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n a recent essay (XIV) we looked at the effects of global warming on glaciers and ice sheets and the resulting effect on ocean levels and coastal cities. Now let’s broaden our scope and include the ripple effect of climate warming on the inhabitants of not only frigid climates but also warmer areas as well. First, let’s look at polar bear population changes and the reasons for their decline.                                                                                              

         From cartoons to Coca-Cola commercials to zoos, no animal is quite as majestic as those beautiful lumbering polar bears. These massive animals, the largest of the Ursines may accomplish what years of environmental activism hasn’t done: convince people that global warming is real and happening now. This “puts a face upon it, a polar bear face” according to Bob Corell, director of the global change program at the Heinz center for Science, Economics, and the Environment. But it may be too late for the 25,000 polar bears that inhabit the wild from Alaska to Greenland. There’s so much climate change inertia built into the system already” he says. (rrrstar, May 18, 2008) Polar bears depend on’ sea ice for hunting seals, which is their favorite food. They rarely catch seals on land or in water and if they do they usually expend a lot of energy (rrstar September 8, 2007 as the following example illustrates. Some polar bears in the arctic are shedding pounds at a time when they should be gaining weight Scientists blame global warming for the shrinking ice cover on the Arctic Ocean. Scientists attached tracking collars to nine female bears (males tend to shed the collars from their narrower necks and smaller heads) in a recent study. Also equipped with video cameras, everything they saw the researchers saw too. They periodically were weighed and had their blood monitored for ten days. Five bears lost weight and four of them lost 2.9 to 5.5 pounds per day. One bear lost 51 pounds in nine days in April when they would later be raising cubs. But because the ice is shrinking they were having a harder time catching seals. With less ice, which is also broken up, they have to travel farther and at times swim to catch their prey which increases the risk of hypothermia and expends more energy just when they need more reserve. Some of the bears traveled more than 155 miles in 10 days along the northern coast of Alaska in the Beaufort Sea. The average bear burned 13,200 calories a day-six times more than an active human female. As stated in an earlier essay the ice cover grows in winter and shrinks in summer but in the last several years the shrinking is far greater than the growth (rrstar February/2, 2018.).

              However, some scientists believe that if the world dramatically changed its increasing emission of greenhouse gases, a total loss of summer sea ice could be averted

         Let’s now turn our attention to a much different aquatic environment–to tropical waters and the effect of ocean warming on coral reefs. Coral are beautiful animals (even though they look like plants) of the phylum Cnidaria, (formerly Coelenterata) that live within stone-like “tubes” that build up into the familiar reefs. These reefs provide food and shelter for countless varieties of

sea creatures. Many corals have a mutualistic symbiotic relationship with algae in which the algae make food (photosynthesis) for the coral and the coral provide a home for the algae.   Coral reefs form the basis for a multibillion-dollar tourism and commercial fishing economy in tropical marine areas around the globe. Reefs also limit damage from hurricanes and tsunamis. They also have recently been shown to be possible sources for new medicines.

         However, bleaching of the coral from record hot water has made world headlines over the last several years. Bleaching occurs when the heated water kills the algae thereby causing loss of color. If coral remains bleached for more than a week, the odds for death increases significantly. Bleached coral are more susceptible to disease. Recently a chunk of brain coral 3 feet in diameter was found that was about 90 percent dead (rrstar November 12, 2017) near St. Thomas in the Caribbean. Zooxanthellae, commonly called “gooks” is the algae found in coral. (Gore, A 2006)

         Let’s examine the effects of human activities on a terrestrial ecosystem, or more correctly, biome–tropical rainforests. From the editors of the Environmental Magazine in the Belvidere Daily Republican October, 2009), 80, 000 acres of tropical rainforests are being lost daily and an equal amount are being degraded.

         Rainforests are extraordinarily rich in nutrients and biodiversity. They help maintain climate by sequestering carbon dioxide and are home to perhaps 50 percent of the world’s species. Twenty five percent of our pharmaceuticals are derived from rainforest ingredients. Why are rainforests being destroyed? Mainly they have fallen (literally) to logging, farming crops and cattle ranching) but also to dam- building and mining.

         Let’s consider the effects of climate change on weather patterns such as storms, including hurricanes, tornadoes, and snowstorms from the viewpoint of their frequency and intensity. In February, 210, Washington D. C. received over two feet of snow followed by a six day cold spell.  Undoubtedly many peoples were saying “where is global warming now?” That doesn’t refute a trend of

rising global temperatures. At the same time snow had to be trucked in to Vancouver, British Columbia, so that the winter Olympics could go on as scheduled. A one- time weather event is still a one-time weather event. (Belvidere Daily Republican February 25, 2010). Also from the Belvidere Daily Republican issue of September 22, 2005, scientists state that warmer ocean temperatures in the tropics between June and November cause instability

in the lower atmosphere which then ‘fuels” developing hurricanes. Following that line of reasoning, it followers that even further warming temperatures will add more strength. The data seems to back that up. Tropical storms in both the Atlantic and Pacific Oceans have increased in duration and intensity by 50 percent since the 19770’sThe hottest years in recorded history up to the date the article was written were the years 1990-2004 which coincided with the greatest worldwide emissions of CO2. That the intensity of hurricanes has increased is borne out by that fact that there was an average of about 11 Category 4, or 5 storms per year in the 1970’s compared to an annual average of 18 in the 1990’s. This increase coincides with a nearly one degree Fahrenheit sea temperature rise. Warmer ocean temperatures increases the water vapor content of the atmosphere resulting from greater evaporation and cloud formation. Remember from essay IV (hydrologic cycle) that water vapor can also be a greenhouse gas since clouds help trap heat. At least one meteorologist questioned the above data saying that wind speed estimates of storms in the 1970’s were based on older technology they may not have been as accurate. However, another scientist countered that increases have been steady over the years. “It didn’t just kick in when the new technology measurement methods kicked in” (rrstar, September 18, 2005).

    References

Rockford Register Star (May 18, 2008) “Polar bear’s impact on people is felt”

Rockford Register Star (September 8. 2007) Report: Massive polar bear deaths predicted”

Rockford Register Star (February 2, 2018) Climate change diet: As ice thins, so do polar bears”

Rockford Register Star (November 12, 2017) “Caribbean coral suffers record bleaching death”

Belvidere Daily Republican (February 25, 2010) “Strange snow patterns are consistent with climate change”

Belvidere Daily Republican (September 22, 2005) “Earth Talk: Does global warming affect tropical storms?”

Rockford Register Star (September 18, 2005) “Study: More hur4icanes growing to strongest categories”

Published By

Larry Baumer

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I now include a little known but conflicting argument for (temporary at least) global cooling. Everyone knows that there have been several ice ages in our planet’s past. The earth is now on the brink of entering another ice age, according to a large and compelling body of evidence that could last for the next 100,000 years. Ice cores, ocean sediment cores, the geologic record, and studies of ancient plant and animal populations all indicate a regular cyclic pattern of Ice age glacial maximums of about 100,000 years each separated by periods of warmer climates lasting about 12,000 years. Enter now the Milankovich Cycles, which include three astronomical phenomena.

They include:

·       the tilt of the earth (23.5°) (see Essay XII)  which varies over a period of 41, 000 years

·       the shape of the Earth’s orbit (elliptical) which changes over a 100,000 year period

·        Precession of the Equinoxes (Earth’s “wobble”) which rotates the direction of the earth’s axis over a 26,000 year period.

         According to this theory, these three astronomical cycles all affect the amount of solar radiation the earth receives and work together to produce the “Ice Age maximums and warm interglacials.” Now for the downside: the original proponents of the above theory, Imbue, Hays, and Schacklton wrote in a 1976 paper that it (Milankovich Cycles) must be qualified in two ways. First, they apply only to the natural component of future climate trends and not to the anthropogenic (human) effects such as those due to the burning of fossil fuels. Second, they describe only the long-term trends since they are linked to periods of 20,000 years or longer.

         Carl Sagan during the 1970’s and later promoted the “anthropogenic global warming” (AGW) theory. This is based largely on the ‘hockey stick” graph presented by Al Gore in the 2008 film “An Inconvenient Truth.” The graph shows an acute spike in global temperatures beginning in the 1970’s and continuing to the present with an exception of the 2006-2007 winter. The main flaw with the AGW theory is that it focuses on the past l, 000 years while ignoring the past million years.

             The British journal “Nature” in 1999 published the Vostok ice core data collected at the Vostok Station in Antarctica. The report written by Columbia University researchers includes a record of global atmosphere temperature, atmosphere CO2 levels and two greenhouse gases from 420,000 years ago to the present.  

         It validates the previously held idea of regular cyclic patterns of ice age maximums and warm interglacials. The data graph also shows that changes in global CO2 levels lag behind global temperature changes by about eight hundred years. That indicates that global temperatures precede or cause global CO2 changes and not the reverse. In other words, the natural cyclic increase in global temperature is causing global CO2 to rise. Global CO2 rise or fall in response to global temperatures occurs because cold water can hold more CO2 than warm water. That’s why warm carbonated beverages lose their fizz and cold ones don’t.      

The earth is warming because of the normal Ice age cycle with the resulting CO2 rise. Ultimately the Milankovich cycles described above drive the over-all process, and not anthropogenic effects.

References

Pravada December 1, 2009 Earth on the Brink of an IceAge

Published By

Larry Baumer

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Scientists have been concerned about climate change for decades. As early as 1965 a science advisory panel to then President Johnson warned that “increasing atmospheric CO2 could lead to marked changes in climate by the year 2000.”  The United Nations formed the Intergovernmental Panel on Climate Change in 1988 which relies on input from hundreds of scientists including well known skeptics. Since 1990 the IPCC has issued an updated report every 5 or 6 years.  According to the first report, the Earth’s average temperature had risen by 0.5 to l degree Fahrenheit in the past 100 years. It concluded, however, that the increase could be due mainly to “natural variability”.  However, by 1995 that possibility had disappeared. The new evidence suggested a “discernable human influence, increased melting in the Greenland and Antarctic ice caps, and the virtual collapse of mountain glaciers around the world. Globally the planet is the warmest it has been in thousands of years, if not more.” “In 2001 the IPCC estimated that global temperatures could rise as much as 5.8ͦ° Celsius by 2100. (Rockford Register Star 1/28 /2007) 

         Russian researchers returned from western Siberia in 2005 and reported the world’s largest frozen peat bog was quickly melting into ‘”shallow lakes” and was probably irreversible and probably connected to climatic warming. Thus, as much as a billion tons of methane gas (formula weight 16), 20 times more potent than carbon dioxide could be released into the atmosphere. Similar patterns are developing in Eastern Siberia and across parts of northern Alaska. If it continues to thaw scientists think it could produce a “tipping point” of no return in the Earth’s ability to self-regulate (Belvidere Daily Republican 7/23/2006)                                    

      According to an article in the Rockford Register Star, (3/5/206) the Antarcticis now showing an ice deficit. The world’s largest reservoir of fresh water is shrinking faster than new snow can fall. Between 2002 and 2005 it lost ice at arate of 36 cubic miles a year. Artic glaciers of Greenland according to researchers at the University of Colorado were melting at a rate twice as fast as five years ago (2001). This amounts to 38 cubic miles of fresh water added to the Atlantic Ocean each year. This suggests that increased global temperatures have altered the seasonal balance of the world’s water cycle (see essay IV). Virtually all measurements are the result of using satellites.  Ice shelves are thick plates of ice that float on the ocean around Antarctica.  Snow, glaciers, and ice flows feed the plates during “winter” and melt during “summer” in a cycle as old as Antarctica itself. Large icebergs calve off on a regular basis. Most scientists believe that recent increases in calving are linked to warming surface air temperatures resulting from human activities. If this continues, sea level rise would make some densely populated coastal areas uninhabitable.  Some 200 million people-in low-lying areas of Vietnam, china, India, and other countries could be displaced. (Belvidere Daily Republican 12/9/2005)

        From the October 19, 2008 issue of the Rockford Register Star in an article titled “On thin ice”, the Arctic Ocean is recording record temperatures as the ocean is getting warmer and less salty as ice melts. “Obviously, the planet is interconnected so what happens in the arctic does matter to the rest of the world” said Jackie Richrter-Menge of the Cold Regions Research and Engineering Laboratory in Hanover, N. H. The report involved scientists from 10 countries. The intergovernmental Panel on Climate Control blames human activity for adding carbon dioxide and other global warming gases to the atmosphere. Rising temperatures help melt the ice which in a vicious cycle allows more solar heating of the ocean. The warmed air affects land and marine life and reduces the amount of sea ice that remains into the following summer.  Arctic land increases in greenness as shrubs move north into areas that were formerly permanently frozen. Other findings included an unprecedented rate of sea level rise of nearly O.1 inch per year. Also reindeer herds that had been increasing in numbers for years are leveling off or beginning to decline.

            The Belvidere Daily Republican’s Earth Talk section of the February 17, 2010 edition contained the following discussion of the world’s oceans changing salinity as polar icecaps continue to melt. Global warming adds fresh water into the oceans. The concern here is that if this continues to happen fast enough, the influx of fresh water could disturb ocean currents enough to change weather patterns on land as well. The Gulf Stream that keeps northeastern U.S. and northwestern Europe warm could stall and shut off some of the worlds highly populated areas natural heating source. This could plunge those areas of two continents in a cold snap that could last for decades or longer. Think of the domino effect that would have on crop and tourism economies. If the salinity of the ocean changes drastically, the water in the warm water stream could instead of getting heavier (which sinks and normally then flows back southward from whence it came completing the cycle) would stall.

         The following pictures represent the same exact area of Boulder Glacier, Glacier National Park, Montana from 1932 (left) and 1988 (right) (Gore, A. 2006). Note the difference.

The graph below shows ice core data charting average temperature from the past thousand years.in the Northern Hemisphere. The line at 0.0 represents average temperature from 1961 to 1990.  Any year with an average temperature below the 0.0 line was colder than average and is shown in blue; any year with an average temperature above the 0.0 line was warmer than average and is shown in red. I’ll let the reader draw your own conclusions.  

At the risk of sending my readers into data overload, I will show you what may be the most important graph of the essay. It compares atmospheric CO2 concentration (blue line) and the Earth’s temperature (gray line) over the past 650,000 years. Do you remember if…then hypotheses from Essay II? Here’s the perfect example of one that can be made? If higher amounts of CO2 are related to higher temperatures, then the blue line and the gray lineshould follow the same pattern. Do they?

The July, 2017 issue of Science Magazine contained this article:A Delaware-sized Antarctic Iceberg Has Broken Into the Ocean

I quote selected paragraphs.

“After months of dangling on by a miles-thin thread of ice, an iceberg roughly the size of Delaware just calved off Antarctica’s Larsen C ice shelf and began drifting out into the ocean.”

“But this trillion ton iceberg, likely to be named A68, was already floating, so it won’t contribute to sea level rise.”

“This ice shelf – a floating patch of ice pushed from a land glacier – is the largest along the Antarctic Peninsula’s coast. The narrow and mountainous peninsula sticks out some 800 miles north from the continent toward Chile. And that location means the region has warmed at least twice as fast as Earth’s overall average.”

“Scientists worry that after this iceberg drifts into the ocean, the shelf behind it might collapse.”

“If the floating Larsen C does collapse, it won’t raise sea levels directly. But once an ice shelf is gone, the glacier feeding it flows faster to the sea. And that will speed up sea level rise.”

Sometime ago in a science class you probably learned that light colored objects reflect light and heat and dark colored objects absorb them. That’s why we wear light colored clothing in the summer and wear light colored clothing at night (unless we don’t want to be seen). I recall a classic demonstration where I would focus a magnifying lens on white paper and then on black construction paper and watch students faces when the black paper smoldered and then burst into flames. Remember as a kid frying ants on the sidewalk with a hand lens? Anyway, my point is that glaciers, because they are light colored, reflect heat back into space but as they melt because of rising temperatures, the darker water or dry earth absorb the heat and speed up the melting thus accelerating climate warning.

            Here are some “shorts” on sea ice and glacier melting:

·       From 2006, Greenland glacier runoff doubles over past decade.

·       The EPA says the sea level along the U. S. coasts are expected to rise 2 feet by 2100.  

·       In 2005 the glaciers discharged twice as much fresh water as in 1996–enough fresh water to supply Las Angeles for 220 years. (Rockford Register Star)

·       From 2007, Artic Sea ice Melting Faster.  Newer satellite measurements compared to older model simulations indicate the ice may actually may be shrinking at an annual rate of 7.8 % instead of the original 5.4% which puts it 30 years ahead of the previous predictions. (yahoo News)

References

Rockford Register Star (January 28, 2007) “Washington wakes up to     global          warming”

Belvidere Daily Republican (July23, 2006) Earth Talk: “How will

         Siberia’s thawing affect the world?”

Rockford Register Star (March 5, 206) “Antarctica now showing ice deficit”

Rockford Register Star (October 19, 2008) “On thin ice”

Belvidere Daily Republican (December 9, 2005) Earth Talk: “What are the effects of broken ice shelves”

Belvidere Daily Republican February 17, 2010 Viewpoint, Boyer, G.

Gore, A. (2006) an inconvenient truth Viking, Rodale New York, NY

Science Magazine (July, 2017) “A Delaware-sized Antarctic Iceberg        Has Broken Into the Ocean”

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Published By

Larry Baumer

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Al Gore in his book “an inconvenient truth” begins his book with this picture and the statement “This is the first picture most of us ever saw of the Earth from space. It was taken on Christmas Eve, 1968 by one of the astronauts aboard the Apollo 8 spacecraft.” Thus, this is the way I begin this essay.

It is essential that that we understand some terms before proceeding further.

• Greenhouse effect: light and heat from the sun enters the atmosphere striking the earth’s surface where some is absorbed by surface features and converted into other forms of energy such as chemical energy of food. QUIZ TIME: What Is the process called? Answer at end of essay. Some is radiated back into space, and some is trapped in the atmosphere by clouds and various pollutants thereby raising the temperature similar to a hothouse or greenhouse; thus the term “greenhouse effect”.
• Global warming: the cumulative result of the greenhouse effect on a worldwide basis

The greenhouse effect exists all the time, maintaining the average climate of the world at about 60 ͦ F. The earth’s atmosphere is what keeps us at an “average temperature”. Global warming and the greenhouse effect are phrases that appear regularly in the mass media. Quoting from an earlier essay, “The transfer rate of carbon from the atmosphere by photosynthesis just about equals the rate at which respiration and decay return carbon to the atmosphere. However, when fossil fuel burning is added to the equation, the rate of CO2 returned to the atmosphere is greatly favored.”

In 1991 the National Association of Biology Teachers (NABT) adopted the following position.

Causes of Climate Change

1. Increased use of fossil fuels
2. Increased rate of deforestation, resulting in less carbon “locked up” in the forest
3. Increased amount of “greenhouse gases” (CO2,CH4 (methane), N2O (nitrous oxide), CFCs (chlorofluorocarbons)) causing the atmosphere to absorb radiant heat
4. Growth of the human population as it affects all of the above

Consequences of Global Warming    .

1. Shifting of agriculture zones
2. Desertification and local mass extinction
3. Changes in animal migration patterns
4. Sea levels rise as a result of melting polar ice and thermal expansion in the oceans, which can cause destruction of human structures and natural habitats along sea coasts

Possible Actions to Reduce Climate Change

1. Reduce fossil fuel consumption by increasing efficient use of energy
2. Decrease deforestation and encourage reforestation
3. Use education to increase public awareness
4. Control human population growth, possible reversing it
5. Use alternative energy resources and recycle
6. Promote education, awareness, political priorities and international efforts and cooperation

Stephen Schneider writing in the Scientific American (September 1989) recalls that in 1957 Roger Revelle and Hans E. Suess of the Scripts Institution of Oceanography noted that “humanity is performing a great geophysical experiment” not in a laboratory or on a computer, but on our own planet. Al Gore in his book “an inconvenient truth” includes a graph of Revelle’s work. It indicates a steadily increasing CO2 in the atmosphere which continues today. Revelle also explains why the CO2 level varies from one hemisphere to the other and why it changes seasonally. As stated in an earlier essay, the majority of land masses lies north of the equator which contains the most vegetation. The levels decrease in summer when photosynthesis is rapidly occurring and increases in fall and winter when deciduous trees drop their leaves

This experiment essentially began at the beginning of the Industrial Revolution. Since then we have increased the atmospheric content of carbon dioxide by about 25 percent by burning oil, coal, and other fossil fuels. This along with clearing forests and decomposition of dead organic matter removes a source of CO2 sequestration from the atmosphere. Carbon dioxide makes only about 0.03% of the atmosphere but along with water vapor and other greenhouse gases such as methane (CH4) greatly affects the earth’s climate. Even as early as the early 1800’s people knew that like a greenhouse which allows sunlight to enter but traps the heat inside, such gases absorb the longer wavelength infrared rays thereby trapping the heat and gradually raising the temperature, Think about which nights trap the heat the most and keep the temperature warmer, cloudy nights or clear?

The following graphs compares the levels of carbon dioxide equivalent in megatonnes in 2005 and 2013 and the worst culprit.

The following diagram indicates how some of the solar radiation strikes the earth and is absorbed, some is radiated back into space, and some is trapped in the atmosphere and the role of greenhouse gasses including water (vapor in the form of clouds). In a later essay I will compare the absorption and reflectivity rates of soil, blacktopped and paved areas, and glaciers including glaciers that have disappeared leaving brown areas

Answer to quiz question: photosynthesi

References

National Association of Biology Teachers (NABT)  1991

Schneider, S. (1996) Laboratory Earth   Weidenfeld & Nicolson   London

Gore, A. (2006) an inconvenient truth Viking, Rodale New York, NY

Published By

Larry Baumer

 In the last essay (Part IX: Organic Molecules), we left off with the question “Did RNA predate DNA. . .?”  The problem with an RNA first scenario is that protein enzymes are required for RNA to be copied from DNA. These proteins should not have been present in an RNA world by itself. For a long time it was thought that RNA could not copy itself. However T. C. Cech at the University of Colorado performed an experiment that indicated that RNA has an enzyme like catalytic activity which theoretically could catalyze its own replication. Finding an organic molecule or group of molecules that can self-replicate gets to the heart of the very origin of life from nonlife. (Curtis, 1989) How could any RNA arise from a nonliving environment? Some believe, in all likelihood, that RNA was not the first self-replicating system.

    Regardless of what nucleic acid molecule came first, it would have to have come from a simpler inorganic molecule. The simpler inorganic molecule to more complex organic molecule sequence would have needed an energy source. Furthermore, the larger biomolecules once assembled would have to be protected from extreme environmental conditions. All of these present difficult issues.

    There is also great debate over where all of these prebiotic and early biotic materials came from.  Darwin liked the “warm little pond” scenario (Darwin, 1859). Stanley Miller and Harold Urey in 1953 performed an experiment in which they added gases that at the time were thought to comprise the early atmosphere (carbon dioxide, ammonia, hydrogen, and methane) in some elaborate flasks and tubes and used an electric spark to simulate lightning as an energy source and succeeded in making some amino acids. The implication here is that the “building blocks” of life might have originated in the atmosphere and supported Darwin’s pond hypothesis (Miller, 1993). Later the composition of the early gas atmosphere came into question and thus Miller and Urey’s hypothesis fell into disfavor. Other scientists have offered deep ocean hydrothermal vents that are warm and nutrient rich as the place where life originated. It has also been shown that some meteorites and comets contain amino acids such as glycine, glutamine acid, valine, and proline. In fact, in 1969 a large meteorite fell to earth in Australia which contained lipids and all five nitrogenous bases found in DNA and RNA (Miller, 1993). As you can see, there are many more questions than answers, or shall we say, more unanswered questions than answered ones.

    Let’s take a closer look at the “prebiotic soup” or “warm little pond” hypothesis, also known as the Oparin-Haldane hypothesis model.

• Assemble simple molecules such as water (H2O), carbon dioxide (CO2),  Hydrogen (H2), and ammonia (NH3) into complex polymers
• Assemble these polymers (i.e. nucleotides and amino acids) that can store information and catalyze reactions
• Add membranes and an energy source to make a living organism

    However, the Oparin-Haldane model is not without its own problems. One is the question of whether liquid water was present on the earth at the time of life’s beginning and another one is that each building block along the way needs to be chemically charged (activated) before it can work in a polymer. Something like a cell membrane would be necessary to concentrate this energy but this step in the process precedes the existence of a cell membrane. Another problem associated with the water issue is that although virtually all biological reactions require an aqueous solution, water also hydrolyzes the products almost as soon as they are made. Could polymers have been made that were long enough to be self -replicating?

    This is a good place to pause and remind ourselves that all life forms use proteins (from the same 20 amino acids), DNA, and other important biomolecules such as ATP (adenosine triphosphate for energy storage). The incorporation of cellular contents by a cell membrane and internal membranes surrounding the organelles was a significant step. Cells exhibit compartmentalization allowing chemicals to be localized where they are needed. Chemical reactions can occur in small steps, waste products can be concentrated, chemicals can he pumped outside, and the internal parts and chemicals can be protected. However, compartmentalization and small step chemical reactions means that every step in a biochemical pathway such as photosynthesis, cellular respiration, or even something as simple as digestion requires its own enzyme. The entire pathway may require dozens of enzymes and if only one enzyme is missing, the overall reaction stops. Something as simple as lactose intolerance or as complex as Tay-Sachs Syndrome results from such failures,

    In the next essay we shall look at some early life forms such as prokaryotes (ie archaea and bacteria) and eukaryotes and ways of classifying living organisms.

References

Curtis, H. N. (1989). Biology. New York: Worth Publishers Inc.

Darwin, C. (1859). “The Origin of Species”.

Miller, K. J. (1993). Biology. Englewood Cliffs, NJ: Prentice Hall.

Published By

Larry Baumer

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Carbohydrates are composed entirely of atoms of carbon, hydrogen, and oxygen. All four of these classes of molecules are composed of basic units of structure. The basic unit of structure of carbohydrates is the monosaccharide or simple sugar. Simple sugars combine in a condensation reaction to produce a disaccharide or double sugar. Since one water molecule is extracted during this process, it is also known as dehydration synthesis. Glucose (blood sugar) and fructose (sugar in many fruits) are examples of simple sugars and sucrose (cane sugar) is an example of a double sugar. Complex carbohydrates such as starch and cellulose (found in plant cell walls) result from many simple sugars that link together like a chain. Carbohydrates are quick energy sources and the simpler the form, the faster the energy is provided since less digestion is required. The following diagrams represent structural formulas that show the geometry (shape) of the molecules and the kinds of atoms that make up the molecule as well as the number of each kind of atom. Where lines of the hexagon or pentagon meet, if no element is shown, assume that it is a carbon atom. Note that where three or more monosaccharides are joined together, the generic name is a polysaccharide and an example is starch. (No one ever said that biology lacked a large vocabulary!)

 In the above condensation reaction also called dehydration synthesis reaction because a molecule of water is removed (see the HOH above), two simple sugars (monosaccharides) join to form a double sugar (disaccharide). The following three diagrams represent condensation reactions of glucose + glucose, glucose + galactose, and glucose + fructose respectively.

Note from the diagram below that glucose, fructose, and galactose all have the same chemical formula but are different sugars with slightly different but unique characteristics. Thus, they are known as isomers (of each other).

Question: What then accounts for their individual differences?

Answer:  at the end of the essay

         Remember that all of the above reactions are anabolic and endergonic reactions and are formed by plants; the reverse reactions occur when disaccharides or polysaccharides are broken down during digestion in animals bodies to the monosaccharides that comprised them with the addition of one molecule of water. Each reaction requires a particular enzyme to makethereaction occur. The enzyme that catalyzes the formation of sucrose is sucrase, the one for the formation of lactose is lactase and the one for maltose is maltase. As you can guess these reactions are both catabolic and exergonic.

Question: Why?

Question: What suffix probably indicates a sugar? An enzyme?

Proteins are called the “stuff of life” since they are necessary for growth and repair of the body. They are formed by long chains of amino acids (the basic unit of structure) which again results from a dehydration synthesis reaction. Ribosomes in the cell assemble the amino acids into polypeptides on the longer chained proteins. Proteins are grouped according to their function. For example, there are those that protect the body (antibodies), those for support and movement (i.e. ligaments, tendons, and muscles), those for speeding up chemical reactions (enzymes), and more. Below is a diagram of the four levels of protein structure and below that some examples of the 20 common amino acids that make up proteins.

             Credit to: proteopedia

 Credit to: biosiva.50webs.org

Credit to: Study.com

Note that this is again a condensation reaction where, in this case, the amino (NH2+) group of the glycine molecule on the right joins the carboxyl (COOH-) group on the left with the removal of one water molecule.

The third group, lipids, includes fats, oils, and wax. Since they are impervious to water, they are often used in waterproofing. Fat is, of course, long term energy storage material and also provides thermal insulation and cushions and protects vital body organs such as the eyes and kidneys. The basic unit of structure of lipids includes a glycerol molecule and three fatty acids. The typical fat or oil molecule consists of a long hydrocarbon chain which is hydrophobic (water fearing) and hydrophilic (water loving) head. This means that the head end dissolves in water and the hydrophobic tail doesn’t. Cell membranes are primarily composed of two layers of lipid. Likewise, lipids are formed by dehydration synthesis in which three water molecules are removed.

Credit to: dic.dcccd.edu

Credit to Columbia University

         The fourth group of organic molecules discussed here are nucleic acids which include DNA and the many RNA’s. We all are aware of one of DNA’s central roles-it contains the hereditary code of life and transmits that code from generation to generation. However, its other function is less well known. It directs the synthesis (in most cases) of that other class of compounds, proteins. Those two functions put DNA right at the head of the class. By the way, the basic unit of structure of nucleic acids is a nucleotide. A nucleotide of DNA consists of a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytocine, or thymine). The DNA molecule is a long double stranded molecule that is twisted into a double helix. There are many kinds of RNA but they all differ from DNA in that the sugar is ribose (with one more oxygen atom), uracil is substituted for thymine, and it is a single stranded molecule that may fold over upon itself in various shapes. Messenger RNA (mRNA, transcribes DNA’s code from the cell’s nucleus to the cytoplasm and specifies which particular amino acid is to be assembly by rRNA (a ribosome). Each amino acid is attached to a particular tRNA (transfer RNA) molecule). I always told my students that it is as if the mRNA says to the tRNA “I’ll meet you at the ribosome and we’ll make a protein.”

Credit to: Aidan balbach

The three major types of RNA structures include:

                            Credit to:quora.com

rRNA, mRNA, and rRNA

Credit to: Lumen Learning

Now that we’ve learned a little bit about each class of biologically important compounds, let’s focus in on one of those groups, the nucleic acids. A hundred years ago no one knew what molecule carried the genetic material. During the first half of the twentieth century a great debate raged among biologists about whether DNA or proteins carried that information. Many biologists favored proteins and their reasoning went something like this. If you think of the code like letters in an alphabet, proteins with their twenty letter alphabet (20 amino acids) could spell more words (greater genetic variability) than could DNA with its four letter alphabet (four kinds of nucleotides based on the four kinds of nitrogen bases). Space limits further discussion here but a series of brilliant experiments that culminated in 1953 with the iconic Watson and Crick model verified that DNA, indeed, is the universal carrier of genetic traits. (I would recommend that for further investigation of the other brilliant experiments, consult any AP or college biology text book)

        The ramifications of this discovery are, of course, immense. As pointed out in a previous essay, virtually every scientific discovery raises more questions than it answers. One of those questions is a which came first the chicken or the egg question. Until 1982, all known enzymes were thought to be proteins. Rbonucleic acid (RNA) was thought to play a supporting role to DNA (deoxyribonucleic acid). It (RNA) simply passed genetic information from DNA to proteins, which carry out the work of the cell. A group lead by Sidney Altman and Thomas Cech discovered ”ribozymes”–RNA enzymes. This changed biologist’s view of the cell’s operations and their view of the origins of the first cells- how they view life’s origins.

 Which substance did life acquire first– DNA or proteins? Proteins can perform many biological functions but they can’t propagate themselves. DNA can propagate (replicate) itself but can’t perform any biological tasks. On the other hand, RNA can transmit and store genetic information and can perform biological work based on the discovery of catalytic RNA (ribozymes) Thus, it is entirely possible that it preceded both proteins and DNA. The RNA molecule has a genotype which is the linear sequence of nucleotides along the RNA molecule. The genotype can record and make small changes in heritable information. It also has a phenotype which results from the ribozyme having an active site that can catalyze a chemical reaction.

Did RNA predate DNA and should RNA be elevated to a higher status than DNA? We will take up that question in the next essay.

 Answers to questions

Their structural formulas (geometry)

Larger molecules are broken down into smaller ones (breaking down process with a release in energy). There is less energy in the products than in the reactants.

-ose

-ase

Published By

Larry Baumer

—

For the more scientifically motivated reader I now submit an interesting corollary to the essay on photosynthesis and respiration. Most everyone knows that our bodies (all living organisms) are made up of one or more discrete units called cells and that inside these cells reside the working parts (cell organelles). I will focus on just two of those organelles here, chloroplasts and mitochondria. Chloroplasts make plants green and are responsible for photosynthesis. Mitochondria, called the “powerhouse” of the cell are responsible for cellular respiration. This is not the same as the mechanical process of breathing. As stated in the previous essay, respiration is a catabolic (breaking down) process in which food is converted into energy with release of CO2 and H2O but more important is the energy that is released. This is an exergonic chemical reaction which means there is less energy in the final state (the CO2 and H2O) than in the initial state because energy was released from the food. This energy can be used to build up molecules of adenosine triphosphate (ATP). Adenosine triphosphate is like money in the bank which can be used when needed. It should come as no surprise that the cells that need the most energy like muscle cells have the most mitochondria. The process of building ATP is an endergonic reaction (one in which the final state, or products, have more energy). It is also an anabolic (building up) process since a more complex molecule is made from simpler ones. So, an exergonic reaction (the breakdown of glucose) provides the energy to make the endergonic reaction (ATP synthesis) go. Then ATP is broken down to ADP (adenosine diphosphate) and energy is released.

I previously alluded to aerobic respiration (with oxygen) and anaerobic respiration (without oxygen). It is interesting to note that during aerobic respiration 36 molecules of ATP are produced for every molecule of food (i.e. glucose) that is oxidized. On the other hand, for every molecule of glucose oxidized in anaerobic respiration only 2 molecules of ATP are produced. Clearly aerobic respiration is more efficient. Now let’s tie this in with early primitive forms of life eons ago to most present day forms. Remember, when life was first formed the atmosphere lacked free oxygen. This means that the first forms of life must have used anaerobic respiration as a means of obtaining energy. That was sufficient for primitive forms of life then but not for most forms today which are more complex and highly specialized. To put it another way, anaerobic respiration yields only 14.6 kilocalories of energy per molecule of glucose whereas aerobic respiration yields 686 kilocalories of energy. Dividing 14.6 by 686 and converting to a percent means that anaerobic respiration (also called fermentation) is only 2.1% as efficient as aerobic respiration. Interestingly though, when we do strenuous exercise, because our body can’t bring in oxygen fast enough to meet demand, it switches over to anaerobic respiration until we rest. This activity produces lactic acid as a waste product which causes fatigue.

Immediately below is a diagram of a cutaway view of a chloroplast and below is a similar diagram of a mitochondrion and also a photomicrograph (Sylvia S. Mader, Biology eighth ed., 2004)

Finally, let’s compare and contrast the chloroplast and mitochondrion.

CHLOROPLAST                                        

• found in autotrophs only (i.e. plants, algae, etc.)
• associated with anabolism
• has its own DNA*
• associated with photosynthesis
• has double membrane
• endergonic Rx

Mitochondrion

• found in autotrophs & heterotrophs
• associated with catabolism
• has its own DNA*
• associated with cellular respiration
• has double membrane
• exergonic Rx

 Taken from Diagrams Of The ATP Cycle – Image Results

 Below is a photomicrograph provided by the author showing the upper epidermis (top layer of cells) and the photosynthetic palisade layer of cells below of a Syringa spp (lilac) leaf.

Virtually all the DNA of a cell is found in the nucleus. However, mitochondria have their own DNA which brings to mind an interesting hypothesis. From the above table we can see that chloroplasts in plants and mitochondria in all eukaryotes (organisms that have a membrane bound nucleus) have their own DNA and are the only cell organelles other than the nucleus supplied with DNA. This fact along with some other puzzling observations has led to an interesting hypothesis about their origin. As we learned in the last lesson, prokaryotes have a singular circular chromosome. This is also true of mitochondria. Furthermore, mitochondria contain ribosomes, which are responsible for protein synthesis that are about the same size as those found in bacteria. Also, mitochondria contain enzymes that are found in bacterial cell walls. Finally these bean shaped organelles, unlike other cell organelles, appear to be produced only by other mitochondria and not by cell division (mitosis and cytokinesis). But therein lies a problem: mitochondrial DNA cannot code for all the proteins found in them.

The Endosymbiont Hypothesis proposed by Lynn Margulis suggests that the first eukaryote cell was formed by a symbiosis among several prokaryotes. In pacman style one cell captured the other cell and both cells benefited. Both cells would have had DNA and ribosomes. In a similar fashion, chloroplasts may have formed when photosynthetic prokaryotes were ingested by larger nonphotosynthetic cells.

Biology is such a fascinating science and it truly builds upon the principles of chemistry, geology, and even physics.

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. 

           Two of the most important chemical reactions on earth are photosynthesis and respiration (cellular respiration, not just breathing). During photosynthesis plants take CO2(from the atmosphere) and water from the soil and make food (i.e. simple sugars) and convert them into more complex molecules while also releasing free oxygen. In the process energy is stored in food molecules (an example of anabolism, a building up process). During cellular respiration all organisms oxidize organic molecules and produce CO2 with the release of water molecules and more importantly energy is released. This is catabolism (a breaking down process). Anabolism and catabolism together are called metabolism. Thus the two reactions are complementary, that is, the reactants of photosynthesis (CO2 & H2O) become the products of respiration, and the raw materials of respiration (O2 & food molecules) become the products of photosynthesis.   Inversely, the products of respiration (CO2 & H2O) become the raw materials for photosynthesis and the products of photosynthesis (O2 & food molecules) become the raw materials for respiration. Photosynthesis is represented by the forward reaction (left to right or green and respiration by the reverse reaction or blue)

                                   Credit to: khanacademy.org

As a preview to the next essay, the diagram below suggests that the two processes are intimately related and that there is an energy flow from the sun to plants (photosynthesis) to all organisms (cellular respiration) with the building up and breaking down of adenosine triphosphate (ATP) with the subsequent release of energy-energy for all life processes. That is why we say that the ultimate source of our energy is the sun.

         This is part of the “balance of nature”. Now let’s jump to rapid oxidation (burning) of –anything. Guess what? The products of burning are the same as those of cellular respiration, CO2 & H2O, and energy is released. Too much of one process or too little of the other and the “balance of nature” is upset. This is what is and has been happening for a long time. With increasingly more people on the planet, the rate of CO2 production is increasing at an alarming rate. 

Carbon dioxide is heavier than oxygen (formula weight = 44 vs 32 for O2). Thus CO2 will hover closer to the earth. It and the other greenhouse gases (water vapor, methane, etc.) trap some of the sun’s energy thus preventing some of the infrared radiation from escaping into space thereby warming the atmosphere. The same phenomenon occurs on a cloudy vs. clear night. On which type of night does the temperature drop the least? Why?

It is interesting that CO2 levels vary with the seasons. During the summer when the Northern Hemisphere is tilted toward the sun, the leaves are actively capturing more CO2 which decreases its levels worldwide. During the winter when the Northern Hemisphere is tilted away from the sun and deciduous trees have dropped their leaves, less CO2 is captured and worldwide levels go up. You might ask “why doesn’t the Southern Hemisphere counterbalance that?” Taking a quick look at a globe should reveal the answer. Hint: compare the amount of land mass in the two hemispheres. Remember that land and the air above the land heat up faster and cool down faster than water does. There are some physical and chemical properties of water that I won’t go into here that account for that. But think about the fact that the temperature of land near large masses of water tends to stay cooler in summer and warmer in winter than land far away from large bodies of water. For example, compare the average temperature of Seattle to Omaha or Chicago’s lakefront vs. O’Hare Airport.

Now let’s look at the facts. First, let me remind you that neither I nor scientists worldwide and over many years are making up what I have described above and discuss below. Observations are made, data collected, and inferences are drawn. Principles of physics, chemistry, and biology as well as earth science and meteorology are intricately at work.       

Average world temperature is and has been rising for years—no argument there, just recorded facts. That means that while some temperatures are normal or subnormal, many others are above normal. Don’t base your opinion on your microenvironment and say “no way, it’s just as cold here as it used to be”. I’m talking about average global temperature.   The result is ocean temperatures rise and weather patterns are disrupted resulting in more severe storms (hurricanes, tornadoes, and floods) which may also occur in greater frequency. Warmer ocean temperatures results in stronger El Nino patterns and warmer ocean currents such as the Gulf Stream. Droughts become more severe and last longer. If you get the idea that all these factors (see paragraph four above) are related, then you know why I used the word “intricately”. Coincidently, the rate of greenhouse gases has been rising too.

I hope I have shared some important concepts to think about. I haven’t even touched on the effects of climate change on glaciers, living things, and even the seasons. That will come later

 [LB1]

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.