As you have probably found out from the early essays, I usually introduced a new topic in my biology classes with a question like “what is science?” In this case I asked the question “In its simplest form, what does evolution mean?” Upon hearing no answers I would suggest a three word answer “change through Time”. Then we would progress to a discussion of evolution of, say, music, hair styles, or cars, soliciting different kinds of cars that have appeared over time. If talking about music invariably Rock ‘n roll would enter the discussion and I would ask “what was considered to be the first Rock ‘n roll song”? So I ask the reader now that question. Bonus: Name the performer. (Hint # one; it was a group: hint # 2, it was the theme song of a popular ’80’s (I think) sit com. Still don’t know— . As usual, find the answer at the end.
When most people hear the word evolution, they immediately think of man from ape and “close their ears”. Again I say that’s not true. However, I don’t plan to get into human evolution anyway. Many people say “that’s just a theory”. Well, yes and no-and that depends on what you mean by a theory. I would recommend you review the scientific definition of a theory in essay II. Evolution, at least in some forms and some levels is a fact. Let me show you what I mean. Do you believe that last year’s flu shot won’t work for this year’s flu strain? Do you believe that viruses and bacteria change in form and function? Do you believe that antibiotics that worked well years ago aren’t so effective now? If you answered yes to one or more of these questions, then you acknowledge that evolution occurs. And in each case an organism changed through time (evolved) and is responsible for, say, a new flu shot or new antibiotics all the time. Penicillin was serendipitously discovered in the late 1920’s by Sir Alexander Fleming, but because he had no method of mass producing it, the world had to wait until the early 1940’s during World War II to use it. Fortunately, mass production saved countless numbers of lives in the war. The years following the war witnessed a period of rapid development of antibiotics. I remember as an early primary grade student taking three kinds of antibiotics to fight yearly bouts of pneumonia, bronchitis, or bronchial pneumonia. Penicillin and its derivatives were hailed as “miracle drugs”. But by the late 1950’s those drugs were rendered relatively useless against bacterial infections. Any ideas why? If you said that they evolved and became resistant to the drugs, you are right. And how did they do that? Well, the usual explanation which, by the way, still holds up today, is that some of the bacteria were just naturally resistant to the drug’s effects. By “naturally” I mean that they were genetically immune, that is, they were genetically endowed. Bacteria, like all living organisms have individual differences (different gene pools). To finish the story, these genetically endowed bacteria proliferated in great numbers while their genetically inferior cousins rapidly died from the drugs. Voila, I just took you through the extremely important concepts of survival of the fittest and natural selection, two cornerstones of genetics and evolution.
Let’s back up a little and quote a paragraph from essay II. “Allow me to comment briefly on direct vs. indirect evidence or observations. Most of what we learn about present conditions results from direct observations. Virtually everything we know about past conditions is derived from indirect evidence. The fossil record and (Earth’s crust) core samples are two examples of indirect evidence.”
James Hutton (1726-1797) proposed that the earth had been sculptured by slow, gradual processes, the constructive and destructive processes described in essay III. This idea became known as uniformitarianism which also suggested that the oldest rock layers were at the bottom and subsequent layer formed on top. This set the stage for the idea of determining the “relative” age of rocks.
William Smith, (1769 – 1839) an English surveyor, was one of the first to scientifically study the distribution of fossils. He studied the geological strata (order of rock layers) and noted that each strata contained characteristic kinds of fossils.
Charles Lyell (1797 – 1875) who influenced Darwin the most, furthered the concept that Hutton had established. Since these forces were extrem-m-m-mely (my word for emphasis) slow, the earth must be very old, much older than previously thought.
Charles Darwin was certainly not the first person to suggest that things change over time, which included “living things” The Frenchman Jean Baptiste Lamarck (1744 – 1829) believed in what he called “acquired characteristics”; his classic example was that giraffe’s necks became long because of many generations of stretching higher and higher to reach leaves in trees. Actually some form of evolutionary thought goes back to the Greeks and Romans. And there were many prominent scientists of Darwin’s day that opposed the idea. (Curtis & Barnes)
Darwin was born in 1809 the son of an English gentleman. As a child, he loved collecting living things and rocks and loved horseback riding. He was encouraged to become a doctor but was horrified at the sight of seeing surgery on a child without using anesthetics. He then was a candidate for the clergy but that didn’t satisfy him. He was assigned to be the naturalist on the ship the HMS Beagle which left England on December 27, 1831 and returned home on October 2, 1836. (Robert McNamara)
The map of the journey follows.
He sketched and collected hundreds of plants and animals along the way, especially from the Galapagos Islands. Upon arriving back in England he spent the next 25 years going over notes and observations and formulating his theories. After returning to England, Darwin read a treatise by Thomas Malthus in which he warned that the human population was increasing so fast that it would soon be impossible to feed everyone. Darwin applied this to all species and that food and other factors hold populations in check. (Curtis & Barnes) I am omitting a lot of important information to summarize nine postulates that Darwin used to explain how organisms evolve.
1. A population of organisms has the tendency and potential to increase at a geometric rate.
2. In the short run the number of individuals in a population remains fairly constant.
3. The conditions of life are limited. Limiting factors include food, water, living space, etc.) (my words)
4. The environments of most organisms have been in constant change throughout geologic time.
5. Only a fraction of the offspring in a population will live to produce offspring.
6. Individuals in a population are not all the sane. Some have heritable variations (variable traits).
7. Life activities (“struggle for existence”) determine which traits are favorable or unfavorable in determining the reproductive success of the individual who possesses the traits.
8. Individuals having favorable traits (variations) will, on average, produce more offspring and those without favorable traits will produce fewer offspring. Remember the viruses and bacteria from the last essay.
9. Natural selection caused the accumulation of new variations and the loss of unfavorable variations to the extent that a new species may arise. (Gibbs, A., A. Lawson)
I used to demonstrate artificial selection (human caused) by reaching into a jar (usually beaker) and pulling out M & M’s and if I pulled out a brown one (my favorite color), I would put it back and try until I withdrew a different color. I also had a small plastic bag with three candy corn kernels, two with a yellow tip and one with a white tip and asked what process was represented. You can find the answer at the end of the essay (below the references).
Note to readers. This is the end of volume I of Essays on Science for the Common Good. This is January 24, 2019(original date of publication ) and with nearly 10 inches of snow on the ground and more forecast for this weekend I am in ski mode (as much as my body will allow) and spending spare time in my biology/chemistry lab at home. I welcome comments good, bad, or indifferent and suggestions on how to improve my blog. Some possible topics for volume II may include:
· The Great Debate: Was it protein or DNA?
· The structure and physical properties of water that make it so important.
· Volume vs. surface area as they apply to physical and life sciences.
· A short treatise on such topics as the inverse square law, chill factor, heat index, dew point, humidity, relative humidity, (with definitions, energy conversions, and cause & effect relationships)
· Revisiting classification with power point notes (converted to essay format)
· A look into the State of Illinois RiverWatch program that I was a part of for many years. I am also toying with the idea of sharing some of my
· Favorite classroom jokes; I was famous (infamous?) for puns and groaners. On nonscientific subjects, I may offer an
· 11th year anniversary tribute to tragedy at my alma mater and share a
· Bitter-sweet tribute to a past pet as submitted several years ago to the Editors of Chicken Soup for the Soul (as yet unpublished).
References
Curtis, H. N. Sue Barness, (1989). Biology. New York: Worth Publishers Inc.
Gibbs, A. A. Lawson (1992) The Nature of Scientific Thinking As Reflected by the Work of Biologists & by Biology Textbooks, The American Biology Teacher, Vol. 54, NO. 3
McNamara, Robert Charles Darwin and His Voyage aboard H.M.S. Beagle Updated December 28, 2018
Answer: “Rock Around the Clock” by Bill Haley and the Comets
(Mutation)
Published by: Larry Baumer
I graduated from Northern Illinois University in 1966 with a Bachelor of Science degree in Education and earned a Master of Science degree in Education also from NIU in 1973. I taught in the Harlem School District (5 years), a Chicago suburb (1 year), and the Rockford, IL School District for 27 years (26 at East High School). I culminated my teaching career at Kishwaukee College (8 years) Two important events occurred in 1988: I married my wife Angie and I received a summer teacher’s research fellowship through the University of Illinois School of Medicine at Rockford. My primary responsibility was light microscopy and Scanning electron miscroscopy of rabbit renal arteries (effect of high cholesterol diet). For 14 years I was a citizen scientist for the Illinois Department of Natural Resources in their RiverWatch program (monitoring water quality) My hobbies and activities include gardening, golfing, bowling, downhill and cross country skiing, photography, including photomicroscopy and time lapse photography, spending time with my wife and our dog, and in the winter playing around in my small home biology & chemistry lab.
Beyond what I have written in past profiles, in the early 1980’s I was an EMT with the Boone Volunteer Ambulance & Rescue Squad (BVARS) which fit in nicely with my science training and teaching. I also enjoy public speaking and made frequent scholarship presentations to graduating seniors and outstanding middle school students through the former Belvidere Y’ Men’s Club. I also made power point presentations of the RiverWatch program. But I most enjoyed making presentations at my high school reunions. Thanks guys for allowing me to do this.