My Favorite Wisdom
notes to my grandchildren about life and living
R. Wayne Morgan
Copyright © 2012 by R. Wayne Morgan
Published by R Wayne Morgan at Smashwords
ISBN: 978-0-9845048-1-7
The Scripture quotations contained herein are from the New Revised Standard Version Bible, copyright © 1989 by the Division of Christian Education of the National Council of the Churches of Christ in the U. S. A., and are used by permission. All rights reserved.
This book is available in print at most retailers.
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Contents
Prologue
Preface: Why do I need wisdom?
Introduction: Why does the world need wisdom?
I. Foundations of Wisdom
1. Beginnings: Where did the Earth come from?
2. Origins: How did life get started?
3. Evolution: Why are there so many forms of life?
4. Instructions: How do genes produce traits?
5. Variation: Why do we all look different?
6. Relatives: How am I similar to other primates?
7. Ancestors: Why are we different from apes?
8. Family: How am I related to all other people?
9. Language: What makes us a unique life form?
10. Culture: Why have humans been so successful?
II. Body Wisdom
11. Vestiges: Why do I get goose bumps?
12. Neoteny: Why am I curious about the meaning of neoteny?
13. Mating: What makes me attracted to some people?
14. Pleasure: Why does sex feel so good?
15. Drugs: How could I get addicted to chemicals?
16. Health: How should I care for my body?
17. Healing: How does my body repair itself?
18. Stress: How does anxiety hurt my health?
19. Touch: Why is massage so relaxing?
III. Mind Wisdom
20. Brain: What’s inside my head?
21. Psychology: What’s going on inside my head?
22. Behavior: Why do people act so strangely?
23. Violence: Why do people hurt each other?
24. Mirroring: What is the basis of empathy?
25. Personality: Why am I so different from most people?
26. Temperament: How can I better understand others?
27. Mind: Why does my mind have a mind of its own?
IV. Soul Wisdom
28. Spirits: Why do we have religion?
29. gods: Why are there so many different religions?
30. Union: What do the Eastern religions believe?
31. Law: How are Western religions related to each other?
32. Christianity: How did Jesus start a religion?
33. Bibles: Who wrote the Western Scriptures?
34. Philosophy: What can we learn from nature?
35. Metaphysics: Can religion and philosophy be blended?
36. God: Can I believe in both science and religion?
V. Living with Wisdom
37. Connect With Nature
38. Stand Against Ecocide
39. Be The Peace
40. Manage Your Multimind
41. Don’t Be Fooled
42. Follow Your Heart
43. Seek In Silence
44. Speak Your Truth
45. Do Unto Others
46. Live In Principle
47. Practice Your Wisdom
48. Epilogue
Bibliography
Author
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Prologue
Dear Adam,
As I begin this writing, it is nearing the end of the opening decade of the twenty-first century. You have just celebrated your first birthday by covering your face with chocolate cake frosting. Actually, your mother did most of the damage because she thought it looked cute and wanted pictures. Your father was a coconspirator.
I am certain you have no memory of this event, but you may have seen the photos and wondered how you could have been so uncoordinated, even as a one year old. You were not. Blame your parents.
I am your grandfather, the one you call “Grampy.” I figure that part of my job as a grandparent is to be a source of wisdom. I expected to have a lot more of it by now, but since the future is uncertain, I thought I had better pass along what I have so far.
If I am still around, I would enjoy discussing these ideas with you. If I am not able to talk with you, perhaps my written words will be helpful. Ultimately, the wisdom that works for you will come through your own explorations and experiences. My hope is that these writings may give you a starting point and a sense of direction.
With Love,
Grampy
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Preface: Why do I need wisdom?
Dear Adam,
In the world today, unlimited information is available at our fingertips. Absorbing and organizing this information leads to knowledge. Wisdom, however, is a higher level of understanding. It connects knowledge to the timeless truths of our humanity.
If you are reading this as a young person, wisdom is not likely a priority for you. I can only say that if I had gotten wiser a little faster, it would have saved me a lot of struggle and pain. The value of wisdom is its ability to increase our satisfaction in life and decrease our suffering.
Wisdom leads to increased happiness and life enrichment. With wisdom, we recognize the difference between short-term desires and long-term fulfillment. Wisdom guides us to go beyond comfort and pleasure. It expands our awareness of possibility, encouraging us to make choices that lead to the realization of our potential.
Every life has painful setbacks. The greatest pain in my life was the death of my wife (your Grandmother) Melody. Wisdom gave me the courage to follow my grief to its darkest depths instead of denying or avoiding it. My previous experiences of loss had taught me that even the most intense emotional pain is temporary, and my personal growth in wisdom allowed me to look past the darkness to find the light of acceptance.
With wisdom, we internalize the Buddhist proverb, “Pain is inevitable, suffering is optional.” Wisdom provides the perspective that allows us to grieve our losses, accept our disappointments, and move forward. Those without the tools that wisdom provides can become stuck in the loop of pain we call suffering.
It was twelve years between the time your Grandmother was diagnosed with an inoperable brain tumor and her death. Those were difficult years, filled with chemotherapy, surgery, radiation, hair loss, fatigue, fear, and debilitation. Your Grandmother faced it all with courage and resilience.
Challenges often speed the growth of wisdom. During those years, we developed a deep appreciation for the blessings that each day brought to us. Our time together became precious because we knew it was limited. We found the wisdom to live in a state of acceptance and gratitude.
I am sorry you have not had the opportunity to know the loving presence of your Grandmother Melody. She had a wisdom of the heart that touched all who knew her.
Wisdom grows through experience, but we can speed the process by learning from those who have come before. Some extraordinary people have gifts of vision, insight, and understanding. We can stand on their shoulders.
The following pages contain some of my favorite wisdom.
Enjoy.
With Love,
Grampy
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“A man is wise with the wisdom of his time only, and ignorant with its ignorance.” - Henry David Thoreau
Introduction: Why does the world need wisdom?
When I was in first grade, a new student joined our class at the beginning of second semester. His name was Brian Shimamoto, and he looked different from the rest of us. Other students began to tease him at recess because of his Asian facial features. This was only a few years after the end of World War II and many adults still harbored hatred for the Japanese. Their children repeated the racial slurs they learned at home.
I remember the sense of injustice I felt as I heard the insults and watched other boys chase Brian around the playground, pushing and hitting him. I found myself joining with Brian to defend against the verbal and physical attacks. We became fast friends. When the other students finally got to know Brian, he became one of the most popular kids in school.
This might have been the beginning of my search for wisdom. I wanted to understand why people could be so mean. My mom said I was a serious child, unusually concerned with fairness and doing the right thing. Perhaps this is why my search for wisdom began at such a young age.
Growing up in the America of the 1950’s, it was easy to assume that the Bible was the book that would contain the wisdom I was seeking. I set about the task of reading it while I was still in elementary school, but found it very difficult. The focus on the history of the Jewish people thousands of years ago did not seem relevant to me, and I was not mature enough to understand the deeper insights that the Old Testament has to offer.
I do not want to discourage you from reading the Bible. No book has had a greater impact on Western civilization. For its cultural significance alone, it is worth exploring. To get the most out of it, however, I recommend the guidance of a class or companion text to help you with historical perspective and allegorical interpretation. The Bible is easily misunderstood.
While I struggled mightily with the Old Testament, I enjoyed reading the New Testament. I read the four Gospels many times and felt a strong connection to the love and compassion exemplified by Jesus.
Although I was confused about certain issues—like the existence of the devil, the relationship between Jesus and God, and why Jesus had to suffer so—I did manage to distill some rules for living from the New Testament that have served me well. The words of Jesus continue to inspire me.
Even as I accepted the teachings of Jesus as a guideline for living, my search for deeper spiritual understanding continued. Like many in my generation who were not completely satisfied with the Bible as the ultimate truth, the mystique of Eastern philosophies caught my attention. I learned to meditate, practiced Yoga, attended spiritual retreats, and read the words of the great teachers of the East. My search for spiritual wisdom is ongoing.
When human populations lived in relative isolation, it was natural for them to develop their own wisdom. Such differences in belief systems have contributed to human conflicts over the centuries, from early tribal disputes to wars between nations.
The toll of human conflict has been staggering. The total dead during World War II was over 50 million, including 20 million Soviets and 10 million Chinese. These numbers dwarf the figure of 400,000 American casualties. Another 10 million, including 6 million Jews, died in Nazi death camps.
These kinds of numbers are not new to history. Tens of millions died during the colonization of Africa and Asia by Europeans and more tens of millions died during the religious Crusades of the Middle Ages. It seems that much of history is the story of war, cruelty and death.
Today, human population growth and competition for limited resources heighten tensions between countries. Intolerance and extremism in the name of religion also increase the chances of armed conflict. At the same time, the development and proliferation of weapons of mass destruction make such conflict unthinkable. Any rational evaluation leads to the conclusion that, while honoring historical and cultural differences between populations, we must adopt belief systems that promote mutual understanding.
Worldwide environmental degradation is another major issue as we begin this new millennium. Demands for rising standards of living and disregard for sustainable practices are depleting our natural resources. In order to protect our planet, it is imperative to move toward belief systems that promote respect for the natural world.
Encouraging understanding between people and caring for the environment are two guiding principles of My Favorite Wisdom.
I taught science for over three decades. I believe in science as a way of approaching the truth about our universe, our Earth, and the human animal. I also believe that fully understanding our humanity requires a spiritual perspective in addition to a scientific one. As Einstein said, “Science without religion is lame. Religion without science is blind.” At this point in history, science and religion are often viewed as competitors for people’s allegiance. For me, the search for wisdom has largely been about the integration of these two ways of understanding. This is another central theme of this writing.
Despite the formidable challenges we face, I believe there is reason for optimism. There is growing consensus, fueled by concerns over climate change, that we must move toward sustainable practices to protect our environment. As I write this, nations are just beginning to address differences in perspectives and priorities that inhibit progress toward responsible stewardship of our Earth. In addition, human population growth is slowing in many parts of the world as a natural consequence of education and economic development. In the short term, we continue to do terrible damage to our biosphere, but in the long term, these two trends may provide hope for our global ecosystem.
Education and economic development are also the keys to reducing conflict between people. The educated are less likely to hold extreme, intolerant beliefs, while economic security reduces the need for aggression.
Modern technology provides the means for transportation and communication that will bring us together as a global community. Increased understanding and acceptance between people will surely follow. Resorting to violence to resolve differences will be less likely when we are no longer strangers.
It is with considerable humility that I pass along my limited understanding. Scientific knowledge is expanding exponentially as I write these words. It is my hope that spiritual understanding will also expand, with the recognition of our common humanity helping to erode religious and cultural barriers. Like sandstone cliffs above the boiling sea, all human constructs eventually concede to the forces of nature.
May you always remain open to new wisdom. Trust your intuition, your innate inner guidance, to help you separate the flowers from the weeds. Worthy ideas will promote the highest virtues of humanity—integrity, respect, cooperation, compassion, selflessness, and love.
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I. Foundations of Wisdom
1. Beginnings: Where did the Earth come from?
2. Origins: How did life get started?
3. Evolution: Why are there so many forms of life?
4. Instructions: How do genes produce traits?
5. Variation: Why do we all look different?
6. Relatives: How am I similar to other primates?
7. Ancestors: Why are we different from apes?
8. Family: How am I related to all other people?
9. Language: What makes us a unique life form?
10. Culture: Why have humans been so successful?__________
Dear Adam,
When I was a child in the middle of the twentieth century, UFO’s (unidentified flying objects) were a hot topic in the news. Movies depicted space aliens as monsters who wanted to capture and harm humans. I remember feeling scared when I looked up at the night sky on a camping trip—or even in my own back yard. I had difficulty appreciating the inspiring beauty of the stars because I was afraid of the unknown.
The antidote to fear is knowledge.
I have called this first section of writings Foundations of Wisdom. It deals with the questions of how we came to be and what makes humanity unique in the world of life. I use the word foundations because I believe any true wisdom must be based on a clear understanding of who we are. Any reliable wisdom about the body, the mind, or even the soul must begin with a scientific understanding of our origins and history.
Wisdom may go beyond science, but true wisdom will not ultimately conflict with science.
By its nature, scientific understanding is always advancing. New knowledge will be available to you by the time you read this, but the main concepts I discuss are so fundamental and well supported that they are unlikely to change over time.
Depending on how old you are and your background in science, these writings may be challenging or just a simple review. In any case, I hope they will serve as a good foundation for future wisdom.
With Love,
Grampy
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“In the beginning God created the heavens and the Earth.”
- Genesis
1. Beginnings: Where did the Earth come from?
I look forward to going camping with you where stars fill the clear-aired darkness and hiking with you where wildflowers and butterflies greet us at every turn. Spending some peaceful time in connection with nature can stimulate reflection on things that get overlooked in the hurried pace of everyday living. When looking at the vastness of the night sky or the beauty of a mountain meadow, it is natural to ask the big questions:
How did the universe begin? How did life begin?
The short answers are: We don’t know and We don’t know
In the absence of scientific knowledge, myth backed up by the authority of tradition has always provided our only answers to these two big questions. Origin myths are universal, from the spiritual traditions of native peoples to the holy texts of the great world religions. For those of us of Judeo-Christian background, the Bible offers a familiar and poetic version in Genesis.
What does science have to say? More than you might expect. Before I begin, however, let me say something about the nature of science.
Science is a way of understanding that relies on careful observations and reasonable, logical conclusions based on those observations. Experiments (controlled observations) are repeated and conclusions challenged until scientists with the proper expertise reach consensus. Even then, the answers provided by science are always considered tentative—open to revision as required by new observations.
The key word here is consensus. Scientists often disagree as they explore new areas of knowledge and some scientists may cling to ideas that have been discredited by the larger scientific community. Nevertheless, as observations are refined and conclusions critiqued through peer review, the truth usually settles out.
Obviously, no scientists were around to observe the beginning of the universe. For a long time, it seemed reasonable to assume that our universe had always existed as it is today. Even Einstein, one of the greatest scientific minds in human history, believed this until late in his career despite mounting evidence to the contrary. Eventually, he would call this belief “the biggest blunder of my life.”
Several scientists, working in the 1920’s with new telescopes and measuring techniques, found strong evidence that the universe was not static, but was actually expanding. Einstein should have expected this, because gravity would logically cause a stationary universe to collapse upon itself. Today, the observation that the universe is expanding has been verified beyond debate.
By measuring the distances between galaxies and the speed of expansion, scientists have been able to calculate when the expansion must have begun. The strong consensus is that our universe came into being approximately 13.7 billion years ago.
The universe contains about 100 billion galaxies, each containing from ten million to one trillion stars. If you left earth traveling in any direction at the speed of light, (186,000 miles per second) you could travel for billions of years without reaching any edge. For all practical purposes, the universe is infinite in size.
Scientists have made tremendous advances in astronomy and cosmology in recent decades, yet even to the brightest minds on the planet, our universe still holds many mysteries.
The question of origin has led scientists to a nearly incomprehensible hypothesis. If you reverse the expansion of the universe and take it to its logical beginning, all the matter in the universe must have been originally contained in a single point. My mind is boggled as I try to think about this. It does not even seem possible. All I can say is that many physicists with a lot more knowledge and brainpower than me have come to this conclusion.
This point that contained our entire universe is sometimes referred to as the singularity. The singularity is a theoretical construct, but scientists generally agree that from this point, the entire universe burst forth in what is called the Big Bang.
In 1965, scientists aimed sensitive antennas into space and found microwave signals that actually stem from the Big Bang itself. Using evidence gathered since then, they have been able to describe the events that took place as the universe formed back to within 10-43 seconds (one tenth of a millionth of a millionth of a millionth of a millionth of a millionth of a millionth of a millionth of a second!) of its expansive beginning.
Of course, this does not answer the question, What came before the singularity? or What caused the Big Bang? As unsatisfying as it might be, at this point we have to be honest and say, We don’t know.
What happened after the instant of creation of our universe is clearer. First, energy was created in the form of gravity, electromagnetism, and the strong and weak nuclear forces. Then followed ungraspable quantities of the most fundamental particles of matter (quarks, leptons), which combined to form the building blocks of atoms (protons, neutrons and electrons). Within a relatively short 300,000 years, the universe cooled sufficiently to allow the building blocks to come together to form atoms of hydrogen and helium. Within the first billion years, under the force of gravity, these atoms began to coalesce into the stars of the galaxies.
Stars shine because of the release of energy when atoms of hydrogen fuse to form atoms of helium (thermonuclear fusion). Heavier elements (composed of larger atoms) are also created in the nuclear furnaces of stars. When some stars die, they shed into space their outer layers that include some of these heavier elements. In addition, when a large star dies the core of the star collapses and the surface of the star explodes, producing a supernova. Again, the blown off outer layers contain many different elements.
Our sun is a medium size star. At 4.6 billion years old, it is almost half way through its radiant lifespan. In another 5 billion years, it will enter a red giant phase and begin expanding before ultimately going dark and releasing its elements. (Stars go though several stages as they use up their hydrogen fuel.)
The sun is a second or third generation star, meaning it was formed from the leftover debris of other stars. The planets of our solar system, including Earth, formed from the same debris.
Six elements—oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus—make up over ninety-eight percent of the mass of the human body. Another fifty-six elements are found in trace amounts. The atoms of all these elements were born in stars.
We are, in fact, made of stardust.
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“Great indeed is the sublimity of the Creative, to which all beings owe their beginning and which permeates all heaven.”
- Lau Tzu
2. Origins: How did life get started?
We have a clear idea how the universe developed after it started, although our vision is increasingly blurred as we reach back toward the actual moment of conception. What do we know about the origins of life on Earth? It turns out to be frustratingly similar. Here are somethings we know.
Less than 5 billion years ago, a great swirl of gas and dust on an arm of the Milky Way Galaxy began to coalesce. Ninety-nine point nine percent of this matter became our sun, with the remainder forming larger and larger clumps that became our solar system— the asteroids and comets, five dwarf planets (including the recently demoted Pluto), and eight planets. Some scientists think that about 4.5 billion years ago, while the Earth was still hot and molten, an object the size of Mars may have crashed into the Earth, blasting out enough material to form the moon. Unable to escape the Earth’s gravity, the moon began to orbit our planet. The impact may have blown the atmosphere off the Earth, allowing more rapid cooling.
In any case, over the next half billion years, the Earth cooled until it formed a surface crust. A primitive atmosphere reformed, and water (perhaps mostly from the impact of meteorites and icy comets) condensed to form the oceans.
Scientists agree that within two hundred thousand years or so after the Earth became hospitable, life had arisen. The earliest known evidence of primitive cells called prokaryotes (think simple bacteria) is dated to 3.8 billion years ago. So where did these cells come from? We don’t know.
There are many competing hypotheses to explain how life on Earth began. Most of them are variations on a theme. Non-living chemicals (methane, ammonia, water, etc.) were synthesized into organic compounds (amino acids, nucleic acids) by intense sources of energy (lightening, UV radiation, thermal vent heat, etc). These organic compounds found their way to just the right environment (like the catalytic surface of clay or iron pyrite) where they formed polymers (long chains). Bubbles (membranes) separated some of these chains from their surrounding environment and the chains developed the ability to self-replicate. Metabolism started within the membranes and life had begun.
Yes, I know, it sounds farfetched. It is about as mind bending as the notion of the entire universe contained in a single point! Scientists have been able to synthesize some organic molecules from inorganic molecules in the laboratory by simulating the conditions of the early Earth, but they have never produced anything close to an actual living system.
In order to produce something that we might label as life, two primary ingredients are necessary. First, you need a molecule that can encode information and is self-replicating (like DNA). Second, you need catalysts (like enzymes) to speed the chemical processes necessary for that replication. DNA cannot act as a catalyst and enzymes are not self-replicating.
RNA, a molecule similar to DNA, can act as an enzyme and self-replicate. Many scientists now think that RNA may be the most logical candidate for the first molecule that led to life on our planet.
Recently, some scientists have seriously considered the possibility that life came to earth from outer space. Meteors and comets contain organic molecules that could have started life on Earth, or perhaps life developed first on Mars and then was blasted to earth by an asteroid impact. Of course, this just pushes back the question, “Where did that life come from?”
Science can only work with observable evidence. Up to this point, for the universe as well as life on Earth, the evidence of beginnings is just not available.
Great wisdom, huh? Two of the biggest questions possible and science has no answers. But don’t let that sour your opinion of science. Scientists have answered many fundamental questions. I will share some of their discoveries as we go. However, I must admit that I do not expect the issue of beginnings to be settled in my lifetime, or perhaps even in yours.
I have enjoyed watching you develop your curiosity about life. As a toddler, you loved to find spider webs and search for the spider. Recently, you have been fascinated by ducks (which you can never quite catch) and colorful caterpillars (and their chrysalises above your front door). Perhaps you will become a biologist! Whether you become a scientist or not, I hope you never lose your sense of wonder about life.
The more we learn about living things, the more astounding they become. In the next essays, I discuss some of the processes that have produced the amazing variety of life on Earth, including the most unique example of that variety—humans.
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In my foregoing discussions, two of the books I used for background information were The Language of God by Dr. Francis Collins (head of the Human Genome Project that first determined the sequence of human DNA) and Finding God in the Questions by Dr. Timothy Johnson (a physician who was the medical editor for ABC News). These men of science use the unfathomable nature of some of our questions about the universe and life on Earth as evidence for the existence of God. Both books are well written and worth reading, but I think this particular kind of argument raises some concerns.
People have always used God or the Supernatural as an explanation for the unexplainable. Before we understood infectious diseases, people thought that these conditions were the work of evil spirits or a disapproving God. Does this mean that we have less reason to believe in God because we have discovered pathogens like bacteria and viruses?
Any understanding of God must be built on something stronger than our need to fill in the blanks of our knowledge. Our scientific understanding is maturing and growing with each passing decade. Our spiritual understanding has to mature and grow to stay relevant. I will come back to this idea in the second half of these writings.
I want to mention here that I intentionally have kept the essays brief and I encourage you to supplement these introductions when a topic sparks your interest. I have included a bibliography as a reading resource (although by the time you read this, perhaps you can download information directly to your brain!).
In addition to the aforementioned books by Dr Collins and Dr. Johnson, I used an excellent book on the history of scientific progress titled A Short History of Nearly Everything by Bill Bryson. If you like science and want a deeper insight into how science makes progress, I highly recommend Bryson’s book.
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“What a man believes upon grossly insufficient evidence is an index into his desires…” - Bertrand Russell
3. Evolution: Why are there so many forms of life?
Although we do not know exactly how life started, we know a great deal about how life has changed over time once it got going. Many people with traditional religious beliefs have difficulty accepting that life on Earth has evolved, even though it is one of the most fundamental and well-supported ideas in all of science.
There are several reasons for this:
People have been taught to reject evolution in their churches. It is difficult to fit evolution into your belief system if you take the Bible literally. If the only choice is between “The Word of God” and the word of scientists, scientists lose every time. Ultimately, science will win this battle, just as it did when the church taught that the Earth was the center of the universe. Religions ultimately lose credibility when they deny scientific progress.
People have not been taught to understand evolution. Most people in the world have limited scientific literacy. Surveys in the United States consistently show that over forty percent of the population does not believe in evolution. This makes about as much sense as saying “I don’t believe that substances are made of atoms” or “I don’t believe that some diseases are caused by germs.” This will change as more people become better educated in science, allowing them to understand evolution and the evidence on which it is based.
People think evolution makes humans less special. Some people feel devalued by the idea that we are related to all living things and, in fact, have evolved from other species of living things. Our language and consciousness make us unique in the world of life, but not separate from it. Rather than being a negative, I think an understanding of the role that evolution has played in our development as a species can provide us with valuable insights into ourselves.
People think evolution makes God less special. If there are natural explanations for the heavens, for the diversity of life, and even for the development of humans, does that take away from the power of God? More simply, if everything has a natural explanation, where does God come in? The vast majority of people believe in God as described by their religion and they are comfortable with their beliefs. It will take time for the widespread acceptance of a concept of God that is compatible with our understanding of the natural world.
The lack of acceptance of evolution is a testament to the power of misinformed belief. The evidence is overwhelming that species are not fixed, but instead have changed dramatically during the history of life on Earth. Humans have even taken advantage of this ability of organisms to change. In a span of only a few thousand years (as opposed to the millions of years available to natural evolution), humans have domesticated the wild wolf (Canis lupus) into over two hundred breeds of dog (Canis familiaris). Perhaps even more dramatic has been our use of selective breeding to change one species of wild cabbage into such strikingly different vegetables as broccoli, cauliflower, kohlrabi, kale, Brussels sprouts, spring greens, collard greens, romanescu, and all of the modern versions of cabbage.
Because evolution is such a key concept, I’m going to start with a few definitions. A population is all of the organisms of a species occupying a particular area at the same time. The gene pool is the sum of all of the genes contained in that population. Evolution is the change in the gene pool of a population over generations.
To use a classic example, if you consider a population of giraffes in a certain region of Africa, then all of the collective genes contained in the giraffes of that population would be the gene pool. As the genes in this gene pool change over time, the characteristics of the population change. This is evolution.
Evolution is a fact. The fossil record clearly shows us innumerable examples of how species have changed and eventually spawned new species. We can even observe evolution in action in rapidly reproducing species. Darwin did not discover the fact of evolution. What Darwin did was to hypothesize the mechanism that causes most of evolution, natural selection.
Let us go back to our population of giraffes. The length of a giraffe’s neck is the result of the interaction of many genes that the giraffe inherits from its parents (modified by environmental factors like nutrition). Within a population are distributed genes that help the neck grow longer, as well as genes that produce shorter necks.
Environmental factors can make longer or shorter necks have an adaptive advantage. For example, longer neck giraffes may have a competitive edge in gathering food from tall trees. This may allow tall giraffes a better chance at reproducing and passing on their genes for the trait of tall necks. The genes carried by shorter necked giraffes may become less common in the gene pool over many generations. Thus, we say that the population is evolving because of natural selection—nature selects the best-adapted individuals to pass on their genes. In this scenario, the average neck length for giraffes will increase.
Will giraffe necks just keep getting longer and longer? No, because having such a long neck can also have disadvantages. Perhaps a longer neck is more vulnerable to injury or makes the giraffe an easier prey for predators. There are always balancing forces at work in evolution. When longer necked giraffes can reproduce more often and contribute more genes to the gene pool, then that trait will become more common. If shorter necked individuals reproduce more, then the species will move in that direction. Changes in the environment determine which traits confer reproductive advantage.
It can be difficult to go back and reconstruct what selective pressures produced the evolution of a trait. Even though food gathering seems a logical reason for long necks in giraffes, an alternative hypothesis involves sexual selection. Male giraffes battle for access to females by clubbing, beating each other with their heads. Males with longer necks dominate such competitions and thus may pass on their genes more often.
There are other causes of evolution besides natural selection and sexual selection. Mutations (changes in genes) will add new genes to the gene pool. This is extremely important as a source of new traits. Gene flow occurs when members of a population enter or leave, also changing the gene pool. In addition, the random chance nature of reproduction (which individuals mate, which sperm fertilizes which egg) can change the gene pool. This effect, called genetic drift, can be especially significant if a population is small. Sometimes a rare gene may not pass to any offspring and be lost to a species forever.
Nevertheless, by far the most important contributors to evolution are natural selection and sexual selection—what scientists often refer to as differential reproductive success.
A common misunderstanding is that evolution is purposeful—that evolution has as a goal the production of more and more complex organisms with human beings as the crowning achievement. On the contrary, evolution involves a great deal of randomness, as an examination of life’s diversity will attest. Human beings are the result of the confluence of some very unlikely events. There is no scientific evidence that our evolution was certain, and our long-term survival has never been guaranteed.
Complexity is produced by the addition of more genetic options. This occurs through the recombination of existing genes (sexual reproduction), and through the addition of new genes (mutation). When complexity gives a reproductive advantage, it is passed on to future generations. On the other hand, if a less complex trait gets the job done—maintains reproductive success—then it will not be replaced by a more complex option.
The vast majority of organisms on Earth are quite simple, with bacteria being the perfect example. There are an estimated five nonillion (10 to the thirtieth power) bacteria in the world—successful in more environments than any other kind of living thing. There are ten times as many bacteria cells in your body as there are human cells.
Bacteria are perfectly content with their diverse lifestyles ranging from photosynthesis and chemosynthesis to decaying matter and (rarely) causing disease. These simple organisms do not sit around dreaming of the day they can move up to the big time by increasing their complexity. As long as they remain well adapted to their particular environment and way of making a living, evolution will not change them.
If the environment changes, however, then bacteria adapt. For example, if we develop a new antibiotic, the bacteria with the greatest natural resistance survive and reproduce, increasing the frequency of their genes in the population. Bacteria reproduce rapidly (some every twenty to thirty minutes), allowing them quickly to evolve resistance to our newest antibiotics.
If we base our judgment on the success of species, it might appear that the goal of evolution is the production of insects! From annoying ants to beautiful butterflies, over one million species of insects have been described, with estimates of total species ranging from six to ten million. Compare this to the roughly five thousand species of mammals alive today and you can see how extraordinary the success of insects has been.
“The mind cannot possibly grasp the full meaning of the term
of a hundred million years; it cannot add up and perceive the full
effects of many slight variations, accumulated during an almost
infinite number of generations.”
Charles Darwin wrote these words in the middle of the nineteenth century. Here, at the beginning of the twenty-first century, it is no less difficult to comprehend how evolution created the enormous variety of life on Earth—unless we comprehend time. Small changes in species can add up to substantial changes when they accumulate over millions or even billions of years.
Think of how many generations of organisms would be produced in a million years, a relatively short length of time in geologic history. Even if the average generational time is long— say about twenty years for humans—it means fifty thousand generations in a million years. If new generations are produced annually, as they are in many species, that is a million opportunities for subtle gene pool changes to add up, guided by natural selection.
This is why there is such a rich diversity of life on our beautiful planet. Time has allowed natural selection and other processes to produce organisms that are adapted to every conceivable environment where life can succeed.
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“… the resemblance of the enzymes of grasses to those of whales is in fact a family resemblance.” - Lewis Thomas
4. Instructions: How do genes produce traits?
I have never liked horror movies. They leave images that stick in my mind and give me nightmares. This must be a minority opinion though, because they have always been popular. Dozens of films have dealt with vampires and werewolves, based on folklore that dates back centuries. Mythology about supernatural beings that consume blood or flesh is found in cultures around the world, but stories specifically about vampires and werewolves flourished in 18th century Europe to the point of near hysteria.
No one knows how these superstitions began, but one intriguing hypothesis involves a genetic disorder called Porphyria. Individuals with this condition have an error in the metabolic pathway that produces hemoglobin, the oxygen-carrying component of red blood cells. This error causes chemicals called porphyrins to build up in the body, producing a variety of serious health issues. Some of the symptoms of this disease include:
- Extreme light sensitivity (exposure to sunlight is painful)
- Red urine and teeth with a reddish tint
- Increased hair growth on unusual places like the forehead
- Seizures and serious mental disturbances
If someone in a medieval village had these symptoms, it is easy to understand how imaginations might start to run wild.
Today we know that people with Porphyria are not vampires or werewolves (which do not exist). We understand the genetic basis of Porphyria and thousands of other disorders. We also understand how genes work when things go well, as they usually do.
I have already used the term gene in the last essay, assuming you know that genes are the chemical instructions that guide the development of an organism’s traits. I consciously used the term guide here instead of determine, because the idea that genes act alone in producing our physical characteristics is a common misconception. It is much more complicated than that.
For one thing, the environment of an organism influences gene expression. To use a simple example, say that you have inherited genes that would normally give you the potential for above average intelligence, but you are born into an impoverished environment where you do not get adequate mental stimulation or education. Your environment may not allow your genes to express fully, resulting in lower than expected mental abilities.
One dramatic and tragic example of modified gene expression occurred during the Dutch famine of WWII. In 1944, German occupying forces restricted food supplies to the Netherlands for many months. Dutch women who were pregnant during this time were severely malnourished, and thus so were their babies. This environmental stress produced permanent changes in the gene expression of these children, causing them to grow up with increased risk of obesity, diabetes, cardiovascular disease, and even premature mental deterioration with aging.
In addition to nutrition, chemicals within and around each cell also regulate gene expression. Hormones are one such class of chemicals, able to influence gene expression far from the glands that produce them. For example, the male hormone testosterone can influence the expression of the gene for baldness. If a male receives a gene for baldness from either parent, he is likely to become bald. Testosterone helps stimulate the gene’s expression. By contrast, a female must inherit a gene for baldness from both parents for her to become bald. This is why baldness is more common in males.
Most of our physical traits are influenced by many genes. In the case of baldness, regulator genes turn the baldness gene on at a particular age, causing you to bald earlier or later in life. Other genes regulate penetrance, that is, how fully the gene is expressed (partially bald or completely bald). There are also genes that control the pattern of the baldness.
I was always comforted by the fact that my father had a full head of hair until his death at age 79. I assumed I would also avoid baldness, especially since my hair looked similar to his—dark, thick and curly. I even followed the same pattern of turning gray at a young age, just as he had (an obvious sign of wisdom).
As I matured, I was surprised when I began to see patches of red scalp showing through on photos of myself. I was even more surprised when my barber asked if I wanted to keep my hair a little longer to cover the bald spot on the back of my head! Unfortunately, my hair is following more of my mother’s pattern. Her hair got very thin as she aged, to the point where she wore a wig when she went out of the house. If she had been a male, she probably would have gone totally bald.
My experience with baldness illustrates the complex interaction of genes and traits. This is an area where an introductory biology class can be misleading. (When my students applied Mendel’s classic heredity rules to their own traits, I sometimes had to reassure them that they were not adopted!) Not only do many genes interact to produce traits, but factors such as nutrition, exercise, and stress can influence the expression of genes. In unexpected findings, even subtle factors like social interaction and thought processes can affect gene activity.
In one classic study, Romanian orphans with limited adult interaction were found to have stunted growth, behavior problems and increased mortality. An increase in positive attention and physical contact actually changed the balance of hormones in the children’s blood, returning them to health.
As I write these words, epigenetics (the science of gene regulation) is one of the most dynamic and promising areas of scientific research. It is the next level of understanding we need to comprehend the complex relationship between genes and traits, including the relationship between genes and disease.
Unfortunately, some companies are using our incomplete knowledge of genes to mislead. They claim the ability to predict your chances of developing certain traits or diseases based on a genetic profile. As you can tell from our brief discussion, this is a venture fraught with potentially dangerous misinformation. At this point, I think it is wise to focus on genes as sources of potential, rather than determiners of fate.
You have probably learned in school about DNA, the chemical code that forms our genes. Here is a quick review:
DNA (deoxyribonucleic acid) is a long, thin chain of chemical building blocks called nucleotides. The chain of nucleotides takes the form of a twisted ladder (double helix), which I am sure you have seen illustrated. There are four different types of nucleotides in DNA (abbreviated A, T, G, & C), which allows them to form a code—like an alphabet with only four letters. Much of our DNA is “junk” left over from evolution; other portions are regulatory regions that guide gene expression. Less than two percent of the DNA in each of our cells forms the coded messages we call genes. Every cell in our body contains the same genes, about 20,000+ from mom and 20,000+ from dad.
As you know, cells are microscopic, yet the DNA contained in each human cell is over 2 meters long. In order to fit, the DNA coils up in the nucleus of cells, forming structures called chromosomes. Since the human body has nearly 100 trillion cells, all of the DNA in your body would stretch out to be 200 trillion meters long—a distance equal to 650 trips to the sun and back!
A human egg cell has 23 chromosomes, as does a human sperm cell. When they get together during reproduction, the fertilized egg has 46 (23 matching pairs of chromosomes). As the new human life grows, each chromosome is copied into each new cell so that every cell in the body has all 46 chromosomes contained in the original fertilized egg. In other words, every cell in the body has the same genes.
Because all of the cells carry the same instructions, the difference between a pancreas cell that makes insulin and a nose cell that helps make mucus is determined by which of the genes in each cell is active. It is as if each cell receives the same cookbook of instructions, but only follows the recipes on selected pages. Cells know where they are in the body and what their job is (which recipes to make) based on chemical messages they receive from the cells around them during development.
How does DNA tell each cell what to do? DNA controls the cell by controlling the production of proteins. You see, at one level you can think of life as an enormously complex set of chemical reactions. Enzymes (protein catalysts) control the chemical reactions of life, and genes (DNA segments) determine which enzymes are produced in any given cell.
More simply, genes control enzymes, then enzymes control cell function.
In a pancreas cell, a group of genes guides the production of enzymes necessary to produce insulin. In a nose cell, those genes are never used, but a different subset of genes is activated which produce the enzymes necessary to manufacture components of mucus.
Of course, some chemical reactions are the same in all cells of the body, and even in the cells of different species. About 25% of genes are common to all life.
Organisms have different numbers of genes and chromosomes, but this is not directly related to size or complexity. A mosquito has 3 pairs of chromosomes while a silkworm has 28. A frog has 13 pairs, a mouse 20, a duck 40, but a cow only has 30. Corn has 10 pairs, sugarcane 40, and some ferns have over 500! The differences reflect packaging rather than function, with most organisms falling in the range of 5 to 25 chromosome pairs.
It is interesting to note that chimpanzees have 24 pairs of chromosomes compared to the 23 pairs for humans. Careful analysis has shown that somewhere in evolutionary history, two of the chromosomes found in chimps fused together in our ancient ancestor to form one chromosome. The species that first carried this new chromosome (labeled chromosome #2 in modern humans) is long since extinct. Yet this new configuration has been passed along to us, carrying genetic messages to us through millions of years of evolution.
While each species has different numbers of genes and chromosomes, the DNA code is the same for all forms of life—from bacteria to whales, from algae to redwoods. This is the most powerful evidence for the relatedness of all living things.
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“We must not say every mistake is a foolish one.” - Cicero
5. Variation: Why do we all look different?
As natural selection has written the book of life, mutation and recombination have provided the creative muse.
Through the eons, the Earth has been characterized by change. Continents have drifted, mountain ranges have lifted and eroded away, ice has moved over the land—only to be replaced by hot desert sands. Although the changes may seem slow from our human perspective, changes in geology and weather have always been a challenge to life on our planet. Variation is life’s insurance policy for success in an ever-changing world. Individuals of any species show variation in their traits, increasing the chance for survival and reproduction of some members as the environment inexorably changes.
Life has two main strategies to insure variation within species, sexual reproduction and mutation.
Sexual reproduction guarantees shuffling of the genetic deck with each new generation. The importance of sex is evident when one considers the extraordinary lengths species go to in order to bring together the genes of different parents.
Strategies for sexual success vary, from the production of enormous quantities of sperm and egg when fertilization is external, to complicated reproductive structures and behaviors that guide sperm to egg inside the protective body of a female.
Plants, rooted to the ground, have had to employ wind, birds, insects, and other sexual helpers—all to make sure that sperm (contained in pollen) meets egg. Animals accomplish the same results with remarkable sexual displays and mating rituals.
Some species can reproduce asexually, but these species often have the ability to use sexual reproduction when the environment allows. Even single cell bacteria, which just divide to reproduce, have a strategy to pass DNA from one to another. This allows them to exchange genes and develop new combinations of traits without sperm and egg.
Plants have a life cycle that alternates sexual and asexual phases. Most of the green plants we see around us are the asexual stage, while the sexual stage is limited to small growths within the confines of a flower or cone. The pollen grains that cause allergic reactions in so many people are actually the tiny sperm producing stage of the plants life cycle.
If you choose to have more than one child, it will become clear how effective the genetic shuffle can be in producing variation in traits!
The other strategy for producing variation is mutation. Mutations are changes in DNA, commonly the result of copying errors or environmental factors like chemicals and radiation. Mutations alter the coded genetic message, and thus alter the enzymes that run the cell.
If this happens to the DNA of a body cell, then only that cell and its descendants will produce the faulty enzyme. The result of this kind of mutation is most often innocuous, perhaps killing the one cell or causing a localized change (like a patch of gray hair or skin discoloration). At the other extreme, mutations can be deadly for an organism, as when they alter the regulation of the cell division cycle and turn a normal body cell into a cancer cell.
From the standpoint of evolution, the mutations in sperm or egg cells are of the most concern, because they are added to the gene pool and may be passed down through generations.
Since organisms are so complex and tightly regulated, mutations that are inherited (thus part of every cell in the body) are usually harmful and sometimes fatal to the individual. These mutations are removed from the gene pool because they detract from an organism’s chances for reproduction. Occasionally, however, mutations can provide positive options for species adaptation.
If a mutation produces a trait that helps an organism adapt to its environment (enhancing its chances for reproductive success), the new gene increases in frequency in the gene pool. These new traits accumulate over tremendous spans of geologic time until a species has undergone dramatic changes or even given rise to new species.
The chemical errors that become mutations are surprisingly common, but the cell has proofreading enzymes that usually correct mistakes as soon as they occur. Only about one out of every 100,000 mistakes makes it past this check system. However, if mutations are usually so harmful, one might reasonably ask why natural selection has not perfected the process to one in a million or one in a billion. The answer may be simple. Some reasonable error rate is actually desirable—because variation is desirable. You might say nature makes mistakes on purpose.
Support for this idea is found in mechanisms that cells have for actually creating mutations and new combinations of genes. One form of recombination involves the crossing over of chromosomes during the cell division that produces eggs and sperm. In this process, chromosomes break, rearrange themselves, and then rejoin to form chromosomes with new combinations of genes—and sometimes mutations.
In addition, there are genes, called mutators, which manipulate the copying errors of other genes and transposons, which remove themselves from one location on the chromosome and then insert themselves into another—again, sometimes causing mutations.
The next time you see someone who looks unusual or behaves strangely, just keep in mind that nature loves experimentation!
To show the power of relatively small changes in genes, consider an enzyme called lysozyme found in saliva, tears and mucus. It helps prevent infections by breaking down the cell walls of bacteria. In the ancestors of modern day ruminants (grass eaters like cows, horses, sheep, etc.), a mutation produced an extra copy of the lysozyme gene. This gene, altered by further mutations, produces a lysozyme that can survive the acid environment of the stomach.
Most animals cannot digest the cell walls (cellulose) of plant tissue—what we call fiber. Ruminants, however, with this altered form of lysozyme, can live on the relatively low nutritional value provided by grasses. They grow bacteria on the grass in their digestive tract and then feed on the bacteria. Their final stomach chamber produces this new form of lysozyme (which remains functional in an acid environment) that digests the bacteria, releasing the nutrients to be absorbed by the animal.
Not only did this mutation produce a variety of grazing animals that have been important to human nutrition, but also the grasses themselves are an evolutionary adaptation to the selective pressure of the ruminants. Some plants (through mutation and natural selection) developed the ability to grow from the bottom up instead of at branch tips like most plants. This allowed them to survive grazing. They became our modern day grasses, many of which produce highly nutritional grains.
It may be fair to say that without the error that produced ruminants, grasses like wheat, oats, barley, rice, and corn would not have evolved—and agriculture, the foundation of civilization, would not have developed.
Sometimes a simple mistake can have profound consequences.
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“Distant relatives are the best kind—and the further the better.” - Kin Hubbard
6. Relatives: How am I similar to other primates?
I love going to the zoo. I especially enjoy the monkeys and apes. There is something fascinating about watching our closest relatives in the animal world, the primates. (Of course, I would rather see animals in their natural habitat, but many high quality zoos are doing a service for wildlife through research, breeding programs, and public education.)
What makes something a primate? The hallmarks are a highly developed brain with complex social behavior, excellent binocular vision, and grasping hands. The principal groups are lemurs, monkeys, apes, and humans. All of the special traits of primates developed as adaptations to an arboreal (tree-dwelling) existence, even though some species (like us) no longer inhabit the trees.
What would start a species of mammal on the path to “primatehood?” As always, it is the impact of the environment on variation. The ancestors of primates were small insect eaters that lived in the tropical and subtropical forests. For over fifty million years, natural selection worked with the raw materials of mutation and recombination to mold the primates to succeed in their forest habitats.
As the gene pools of primates changed in response to the selective pressures of life in the trees, certain traits emerged. Eyes became forward facing and snouts reduced to allow binocular vision—a life-saving asset in judging the distance to the next tree limb.
Dexterous hands with opposable thumbs were valuable for grasping branches, food, and fur (think of a young primate clinging to a parent). Nails on sensitive fingers with independent control replaced claws. This permitted the plucking of insects, the pealing of fruit—and the social grooming of companions.
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