Category Archives: Nature & Environment

Why is The Earth a Life-Sustaining Planet?

landscape-at-sunsetWhat has allowed the earth to maintain stable conditions that are favorable for life? To answer this question we need to look at our planet’s history, and ask why the earth has been habitable for almost 4 billion years. This is an extremely long time, and probably the time needed for intelligent life to evolve. Scientists have second-hand evidence to go by, like entering a crime scene after the fact. But there is plenty of evidence to reconstruct the major historical events of our planet; this comes from a wide range of scientific fields.

The earth is the home of all life that we know about, possibly the only home humans will ever have. However, given enough time, it is possible that much like ancient sailors settled new lands, spaceships will cross space to new worlds. Up until now we should consider ourselves very fortunate that our planet has maintained the conditions necessary for life. For sure, the earth has gone through dramatic changes in its lifespan, but not significant enough to snuff out life. Let us examine a number of plausible reasons why a life-friendly earth has endured for so long:

The Goldilocks Zone

The earth’s location in relation to the sun has been called the ‘Goldilocks Zone’ or ‘Habitable Zone,’ because it is just the right distance from the sun to support life. Specifically, the temperature on earth is within a range that allows for water to flow (life as we know it needs liquid water). The right location is the starting point for a living world.

It is possible that life could exist with other chemicals that are liquids at other temperatures. For example, it has been suggested the liquid methane at extremely cold temperature could support life, such as the lakes of Titan (Saturn’s largest moon). But this is speculative, and that form of life would be unfamiliar to us. Nevertheless, finding evidence for liquid water on other worlds is challenging, as Goldilocks Zones are hard to come by. Although over 2 thousands exoplanets (planets outside our solar system) have been discovered, planets in habitable zones are rare.

The Solar System

solar-system-planetsThe earth is in constant motion and in relation with other celestial bodies in the solar system. Somewhat like a mobile hanging above a baby’s crib, all the bodies have influence on the system. In addition to a habitable zone, a long-term stable system is necessary. At least, the overall effects of the celestial bodies must stabilize the movement and climate of one body (like the earth). Here are 4 earth-friendly characteristics of our solar system:

  1. Earth’s Tilt: The earth is tilted at an angle of 23.5 degrees away from the plane of the elliptical orbit. The tilt gives us our seasons, which allows a greater surface to attract heat from the sun. Without seasons, only the region around the equator would be habitable. This would have drastically changed life on the planet?
  2. The Sun: The sun is 4.5 billion years old and will live for another 5 billion years. Some stars only live for a few million years. For complex life to evolve it takes several billion years, therefore a long-lived sun is needed.
  3. The Moon: The earth-moon system seems to have attained a stable relationship. The moon is just the right size to help prevent a chaotic wobble of the earth’s axis. The moon also aids in creating larger tides, which is thought to have played a role in transitioning life from water to land. And the speed of the earth’s spin has slowed over time due to the moons presence, thus moderating climate extremes.
  4. The Gas Giants: Jupiter and Saturn are the largest of the outer planets. Their orbits outside the earth’s orbit have protected the earth from large impacts. In the early development of the solar system, there were many large moving objects. The gas giants are believed to have ejected some of the large debris out of the system, and aided the inner planets to form sooner. And who knows how many potential collisions with the earth were absorbed by the gas giants.

Climate Stability

It is remarkable that the earth has maintained a stable climate for billions of years. I mean stable in the sense that the climate has not varied enough to wipe out life. Since life has appeared the earth has gone through a number of ice ages and periods of intense warming. Average temperatures may have varied by as much as 100 degrees C. But for reasons only partially understood, the climate has always returned to moderate levels.

Factors controlling the temperature have fluctuated throughout planetary history, such as: the heat generated by the sun, the earth’s heat absorption rate, and the amount of greenhouse gases that trap heat in. Could there be a regulating effect or cancelling-out effect that has prevented a runaway process? The earth has avoided irreversible climate change, unlike our two cosmic neighbors (Venus is to hot and Mars is to cold). Currently the average global temperature is about 15 degrees C.

Moderate and Gradual Change

Changes to the climate and environment are essential for the evolution of life, provided that the changes are moderate and gradual. Evolution is a multi-generational process, in which individuals that are better suited to their environments survive longer and reproduce. Beneficial genes are passed on to future generations; however, what constitutes beneficial genes is unstable, because the earth is constantly changing.

As a result of moderate and gradual changes species evolve into other species. If the planet was unchanging, the earliest life forms would not have evolved into more complex forms. On the other hand, if the changes were too drastic life could not have adapted successfully. Earth’s history shows that environmental changes have caused some species to go extinct, while others have evolved and branched out into new species.

The Gaia Hypothesis

James Lovelock, a NASA chemist in the sixties, proposed the Gaia Hypothesis when he was searching for life on other planets. While comparing the atmospheres of Earth, Mars and Venus he noticed that the earth was chemically in a state of flux. Conversely, Mars and Venus were chemically unchanging and predominately composed of carbon dioxide. The fact that the earth’s atmosphere was an active mixture of gases and still retained its overall composition, suggested some form of planetary regulation. His conclusion was that life regulated the atmosphere by its many processes.

earthLovelock expanded the Gaia Hypothesis (also called Gaia Theory) to include the whole biosphere (climate, rocks, oceans, biology, etc.) and described the earth as a self-regulating system. In other words, the earth acted as one organism. Gaia was controversial as a scientific hypothesis when first proposed. The main objection was evolutionary theory, as organisms are not believed to act in concert with their environment (sometimes supportive and sometimes destructive). The argument against Gaia Theory was that organisms would somehow have to communicate with each other, and act altruistically towards the planet. This was impossible.

Lovelock’s counter-argument was that Gaia was not intentionally achieved, yet that natural selection was critical in shaping the regulatory patterns of the planet. Gaia did not need a controlling center; it was a consequence of natural selection. Nevertheless, loosely applied it points to life processes as being critical in creating and maintaining living conditions. Over time Lovelock’s idea gained more popularity as evidence grew for an ever more interconnected and interdependent biosphere.

It could be that natural selection allows life to adapt to whatever conditions arise, giving the impression of Gaia. Or possibly, that long-term climate and atmospheric stability is in large part due to the existence of life.

Good Luck

It could be that the earth is a rare and unique planet, which has benefited from an extraordinary amount of good luck. Evidence for planets outside our solar system is mounting. There are a number of earth-like candidates, but the odds are stacked against finding a place just like earth. This does not mean that other earths don’t exist, just that they would be extremely far away. Paradoxically, the unfathomable size of the universe could mean that life is both rare and plentiful.

Anthropic reasoning would suggest that the earth has endured through a long succession of fortunate events. Intelligent observes are the result of anthropic selection, of which other lifeless worlds have no one to observe them. If events had not worked out just right for us, we wouldn’t be here. Still, it is difficult to comprehend the many unlikely phases of earth’s evolution. For example:

  1. The emergence of life.
  2. Multi-cellular life.
  3. Atmospheric transformation from carbon dioxide rich to available oxygen.
  4. Life moving from water to land.
  5. The rise of consciousness and intelligence.

These examples are major thresholds that were crossed, yet countless other variables could have changed the course of history. Life could have taken a completely different direction, even to the point of total extinction. Obviously, this has not happened, either from cosmic events or global catastrophes. When life began there was no guarantee that it would survive for nearly 4 billion years. And the specific circumstances that led to human beings were even more tenuous. We should consider ourselves very lucky to be here, on such a special planet.


References: David Waltham, Lucky Planet (New York: Basic Books, 2014).

Beautiful Minds – James Lovelock – The Gaia Hypothesis / Gaia Theory, Published on Sep. 12, 2013.

Life on Earth Can Thank Its Lucky Stars for Jupiter and Saturn, By Sarah Lewin, Staff Writer | January 12, 2016 07:30 am ET,

What Makes Earth So Perfect for Life? Dec 13, 2012 03:00 AM ET,


Photosynthesis: The Breath of Life

large-leafPhotosynthesis is a chemical process, by which plants, algae and some bacteria convert solar energy into chemical energy. Basically, the organisms take in carbon dioxide and water, and use sunlight to make glucose, thus releasing oxygen as a by-product. The organisms are able to make their own food (glucose) by capturing sunlight. Other elements, such as nitrogen, phosphorous and magnesium are also needed to complete the process.

Sunlight provides the energy needed to transfer electrons from water molecules, an essential part of the process. The electrons are extracted from water molecules and passed along a chain, and finally forced onto carbon dioxide to make sugars. Photosynthetic organisms are called autotrophs. People and animals cannot photosynthesize; they are called heterotrophs. Today, plants are the most familiar form of autotrophs, but they were not the inventors of photosynthesis.

It Started Way Back

The evolution of photosynthesis is believed to have stared about 3.4 billion years ago. It was developed by primitive bacteria, first using elements such as hydrogen, sulfur and organic acids. These early bacteria manufactured food without using water, and did not produce oxygen (a process called anoxygenic photosynthesis). This was, however, an important development in the evolution of life.

algaeAround 2 billion years ago, a variant form of photosynthesis emerged. These bacteria lived in the ocean, used water as electron donors, and the release of oxygen into the atmosphere was the result (oxygenic photosynthesis). Photosynthesis was one of the most important developments in earth’s history. Learning to use sunlight to produce food took advantage of an endless supply of energy.

The introduction of free oxygen into the atmosphere was a game changer for all life. For some microbial life that existed then, oxygen was a toxin; this led to a significant extinction event. However, it opened up new opportunities for complex life to evolve, which it did. Oxygenating the atmosphere was an extremely slow process, as it took in the range of 1 billion years before complex life emerged.

How Did Plants Acquire the Ability to Photosynthesize?

Inside the cells of plants there is a separate compartment called the chloroplast. The chloroplast contains the green-colored pigment chlorophyll, which absorbs blue and red light. These are the wavelengths used in photosynthesis. The green wavelengths are deflected out, and that is why plants look green to us. In the chloroplast a number of complex interactions occur to produce food for the plant cell.

The chloroplast originated from primitive bacteria. In fact, in an earlier period chloroplast were bacteria, which eventually formed a symbiotic relationship with more complex cells. This relationship was the beginning of plant life on earth. It seems that the complex cells took advantage of the bacteria in order to get a free lunch. However, there was probably a benefit for the bacteria as well, perhaps the protection of an outer membrane or some other survival advantage.

The Ultimate Recycling Project

Photosynthetic organisms are the original source of oxygen and food for other life forms. If not for plants, there wouldn’t be any food for animals to eat. So the food chain in any ecosystem begins with photosynthesis. The food chain starts with plants, which are consumed by herbivores; the chain continues with carnivores and omnivores.

athmosphereThe earth’s atmosphere contains 20.95% oxygen and .039% carbon dioxide. The remainder is mostly nitrogen (78.09%). What concerns us here is the oxygen/carbon dioxide relationship. Most of the oxygen is provided by terrestrial green plants and microscopic phytoplankton in the ocean (they consume carbon dioxide and release oxygen). Non-photosynthetic organisms, like humans, animals and fish do the opposite (they breathe in oxygen and breathe out carbon dioxide).

Oxygen and carbon dioxide are continually recycled into the air. Life as a whole has evolved to function with the present mix of oxygen and carbon dioxide. What we don’t know is how delicate the balance is and if human carbon emissions will drastically change the balance. Scientists know that the atmosphere has changed significantly over evolutionary time; the result being the extinction of some species and the evolution of other species.

Given that life has created and maintained the atmosphere for billions of years, it will no doubt continue to do so. Life as a whole is safe. The questions for humans are: What are the long-term implications of releasing more carbon dioxide in the atmosphere? Which species will adapt successfully? And whether the atmosphere is changing in a direction that is less favorable for us?


References: In Our Time: Science, Photosynthesis, May 14, 2014.

livescience, What is Photosyhthesis? by Aparna Vidyasagar, July 31, 2015.

Earth and Sky, How much do oceans add to world’s oxygen? June 8, 2015.


The Agricultural Revolution

For much of human history foraging for food was the norm. For nearly 200,000 years people lived on what they could find in their natural environment. This meant gathering food from the land and hunting wild animals. This way of life meant that relatively small groups of people were subject to what their environment could provide. They could either find sustenance in one area or move as needed. If their present location was insufficient in resources, they could follow migration patterns of wild animals or look for more naturally fertile areas.

What Changed?

Agriculture originated in about 9,000 BC. What follows is a brief time line of the early stages of agriculture:

  • Around 9,000 BC agriculture begins east of the Mediterranean in the place known as the Fertile Crescent. Relatively close by agriculture also appears in the Nile Valley. Wheat is the crop of choice in these regions.
  • Then in about 6,000 BC there is evidence of rice farming in China, and in Papua New Guinea they are growing yam and taro.
  •   After a few thousand years in roughly 2,000 BC framing pops up in scattered regions of the world: In West Africa sorghum and millet are being harvested, South America is cultivating potatoes and Central America is now growing maize and squash.

Ancient agricultureInterestingly, most of the plants that feed humans today were domesticated before the first century. From these initial regions framing would continue to spread around the globe. Why did humans change their way of life after so many years of foraging? One factor worth considering is that agriculture developed independently in unconnected parts of the world. What could account for this fact? It happens that the beginning of agriculture coincides with the end of the last ice age. This was a global phenomenon; as regions warmed framing became possible.

Another factor was increasing population. In a scarcely populated planet it would have been much easier to find fresh areas to forage even if some distance had to be covered. As population grew it became more difficult to keep up with rival groups coveting the same lands. At this point, the best option was to settle in one area and farm. Once this happened population continued to grow and villages sprang up.

Settling down had an exponential effect on population; mainly because woman no longer needed to travel with children. As you can imagine, all this was a gradual process. The earth warmed over time and not all people adopted framing at once. Around 10,000 BC the earth had somewhere between 5 to 8 million foragers; by the first century only 1 to 2 million people were foragers and farmers consisted of 250 million people. With the adoption of agriculture a threshold in human development had been reached.

The Birth of Civilization

Adopting agriculture initiated a huge shift in how humans lived. When groups of people made the decision to settle in one region, a whole series of events followed. Along with agriculture came the domestication of animals; the most docile and fattest species were chosen. These animals could be used for their skin, fur, meat, milk and eggs. Some farm animals were also valuable for labor. Perhaps land that could not be harvested before could now be plowed with the aid of domesticated animals.

old farmhouseOnce villagers became dependent on agriculture for sustenance, they now had something very valuable to protect. Their lives depended on farm land, animals, and crops. The notions of property, state, law and quite possibly economics can be traced back to the early agrarian villages. What’s more, in time the shift to agriculture made cities and empires possible. With the first crops came questions that did not previously exist. Who manages the land, animals and crops? How will the area be protected from other humans and pests? If there was a surplus of food, should it be traded and who acquired the wealth?

Not All its Cracked up to be   

farmerIn most cases development come with a cost; the adoption of agriculture was no exception. As you can imagine, the life of foragers was probably not an easy existence. However, it does not mean that early farmers had an easy time of it. Framing with primitive tools was hard work and as societies emerged a hierarchy was created. This usually meant that a large group of people toiled for the benefit of the higher class. I can’t help but think that if it were not for agriculture, would slavery have existed in the same way? And let’s not forget the fate of farm animals, who in effect, have been enslaved for thousands of years. At the hands of humans, some of these animals have been subjected to cruelties too numerous to mention.

Along with farming came villages and cities. Larger groups of people living in close proximity were more susceptible to disease than in the past. At a time when little was known about infectious disease, the early agrarian societies had to deal with sickness that could spread like never before. Also vulnerable was the food supply itself. Now dependent on a successful harvest, what then if crops failed? They could stock pile grain if there was a surplus, but a succession of poor growing seasons could mean starvation. Still today we celebrate Thanksgiving at harvest time, because a good harvest meant so much for so long.

Even if growing seasons were stellar, the invaluable farm land needed to be protected. War was a natural consequence of agriculture because territory became more valuable than ever before. Think for a moment of how many wars have been fought over territory. The idea of controlling or owning land was a game changer in human behavior, and not always for the best.

 A New Way of Thinking About the Future   

Looking ahead and planning is something we all do without much thought. Thinking about the future is virtually a necessity in the modern world. The life of foragers would have been far more present oriented. They would have likely consumed most of the meat they hunted on a particular day, saving only a little extra. Their foraging needs would have been best served by picking daily. There is no better preservative than nature. The food supply was out there, in the wild. Realistically, how far ahead could they really plan for?

Agriculture made it necessary for humans to foresee into the future (more so than before). Cultivating land, planting and harvesting are future oriented endeavors. Working for a pay off several months down the road requires planning. From the moment humans began the ambitious task of farming, our lives were destined to become more complicated. Farming led to civilizations; which entails governments, laws, economics and a multitude of complications. On the other hand, this future mind-set has allowed us to progress far beyond what the early farmers could have ever imagined. Nevertheless, it was their venture into agriculture which started the ball rolling on a path to civilization.


References: Yuval Noah Harari, Sapiens (Canada: Signal Books, an imprint of McClelland & Stewart, 2014).

Why Was Agriculture So Important? | Big History Project, Published on May 19, 2014,

Mankind: The Story of All of Us: Birth of Farming | History, Published on Dec 2, 2012,


The Evolutionary Arms Race

Evolution is guided by an intense competition for survival. When one individual or species gains an advantage, natural selection will cause competitors to catch up. Because there is always competition, over time species are pushed to improve, and a stable balance is generally established. It would be more economical for all to keep things as is, but that’s not how it works. Evolution requires change, and change is continual. An evolutionary arms race is an unavoidable consequence of evolution. To see how this works let’s look at a few examples:

The Tree Canopy

tree canopyHave you ever wondered why mature trees in a forest are roughly the same height. Given the fact that there is tremendous diversity in nature, why not have trees of various heights. Although different species can naturally grow to different heights, they are not found in the same forest environment. The reason is due to a race upward for sunlight. All the trees in a forest are competing for solar energy.

Forests could easily have been populated by low growing trees, at an energy cost savings for all. But nature has selected the trees that gained a competitive advantage (those that grew a little taller). The other trees were forced to keep pace or be left behind. Trees have evolved to grow higher because competing trees were also reaching for sunlight. Individual trees compete with their own species and also with other species. It does not matter whether it’s an individual or an entire species, those that cannot keep pace will not be successful at passing on their genes. In The Greatest Show on Earth, Richard Dawkins writes:

“In fact, what we actually see is a forest in which each tree species evolved through natural selection favouring individual trees that out-competed rival individual trees, whether of their own or another species.”

Of course, this was a slow process that was played out over evolutionary time and at the genetic level. Genes favorable for growing tall trees were passed on, because the trees that contained them were more likely to survive and seed the next generation. This competition continued for millions of years until an optimal height was achieved. There is a limit to the amount of energy a tree can divert towards growth, and a limit to the height a tree’s structure can support. Eventually the forest settled at a maximum height, when it was no longer an evolutionary advantage to grown higher.

Running Speed of Predator and Prey

predator and preyThe relationship between predator and prey is a complicated one, with each trying to outwit the other. Both predator and prey will evolve their own skill set. Some traits are specific for catching prey, while others are specific for avoiding predators. But there is an overlap as some traits are shared. For example, let’s consider the running speed of animals, which is just one of many skills needed by both sides. Running speed is valuable for both predator and prey.

Predators like cheetahs have evolved to run faster and faster, while gazelles (their prey), have also evolved to run faster. The end result being that neither gains ground. Richard Dawkins explains:

“Natural selection drives predator species to become ever better at catching prey, and it simultaneously drives prey species to become ever better at escaping them. Predators and prey are engaged in an evolutionary arms race, run in evolutionary time.”

Running speed is important, but it is part of a delicate balance with other important traits: such as endurance, strength and eyesight. The evolutionary winners will be those that get the balance right, yet running speed will be in the mix. Although less obvious, it is just as important for an individual to outrun individuals from the same species. For instance, a gazelle which runs slightly faster than the average gazelle will escape the predator at the expense of the slower gazelles. The fastest gazelle in the herd will be favored just as much as the overall speed of the herd.

Bacteria, Viruses and Human Defenses

In the two examples listed above (the tree canopy and the running speed of predator and prey), evolution acted at the subconscious level. No conscious agent designed any particular trait. The arms race was fought by natural selection. Because of our knowledge of viruses and bacteria, another level of the arms race is added. That is, the production of vaccines and antibiotics.

The Influenza Virus and Vaccines: In 1918 the Spanish Flu was responsible for the death of about 50 million people (the worst pandemic in world history). The pandemic struck in the last year of World War 1. The world war was critical in spreading the disease as masses of soldiers moved across the globe. The poor living conditions and ill-health of the solders may also have contributed. Pandemics have reoccurred throughout history, and experts caution that it could happen again. Different strains of the flu still come around every year. Today, much progress has been made in developing vaccines, which along with sanitation is our best defense against viruses.

influenza virusViruses attack the human body by invading cells. The immune system produces antibodies that fight off the virus. Therefore, a specific virus can only infect a host body once. However, viruses evolve very fast and are inaccurate replicators. As a result they evolve into different strains that can evade the human immune system. Viruses are not trying to change; they change because of chance mutations. The ones that are resistant to antibodies populate. It may appear that viruses are attempting to outsmart the immune system, but they simply evolve through the process of natural selection in their environment.

An arms race between viruses and their host is ongoing. Each year experts predict which strains of influenza will be dominant, and they product vaccines in accordance. It is an educated guest, which sometimes they get right and sometimes they don’t. Except for particularly dangerous strains, such as the H1N1 pandemic in 2009, it is debatable whether wide-scale vaccinations for the flu are effective or necessary.

The arms race will surely continue. We have the natural competition between viruses and antibodies, and the additional armament of vaccines. The speed in which viruses replicate and evolve insures that they are here to stay. Humans are faced with every-changing viruses, which we have to keep pace.

Bacteria and Antibiotics: Common bacterial infections for today’s standards were often fatal in the past, but thanks to antibiotics are now easily treatable. Antibiotics can kill bacteria inside a human body, however it kills good bacteria as well as bad bacteria. Good and bad are subjective descriptions based on their influence on humans. Bacteria are single cell organisms that have evolved to live in symbiotic relationships with humans (bacteria cells in the body outnumber human cells). The beneficial bacteria will defend its turf against invading bacteria, and thus can be considered as part of the immune system.

bacteriaAlthough the antibiotics are engineered to target the invaders, they are not perfect and they kill some of the symbiotic bacteria. Because antibiotics have been widely used, this has changed the balance of bacteria that dwell in humans. The effects of these changes is not clear, but there is evidence it can contribute to some diseases.

When an antibiotic is used to treat an infection it does not kill all the invading bacteria. And similar to viruses, the bacteria develop resistance to the antibiotic. The surviving bacteria will multiply and evolve until that specific antibiotic becomes ineffective. New antibiotics need to be developed in order to keep up. Even though a patient is cured, surviving bacteria can still spread to other people. Once again, the battle is similar. Unwanted bacteria verses beneficial bacteria and human ingenuity. The arms race is on with no end in sight.


References: Richard Dawkins, The Greatest Show on Earth (New York: Free Press, 2009), 380, 381.

Big Picture Science, Skeptic Check: Evolutionary Arms Race (June 22, 2015).


Why do Leaves Change Colors in the Fall?

Road in fallFor many years I have enjoyed the fall colors, yet without knowing exactly why the leaves change colors. People have given me a number of one-line explanations, such as: It is because of cooler temperatures. It is caused by lack of sunlight. The fall colors are already in the leaves, but are covered up in the summer by the green color. At some point I became curious enough to look it up. It turns out that I had received a collection of partial answers, and the fall colors are due to more than one cause.

The Colors

Eastern Canada and the northeastern United States have ideal conditions for brilliant fall colors. The colors of the leaves in deciduous trees turn to variations of yellow, red, orange and brown. The different colors are produced by different pigments in the leaves, which become dominant when the green color fades.

orange leavesDuring the growing season the leaves produce chlorophyll, which is responsible for the normal green color. The production of chlorophyll is part of the chemical process of photosynthesis. This is the process that converts sunlight into energy the tree needs to grow. When the fall arrives the daylight hours get shorter and this decreases the production of chlorophyll, until it will eventually stop altogether.

Yellow pigments, called carotenoids, have been produced throughout the growing season, but in smaller amounts than the green pigment. When the green color dissipates the yellow becomes visible. The red color comes to the leaves later in the season, mostly being produced in the autumn. The pigment name for red in trees is anthocyanins. When these pigments are lacking, other pigments called tannins can affect the leaf color. Tannins are mainly responsible for the brown colors.

Variations in Color and Intensity

The 4 pigments (chlorophyll, carotenoids, anthocyanins and tannins) can be present in various amounts. Therefore leaves are not always pure green, yellow, red or brown; they can be a mixture of more than one color. For example, when the yellow and red pigments are dominant the leaves will appear orange; there is no single pigment that will produce orange.

Different species naturally produce specific pigments, which will keep the colors of the same species fairly consistent from tree to tree and year to year. That being said, each autumn the climate is slightly different. Changes in sunlight and temperature will result in varying amounts of pigments, thus affecting the fall colors.

red orange leavesThe yellow pigments are always present in the leaves and this will keep the yellow colors fairy consistent. However, red pigment production is whether dependent. Falls that have warm sunny days and cool nights (but above freezing) will result in the most spectacular red and orange colors.

So, if you have noticed that some years the fall colors are more vibrant, it is not your imagination. In those years the conditions were probably ideal. Nevertheless, having some knowledge as to why the leaves change can deepen the enjoyment of the fall colors. Combined with the crisp cool air and generally low humidity, autumn is my favorite time of year. But as it is with many of nature’s spectacles, it does not last for very long. My suggestion is to get out, take a walk or a drive and simply observe.

References: USDA Forest Service, Why Leaves Change Color,, July 7, 2011.

ESF, Why Leaves Change Color,, 2015.

Why do Leaves Change Colors in the Fall?, Uploaded on October 20, 2009.


A Gene Centered View of Natural Selection

Natural selection was Darwin’s term for the mechanism of evolution. In the slow process of evolution nature selects which organisms adapt to their environments successfully (that are most successful at surviving and reproducing). But what is the unit of selection? Is it the species, group, individual or gene? At what level do natural environments shape the evolution of life? Could there be a blending of different units or is one dominant? For example, do species evolve as a consequence of group selection, or do groups evolve as a result of individual selection; or do genes ultimate control the process?

Richard DawkinsThese questions have been debated by biologists and academics for a long time. Richard Dawkins, with the publication of The Selfish Gene, sided on the gene centered camp. The idea of gene selection had been proposed in scientific papers: First by Bill Hamilton in 1964 and then by others, such as John Maynard Smith and Robert Trivers in the early seventies.

Published in 1976, The Selfish Gene placed gene selection into the public sphere by getting beyond the technical aspects of the scientific papers. Dawkins’ book was accessible to a general audience, and has been influential in shaping evolutionary thinking (the 30th anniversary edition was published in 2006). It was, however, controversial as much for its implications as for the gene centered view it supported. According to Dawkins, the book was misinterpreted and used by some groups as biological justification for selfishness in humans; but his intention was to explain how natural selection works, not how people should behave. Dawkins clearly points this out in the first chapter of the book:

“I am not advocating a morality based on evolution. I am saying how things have evolved. I am not saying how we humans morally ought to behave.”

The Metaphor

The title, The Selfish Gene, is a metaphor for how genes propagate. By controlling the traits of organisms, genes influence their own survival. The genes that aid in survival and reproduction are more likely to be copied in future generations. In that sense the genes are selfish and potentially immortal (in the form of replicas), while the bodies that contain them are mortal. Dawkins writes:

“Individuals are not stable things, they are fleeting. Chromosomes too are shuffled into oblivion, like hands of cards soon after they are dealt. But the cards themselves survive the shuffling. The cards are the genes…They are the replicators and we are their survival machines. When we have served our purpose we are cast aside.

genesThe selfish gene metaphor, though powerful, has its limitations; a single gene can’t do very much. Genes interact with each other and combine in complex ways to give rise to physical traits. It is essentially groups of genes that survive (genes that work well together). Therefore, a successful gene can be defined as a portion of genetic material that survives through a number of successive generations.

 Explaining Altruism

“Survival of the fittest,” that is the popular catchphrase for evolution. But an analysis of the mechanisms of evolution requires that we ask: the fittest what? For Darwin, it was the fittest individual that would survive and reproduce. In the middle of the 21rst century, biologists were reintroducing and debating Darwinian ideas. Group selection (the idea that the fittest groups would survive) was gaining popularity. The propagation of the species was the consequence of the fittest groups. However, some biologists were pointing out that group selection was inadequate to explain altruism in animals.

Altruistic Behavior in  Animals

Dawkins is a zoologist by training, and The Selfish Gene focuses mainly on the role of genes in animal behavior. He analyses animal behavior in a variety of species, and points out the correlation between altruistic behavior and relatedness. In other words, the closer the relationship (in terms of shared genes) the more altruism we can expect to see. In this view the genes are at the core of the altruistic behavior, as they aid in the survival of copies of themselves.

zebrasWhen an animal acts altruistically, it appears that the animal is sacrificing some survival need in order to increase the chance another will survive. It does not matter how small the sacrifice is, because a number of small sacrifices can accumulate over time, and also can be reciprocated. The group selection hypothesis interprets altruism as benefiting the group, and in the long run, these groups will be more successful. However, others claimed that selfish individuals would undermine the altruistic group. The selfish individuals within the group would exploit the altruistic system, eventually winning out. The struggle for existence would favor the selfish individuals over the altruistic individuals.

Dawkins argues that seemingly altruistic behaviors can be interpreted differently from a gene centered view. From the gene point of view, the act is still selfish because it aids exact copies of itself (in the form of children, siblings, cousins and so one). Animals are sometimes altruistic because they are programed by their genes to be so. Whether to be selfish or altruistic is a delicate balancing act that is ultimately guided by the genes chances of survival. In addition to helping close relatives, individuals are also dependent on groups. Therefore some consideration for the well-being of the group would likely come into play.

The Social Insects

Perhaps no other example of altruism in animals is as evident as in social insects. This is probably the best example of which a gene centered view of natural selection is adequate. Honey bees, wasps, ants and termites are familiar social insects, and they live in large colonies. The colony functions as a highly organized unit, where each individual has a specific role. Although the roles vary, they can be broken down into two main categories: Carers and bearers. The carers are sterile workers; the bearers are the reproductive females (queens) and reproductive males (drones or kings).

In most species each individual shares in the caring and bearing roles (not necessarily equally). But with social insects it is clearly divided. The sterile workers will devote their lives to providing and protecting the reproducers, even to the point of suicidal actions. This is what we observe when a bee stings a perceived threat to the hive. The bee will almost certainly die.

With an individual selection view, we would not expect suicidal behavior to evolve, because there is nothing to gain for the individual. However, the fact that the workers cannot bear offspring of their own, self-sacrifice for the good of the colony aids in the survival of their genes (shared genes with the reproductive members of the colony). From the gene centered view, what really matters is not just reproducing offspring, but assisting the survival of one’s own genes. There are many strategies in which this can occur (usually a balance of risk and reward). The triggers for the behaviors are surely subconscious. You could say they are controlled by the genes, or call it instincts.

Are Genes Really in Control?

Although there are mountains of evidence that shows life does evolves, determining the level of selection is tricky; it seems like a matter of interpretation. It is not hard to see how each unit of selection would naturally influence the others in the same way (either positively or negatively). For example, if the fittest individual is selected, it will aid its group, species and genes to propagate. We could change the last sentence by randomly shuffling the units (individual, group, species and genes) and it would still hold true.

Maybe natural selection is a complicated process that includes several units of selection. Species, groups, individuals and genes are likely interconnected in ways that are difficult to quantify. I suspect that this issue is not completely resolved among scientists. Nevertheless, I find that the gene centered view is both fascinating and compelling. It is a somewhat counter-intuitive way of looking at evolution, and yet upon closer examination it makes so much sense. Logically, it all hangs together.


References: Richard Dawkins, The Selfish Gene (Oxford: Oxford University Press, 30th anniversary edition, 2006).

Beautiful Minds: Richard Dawkins, Published on April 25, 2012. BBC4


The Tao Does Nothing, But Leaves Nothing Undone

This is the opening line in the 37th verse of the Tao Te Ching, an ancient Chinese book of wisdom. The Tao (pronounced dow in English) is an indescribable force that permeates all things. The Tao does nothing in the sense that it can’t be identified in precise terms, but leaves nothing undone in the sense that all things contribute in an interconnected way. And speaking of way, the word Tao is generally translated as the way. The way, meaning a path that one follows, which is in harmony with nature. Te is translated as power or virtue, and Ching is a book.

The Tao is a mysterious concept and its true meaning is almost impossible to express in language. The 1st Verse of the Tao Te Ching begins as follows: “The Tao that can be told is not the eternal Tao. The name that can be named is not the eternal name.”

Some contemporary spiritual teachers have written and lectured about the wisdom of the Tao Te Ching. Although I am sure there are many, 3 influential figures come to my mind: Alan Watts, whose lectures from the sixties and seventies are still posted on You Tube. In recent years, Eckhart Tolle and Dr. Wayne W. Dyer have incorporated Tao philosophies into their teachings. In his book, Change Your Thoughts-Change Your Life, Dyer describes his interpretation of the concept that is called “the Tao.”

“The Tao is the supreme reality, an all-pervasive Source of everything. The Tao never begins or ends, does nothing, and yet animates everything in the world of form and boundaries, which is called “the world of the 10,000 things.”

The Legend of Lao-tzu

Loa-TzuLegend has it that a wise old man, named Lao-tzu, wrote the Tao Te Ching (sometime between the 6th and 4th century B.C.). Lao-tzu was the keeper of the archives of imperial China. He became frustrated with the unrest in the empire. He decided to leave and headed west, where he was recognized by a border guard. Lao-tzu was asked to write down his wisdom before he left, which became the Tao Te Ching. Afterwards, he left the kingdom and was never seen again.

There is, however, no way to verify if this is historically accurate. Lao-tzu actually translates to old master. It could be that the original text is a collection of proverbs from various sources, or perhaps what has survived is an incomplete version. Nevertheless, the book has been translated thousands of times in many languages. A few centuries later a movement began, which became Taoism. There is also some speculation that the Tao Te Ching may have influenced the birth of Buddhism.

Religion or Philosophy

The core concept of the Tao has led to the development of the Taoist faith. I use the word faith as opposed to the word religion, because Taoism is fundamentally different from other world religions. The Tao is not a God in the traditional western sense. The concept of God as a controlling figure is absent in Taoism. In the Tao, there is no controlling center; everything is allowed to be, and each component is viewed as part of a harmonious system.

Based on the Tao, there are no prescribed directions to follow; it is left to individuals to find their own way. The Tao Te Ching is a guide for living in harmony with nature, but it is not a manual. Taoism is as much a philosophy as it is a religion.

The Way of Nature

The flow of water is a powerful symbol for the Tao. Flowing water finds the lowest or easiest path. There is also the inevitability of the direction of the water. Take for example, the flow of a river; much better to go with the current than to try to go against it. There is a way to nature and the universe, but it is difficult if not impossible to pinpoint. The main goal is to experience the Tao by allowing and accepting nature as it is, not by trying to control it.

Ying and YangThe Tao Te Ching also points out the paradoxes of nature. Even polar opposites are viewed as working together. Hence the terms and symbols of yin and yang, which represent opposite forces in nature; they are seen as complementary and interconnected. For example, there is a balance between high and low, soft and hard, hot and cold and light and dark. Or one could say there is no light without darkness. Following the way is living in balance.

The Way Forward

We could do worse than adopt an open philosophy of life that aligns with nature. When we consider the immense problems caused by extreme and competing religious dogmas, and financial greed and inequality that disregard the well-being of the environment, it should make us pause: “Where are we going?”  If humans are going to find their way in such confusing times, we will have to incorporate principles that are compatible with nature.

waterfallI find it refreshing that ancient concepts contained in the Tao Te Ching are lining up with a modern scientific view. Science has discovered a multitude of interconnected parts that make up our world. Life is so interconnected that it is sometimes difficult to determine when one living system begins or ends. The whole planet (or even the universe) can be viewed as one system or organism. Everything that exists is compatible with the whole. If it were not, it wouldn’t be here. Alan Watts summarizes the Tao in the following manner:

“The whole conception of nature is as a self-regulating, self-governing, indeed democratic organism. But it has a totality, it all goes together, and this totality is the Tao.”


References: Dr. Wayne W. Dyer, Change Your Thoughts-Change Your Life (United States: Hay House Inc., 2007).

Alan Watts – The Taoist Way, Published on Jan. 13, 2014.

In Our Time Philosophy: Daoism (Dec. 15, 2011).


The Epic Journey of the Monarch Butterfly

Monarch and flowerThe migration of the Monarch butterfly is one of the most incredible adaptations in the natural world. There is nothing that we observe in the delicate-winged creatures that would predict the immense journey of the butterflies. And yet, they will undertake a 4 generation migration, which will cover 2,000 to 3,000 miles (each way). The migration begins in a remote mountain range in Mexico, goes across America to Canada and back to Mexico again.

The Migration Route

After overwintering in Mexico, the Monarchs begin the migration to Canada. These butterflies are the 4th generation in the cycle, and they are unique. They have made the migration from Canada to Mexico, arriving in October. The following spring they will start the migration back to Canada. They begin the journey by flying to the southern United States, where they will mate and die. The 2nd generation will make it as far as the northern states; they to will mate and die (living only one month). The 3rd generation will settle in various locations in Canada and the northeastern United States (also living one month).

The 4th generation will make the trip to Mexico before winter comes again. They will live almost nine months, and make the epic journey from Canada to Mexico, all on their own. They will have to fly an average of 50 miles per day. On their way the butterflies will cross the Great Lakes, the Great Plains, hundreds of miles of deserts and the Sierra Madre Mountains. Starting from different locations in the northeastern U.S. and Canada, the Monarchs will find their way south and converge in huge flocks near Mexico. Millions of butterflies take part in the 2 month-long migration.

How do They do it?

Monarch migrationNaturalists are unable to explain how the Monarch butterfly accomplishes such an incredible flight. Each butterfly weighs less than one fifth of an ounce, and its delicate wings must withstand the journey. Also, a large amount of energy is needed to fly such long distances. A butterfly is built more like a helicopter than an airplane, thus it is not the most efficient flyer. There are, however, ways that they can maximize their energy. They only fly when the conditions are perfect. And they can take advantage of rising columns of air. This occurs when the sun heats the ground, causing the air directly above to become hotter. The hot air gets lighter and then rises, carrying the butterflies up. In this case their light frames are a bonus.

Perhaps the most puzzling question regarding the migration is: how do the Monarchs navigate? The 4th generation will begin the journey from a wide variety of locations, and find their way to a forest in the mountains of Mexico (a place they have never seen). Scientists can only speculate how they do it. Maybe they follow a specific angle of the sun or the earth’s magnetic field. Maybe they are guided by wind directions or follow landmarks. And why is the 4th generation more adept at flying long distances, and able to live much longer?

The Power of Multiple Generations

I find it particularly interesting that multiple generations are needed to accomplish the full cycle of the migration. It brings to mind a comparison with human life. In many ways, recent generations are special. We are special in the sense that we benefit greatly from the labors of past generations. Our modern life is the product of people who are no longer here. Like the Monarchs, each generation has passed on something to the next, and over time it has built up.

Today, humans can achieve great things, because we have been given great opportunities. Much of which we take for granted has come about through multiple generations. For example, democracy, human rights, technology, industry, agriculture and so on. Some challenges are so immense that it takes more than one lifetime to overcome them. We should also keep in mind that we will leave something to the next generation.

On personal note: I live in Atlantic Canada, and I have on occasion observed a passing butterfly. They are beautiful creatures, and seem to have a mystical quality to them. In addition to their vibrant colors and elegant flight, the thought of having come from a grounded caterpillar is remarkable. The transformation from caterpillar to butterfly is one of the most amazing transformations in nature. For me, the Monarch is the most familiar of the butterflies. And even before I knew of the migration, I would still pause in admiration when one flew by.

The story of the Monarch Butterfly is so incredible that if it had not been observed and documented, no one would believe it. In fact, the full extent of the migration was not known until 1975. There are Monarchs in other parts of the world, but only in North America do they migrate such great distances. The Monarch butterfly is clearly one of the most amazing animals on earth. And it shows us that very often nature is more creative than we are.


References:  Journey of the Butterflies, Aired November 30, 2011 on PBS


The Abundance of Nature

wild flowersIn many respects planet Earth is a rare and unique place. This is partly due to the abundance of nature. There is abundant opportunity, quantity and diversity, as well as abundant time and space. No matter where we look, we will find that things come in large quantities. There is rarely just one of anything in nature; if there is, it probably won’t last for very long.

For our convenience, we separate and categorize the components of nature. Inanimate substances and living things make up two large categories, which are broken down into smaller subgroups. This is useful for us, but in reality the Earth is a living planet. What we consider as inanimate is shared and circulated to maintain all life on earth. For example: soil, water, air and sunlight are part of the living world (in a roundabout way).

Natural Selection and Exponential Growth

Natural selection, Darwin’s term for nature’s sorting process, has a subtle implication; similar patterns and forms are repeated over and over again. This is an unavoidable consequence of natural selection. In order for environmental conditions to serve as a shaping force, it must be favorable for numerous life forms. If only a few individuals are favored, then randomness necessitates that their genes will not be passed on in the long term. On the other hand, when selection acts positively on large numbers (of genes, individuals, groups or species), then the odds are high that they will prosper.

Success from an evolutionary standpoint means survival and replication. There is a constant competition for resources; there are always winners and losers. Once something gains an upper hand, exponential growth will lead to an abundance of that particular life form. It is similar to compound interest in a bank account. Of course, abundance does not entail permanent growth. All species will eventually decline or become extinct due to ever-changing conditions. Nevertheless, when anything survives the process it will do so in large numbers, otherwise it would not be here.

butterfliesFor example, if favorable conditions (such as a plentiful food supply, lack of predators and a temperate climate) are present for a particular species, then the numbers will likely grow. This may at some point lead to overpopulation and stress the survival needs of the species, which can create an opportunity for competing species. The growth of species will usually fluctuate; but most of the time a balance will develop, somewhat like the swinging of a pendulum. In the end the diversity of life will almost ensure that life as a whole will be plentiful.

Self-Organization, Order and Randomness

Both the living and non-living world has the ability to self-organize. That can partially explain how order emerges from a random and chaotic world. The process of self-organization in nature is messy, nothing like we organize our daily lives. With humans there is usually a clear direction or purpose when we make plans. But not all the time; humans also self-organize when groups of people act in a similar way, even if no one is in control.

In nature, the terms trial and error best describes how order and structure arises. There is a role for both order and randomness in this process. The order allows for stability, the random component creates opportunities for change. For example, if we think of how seeds from plants are dispersed, we can see that they fall to the ground in irregular patterns. There is no reason why any seed will come into contact with fertile soil. In fact, the majority of seeds will be wasted. Still, within each seed contains the information necessary to produce the plant. And due to the abundant production of seeds, by random factors alone some seeds will find a prosperous location.

treeFor instance, a mature tree can produce thousands of seeds, and yet, only a tiny fraction of those seeds will become trees. Looking at this process from an individual seed, it seems that the survival chance of a seed is extremely low. But if we account for all the seeds of a tree, there are bound to be seeds that are deposited in just the right location. This is just one example of many similar situations where the abundance of nature assures that life will go on and flourish.

 The Goldilocks Zone

The term Goldilocks Zone is often used to identify the location of the Earth. The idea being that our planet is just the right distance from the sun to support life. The Earth’s location allows for a narrow band of temperature variations (in relation to the universe), a range that can provide liquid water. For water to exist it cannot be too hot or too cold. For life as we know it to exist, liquid water is an absolute must.

At first glance the Earth’s precise location seems highly improbable; however, like the seeds from a tree, there are huge numbers of planets that can’t support life. Hundreds of planets outside our solar system have been discovered, and there are surely countless more. Thus far only a few exoplanets (planets outside our solar system) could be considered as earth like. Out of over 1800 that have already been found, most cannot support life as we know it.

Goldilocks Zones are applicable to situations on earth as well. All life is sustained by a narrow range of conditions. However, because nature allows for abundant opportunity, quantity and diversity something will always find the right location (or conditions). Clearly, from any perspective, there is abundance of every kind. This is what we observe when we examine the natural world. That is why in the grand scheme of things, nature always flourishes.