Autumn

I’m not sure what is is about autumn; but, for me, there is an enchantment that pervades the world. I was walking on our street and noticed the lovely yellow plumage of the trees in front of our condominium complex, which reminded me of Van Morrison’s song Moondance. Interestingly, as the song ran through my mind, it was the arrangement of leaves on the ground that brought  the romance of the season into focus…

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And all the leaves on the trees are falling

To the sound of the breezes that blow

And I’m trying to please to the calling

Of your heart-strings that play soft and low

You know the night’s magic

Seems to whisper and hush

And all the soft moonlight

Seems to shine, in your blush…

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(from Moonlight, by Van Morrison)

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An August Sunset

When I stepped outside last night, the sun was just about to disappear; sunlight was radiating through the clouds, which fanned the sun’s rays across the sky. I took a few quick pictures; the one below was the best, although a picture never quite seems to capture the aura and awe of the moment

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The Caddis Fly Larvae

I spent a great deal of my childhood hiking through the rainforest on the side of Grouse Mountain. In particular, my friends and I explored the areas around Mackay Creek, a small stream that burbled over a rocky bed. The creek was filled with small trout, crayfish, and caddis fly larvae (apparently a sure sign of pollution-free water: we often drank the cold, clear water in cupped hands with no noticeable deleterious effects). About a decade ago I visited my old stomping grounds and I was so distressed with the loss of habitat to the burgeoning suburbia that I haven’t been back since; fortunately, my memories are, for the most part, intact.

Remarkably, the caddis fly larvae left one of the greatest impressions on my memory. I didn’t know what the creatures were at the time (I had no idea they were a larval form of a flying creature: to me they were aquatic bugs), but they fascinated me, and it was the caddis fly larvae, I think, that helped spark my life-long interest in biology (and, now that I think about it, the time I spent peering into the crystal water — long after my friends had gone home — was possibly my initiation into meditation).

There are over a thousand species of caddis fly in North America, and the Pacific Northwest is home to nearly two-hundred, but there is a particular species that attracted my attention.

Caddis fly adults are nocturnal and look like small moths with long antennae and silken hair on their wings; but they are not moths, they are in the Order Trichoptera (from the Greek for hair and wings). The adults are a favored snack of trout and are commonly used as models for fly-fishers. The caddis fly’s adult life is brief, just long enough for reproduction. Some adult female species deposit their eggs on the surface of the water and others dive underwater to lay their eggs.

As I mentioned, it was the larvae stage that fascinated me as a boy. A caddis fly larva is a long, segmented creature: its head and six legs are packed into its anterior end and two grasping hooks are situated at the posterior end.

Some larva species live like underwater spiders, spinning webs as a home and as a means to gather food, but most species build homes around their bodies. The habitats are constructed from various materials; some use slivers of wood, tree needles, or grains of sand, but there is a small group of species that uses miniature stones to create a cylindrical structure (the larvae secret a cementing chemical and laboriously build a house of pebbles around themselves), and it is this variety — two or three centimeters long (about an inch) and about a half-centimeter in diameter — that caught my attention while wading in and around Mackay Creek.

Using the grasping hooks at their anterior end, they hold fast to rocks in the stream and maneuver about using their six legs. I studied the creatures and, though they were all obviously quite similar in structure, each home was composed of tiny pebbles that were unique in color, size and shape. I tried to imagine each tiny creature choosing pebble fragments as they flowed downstream within reach: the creature would presumably grasp a stone, turn and spin it this way and that, and then mysteriously fasten the stone to the outside of its body (perhaps they forage for construction material and assemble their homes in an area of the creek that has no current, but I preferred the image of creatures plucking boulder-sized (to them) rocks from the stream’s current). I suppose the construction is instinctual, like a spider’s web, but it baffled my young mind.

At a glance they appeared to be sessile creatures, but I watched long enough to observe them as they crawled across small boulders in the middle of the current. I marveled at their tenacity: their petite black heads could be observed bobbing out the top of their homes, and their dark legs moved slowly and carefully across the rock surface: it appeared as though the legs helped anchor the larva for motility in the current. The cylindrical structures waggled in the current, but I never saw one lose its grip (I tested their resolve by plucking some of the creatures off of their boulder: they held on tenaciously, but I was able to tear them off. I tried to place them back on the boulder, but they had retracted their legs, probably fearing the worst. I have no idea whether I had injured them; I hope not).

Apparently, the larvae writhe inside their home, which enables oxygenated water to flow through fissures in the pebble-structure and along the gills that are located on the creature’s abdomens.

Before pupating in late summer, the larva attaches itself to a rock and seals its casing; within two weeks an adult emerges from the pupal enclosure, makes its way to the water-surface and searches for a mate in order to continue its genetic heritage by contributing to the succeeding generation.

I’m almost curious enough to go back to Mackay Creek and check for larvae, but I think my memory will suffice.

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encounter with a bird

On the way home from work several yeas ago I stopped for a ‘cleansing’ walk in Pacific Spirit Park.

I kept to the public pathway until I spied an intriguing, overgrown deer-path. I held my breath and looked both ways along the public path; heard nothing, saw nothing, so I climbed over the rustic, wooden fence and followed the deer-path as it wended its way between maples and alders. After a few minutes I came to a particularly pleasant spot: a circle of alder trees delineated a clearing about ten meters in diameter. A large, flat boulder — stippled grey-green — sat in the middle of the circle.

A rustling caught my attention; at the edge of the clearing, to my left, a small bird regarded me out the corner of her eye; her feathers were mottled greys and pale yellow-greens; these colors, along with her moss-green head and elongated, ochre beak, provided natural camouflage against the leaf-strewn earth.

She began to chatter her beak while simultaneously producing a guttural cawing.

I took a step toward her; she hopped backward and discharged chatter-caw profanity, so I sidled a wide-berth around her and sat on the boulder. She seemed amenable to sharing, as long as I respected her personal space.

She glanced at me, hopped about, and then flew into the branches of the tree directly behind her. She was filled with nervous energy; she flitted down to the ground, then up into the next tree, down, up, down, working around the clearing counter-clockwise from tree-to-tree. When she was about three-quarters of the way ’round the circle, paranoia bubbled up from the dark depths of thought: I imagined that she was spinning a trap; I jumped up, dashed out of the clearing, and back to my car.

Once inside the car I had a good chuckle at myself.

The next day I decided to go back to the clearing. I couldn’t find it. I’ve searched a half-dozen times, but I must have forgotten exactly where I’d stepped off the public trail.

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Slime mould and bio-computers

Slime moulds germinate from a spore and begin life as a haploid (one set of chromosomes) amoebae organism, flowing along the floor of a forest, eating bacteria. When food supply becomes scarce, a chemical (cAMP) is released, which induces the individual amoebae to congregate into a mass: they form streams of cells, referred to as pseudoplasmodium, and the separate streams congregate to form a mass as large as one-hundred thousand cells. The individual amoeba secrete adhesion molecules; they bond together, and develop a slime sheet ‘cap’ that envelops the mass. The mass then behaves as a single organism, gliding across the forest floor, leaving a trail of slime in its wake.

It is a brainless, primeval organism, yet Japanese scientists have studied the slime mould colonies for years as the colonies have navigated mazes. The scientists believe that the behavior of the slime mould may facilitate the design of complex problem-solving bio-computers.

[Image by Toshiyuki Nakagaki].

According to Toshiyuki Nakagaki (at Hokkaido University’s Research Institute for Electronic Science), slime mold colonies use a form of information-processing to optimize a path through a maze (toward a food-source, which is signaled by a higher concentration of ammonia); and, at the same time, the organism avoids stressors that would damage it. They are able to adapt to environmental variations and can develop resistance to new stimulus. 

Nakagaki’s research of slime mould garnered an Ig Nobel  prize (Ig Nobel prizes are a spoof of Nobel Prizes and are awarded to scientists who “first make people laugh, and then make them think.”).

Apparently, slime moulds are able to develop more efficient networks than our most advanced technology. Masashi Aono, a researcher at Riken (in Waka, Japan) would like to develop a bio-computer: his lofty plan is to eventually duplicate the human brain with slime moulds.

For some reason the movie The Blob just burbled into consciousness.

 

 

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of cow belches, whale poo, and the environment

A colleague of mine enjoys challenging my views with humorous jabs; recently, when I was decrying the fact that our society (myself included) is apathetic in regards to the pollution effects of fossil fuels, he suggested that the world’s one-and-a-half billion cows are to blame for the greenhouse gas problems.

[Image found at Science Hax]

“A cow,” he informed me, “farts out as much pollution as a car.”

I looked it up; he was almost correct, but it is cow burps (scientific types, and other straight-laced characters, prefer the term eructation), not flatulence, that releases the bulk of the methane — a significant greenhouse gas component — from cows into the atmosphere.

In fact, ruminant animals (cows, sheep and water buffalo in particular) account for almost thirty percent of the methane in the environment. It is a big enough problem that there are even plans to add antibiotics to cattle feed to impede the production of methane. Personally, I’d prefer that we decrease our consumption of beef, which would reduce the population of cows required on the planet, thereby lowering the eructation of ruminant-methane. Our planet maintains a natural balance, but humanity has a nasty tendency to push past the level that the environment can correct for.

When I reported my findings back to the colleague who had prompted my research, he nodded; I was thus encouraged, and went on to explain that the real problem was our diet: apparently, in Canada and the United States, animal consumption accounts for about seventy percent of our dietary intake, and we could reverse the methane-eructation problem if we  reduced our livestock herds by modifying our eating habits. The carbon footprint of vegetables, beans and grains is a fraction of that created by animal husbandry. And, if our society reduced its consumption of animals, we would receive the added bonus of a healthier population.

“Okay,” my esteemed colleague said; “but what about the whales?”

“Huh?” I replied.

And then he began to (humorously) malign whales for their colossal contribution to global warming due to their excessive exhalation of carbon dioxide (CO2), a familiar greenhouse gas pollutant. “There have been estimates,” my colleague informed me, “that whales contribute the equivalent of forty-thousand CO2-belching automobiles.”

So I did some more research…

And he was correct, as far as he went; however, he hadn’t looked at the big picture.

Australian researchers, while studying baleen (krill eating) whales, have discovered that although whales exhale huge quantities of CO2, their feces are responsible for the reduction of greenhouse gases.

Whales move their bowels at the surface and, because their feces are rich in iron, this acts as a fertilizer for phytoplankton, the wonderful marine plant that uses CO2 from the atmosphere to drive photosynthesis. In fact, it turns out that the reduction of CO2 by phytoplankton, as powered by the iron from whale feces, is twice the amount exhaled by the whales; therefore, the net contribution of whales is beneficial in the battle against greenhouse gasses and global warming.  This is an example of how nature — if we take humans out of the equation — performs its own checks and balances.

So, when I was back at work again, I reported the findings to my colleague.

He nodded, accepting my research, and said, “Okay, but what about…”

But I didn’t hear the rest because I’d stuck a finger in each ear and walked away, humming loudly…

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Chlorophyll (and a couple of cousins)

When a metal ion is bonded in the center of an organic molecule, it is referred to as a chelate. Chlorophyll, the green pigment in plants, is one of the most important naturally-occurring chelates. The central ion in chlorophyll is magnesium, which is bonded to an organic molecule called a porphyrin, which contains four nitrogen atoms that bond with the central magnesium (to be overtly pedantic, they bond in a square planar arrangement).

[image credit: Learn for knowledge]

Chlorophyll absorbs in the red and blue-violet spectrum and reflects yellow-green, hence its name (from the Greek, chloros, for yellow-green).

Chlorophyll’s most extraordinary feature, of course, is its ability to absorb the energy of our sun and, through the process of photosynthesis, use the sun’s energy to transform carbon dioxide and water into carbohydrates and oxygen. The carbohydrates produced (designated below as the empirical formula (CH₂O)) are the energy that fuels biochemical reactions in almost all living organisms on our planet.

CO₂ + H₂O  → (CH₂O) + O₂

Chlorophyll is the catalyst in the electron transfer, oxidation-reduction reaction between carbon dioxide and water (and isn’t it grand that one of the by-products of photosynthesis is oxygen for us to breathe?).

As with many things regarding life on this planet, designs are repeated: blueprints are used over and over. For example, there are molecules with similar structures to chlorophyll that are essential in other biochemical electron-transfer (oxidation-reduction) reactions.

Heme is a close-cousin to chlorophyll with a similar porphyrin structure, but heme is bright red and has an iron(II) ion in its center.  In our red blood cells, heme is bound to proteins and forms hemoglobin; which, in turn, combines with oxygen in our lungs and releases the oxygen into our tissues through the flow of blood.

Vitamin B₁₂ (also called cobalamin), another close-cousin to chlorophyll, has a cobalt ion at the center of the porphyrin structure. B₁₂, like heme, is bright red and is required for cellular metabolism, the formation of DNA, and energy production. B₁₂ is not produced by higher plants, so vegetarians and vegans must ensure they consume other sources or their diet can lead to a B₁₂ deficiency.

It never ceases to amaze me that the underlying patterns of life on this planet are so similar, or that all life on Earth is intrinsically interconnected. It’s the reason I studied bio-sciences at university (though I can’t quite explain my years studying and working with electronics and mechanical systems), and I’ll never forget Cyril, my first-year biology Professor at SFU, who, when I stared at him with the wide-eyed disbelief of thunderstruck knowledge, smiled and said to me: “So; do you believe in God?”

Thank you Cyril (and the many others), for opening my eyes to the light of knowledge.

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The Dandelion

I grew up in a home with a huge back yard that was filled with gardens, pathways, and a small grove of vine maples (Acer circinatum), so I don’t understand the concept of a lawn; to me, it is an over-manicured, outdoor carpet.

I like grasses, but I think they should be allowed to grow to their instinctive length; in a natural setting, in a garden, lining a walkway, or growing from a crack in the sidewalk.

And I love a field of dandelions, which are surely an archenemy of the lawn fancier.

 

The Dandelion

O dandelion, rich and haughty,

King of village flowers!

Each day is coronation time,

You have no humble hours.

I like to see you bring a troop

To beat the blue-grass spears,

To scorn the lawn-mower that would be

Like fate’s triumphant shears.

Your yellow heads are cut away,

It seems your reign is o’er.

By noon you raise a sea of stars

More golden than before.

by Vachel Lindsay

 

Tripod Fish

The Tripod fish (Bathypterois grallator) is named for its two elongated pelvic fin rays and tail, which the fish uses to balance on the ocean floor. They are deep sea, benthic fish, and they face into the current, waiting for prey to flow to them. They have very small eyes and presumably sense prey by vibration. Their front fins are very sensitive and, when prey is detected, these fins act like hands and guide the prey into their mouth.                                                        [photo of tripod fish found here]

Tripod fish are hermaphrodites; and, possibly because of sparse distribution, both sets of sex organs mature at the same time and, if they cannot find a mate, a tripod fish is capable of fertilizing its own eggs and reproducing alone.

 

Tobacco kills (insects)

Tobacco is definitely bad for humans, but it can be imminent death for insects.

The wild tobacco plant (Nicotiana attenuata) is a desert weed that has evolved a pair of useful defense mechanisms to combat insect predators.

[photo credit: Danny Kessler]

Its first line of defense is a poisonous neurotoxin, nicotine, which is effective against a wide array of insect species. Nicotine was once commonly utilized as an insecticide, but now nicotine-analogs are produced and distributed world-wide to battle  insect infestations (e.g.: Imidacloprid — probably the most widely used insecticide in the world — for agriculture, animals (fleas and ticks), gardens, home protection, et cetera).

The tobacco plant’s secondary line of defense is a release of terpenes (herbivore-induced plant volatiles (HIPVs)), which are phytodistress signals synthesized and released in response to an insect assault.  If insects graze on tobacco leaves, the bug’s saliva triggers the production of terpenes from chewed and untouched leaves. For example, when the nicotine-resistant tobacco hornworm (Manduca sexta) grazes on the tobacco plant, the plant emits terpenes that attract the big-eyed bug (Geocoris paliens), which just happens to be a predator to the hornworm (and consumes the hornworm and its eggs).

I think from now on I’ll be extra kind to plants, just in case there is a terpene that attracts grizzly bears.