Tag: evolution

“Nothing in biology makes sense except in the light of evolution” – Theodosius Dobzhansky, 1973.

Biology, the science of life, has an enormity of subfields – marine biology, biochemistry, botany, genetics, microbiology, ecology, which interact with many other fields – medicine, agriculture, economics, environmental science, climate that influence our everyday lives.  Understanding evolution is therefore critical in making informed decisions about various topics, problems, and issues.  Let’s take a look at some of the more important topics of the day to better understand why evolution matters to everyday people.

Why Evolution Matters

Medicine – Since bacteria and virus have such short generation times, they evolve very quickly.  Understanding this salient fact yields some useful knowledge such as:

• Flu vaccinations should be taken yearly as viral strands rapidly evolve
• Antibiotics shouldn’t be overused (or taken for viruses for that matter) as it will encourage the evolution of resistant strands
• If antibiotics are proving unhelpful in fighting a bacterial infection you may be up against a resistant strand.  Taking a stronger dose will only increase the selection pressure.  Instead, take a combination of different antibiotics.
• Understanding genetics allows people to manage hereditary diseases

Agriculture – Billions of dollars are lost every year as a result of ignoring evolutionary theory.

• Monoculture can lead to a lack of genetic variation, making them vulnerable to disaster due to changing environmental conditions
• Using a preventive spraying of pesticides leads to pests evolving resistances to those pesticides and rendering them less useful in the future.  Pesticides should only be used as necessary.

Economics – Misunderstanding evolutionary theory results in economic losses in many industries.  A new field called Evolutionary Economics is growing up around the idea of combining evolutionary theory with economics.

Environmental Science – We are rapidly learning about the ecosystem services that maintaining a healthy environment provides humanity

• Hunting and farming for the largest animals, or animal traits, puts a strong selection pressure on being smaller.  As elephant poachers hunted for elephants with the largest tusks, those with smaller tusks had a reproductive advantage resulting in small tusks spreading through the population.  Fishing for the biggest fishes results in selection pressures for smaller fishes.  Hunting and farming should strive for proportional size yields.
• Understanding the evolutionary history of organisms can help preserve biodiversity that allows ecosystem services such as: clean drinking water, decomposition of waste, nutrient dispersal and recycling, providing energy, food, and raw materials, and so on

Climate – Climate provides a strong selection pressure on nearly all life on Earth

• Plants sprout, flower, and grow earlier in the season if the climate is cooling and later in the season if the climate is warming.  This affects planting and harvesting of many crops.

This is not by any means a comprehensive list although it should be easy to see that understanding and applying evolutionary theory has a wide range of effects on humanity.

Further reading: Guns, Germs, and Steel by Jared Diamond; Collapse by Jared Diamond; The Revenge of Gaia by James Lovelock; One With Niniveh by Paul and Anne Ehrlich; Betrayal of Science and Reason by Paul and Anne Ehrlich

The Theory of Evolution by Natural Selection is the only known process able to accurately explain the diversity of life that accounts for all the observable evidence. Evolution by natural selection was discovered simultaneously by Charles Darwin and Alfred Russell Wallace in the middle of the 19^th century and was jointly presented to the Linnean Society on July 1, 1858.  Charles Darwin historically receives a bulk of the credit for this revolutionary discovery, justifiably, as he published a comprehensive book, On the Origin of Species, one year later that contained abundant documentary evidence to support his conclusions.

Despite the incredulity of some people, the process of natural selection is remarkably simple to understand. Variations among individuals exist within a population of species and as a result each individual interacts with their environment slightly differently. Some individuals will necessarily be suited slightly better or slightly worse in relation to others to survive and reproduce in their particular environment. Those suited slightly better will survive longer (at least long enough to reproduce) and reproduce more, passing those slightly better characteristics on to their offspring, who in turn will reproduce more. Those suited slightly worse will not survive as long (or not even long enough to reproduce) and reproduce less offspring. Eventually those characteristics favorable to survival and reproduction will come to predominate the population, and the species will have evolved. Characteristics could be the color of a bird, or they could be the size and shape of its beak, the design of its wing, the shape of its eye, or anything else that would aid in survival and reproduction.  This process of differential survival and reproductive success is called natural selection.

“The ideas behind natural selection were that there was such a thing as a hereditary material, that there were spontaneous changes in the hereditary material, that those changes were expressed in the external form and function of the organism, that organisms made many more copies of themselves than the environment could support, and therefore that some selection among various natural experiments was mad by the environment for reproductive success, that some organisms, by pure accident, were better suited to leaving offspring than others.” – Carl Sagan

Evolution by natural selection has been called “decent through modification” and it works like an algorithmic process. Algorithms are logical rules that if followed will yield a certain result.  If certain conditions are meant, by means of an underlying mindless process, the results are guaranteed.  Long division is a simple example of an algorithmic process, as are all computer programs.   Darwin’s algorithm goes as such:

• 1)      Heredity: Characteristics of organisms are passed onto decedents, but with slight variations – no two organisms are exactly alike
• 2)      Competition: There is competition and a struggle for life.
• 3)      Selection: Those decedents with advantageous variations – any that help one survive and reproduce – will out-reproduce all others, and their characteristics will then become commonplace within the population
• 4)      Repeat: These slightly modified decedents are organisms capable of having children, so repeat step 1

Naturally, some people still will read this and be inclined to reject the notion that evolution occurs in nature. Thankfully, there is an overflowing wealth of evidence available to support the theory.

Further reading: Climbing Mount Improbable by Richard Dawkins; The Blind Watchmaker by Richard Dawkins; Darwin’s Dangerous Idea by Daniel Dennett

I cannot tell you how many times I have read or heard people say ridiculous things when talking about evolution like “So a monkey gave birth to a human” or “We evolved from apes” or “There is no evidence for evolution” or “It can’t prove how life started so it’s worthless” or one of the classic arguments from the ignoramus “Evolution is just a theory so it could be wrong”. Then I have to correct them by explaining that species don’t just give birth to new species because evolution happens slowly and gradually, and that we didn’t evolve from apes rather we shared a common ancestor with the apes, and that the evidence for evolution is overwhelming, and that Charles Darwin’s theory explains the origins of species, not the origin of life, and that evolution is just a theory in the same sense that the germ theory of disease and the theory of gravity are just theories.

Evolution is the cumulative adaptation to environmental pressures. Evolution is cumulative because it builds upon the current features and traits of the organism through successive additions. Adaptations are any traits that contribute to the probability of the organism surviving and multiplying. The environment is where the organism lives, and environmental pressures are any factors that affect an organism’s ability to survive and reproduce.

A species living on flat plains could be adapted to avoiding predators and catching prey by being spindly and speedy. On wide open, flat land, speed would be a survival advantage. If some members of its species wander onto the nearby mountainside, maybe due to overpopulation on the plains or scarcity of food or introduction of a new predator on the plain environment or because they got lost in a storm – the reason itself doesn’t matter; a new trait other than speed might be selected for, like strength for climbing over hills and rocks. Over many successive generations the stronger and bulkier –but slower – members of the group will have more reproductive success, passing on their traits of strength and bulk to their offspring. The fast spindly members of the group will eventually fade from existence as their traits are not suited to this new mountain environment. Their spindly and speedy cousins on the nearby plain will still be selected for being spindly and speedy. If the two groups stay separated long enough, eventually the stronger and bulkier group will grow further and further apart from their spindly and speedy cousins and the two groups will have evolved into two separate species. But remember, they shared the same distant common ancestors. Something like this probably happened to donkeys and horses in their evolutionary history. 

That’s it. That’s what evolution is in a nutshell. A good way to visualize how it works is by imagining a branch on a tree splitting into two different twigs. The tips of the two twigs are the new species, but they connect back to the one branch on the tree. With that, it’s time to take a look at the process by which evolution works.

Further reading: Climbing Mount Improbable by Richard Dawkins; The Blind Watchmaker by Richard Dawkins

The Theory of Evolution by Natural Selection is the fundamental insight of biology, and one of the greatest scientific insights that has ever been revealed to humanity.  Unfortunately, it is one of the least understood even though it answers some of the biggest questions people have been wondering about all over the world since at least the beginning of civilization, and almost certainly earlier.  If I am to use world religions as a measuring stick then people all over the world and throughout all of civilized history have been asking the same basic questions.  Who are we?  Where did we come from?  And why are we here?  Countless creation myths have been conjured up to explain those questions.  Many still persist and are taken quite literally today, despite them easily being shown as demonstrably false for anyone serious, curious, and intellectually honest enough to find out the facts for themselves.  Many of the books I have listed in my library section do this and would be a good place to start.  Anyway, apparently then, since all groups of people from all over the world in all times have asked these questions, it is in our human nature to want to know the answer.  But people living 2000 years ago at a lower scientific level than us had no way of knowing the answers, so they made up answers that seemed to work well enough for them given the limited knowledge of the world they had at the time.  People living near the coast created lots of sea gods to help them answer those questions, people living in the deserts invented sun gods, and so on.  This is not to say that the answers the people made up were correct, but they did provide a satisfactory answer to those questions so people could stop wondering about them. But people did not stop wondering about them, at least not all people.

A Scientific Revolution Emerges From the Dark Ages

The Middle Ages in Western Europe was by and large a total Christian society, molded by the writings of one of Christianity’s most influential figures, St. Augustine of Hippo.  During end the Middle Ages in Europe however, the unquestionable, accepted dogma of the Catholic Church was starting to come into question in various forms.  Around the 14th century in Venice, Florence, and other cities in Italy, there began a revival in the arts – sculpting, painting, and architecture, and a spirit creative spirit began flowing in Western Europe that had not been around in over a millennium.  A century later, around 1450, the printing press was invented and introduced into Europe by Johannas Gutenberg.  Three years later, Constantinople, the capital city of the Byzantium – the Eastern Roman Empire, fell.  The significance of this event is that the Eastern Roman Empire was most Greek and Constantinople held in it its great Imperial Library, containing many of the ancient Greek (and Roman) texts which by this time had been forgotten about in Western Europe.  So the city was sacked, the library was pillaged, and many of these books found their way to the printing press and began to facilitate around Western Europe, further kindling the intellectual spirit.   Then in the early 16th century the Protestant Reformation hit Europe like a bombshell, questioning the absolute authority of the Bible, and ultimately proving to be a triumph of literacy and the power and influence of the printing press.  At about the same time Nicolaus Copernicus published his book, On the Revolutions of the Celestial Spheres, challenging the Church’s geocentric cosmology and instead proposed that the Sun was at the center of the solar system.  This was confirmed within the century by Galileo Galilei and proved by the invention of the telescope.

The Great Chain of Being, a central dogma of the medieval church that has since quietly vanished from the public discourse, was being torn down and demolished by the scientific revolution.  One obvious question to the educated aristocracy of the time was if the church’s cosmology was all wrong, then maybe their dogma on the origins of species was all wrong too.  Evolution was not a novel idea before the time of Charles Darwin and Alfred Russell Wallace independently came to their same conclusion of natural selection as the mechanism for evolution.  The most famous promoter of the idea of evolution was by the French naturalist, Jean-Baptiste Lamarck, commonly known as Lamarck, who at the end of the 18th century proposed that species do change through the inheritance of acquired characteristics.  In simple terms, inheritance of acquired characteristics would mean that if a lumberjack built up large arms cutting down trees over the course of his life, then he would pass those acquired characteristics on to his offspring.  Obviously Lamarck’s hypothesis was rigorously challenged.  For example, it is quite obviously that if I get a scar on my wrist during the course of my life, that scar isn’t passed down to my offspring.  However at this time it was becoming increasingly apparent that species do change over time, or evolve.  Fossils were beginning to turn up in rocks and it was clear that species could go extinct.  The question no one could answer was, what was the mechanism for evolution?  This is what Darwin and Wallace achieved.  They explained the process by which species evolved, and by understanding that process we can understand who we are and where we came from.  But first, we need to understand what evolution is.

Further reading: Theory of Evolution: A History of Controversy (12 lectures) by Professor Edward Larson