willows, a cancer drug from yews).
When a forest tree dies and falls to the ground, it is food and shelter for a long succession of creatures until finally there remains only a barely detectable elongate mound on the forest floor.
Monday, September 27, 2010
Seasonal Essay for October
In the clear skies of October we are encouraged to look upward and marvel at the vastness of the universe. The book, "October Skies", and its derivative movie tell of a teenager with a driving fascination with rocket propulsion. It is by such means that in the far distant future, humankind may break free from a decaying solar system and seek another home. Even now, with robotic travel to Mars and other planets, we are taking the first tentative steps toward that ultimate necessity.
It was in the 1950's that I heard the astronomer Harlow Shapley tell of Edwin Hubble's finding in 1924 that many of those stars we see in such profusion are not suns like ours, but great numbers of clustered suns like our Milky Way galaxy, though far distant from it. Many astronomers think it reasonable to suppose, there being such an enormous number of galaxies, each containing within it such an enormous number of suns, that among these suns must be some with planets which are similar enough to ours to support life as we know it. Already astronomers have detected 490 such extrasolar planets within our own galaxy. It comforts me to think, as George Wald the Harvard physiologist expressed it, that it is possible if not probable that, if our life on earth should somehow destroy itself or not escape our planet home before it self-destructs, there will be life forming somewhere else in some far distant star or galaxy and we wish it well.
It was in the 1950's that I heard the astronomer Harlow Shapley tell of Edwin Hubble's finding in 1924 that many of those stars we see in such profusion are not suns like ours, but great numbers of clustered suns like our Milky Way galaxy, though far distant from it. Many astronomers think it reasonable to suppose, there being such an enormous number of galaxies, each containing within it such an enormous number of suns, that among these suns must be some with planets which are similar enough to ours to support life as we know it. Already astronomers have detected 490 such extrasolar planets within our own galaxy. It comforts me to think, as George Wald the Harvard physiologist expressed it, that it is possible if not probable that, if our life on earth should somehow destroy itself or not escape our planet home before it self-destructs, there will be life forming somewhere else in some far distant star or galaxy and we wish it well.
Friday, September 3, 2010
Seasonal Essay for September
In September tufts of white fly across fields and roads, liberated from the swollen pods where they developed. Milkweed seeds, like the clouds of aspen seeds we see in June, are being carried to new fields in the eternal struggle for survival and expansion of range. The milkweed flower which forms the seeds is a complex structure, so formed that insects seeking food there find their legs trapped in crevices. In extricating them, they tear free small packets of pollen which they then carry to other milkweed plants where fertilization occurs. Occasionally one sees a dead insect hanging in the flower, trapped too tightly to escape.
Also in September, Monarch butterflies begin their long flight southward. Their lives and that of milkweed plants are closely intertwined. As is true of many plants, milkweeeds contain a substance which is poisonous to some kinds of insects, but Monarch caterpillars are able to detoxify it and to feed on milkweed leaves. And it is within a silvery case attached to these milkweed plants that the caterpillar transforms into the adult we know so well. One fall, finding one of these cases, I picked the leaf it was fastened to and took it on a visit to a grandson, telling him to watch carefully for the emergence. Sure enough, a day or so later he called out, "Come quickly, it's happening!" And there it was, the slow emergence, the expansion of wings and their drying out. Then we bid it goodbye as it left to begin its long journey.
Also in September, Monarch butterflies begin their long flight southward. Their lives and that of milkweed plants are closely intertwined. As is true of many plants, milkweeeds contain a substance which is poisonous to some kinds of insects, but Monarch caterpillars are able to detoxify it and to feed on milkweed leaves. And it is within a silvery case attached to these milkweed plants that the caterpillar transforms into the adult we know so well. One fall, finding one of these cases, I picked the leaf it was fastened to and took it on a visit to a grandson, telling him to watch carefully for the emergence. Sure enough, a day or so later he called out, "Come quickly, it's happening!" And there it was, the slow emergence, the expansion of wings and their drying out. Then we bid it goodbye as it left to begin its long journey.
Thursday, August 5, 2010
Seasonal Essay for August
I call August the month of the Orthoptera, that order of insects which includes crickets, grasshoppers and katydids, because in August they fill the evening and night air with their calls. These calls serve to bring the sexes together for mating although the cricket's chirp doesn't sound much like a love song to some of us. The Japanese used to keep crickets in cages. They enjoyed their cheery, homey sound, but it also served as an alarm. The footfalls of a nighttime intruder would cause the cricket to stop chirping and the sudden quiet would awaken the sleeping resident.
The snowy tree cricket has a call that is more musical to our ears. Its fairly high tone is difficult to locate, partly because the sound can be focused by its front wings and as the insect turns on its perch, the sound seems to come from different directions. But with patience, searching with a flashlight will disclose the small (3/4 inch), pale green singer. Rate of calling varies with temperature so that if you add 40 to the number of its calls in 15 seconds, you get the approximate temperature in degrees Farenheight.
Many kinds of insects produce sound, but the Orthopterans are especially known for this because the sound is loud and within the range of our hearing. Some produce the sound by rubbing roughened parts of the front wings together. Others rub their hind legs. And of course, making sound has no function if it can't be heard, so they have organs of hearing, located in some species on the abdomen, in others on the front legs, and elsewhere.
Sound making and hearing occur in insects other than Orthopterans. The whine of the wings of a female mosquito is heard through the fluffy antennae of the male. Some animal voices we don't hear at all. The humanly inaudible, high-pitched sound (sonar) of a hunting bat's voice is reflected back to the bat's ears and serves as an echo locator. The sound is also heard by prey moths who take evasive action which fortunately, from the bat's point of view, is not always successful. With a tape recorder you can record some of the animal voices, analyze them by playing back at different speeds, or simply create the chance to enjoy them all year long.
The snowy tree cricket has a call that is more musical to our ears. Its fairly high tone is difficult to locate, partly because the sound can be focused by its front wings and as the insect turns on its perch, the sound seems to come from different directions. But with patience, searching with a flashlight will disclose the small (3/4 inch), pale green singer. Rate of calling varies with temperature so that if you add 40 to the number of its calls in 15 seconds, you get the approximate temperature in degrees Farenheight.
Many kinds of insects produce sound, but the Orthopterans are especially known for this because the sound is loud and within the range of our hearing. Some produce the sound by rubbing roughened parts of the front wings together. Others rub their hind legs. And of course, making sound has no function if it can't be heard, so they have organs of hearing, located in some species on the abdomen, in others on the front legs, and elsewhere.
Sound making and hearing occur in insects other than Orthopterans. The whine of the wings of a female mosquito is heard through the fluffy antennae of the male. Some animal voices we don't hear at all. The humanly inaudible, high-pitched sound (sonar) of a hunting bat's voice is reflected back to the bat's ears and serves as an echo locator. The sound is also heard by prey moths who take evasive action which fortunately, from the bat's point of view, is not always successful. With a tape recorder you can record some of the animal voices, analyze them by playing back at different speeds, or simply create the chance to enjoy them all year long.
Saturday, June 26, 2010
Seasonal Essay for July
July
One of the delights of childhood on a July evening is catching fireflies (lightning beetles) and placing them temporarily in a jar to watch their amazing tiny flashlights. The intermittent luminescence serves to bring males and females together. There are several species in our area and the rate of flashing varies among them so that only members of the same species will mate. Lightning beetles are beetles (not flies), a group containing at least 300,000 described and named species, roughly a third of all insects. The British biologist, J.B.S. Haldane, was asked by a cleric, "As a biologist, what have you learned about the nature of God?" Haldane replied, "He is inordinately fond of beetles."
Many years ago in New Guinea, a friend and I were collecting biological specimens when in the near distance we saw an intermittent glow. We initially thought that some other crazy biologist was roaming the woods, but when we reached the source it was a tree covered with many hundreds of lightning beetles and they were flashing in unison! It made biological sense. Whereas the light from a single beetle flashing in the dense forest wouldn't carry far, the bright light from many could draw mates from a much larger distance. Synchronous behavior occurs in other animals too. The scattered individual voices of spring peepers (tiny tree frogs) often settle down into synchronous calling.
The organ which produces the light in a lightning beetle is modified muscle, just as is the electric organ of electric eels. The light is efficiently produced, roughly 90% of the energy that goes into the reaction comes out as light. In an incandescent light bulb, the best we can do is 15%, the rest being lost as heat. Fluorescent bulbs are still only about 20% efficient in converting electricity to light, but in comparison with incandescents, for the amount of electricity they do convert, they get much more light.
The next time you push a light switch, think orf those many creatures who come equipped with their own built-in lights.
One of the delights of childhood on a July evening is catching fireflies (lightning beetles) and placing them temporarily in a jar to watch their amazing tiny flashlights. The intermittent luminescence serves to bring males and females together. There are several species in our area and the rate of flashing varies among them so that only members of the same species will mate. Lightning beetles are beetles (not flies), a group containing at least 300,000 described and named species, roughly a third of all insects. The British biologist, J.B.S. Haldane, was asked by a cleric, "As a biologist, what have you learned about the nature of God?" Haldane replied, "He is inordinately fond of beetles."
Many years ago in New Guinea, a friend and I were collecting biological specimens when in the near distance we saw an intermittent glow. We initially thought that some other crazy biologist was roaming the woods, but when we reached the source it was a tree covered with many hundreds of lightning beetles and they were flashing in unison! It made biological sense. Whereas the light from a single beetle flashing in the dense forest wouldn't carry far, the bright light from many could draw mates from a much larger distance. Synchronous behavior occurs in other animals too. The scattered individual voices of spring peepers (tiny tree frogs) often settle down into synchronous calling.
The organ which produces the light in a lightning beetle is modified muscle, just as is the electric organ of electric eels. The light is efficiently produced, roughly 90% of the energy that goes into the reaction comes out as light. In an incandescent light bulb, the best we can do is 15%, the rest being lost as heat. Fluorescent bulbs are still only about 20% efficient in converting electricity to light, but in comparison with incandescents, for the amount of electricity they do convert, they get much more light.
The next time you push a light switch, think orf those many creatures who come equipped with their own built-in lights.
Wednesday, June 2, 2010
Seasonal Essay for June
June
The singing of birds reaches its height in June. Even though, for the most part, we find bird song to be beautiful, it is not designed for our pleasure. Just as with those flowers we call beautiful, but which evolved not for us, but because their bright colors attract pollinating insects, so also with bird song which serves to attract mates and identify territory. But we can listen and gain great pleasure, and the singing, once we have learned a song, serves to identify the bird that makes it even when we don't see it. Three walks in the Skidmore woods a few years ago produced a total of 55 different kinds of birds, some seen, some heard, and some both seen and heard. Among them were the brightly colored Indigo Bunting, Scarlet Tanager and Baltimore Oriole and eight different Wood-Warblers. Others, like the Wood Peewee, the Red-eyed Vireo, and the Oven Bird might well have been missed had I not heard their songs.
Bird watching has become a national pastime which is fortunate for anyone newly attracted to this rewarding recreation because there are many good published guides to bird identification and recordings of their songs. Our geographic area is so attractive that with climate change, even some more southern birds over the last few decades have come to call it home: Cardinal, Carolina Wren, Tufted Titmouse, and Red-bellied Woodpecker.
The singing of birds reaches its height in June. Even though, for the most part, we find bird song to be beautiful, it is not designed for our pleasure. Just as with those flowers we call beautiful, but which evolved not for us, but because their bright colors attract pollinating insects, so also with bird song which serves to attract mates and identify territory. But we can listen and gain great pleasure, and the singing, once we have learned a song, serves to identify the bird that makes it even when we don't see it. Three walks in the Skidmore woods a few years ago produced a total of 55 different kinds of birds, some seen, some heard, and some both seen and heard. Among them were the brightly colored Indigo Bunting, Scarlet Tanager and Baltimore Oriole and eight different Wood-Warblers. Others, like the Wood Peewee, the Red-eyed Vireo, and the Oven Bird might well have been missed had I not heard their songs.
Bird watching has become a national pastime which is fortunate for anyone newly attracted to this rewarding recreation because there are many good published guides to bird identification and recordings of their songs. Our geographic area is so attractive that with climate change, even some more southern birds over the last few decades have come to call it home: Cardinal, Carolina Wren, Tufted Titmouse, and Red-bellied Woodpecker.
Tuesday, May 18, 2010
Seasonal Essay for May
May
This is the month to talk about what it is that April showers bring: flowers. And one of the first flowers to appear is the dandelion. It sprouts along roadside grass strips, in fields and to most people’s dismay, in lawns. That flower which most of us think of as single, is in fact a tight cluster of many tiny florets. It is what botanists call an inflorescence. Some inflorescences like the snapdragon are elongate with large distinct florets. Others like the daisy are made up of many densely-clustered fertile florets in the center (the eye of the flower) and an outer circle of conspicuous, sterile, single-petaled florets, the ray florets.
If we take a dandelion flower and, looking at it sideways, split it open with a thumbnail into two halves, we can see its multiple nature. If with a hand lens we look at one of the tiny individual florets we can see that it has a pistil with a divided tip (the female component), that the pistil is wrapped around with five pollen-producing anthers (the male part), and that each elongate yellow petal has five lobes at its tip which represent five fused petals. When mature, each floret takes off separately in the breeze with its tiny umbrella, carrying a single seed in a protective coat.
So plants have more than one way to attract pollinators. They can, like some lilies, produce a few large showy flowers, each producing dozens of seeds, or, like the dandelion, cluster many small florets into a showy inflorescence, each floret making one seed, but the inflorescence making many.
This is the month to talk about what it is that April showers bring: flowers. And one of the first flowers to appear is the dandelion. It sprouts along roadside grass strips, in fields and to most people’s dismay, in lawns. That flower which most of us think of as single, is in fact a tight cluster of many tiny florets. It is what botanists call an inflorescence. Some inflorescences like the snapdragon are elongate with large distinct florets. Others like the daisy are made up of many densely-clustered fertile florets in the center (the eye of the flower) and an outer circle of conspicuous, sterile, single-petaled florets, the ray florets.
If we take a dandelion flower and, looking at it sideways, split it open with a thumbnail into two halves, we can see its multiple nature. If with a hand lens we look at one of the tiny individual florets we can see that it has a pistil with a divided tip (the female component), that the pistil is wrapped around with five pollen-producing anthers (the male part), and that each elongate yellow petal has five lobes at its tip which represent five fused petals. When mature, each floret takes off separately in the breeze with its tiny umbrella, carrying a single seed in a protective coat.
So plants have more than one way to attract pollinators. They can, like some lilies, produce a few large showy flowers, each producing dozens of seeds, or, like the dandelion, cluster many small florets into a showy inflorescence, each floret making one seed, but the inflorescence making many.
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