Archive for the ‘Insights and Visions on the State of the Earth’ Category

The Strange History of Birds

Saturday, January 17th, 2015

 

     A dramatic expansion in genetics research capacity has enabled scientists to learn some surprising things about birds and their evolutionary history.

     Using new DNA research techniques, scientists have gained knowledge that turns traditional groupings of bird species upside down.  For example, field guides typically grouped bird species by observable similarities like size, color, and habitat.  But the new research shows that living bird species may be far more genetically similar to birds that seem very different than they are to species that seem similar.

     Recent research reveals that falcons, for instance, are more closely related to parrots than they are to hawks, even though they look much more like hawks.  And flamingoes, it turns out, are more closely related to pigeons than they are to almost all other waterbirds!

     The new bird research, according to Science News, was conducted by a consortium of 200 scientists from around the world and funded by the Chinese genetics institute BGI and other sources.  Findings suggest that many bird species that appear closely related are not examples of close ancestral relationships after all.  

     Instead, such bird species’ similarity is the result of convergence over time.  These different species evolved in different parts of the world.  But they developed in some of the same ways because they occupied a similar environmental niche.  With similar environmental forces operating in these species’ distant niches, birds in far distant areas developed some of the same characteristics, even though they are not related genetically.

     Sorting out which modern bird species are truly related to one another and which are not had long posed a problem for researchers, explains ornithologist Shannon Hackett of the Field Museum of Chicago.  An avian ‘big bang,’ she explains, took place around the time dinosaurs went extinct and sent many lineages ‘flying’ off in different directions.  

     Before current genetic research techniques became available, it had been hard to figure out which fossils belonged with which emerging group, Hackett explains.  In fact, many scientists believed it would never be possible to sort out which birds were truly most related to which other species.

     One fascinating aspect of this new research is that parrots, songbirds, and humans, for that matter, have converged on very similar genes involved in vocal learning.  In fact, birds may prove to be a useful species for further insights into human speech disorders.  The usual medical research species–monkeys and mice–don’t learn sounds as birds and humans do.–April Moore 

 

 

 

 

Amazing Rocks!

Saturday, December 6th, 2014

On a recent hike in the Shenandoah National Park with my friend Kathy, we saw some rocks that were truly amazing!  They were unlike any I’d ever seen.

A sign along the main trail directed us to a side trail that would lead us to an unusual rock formation called columnar jointing.  We took this side trail down a steep hill, past a massive rock.  It was only when we turned to look back up at that rock that we suddenly understood why these rocks were not to be missed!

The downhill side of the giant rock face looked like a bundle of hexagonal columns, all sliced crosswise to similar but not identical lengths.  The hexagonal shape of each column was so distinct that these rocks looked like crystal formations.  Here is a photo I took of the rocks:

columnar jointing

Like many hikers before us, no doubt, Kathy and I were intrigued by these rocks and wondered how they had been formed.  So a few days later, I did a little research.

Apparently, these rocks are well-preserved cooling columns from major lava flows that occurred some 570 million years ago.  At that time, two tectonic plates began to spread apart along a system of rifts thousands of miles long.  Molten basalt from deep inside the earth rose through these rifts, spilling out onto the earth’s surface in vast quantities that eventually covered more than 4,000 square miles.

As the liquid basalt cooled, it solidified, forming very angular, polygonal cracks similar to those found in drying mud.  Under the right conditions, these cracks can extend many tens of feet and produce a structure that looks like long, polygonal columns of rock, which geologists call columnar jointing.–April Moore

 

The Magnificent–and Elusive–Snow Leopard

Friday, October 10th, 2014

 

Briefs_Castner2-300x210 copy

     When the great writer/naturalist Peter Matthiessen died earlier this year, I read a tribute to him that piqued my interest.  Having noticed his book THE SNOW LEOPARD on numerous friends’  bookshelves over several decades, I  decided now was the time to read it.

     What an extraordinary book!  Published in 1978, the book chronicles Matthiessen’s trek along the Tibetan Plateau in the Himalayas a few years earlier, along with conservation biologist George Schaller.  While Schaller was on a mission to learn more about the mating habits of bharal sheep, Matthiessen’s journey was personal and spiritual.  Both men longed to catch a glimpse of the snow leopard, a predator of the bharal that had been spotted by westerners only twice in the preceding 25 years.

     While neither Matthiessen nor Schaller did see a snow leopard during the two months they walked the rugged Himalayas, they did come across prints and scat left by the animal.  Indeed, it would have been next to impossible actually to see the snow leopard.  

     Below is a beautifully written description of the extremely elusive animal from Matthiessen’s book:  

“By firelight, we talk about the snow leopard.  Not only is it rare. . . but it is wary and elusive to a magical degree, and so well camouflaged in the places it chooses to lie that one can stare straight at it from yards away and fail to see it.  Even those who know the mountains rarely take it by surprise:  most sightings have been made by hunters lying still near a wild herd when a snow leopard happened to be stalking. . . .

“The snow leopard is usually found above 5000 feet and occurs as high as 18,000 feet.  Though nowhere common, it has a wide range in the mountains of Central Asia, from the Hindu Kush in Afghanistan eastward along the Himalaya and across Tibet into southern China, and also northward in the mountains of the USSR and west China to the Sayan Range, on the Siberian border of Mongolia. . . 

“The typical snow leopard has pale frosty eyes and a coat of pale misty gray, with black rosettes that are clouded by the depth of the rich fur.  An adult rarely weighs more than a hundred pounds or exceeds six feet in length, including the remarkable long tail, thick to the tip, used presumably for balance and for warmth, but it kills creatures three times its own size without much difficulty.  It has enormous paws and a short-faced heraldic head, like a leopard of myth;  it is bold and agile in the hunt, and capable of terrific leaps;  and although its usual prey is the blue sheep, it occasionally takes livestock, including young yak of several hundred pounds.  This means that man would be fair game as well, although no attack on a human being has ever been reported.

“The snow leopard is the most mysterious of the great cats;  of its social system, there is nothing known.  Almost always it is seen alone;  it may meet over a kill, as tigers do, or it may be unsociable and solitary, like the true leopard.” 

THE SNOW LEOPARD TODAY

The book left me wondering how snow leopards are doing today, 40 years after Matthiessen’s trek.

I did a little research and learned that yes, the snow leopard is endangered.  Fewer than 7,000 are believed to exist in the wild.  Despite the remoteness of their range, these animals have been threatened by poaching and by the overhunting of the animals on which they prey.  But perhaps the greatest long-term threat to the snow leopard, according to the World Wildlife Fund (WWF) is global warming, which could result in a loss of  30% of the snow leopards in the Himalayas.  

But there is good news too.  Protective efforts by international conservation organizations, like the WWF and the Snow Leopard Conservancy, together with governments and local communities in the snow leopard’s range have been effective.

For example, conservation groups facilitated a joint effort among Central Asian nations to create a large protected area for snow leopards that spans parts of China, Pakistan, Afghanistan, and Tajikistan.  And China and Pakistan are cooperatively managing adjacent natural reserves in their two countries. 

Also, with international help, 55 villages in Afghanistan’s Pamir Mountains and 65 villages in northern Pakistan have recently formed committees to protect snow leopards and safeguard other natural resources.  These committees have deployed almost 200 volunteer rangers who monitor snow leopards and their prey and enforce anti-poaching regulations.
Even the monks of remote Buddhist monasteries in the snow leopard’s range are getting into the act.  They are preventing poaching by patrolling the forests near their monasteries. – April Moore

 

 

 

 

 

 

Putting Population in Perspective

Thursday, August 28th, 2014

 

I remember the late 1960s and early 70s, when the issue of overpopulation first gained widespread attention.  Paul Ehrlich sounded the alarm with his popular book THE POPULATION BOMB;  environmentalists and others warned that the human population was simply growing too large to be sustainable.  Well, since that time, the earth’s human population has more than doubled! We are now past seven billion and climbing.

It seems clear to me that our inability to keep our human numbers in check threatens human health and well-being, not to mention the very survival of many other species with whom we share the planet.

I am posting here today a link to an accessible, informative research graphic called The Effect of Overpopulation on Public Health   

This vivid, easy-to-understand presentation was sent to me by Earth Connection reader Emily Maynard, who helped prepare it for MPHonline, a website that provides information on Master’s degree programs in Public Health.–April Moore

 

 

World Population Day

Thursday, July 10th, 2014

       I recently read a statistic that I could hardly believe.  Every day, the world’s population increases by 227,000 people!  

     227,000!  That’s like adding a mid-sized city every single day.  And this 227,000 figure is not the number of births each day;  it’s the number of births minus the number of deaths, or the net increase.  

     I am thinking about world population because tomorrow, Friday, July 11, is World Population Day.  This annual observance was established by the United Nations in 1989 as a vehicle to build awareness of population issues and the impact they have on the environment and on development.  The United Nations Population Fund encourages governments, non-governmental organizations, institutions, and individuals to organize educational activities to mark the annual event.

     Why July 11?  That was the day in, 1987, when the global human population first reached five billion.  The Day of Five Billion attracted so much interest all around the world that the UN and population educators joined together to create an annual occasion to focus the world’s attention on the challenges posed by population growth.

Global population growth is truly a fascinating phenomenon.  Long, long ago, when humans lived in bands of hunters and gatherers, the population was small and stable.  Then, with the advent of agriculture about 10,000 years ago, more food became available and the human population began to grow.  Then came the Industrial Revolution in the 1700s.  With expanded agriculture and life-saving medical advances, the human population started to increase exponentially.

Consider the following:

  • About 8,000 BC when farming began, the global population was about 5 million.
  • By about 1 AD, 8,000 years later, the population was about 200 million.
  • About 1800 years later, by 1800 AD, the human population reached its first billion.
  • By 1930, just 130 years later, the population crossed the 2 billion mark.
  • By 1959, a mere 29 years later, the population had grown to 3 billion.
  • By 1974, only 15 years later, the world population reached 4 billion.
  • In 1987, 13 years later, there were 5 billion of us.
  • The 20th century began with 1.6 billion people and ended with 6.1 billion.  
  • Most of the population growth throughout history took place in a single century!
  • Today, the global population is 7.2 billion.  

Population growth rates are falling throughout the world.  But because of rapid population increases in past decades, the number of people in their childbearing years is very high.  Thus, even with a low birth rate, the actual number of people will continue to grow for several decades.  Demographers call this phenomenon ‘demographic momentum.’

Demographers predict that population could grow to 9 billion by 2050 and then stabilize.–April Moore

 

The Magnificent Catalpa Tree

Wednesday, June 11th, 2014

 

photo by Gary Fewless

I am happy to repost here a piece my friend Elizabeth Cottrell wrote recently about a majestic catalpa tree she has been getting to know.  I too have been interested in this tree with its giant leaves and foot-long seed pods.  In her light, informative article, complete with photos, Elizabeth has helped me to feel that I too now know this large, graceful tree better.

I invite you to read Elizabeth’s piece at her website, Heartspoken, by clicking here: The Lovely Catalpa Tree
 April Moore

 

It’s Spring–The Shadbush Is Blooming!

Sunday, April 20th, 2014

For the last week or so, my forest walks have yielded a special delight.

Here and there, against the still-winter grey of the forest, is a full, rounded, bright spot of white.  It’s the serviceberry, or ‘shadbush,’ in bloom.  This slender little tree signals that spring has indeed come to the forest, and soon other trees–the dogwood and the redbud–will follow along with blooms of their own.  But the serviceberry is first.

I have long heard that the reason the serviceberry is also called ‘shadbush’ is that the tree blooms just when the shad are spawning.  I like the folklorish sound of that and decided to learn a little more.

As it turns out, ‘shadbush’ is just one of many names for the serviceberry, or, in Latin, amelanchier.  And yes, in olden times, people along the eastern seaboard noticed that these Atlantic Ocean-dwelling fish entered the rivers and streams that flow into the Atlantic, and swam up these waterways to spawn in the early spring, just when these delicate woodland trees were blooming.  Hence the name ‘shadbush,’ and also ‘shadblow’ and ‘shadwood.’

But the serviceberry has another name, ‘ juneberry,’ for its dark, blueberry-looking berries that ripen in early summer.  These berries are a big hit with many birds–bluebirds, cedar waxwings, robins, ruffed grouse, and pheasants, to name a few, and also with foxes, bears, and other mammals.

The name serviceberry has its own folk history.  All three possibilities I’ve heard for the name’s origin have to do with church services.  One is that the blooming serviceberry in Appalachian forests meant that mountain roads had become passable again after the winter snows, and that church services would resume, since the circuit-riding preacher could now make it to the small country churches.

Another church-related explanation is that the blooming of the serviceberry coincided with Easter services.  And the third, that with the blooming of the serviceberry and the passability of the roads, funeral services could now be held for those who had died during the winter.

In learning about some of the serviceberry’s other names, I inadvertently solved a small mystery that had arisen for me many years ago.  I just learned that a name for a western variety of serviceberry is ‘saskatoon.’  Many years ago, on a family trip in Montana, we encountered saskatoon berries.  I had never heard of them and wondered where they grew.  No one I asked seem to know, but I assumed they grew on some shrubs in that area.  Now I know that saskatoon berries are from a type of serviceberry tree that grows in the mountain west.  So not just animals enjoy the fruit of the serviceberry;  we humans do as well.  

Indeed, there are more than a dozen varieties of serviceberry tree throughout the U.S. and Canada.–April Moore 

 

Juncoes and Winter

Friday, March 7th, 2014

Something about juncoes has long puzzled me.  So I decided to look into it. . . . 

     Since moving to Virginia’s Shenandoah Valley more than 20 years ago, I have come to look forward to our annual winter visitors, the  juncoes.  When the weather starts to turn cold, these plump little grey and white birds appear.  All winter, I enjoy their soft murmurs and cheeps, emanating from the bushes.  And I love watching these little birds do their forward-and-back ‘dance’ on the cold ground as they try to stir up something to eat.  When spring comes, the juncoes disappear.  

     I have read that juncoes spend the summer months in Canada.  Then when the weather up there starts to turn cold, they fly south, fanning out across much of the United States for the winter months.

     This migratory pattern has puzzled me.  I can well understand why juncoes would want to head south as the cold Canadian winter gets underway.  But why do many of them choose Virginia as their winter destination?  Why wouldn’t they keep right on flying until they reach a much warmer place like Florida or Mexico, as many other bird species do?  After all, our winters here in the Shenandoah Valley are cold, and the forests where the juncoes flit about are often snowy.  Surviving a Virginia winter looks like work to me, especially for such small birds.

     So I consulted an ornithologist.  He explained to me that, unlike some birds that spend every winter in the same precise location, juncoes have a large geographic range.  When they fly south to escape the Canadian winter, there are many areas in the U.S. where they can find enough food and shelter to survive the winter.  Virginia is one such place.

     From an evolutionary perspective, it seems that perhaps juncoes have developed an effective survival strategy.  Since they have proved capable of surviving fairly cold winters, they do not need to fly farther south as some other species do.  By halting  their migratory flight here in Virginia, they don’t face a lot of competition for food and shelter.  There simply aren’t that many birds around here during the winter months.   If juncoes were to fly much farther south, say to Central America, where many, many bird species spend their winters, the competition for food and shelter would be great.  

     Besides, a very long migratory flight to a winter home is arduous.  Thus, it can be advantageous to birds not to have to fly such a long distance.  If juncoes can find what they need to survive closer to their summer breeding grounds, they opt for it.  And it seems to work.–April Moore

 

Palm Trees–Not Trees After All!

Sunday, January 26th, 2014

I once heard, many years ago when I lived in Florida, that a palm tree is not really a tree;  it’s a grass!  I had never investigated the truth of that statement.  But spending time recently in San Diego and admiring the many tall palms towering high over houses and even over other trees, made me want to find out whether it is, in fact, true that palm trees are actually grasses.

Even though palms seem like trees, with their height, their leaves, and what seems to be a trunk, it turns out that those traits are not enough to make them trees.

In fact, there are important differences between actual trees and palms.  For example, unlike trees, palms have no bark or woody tissue.  Palm trees do not produce a cambium layer–that part of a tree between the bark and the interior, that produces new growth each year.  A horizontal cut through a tree’s trunk would show growth rings;  a cut across a palm’s would not.  A palm’s ‘trunk’ is simply a mass of spongy, hardened material that expands as the palm grows taller.

And palm trees lack a key ability trees have–to resist death from disease or injury.  A tree can ‘seal off’ a damaged portion, entirely separating it from the tree’s healthy part, so that the tree can continue to live and grow.

In addition, conventional trees experience a secondary growth phase, when functioning tissues are replaced with younger cells.  But palm trees do not undergo such a process of cell replacement.  Instead, a palm tree’s individual cells endure for the plant’s entire lifespan of 100-740 years.

Palm trees, of which more than 2,000 species exist, are grouped botanically with grasses, sedges, bamboo, grains, lilies, onions, and orchids.  In fact, as it turns out, a palm tree has more in common genetically with turf grass or corn than it has with an oak tree!  A palm tree is truly a grass giant!

Palm trees are indeed amazing.  But, as it turns out, they’re amazing grasses, not amazing trees.–April Moore

 

The Beak of the Toucan

Friday, January 10th, 2014

the brown-mandibled toucan

My husband and I had the good fortune two years ago to visit Costa Rica.   Some of my happiest memories of that trip are of sitting outside our rustic room at a rainforest eco-lodge and watching toucans.  High in a tree just yards away, these colorful birds would perch on a branch and  leisurely  pluck the tree’s round fruits with their massive beaks.

And I mean massive!  Toucans have longer beaks relative to body size than any other birds in the world.  Some of the several dozen toucan species have a beak that accounts for a third of the bird’s length and as much as half its surface area.

I can’t help but wonder what evolutionary advantage such a massive beak serves.  Even scientists don’t know how the process of natural selection led to such an outsized toucan beak.

The kinds of answers that explain many other adaptations in nature don’t seem to apply to the toucan’s beak.  For example, sexual selection does not account for the size of the toucan’s beak, since the beak of both genders is about the same.  Nor would the bird’s diet lead to such a giant beak.  After all, toucans are fruit eaters, as are many other avian species with much smaller beaks.  A giant beak is not necessary to get the fruits toucans consume.

While scientists don’t know why the toucan evolved its large beak, they have learned in recent years more about what the beak does for the toucan. Scientists now view the toucan’s beak as a system to warm or cool the bird’s body as needed.  

Unlike humans, birds don’t sweat.  But the surface of the toucan’s beak is full of tiny blood vessels, which play a key role in the toucan’s ability to maintain a comfortable body temperature as the ambient temperature rises and falls.

Scientists used thermal-imaging cameras to record toucans’ bill and body temperatures separately in rooms where the temperature could be adjusted up and down over a range of temperatures the birds encounter in their natural habitat.  As the room heated up, the surface of the toucan’s bill warmed rapidly.  The body was ‘dumping’ excess heat to the bill.  At cooler temperatures, the reverse happened;  the body needed the warmth and the bill cooled.  

In the heat of a tropical day, scientists have learned, the toucan’s beak may be 10 degrees Centigrade warmer than it is at sunset.  And during sleep, the toucan’s beak temperature fluctuates, as a constant body temperature is maintained. 

While scientists have increased their understanding of the toucan beak’s ‘thermoregulating’ function, they are unsure if natural selection increased the bird’s bill size for the purpose of regulating temperature, or whether that function is simply a beneficial byproduct of some other selective process.  After all, if the thermoregulating function is so important, why don’t more birds have it?April Moore

 

 

 

 

 

 

 

 

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