Darwinism vs, the real world XXXI

The Digestive System: The Stomach and Beyond
Howard Glicksman February 26, 2016 11:24 AM

Editor's note: Physicians have a special place among the thinkers who have elaborated the argument for intelligent design. Perhaps that's because, more than evolutionary biologists, they are familiar with the challenges of maintaining a functioning complex system, the human body. With that in mind, Evolution News is delighted to offer this series, "The Designed Body." For the complete series,  see here. Dr. Glicksman practices palliative medicine for a hospice organization.


Except for molecular oxygen (O2), which comes in through the lungs, everything else the body needs to survive enters through the gastrointestinal system. This includes things like water, sugars, amino and fatty acids, cholesterol, electrolytes, minerals, and vitamins. But most of the nutrients the body needs are trapped inside more complex molecules, like carbohydrates, proteins, and fats, and are too large to enter the body. The gastrointestinal system must first break down these large molecules into much smaller ones, in a process called digestion, so it can then absorb the nutrients the body needs into the blood. In my last article I showed that digestion is similar to how a pulp and paper mill works. They both use mechanical and chemical means to break down large things into smaller ones and only use their equipment and chemicals when needed.

The process of digestion begins as soon as food enters the mouth. Its presence, along with its taste and smell, are detected by the nervous system, which stimulates the release of saliva from the glands in the mouth. Saliva contains the enzymes amylase and lipase, which begin the chemical breakdown of carbohydrates and fats respectively. As the food mixes with saliva, it is mashed by the teeth and the tongue, formed into a small mushy lump called a bolus, and moved back toward the pharynx.

Sensors in the pharynx detect the bolus and send information to the brain, initiating the swallow reflex. Swallowing involves the coordinated action of about twenty-five different pairs of muscles to protect the airway and propel the bolus into the esophagus, where it is moved by peristalsis down into the stomach. This article will show how the body follows the rules and takes control to continue digestion and absorption within the stomach and beyond.

Seeing, smelling, and tasting food causes the brain to send nerve messages to the stomach, which begins the first or cephalic phase of gastric secretion. This causes the release of mucous, hydrochloric acid, and pepsinogen. The mucous protects the cells that line the stomach from its own chemicals. The acid both kills microbes and converts pepsinogen into a powerful digestive enzyme called pepsin, a protease that begins to chemically breakdown protein. This phase also results in specialized cells in the stomach secreting a hormone called gastrin,which travels in the blood and tells the stomach cells to send out even more mucous, hydrochloric acid, and pepsinogen.

As the stomach fills up and distends with fluid, the stretch-sensitive mechanoreceptors in its walls send out more nerve messages. These stimulate the cells in the stomach to send out even more mucous, hydrochloric acid, and pepsinogen in what is called the second or gastric phase of gastric secretion. The contents of the stomach are then churned and mixed to further help in the digestive process, creating an acidic liquid called chyme.

It is important to note here that besides playing a major role in digestion, the stomach does two other important things: use its acid to help iron be absorbed later on and produce intrinsic factor to protect Vitamin B12 from being broken down by its acid. Both of these nutrients are needed for the production of hemoglobin.

The stomach absorbs very few nutrients (mainly water) and once it has done its part of digestion it passes the chyme into the first part of the intestine called the duodenum. To prevent damage to the duodenum and allow for more efficient digestion and absorption, it is important that the stomach control how fast it releases the chyme. This is accomplished by the pyloric sphincter, a ring-like band of muscle at the end of the stomach that is able to constrict and relax to send out the right amount of chyme for the right situation. Sensors in this region send messages to nerve cells, which help to control gastric emptying. In general, the more fat and protein is present and the more acidic the chyme, the slower the stomach empties its contents into the duodenum. This is why, when you have a heavier meal, your stomach feels full for a longer period of time.

As the stomach works on the acidic chyme and slowly sends it into the duodenum, the stretching of the intestinal walls signals it to start producing its own fluid. Intestinal juice mainly contains saline (NaCl), mucous, bicarbonate (HCO3-), and digestive enzymes. The alkaline bicarbonate begins to neutralize the acidic chyme that the intestine receives from the stomach. The enzymes produced in the lining of the intestine mainly help to break up the bonds between molecules that contain two sugars. Maltase breaks up the bonds between the two glucose molecules that make up maltose, lactase breaks up the bonds between glucose and galactose which make up lactose, and sucrase breaks up the bonds between glucose and fructose which make up sucrose. The intestine also produces enterokinase, a protease that is important for activating many of the enzymes that come from the pancreas.

As the chyme moves from the stomach into the duodenum, sensors on specialized gland cells detect simple molecules, like fatty and amino acids. The gland cells respond by sending out two hormones, secretin and cholecystokinin, to tell the pancreas to deposit its fluid into the digestive tract. Pancreatic juice contains high amounts of bicarbonate and is very alkaline. The addition of the alkaline pancreatic juice helps to further neutralize the acidic chyme that has entered the intestine from the stomach. The pancreatic juice also contains most of the enzymes needed to finish off the digestion of carbohydrates, fats, and proteins. In addition to amylases and various lipases, the pancreatic juice contains many different proteases that break down proteins. This includes trypsin, chymotrypsins, elastases, and carboxypeptidases. All of these proteases are produced inside the pancreatic cells in the inactive form so they won't digest the pancreas itself.

Trypsin enters the intestine as trypsinogen and becomes activated by its alkaline environment and enterokinase, which, by snipping a few atoms off, changes its shape so it is ready to go to work. Trypsin then activates the other enzymes and proteases, mentioned above. Finally, since lipids are not very soluble in water, they require the presence of bile from the liver and gall bladder to help in fat digestion. The presence of fatty acids in the duodenum contributes to the release of cholecystokinin, which tells the pancreas to release its juice and the gall bladder to contract and send its concentrated bile into the intestine to help in fat digestion.

The intestine, which consists of the duodenum, jejunum, and ileum, is where most of digestion and absorption take place. In addition to water, glucose, amino acids, cholesterol, and simple fats, the intestine also absorbs other vital chemicals, such as minerals, like calcium and iron, electrolytes, like sodium and potassium ions, and vitamins like A, C, D, E, K, and all of the B vitamins, including Vitamin B12. About 1.5 liters of fluid makes its way from the intestine into the colon daily, where mostly water, sodium, and chloride ions are reabsorbed. The remaining 100-150 gm of feces that daily exits the gastrointestinal tract through the rectum and anus usually consists of about 70 percent water and 30 percent solids from undigested plant fibers, like cellulose, cells shed from the lining of the gastrointestinal tract, and bacteria.

A quick review of gastrointestinal function shows that, to do its job properly, it needs separate control systems to turn on different organs, each using enough fluids and chemicals to adequately digest food and absorb enough nutrients. The cephalic and gastric phases of gastric secretion, along with gastrin, make sure the stomach sends out enough acid to activate pepsin for the digestion of proteins to begin. The amount of fatty and amino acids and the acidity of the chyme determine the rate of gastric emptying to help in proper digestion and absorption.

These chemicals also stimulate certain gland cells to release secretin and cholecystokinin, which together tell the pancreas to release its juices into the intestine and the gall bladder to release concentrated bile. Alkaline intestinal and pancreatic juices neutralize the acid coming from the stomach, which, with the help of enterokinase, activates trypsin. Trypsin then activates many other pancreatic enzymes that do most of the work of digestion. Bile from the liver and the gall bladder are needed to help fat digestion as well. Having completed digestion, the intestine then absorbs the nutrients that have been freed up. Finally, the intestine and colon reabsorb most of the water, sodium, and chloride ions that have been previously secreted so that very little is lost through the feces.

The total absence or significant deficiency of any one nutrient would have made it impossible for our earliest ancestors to survive long enough to reproduce. The gastrointestinal system demonstrates irreducible complexity because every component has to be present for it to be able to do its job. It also demonstrates natural survival capacity because each of its components has to provide enough of the right fluid and chemicals to cause adequate digestion and allow for the absorption of what the body needs for survival. Evolutionary biology usually points to similar systems within simpler organisms to explain how the gastrointestinal system may have come into being. Of course, this does not explain how the simpler systems developed in the first place or how it must work within the laws of nature to allow for survival.


The body must breathe in air every few seconds because its need for oxygen is so acute that without it, it dies in just a few minutes. When it comes to water, because the body is able to move some of it from its cells into the blood to compensate for its loss, it only has to drink fluids every few hours. What about glucose? After all, we know we don't have to take in glucose as often as oxygen or water to stay alive. So, how does the body go about making sure it has enough for its energy needs and how does evolutionary biology explain the development of the system it uses? That's what we'll start to look at next time.

As just so as it gets(yet)

New Solution to Darwin's Doubt: Earth Wandered into Cambrian Explosion
Evolution News & Views February 26, 2016 3:14 AM

Since the debut of Darwin's Doubt, we have welcomed all comers to give Darwinian explanations for the Cambrian explosion. We've seen scientists propose a rise in oxygen, the emergence of hard parts, a rise in fecal material, and other creative ideas, including sheer dumb luck. If nothing else, it's entertaining, like watching Britain's Got Talent but, it sometimes seems, a bit light on the talent.

Now there comes along a new solution to the Cambrian enigma, proposed by a team from the University of St. Andrews. The announcement arrives under the promising title, "Unlocking one of the great secrets of Earth's evolution."

They start by making huge promises:

An international team including scientists at the University of St Andrews has unlocked the secret of one of the great events of Earth's evolution -- the Cambrian explosion. [Emphasis added.]
Expectation mounts:

Around 520 million years ago, a wide variety of animals burst onto the evolutionary scene in an event known as the Cambrian explosion. In perhaps as few as 10 million years, marine animals evolved most of the basic body forms that we observe in modern groups.
The event has sparked fierce debate all the way back to Darwin. Some paleontologists see the Cambrian explosion as a real, astonishing episode of unprecedented, fast evolution. Others suggest it is a false artifact of an unreliable fossil record.

The conflict has been established: the realists vs. the artifactualists. It's good to see that this contestant doesn't sidestep the brevity of the record. The team acknowledges that the "unprecedented, fast evolution" occurred in "as few as 10 million years." The alternative, the suggestion of a "false artifact of an unreliable fossil record," leaves much to be desired, since that idea perished quickly after Darwin. The team seems in a bind. Can they pull off a miracle?

Yes! They're going to get the whole planet involved in unlocking the great secret. Here is the main theme:

Now work published in the American Journal of Science shows that these competing theories can be unified by the geography of Cambrian Earth, as it underwent a wholesale lurch that clustered most of Earth's continents around the equator.
Co-author Dr Timothy Raub of the Department of Earth and Environmental Sciences at the University of St Andrews said: "In a nutshell both camps were right. The particular locations of Cambrian continents relative to each other was special in a way that supercharged animal speciation while preserving an unusually good record of those early fossils."

Is this the "lurch" theory of Cambrian animals? OK, you get the continents together; so what? How exactly does that "supercharge speciation"? Fossils can be preserved; great. Fossils of what?

They argue that the Earth lurched about in its orbit so that the continents cluster near the equator. This is dubbed "true polar wander." By chance, the continents created a hothouse ready to nurture the new complex animals.

Earth's continental and oceanic plates are in constant motion relative to one another, but in rare episodes of true polar wander, the entire solid Earth slips about its liquid outer core over the course of five to ten millions years, causing the geographic locations of Earth's plates to shift altogether in the same sense.
The paper suggests that about 520 million years ago a lurch of more than 60 degrees moved most continents from polar to tropical latitudes. For reasons that are still debated, biological diversity reaches a global peak around the equator and tapers off closer to the poles. This early Cambrian rotation therefore would have dramatically increased shallow coastal area in Earth's biodiversity hotspot.

Then, they say, a great bulge of water swamped continental coastlines, burying organisms under floods of sediment. The setting "would have opened up new habitats for rapid diversification, in particular vast continental seaways rife with previously unexplored ecological niches" and then preserving whatever, well -- whatever took advantage of the habitats.

That rather awkward ending deserves to be greeted with courtesy applause. One imagines Simon Cowell responding, "Thank you for that, but I do have a question; I'm a little confused where the animal body plans come from. You've set the table for them, surely; you've provided them with a nice hothouse and some unexplored habitats, but isn't the challenge how to explain the animals themselves?"

They never really grapple with the problem of new body plans, settling for vague language:

Cambrian true polar wander happened at a time when Earth was already seeded with many of the traits that subsequently radiated throughout the Tree of Life.
If one of us were a judge on this imaginary competition, the dialogue might go something like this: "I see, but...seeds? Are you saying that simple Ediacaran animals planted trilobite seeds and worm seeds and jellyfish seeds? I'm not sure I follow this line."

Dr Raub said: "A bunch of wonderful ideas have been published emphasising one or another aspect of the Cambrian biosphere as the crucial link in the explosion of animal life. An appealing aspect of our study is that a geographic contingency -- the shape and arrangement of the Cambrian continents and the direction of the remarkable true polar wander shift -- can support almost all those ideas simultaneously. At the same time, it turns out that preservation of Cambrian fossils really was enhanced over that of other ages....
Another judge chimes in: "Geographic contingency...are you telling us that it happened by chance? We were hoping to hear you explain the origin of nearly twenty unique animal body plans through a plausible biological mechanism in a very short period of time."

Another judge: "You can't fossilize what doesn't exist. Even if the continents lined up near the equator like you say, there should have only been Ediacaran organisms at the time. Where did the information come from to build all those body plans?"

They really haven't addressed the main issue. What could this presentation possibly do to, as they claim, "unlock the secret" of the Cambrian explosion?

"This new geographic framework answers a debate going back over a hundred years. It should encourage scientists to review all sorts of old and new hypotheses, which no longer must fit into the evolution or preservation camp exclusively."
The uncomfortable exchange continues: "You mean, like the intelligent design camp perhaps?" With a shocked expression, he responds, Well, no; of course not. Cowell continues, "Doesn't that qualify for inclusion in "all sorts of old and new hypotheses?" The respondent gulps. I thought we were talking scientific hypotheses. "So contingency is a scientific hypothesis?" Well, no, but... "Where did the information come from to build twenty new animal body plans?" Our model wasn't concerned with that, but rather with how the continents became rearranged to make whatever happened possible.


Thank you for your time. Next.

The Watchtower Society's commentary on the book of Habakkuk.

HABAKKUK, BOOK OF;

A book of the Hebrew Scriptures in eighth place among the so-called minor prophets in the Hebrew and Septuagint texts, as well as in common English Bibles. It is in two parts: (1) A dialogue between the writer and Jehovah (chaps 1, 2); (2) a prayer in dirges.—Chap 3.

Writer. The writer is identified in the book itself. The composition of both sections is ascribed to “Habakkuk the prophet.”—1:1; 3:1; see HABAKKUK.

Canonicity. The canonicity of the book of Habakkuk is confirmed by ancient catalogs of the Hebrew Scriptures. While they do not mention it by name, the book evidently was embraced by their references to the ‘twelve Minor Prophets,’ for otherwise the number 12 would be incomplete. The book’s canonicity is unquestionably supported by quotations from it in the Christian Greek Scriptures. Though not referring to Habakkuk by name, Paul quoted Habakkuk 1:5 (LXX) while speaking to faithless Jews. (Ac 13:40, 41) He quoted from Habakkuk 2:4 (“But as for the righteous one, by his faithfulness he will keep living”) when encouraging Christians to display faith.—Ro 1:16, 17; Ga 3:11; Heb 10:38, 39.

Among the Dead Sea Scrolls is a manuscript of Habakkuk (chaps 1, 2) in a pre-Masoretic Hebrew text with an accompanying commentary. It is noteworthy that in the text Jehovah’s name is written in ancient Hebrew characters, whereas in the commentary the divine name is avoided, and instead, the Hebrew word ʼEl (meaning “God”) is used.

Scholars believe that this scroll was written toward the end of the first century B.C.E. This makes it the oldest extant Hebrew manuscript of the book of Habakkuk. At Habakkuk 1:6 this manuscript reads “Chaldeans,” thus confirming the correctness of the Masoretic text in showing that the Chaldeans (Babylonians) were the ones Jehovah would raise up as his agency.

Date and Setting. The statement “Jehovah is in his holy temple” (Hab 2:20) and the note that follows Habakkuk 3:19 (“To the director on my stringed instruments”) indicate that Habakkuk prophesied before the temple built by Solomon in Jerusalem was destroyed in 607 B.C.E. Also, Jehovah’s declaration “I am raising up the Chaldeans” (1:6) and the prophecy’s general tenor show that the Chaldeans, or Babylonians, had not yet desolated Jerusalem. But Habakkuk 1:17 may suggest that they had already begun to overthrow some nations. During the reign of Judah’s good king Josiah (659-629 B.C.E.), the Chaldeans and Medes took Nineveh (in 632 B.C.E.), and Babylon was then on its way toward becoming a world power.—Na 3:7.

There are some who hold, in agreement with rabbinic tradition, that Habakkuk prophesied earlier, during the reign of King Manasseh of Judah. They believe that he was one of the prophets mentioned or alluded to at 2 Kings 21:10 and 2 Chronicles 33:10. They hold that the Babylonians were not yet a menace, which fact made Habakkuk’s prophecy more unbelievable to the Judeans.—See Hab 1:5, 6.

On the other hand, in the early part of Jehoiakim’s reign, Judah was within the Egyptian sphere of influence (2Ki 23:34, 35), and this could also be a time when God’s raising up of the Chaldeans to punish the wayward inhabitants of Judah would be to them ‘an activity they would not believe, though it was related.’ (Hab 1:5, 6) Babylonian King Nebuchadnezzar defeated Pharaoh Necho at Carchemish in 625 B.C.E., in the fourth year of King Jehoiakim’s reign. (Jer 46:2) So, Habakkuk may have prophesied and recorded the prophecy before that event, possibly completing the writing thereof about 628 B.C.E. in Judah. The use of the future tense regarding the Chaldean threat evidently indicates a date earlier than Jehoiakim’s vassalship to Babylon (620-618 B.C.E.).—2Ki 24:1.

Style. The style of writing is both forceful and moving. Vivid illustrations and comparisons are employed. (Hab 1:8, 11, 14, 15; 2:5, 11, 14, 16, 17; 3:6, 8-11) Commenting on Habakkuk’s style, S. R. Driver said: “The literary power of Habakkuk is considerable. Though his book is a brief one, it is full of force; his descriptions are graphic and powerful; thought and expression are alike poetic.” Such qualities are, of course, primarily due to divine inspiration.

The book of Habakkuk emphasizes Jehovah’s supremacy over all nations (Hab 2:20; 3:6, 12), highlighting his universal sovereignty. It also places emphasis on the fact that the righteous live by faith. (2:4) It engenders reliance upon Jehovah, showing that he does not die (1:12), that he justly threshes the nations, and that he goes forth for the salvation of his people. (3:12, 13) For those exulting in him, Jehovah is shown to be the God of salvation and the Source of vital energy.—3:18, 19.

[Box on page 1013]

HIGHLIGHTS OF HABAKKUK

An answer to the question, Will God execute the wicked?

Written evidently about 628 B.C.E., when the Chaldeans were rising in prominence but before Jehoiakim became their vassal

Habakkuk cries out for help, asks how long God will allow the wicked to continue (1:1–2:1)

When Jehovah answers that He will raise up the Chaldeans as His instrument for punishment, Habakkuk cannot understand how the Holy One could countenance such a treacherous agent, one who makes a god of his war machine, whose dragnet gathers up men like fish, and who mercilessly kills peoples

The prophet waits for Jehovah’s answer, recognizing that he is in line for reproof

Jehovah replies that he has an appointed time, pronounces woe upon the Chaldean agency (2:2-20)

Jehovah gives the assurance that even though there might seem to be delay, the prophetic vision is “for the appointed time, and it keeps panting on to the end,” eagerly moving toward its fulfillment

Pronouncements of woe indicate that the Chaldean instrumentality would not remain unpunished for plundering other nations, cutting off many peoples, building cities by bloodshed, making others drink the cup of shameful defeat, and engaging in idolatry

The prophet appeals for Jehovah to act and yet to show mercy during the coming day of distress (3:1-19)

Recalling past manifestations of Jehovah’s power, the prophet is seized with fear and trembling, but he is determined to wait quietly for the day of distress, exulting in the God of his salvation


Even if the very means for supporting life were to fail, Habakkuk determines to rejoice in Jehovah as the God of salvation, the One who strengthens him

Darwinists brainstorm yet another just so story.

How to Build Life in a Pre-Darwinian World:
By: Emily Singer


How did life’s myriad parts come together? At a minimum, the first life forms on Earth needed a way to store information and replicate. Only then could they make copies of themselves and spread across the world.One of the most influential hypotheses states that it all began with RNA, a molecule that can both record genetic blueprints and trigger chemical reactions. The “RNA world” hypothesis comes in many forms, but the most traditional holds that life started with the formation of an RNA molecule capable of replicating itself. Its descendants evolved the ability to perform an array of tasks, such as making new compounds and storing energy. In time, complex life followed.

However, scientists have found it surprisingly challenging to create self-replicating RNA in the lab. Researchers have had some success, but the candidate molecules they have manufactured to date can only replicate certain sequences or a certain length of RNA. Moreover, these RNA molecules are themselves quite complicated, raising the question of how they might have formed through chance chemical means.

Nick Hud, a chemist at the Georgia Institute of Technology, and his collaborators are looking beyond biology to the role of chemistry in the development of life. Perhaps before biology arose, there was a preliminary stage of proto-life, in which chemical processes alone created a smorgasbord of RNAs or RNA-like molecules. “I think there were a lot of steps before you get to a self-replicating self-sustaining system,” Hud said.

In this scenario, a variety of RNA-like molecules could form spontaneously, helping the chemical pool to simultaneously invent many of the parts needed for life to emerge. Proto-life forms experimented with primitive molecular machinery, sharing their parts. The entire system worked like a giant community swap meet. Only once this system was established could a self-replicating RNA emerge.At the heart of Hud’s proposal is a chemical means for generating a rich diversity of proto-life. Computer simulations show that certain chemical conditions can produce a varied collection of RNA-like molecules. And the team is currently testing the idea with real molecules in the lab; they hope to publish the results soon.

Hud’s group is leading the way for a number of researchers who are challenging the traditional RNA-world hypothesis and its reliance on biological rather than chemical evolution. In the traditional model, new molecular machinery was created using biological catalysts, known as enzymes, as is the case in modern cells. In Hud’s proto-life stage, myriad RNA or RNA-like molecules could form and change through purely chemical means. “Chemical evolution could have helped life get started without enzymes,” Hud said.

Hud and his collaborators have taken this idea one step further, suggesting that the ribosome, the only piece of biological machinery that is found in all living things today, emerged through chemistry alone. That’s an unconventional thought to many in the field, who think that the ribosome was born of biology.

If Hud’s team can create proto-life forms under conditions that might have existed on the early Earth, it would suggest that chemical evolution may have played a much more significant role in the origins of life than scientists expected. “Maybe there was some simpler form of evolution that preceded Darwinian evolution,” said Niles Lehman, a biochemist at Portland State University in Oregon.

The Pre-Darwinian World

When most people think about evolution, they think about Darwinian evolution, in which organisms compete with one another for limited resources and pass on genetic information to their offspring. Each generation undergoes genetic tweaks, and the most successful progeny survive to pass along their own genes. That mode of evolution dominates life today.

Carl Woese, a renowned biologist who gave us the modern tree of life, believed that the Darwinian era was preceded by an early phase of life governed by very different evolutionary forces. Woese thought it would have been nearly impossible for an individual cell to spontaneously come up with everything it needed for life. So he envisioned a rich diversity of molecules engaged in a communal existence. Rather than competing with each other, primitive cells shared the molecular innovations they invented. Together, the pre-Darwinian pool created the components needed for complex life, priming the early Earth for the emergence of the magnificent menagerie we see today.

Hud’s model takes Woese’s pre-Darwinian vision even further back in time, providing a chemical means for producing the molecular diversity that primitive cells needed. One proto-life form might have developed a way to make the building blocks it needed to make more of itself, while another might have found a way to harvest energy. The model differs from the traditional RNA-world hypothesis in its reliance on chemical rather than biological evolution.

According to RNA world, the first RNA molecules replicated themselves using a built-in enzyme called a ribozyme that was made of RNA. In Hud’s proto-life world, that task is accomplished through purely chemical means. The story begins with a chemical soup of RNA-like molecules. Most of these would have been short, as short strands are more likely to form spontaneously, but a few longer, more complex molecules might have come together as well. Hud’s model describes how the longer molecules might have replicated without the aid of an enzyme.In Hud’s vision of a prebiotic world, the primordial RNA soup underwent regular cycles of heating and cooling in a thick, viscous solution. Heat separated the bound pairs of RNA, and the viscous solution kept the separated molecules apart for a while. In the interim, small segments of RNA, just a few letters in length, stuck to each long strand. The small segments eventually got sewn together, forming a new strand of RNA that matched the original long strand. The cycle then began again.

Over time, a pool of varied RNA-like molecules would have accumulated, some of them capable of simple functions, such as metabolism. And just like that, purely chemical reactions would have produced the molecular diversity needed to create Woese’s pre-Darwinian cornucopia of proto-life.

Hud’s team has been able to carry out the first stages of the replication process in the laboratory, although they can’t yet glue together the short segments without resorting to biological tools. If they can get over that hurdle, they’ll have created a versatile way of replicating any RNA that pops up.

Yet some scientists are skeptical that chemically mediated replication could work well enough to produce the pre-Darwinian world Hud describes. “I don’t know whether I believe it,” said Paul Higgs, a biophysicist at McMaster University in Hamilton, Ontario, who studies the origins of life. “It would have to be sufficiently accurate and rapid to pass on the sequence” — that is, it would need to produce new RNAs more quickly than they broke down and with enough fidelity to create near copies of the template molecule.Chemical change on its own wouldn’t have been enough to trigger the emergence of life. The pool of proto-life would also have needed some kind of selection to make sure that useful molecules succeeded and multiplied. In their model, Hud’s team proposes that very simple proto-enzymes might have spread if they did something helpful for their maker and the larger community. For example, an RNA molecule that made more of its own building blocks would benefit itself and its neighbors by providing additional raw materials for replication. In computer simulations that Hud’s team performed, this type of molecule did indeed take root. “If a sequence comes along that does something useful, it can then be enriched in the pool,” Hud said.

Ribosomal Roots

One possible glimpse of the pre-Darwinian world can be seen in the ribosome, an ancient piece of molecular machinery that lies at the heart of our genetic code. It is an enzyme that translates RNA, which encodes genetic information, into proteins, which carry out the many chemical reactions in our cells.

The core of the ribosome is made of RNA. This feature makes the ribosome unique — the vast majority of enzymes in our cells are made from proteins. Both the ribosomal core and the genetic code are shared among all living things, suggesting that they were present very early in the evolution of life, perhaps before it crossed the Darwinian threshold.

Related Articles:

Chemists Seek Possible Precursor to RNA
Scientists have discovered building blocks similar to those in modern RNA that can effortlessly assemble when mixed in water and heated.

New Twist Found in the Story of Life’s Start
All life on Earth is made of molecules that twist in the same direction. New research reveals that this may not always have been so.

How Structure Arose in the Primordial Soup
Life’s first epoch saw incredible advances — cells, metabolism and DNA, to name a few. Researchers are resurrecting ancient proteins to illuminate the biological dark ages.

Hud and his collaborator Loren Williams, also at Georgia Tech, point to the ribosome as support for their chemically dominated world. In a paper published last year, they made the controversial proposal that the core of the ribosome was created via chemical evolution. They also suggested that it arose before the first self-replicating RNA molecule. Perhaps the ribosomal core was a successful experiment in chemical evolution, they said. And after it took root in the pre-Darwinian soup, it crossed the Darwinian threshold and became an essential part of all life.

Their argument centers on the relative simplicity of the ribosomal core, more formally known as the peptidyl transferase center (PTC). The PTC’s job is to bring together amino acids, the building blocks of proteins. Unlike traditional enzymes, which speed up chemical reactions by using “fancy chemical tricks,” as Lehman put it, it works almost like a dehydrator. It coaxes two amino acids to bond simply by removing a molecule of water. “It’s kind of a poor way to drive a reaction,” Lehman said. “Protein enzymes typically rely on more powerful chemical strategies.”

Lehman notes that simplicity likely preceded power in the earliest stages of life. “When thinking about the origins of life, you have to think about simple chemistry first; any process with simple chemistry is probably going to be ancient,” he said. “I think that’s more powerful evidence than the fact that it’s [shared] among all life.”

Despite the powerful evidence, it’s still hard to imagine how the ribosomal core could have been created by chemical evolution. An enzyme that makes more of itself — like the replicator RNA of the RNA-world hypothesis — automatically creates a feedback loop, continually boosting its own production. By contrast, the ribosomal core doesn’t produce more ribosomal cores. It produces random chains of amino acids. It’s unclear how this process would encourage the production of more ribosomes. “Why would making random peptides make that thing better?” Higgs said.

Hud and his collaborators propose that RNA and proteins evolved in tandem, and those that figured out how to work together survived best. This idea lacks the simplicity of the RNA world, which posits a single molecule capable of both encoding information and catalyzing chemical reactions. But Hud suggests that facility might trump elegance in the emergence of life. “I think there’s been an overemphasis on what we call simplicity, that one polymer is simpler than two,” he said. “Maybe it’s easier to get certain reactions going if two polymers work together. Maybe it’s simpler for polymers to work together from the start.”

This article was reprinted on TheAtlantic.com.

The crisis continues. II

Conversations with Dr. Denton: The Hierarchy of Nature
David Klinghoffer February 24, 2016 4:13 AM 

Tardigrades vs. Darwin.

That's a Tough Tardigrade
David Klinghoffer February 24, 2016 3:23 AM

Last month, Evolution News explained the problem of accounting in evolutionary term for the superpowers of tardigrades, or "water bears." These incredibly tough little creatures, just a millimeter long, are capable of surviving under the most trying circumstances on Earth -- and off Earth, in outer space, that is to say in a vacuum. Yet they originated in the Cambrian explosion, just like that, presumably ready for action.The Abstract in the journal Cryobiology reporting this achievement elaborates:

Long-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers. In the available studies of long-term survival of micrometazoans, instances of survival have been the primary observation, and recovery conditions of animals or subsequent reproduction are generally not reported. We therefore documented recovery conditions and reproduction immediately following revival of tardigrades retrieved from a frozen moss sample collected in Antarctica in 1983 and stored at −20 °C for 30.5 years. We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade, Acutuncus antarcticus, providing the longest records of survival for tardigrades as animals or eggs. One of the two resuscitated individuals and the hatchling successfully reproduced repeatedly after their recovery from long-term cryptobiosis. This considerable extension of the known length of long-term survival of tardigrades recorded in our study is interpreted as being associated with the minimum oxidative damage likely to have resulted from storage under stable frozen conditions. The long recovery times of the revived tardigrades observed is suggestive of the requirement for repair of damage accrued over 30 years of cryptobiosis. Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms.

They not only survive but on waking, go about repairing the damage entailed by three decades of such abuse. This confirms what we said earlier:

What researchers should be focusing on is the amazing design of these tiny animals. They have stubby legs with claws. They have a mouth and eyes. They lay eggs. They molt periodically. They have a digestive tract and sexual organs. They have muscles and nerves. That's a lot of specialized tissue to pack into half a millimeter! And to think that these are among the most durable animals on Earth, able to survive in habitats beyond all necessity for a Cambrian marine organism, including outer space -- that should challenge all notions of unguided evolution. Organisms should only adapt to their immediate circumstances, not to distant unknown habitats they might encounter some future day, or never.

Warning: Don't try this trick with food currently stored in your freezer.

Cambrian life continues to redefine the meaning of "primitive"

Cambrian Arthropod Was a Loving Mother
Evolution News & Views December 21, 2015 3:18 AM


An egg clutch has been identified within the carapace of Waptia, an arthropod previously known from the Burgess Shale (Middle Cambrian, dated 508 million years ago). The eggs are highlighted in a photo from the University of Toronto (above), which calls this the "oldest evidence of brood care" in any animal.

Long before kangaroos carried their joeys in their pouches and honey bees nurtured their young in hives, there was the 508-million-year-old Waptia. Little is known about the shrimp-like creature first discovered in the renowned Canadian Burgess Shale fossil deposit a century ago, but recent analysis by scientists from the University of Toronto, Royal Ontario Museum, and Centre national de la recherche scientifique has uncovered eggs with embryos preserved within the body of the animal. It is the oldest example of brood care in the fossil record. [Emphasis added.]

Five examples of the egg clusters were found. The research paper in Current Biology lists the following highlights from this fossil discovery:

Brooded embryos are described in the bivalved arthropod Waptia fieldensis

Waptia from the middle Cambrian Burgess Shale had few but large eggs

A diversity of clutch and egg sizes evolved during the Cambrian explosion

Brooding in primitive arthropods might have required presence of a carapace

The authors explain the significance of the find: "Brood care, including the carrying of eggs or juveniles, is a form of parental care, which, like other parental traits, enhances offspring fitness with variable costs and benefits to the parents." Pointing to another arthropod with smaller eggs from 515 million years ago, they attempt to weave an evolutionary narrative:

The presence of these two different parental strategies suggests a rapid evolution of a variety of modern-type life-history traits, including extended investment in offspring survivorship, soon after the Cambrian emergence of animals. Together with previously described brooded eggs in ostracods from the Upper Ordovician (ca. 450 million years ago), these new findings suggest that the presence of a bivalved carapace played a key role in the early evolution of parental care in arthropods.

The other Cambrian arthropod carried its eggs differently, but no less effectively:

Kunmingella douvillei also presented a different method of carrying its young, as its eggs were found lower on the body and attached to its appendages.

Connecting the dots between small eggs and larger eggs (2mm in Waptia) or where they were carried is the least of the Darwinians' worries. Waptia is a "shrimp-like arthropod" with a lot more body complexity than the ability to lay eggs and hold them under its carapace. It had a nervous system, sensory organs, stalked eyes, antennae, respiration, digestion, and the ability to swim. Nevertheless, the ability to lay eggs and transport them to a protective place constitutes an additional design in this animal, requiring genetics and behavioral preparedness.

It's amusing to see the euphemisms evolutionists use for the Cambrian explosion. The paper spoke of the "Cambrian emergence of animals." The news release calls the Cambrian explosion "a period of rapid evolutionary development when most major animal groups appear in the fossil record." Why call it evolutionary development? If animal groups just "emerged" or "appeared" in the record, that's not evolutionary.

Graham Budd's New "Savannah" Hypothesis

Meanwhile, Graham Budd is back. We saw him in October admitting that the trace fossils at the base of the Cambrian are "bilaterian in origin," not precursors to bilaterians. That notion was strengthened by the news that the "small shelly fossils" may include sclerites from complex animals known as kinorhynchs (see our report). That's not helpful to Darwinians. Now, accompanied by Sören Jensen, Budd has a new idea to run up the flagpole. In Biological Reviews, he presents "The origin of the animals and a 'Savannah' hypothesis for early bilaterian evolution." The news from the University of Uppsala sets the stage:

The fossil record of animals starts for sure by about 540 million years ago, but their origins before this point have remained obscure. Darwin himself worried about this problem at length in the "Origin of species". But after Darwin was writing, a famous group of fossils were discovered called the Ediacaran biota, named after a remote mine in South Australia where many were found. They are now known to be widespread around the globe from the interval of time just before the animal fossil record starts.

But what are these peculiar organisms? Their very strange morphology has made relating them to modern organisms very difficult, and they have been suggested to be related to anything from plants, fungi and lichens through to recognisable animals such as worms and arthropods.

So what is Budd and Jensen's "savannah" hypothesis? The term is drawn from an evolutionary notion that humans evolved when forests were replaced by grasslands, isolating the forest "hotspots" with distances between them. The change in environment forced our tree-climbing ancestors to come down to the ground so they could travel between the forests, learning to walk upright and forage in the open as they did. A similar situation occurred when the Ediacarans came along, they suggest; scattered nutrient hotspots constituted a "savannah" that created new opportunities for the evolution of motile animals:

In their new 'savannah' hypothesis, they propose that concentration of nutrients both above and below the sediment-water interface were enhanced around the stationary Ediacarans, and the creation of these resource "hot spots" created a very diverse environment, ideal for both diversification and for investment of energy into movement. Rather than the Ediacarans and later animals being direct competitors then, the Ediacarans themselves created a permissive environment that was ideal for higher animals to evolve in. This idea fits well into a modern view of evolution, called "ecosytem engineering" whereby key species (such as beavers) influence the environment in order to create new evolutionary and diversity opportunities for other species. Perhaps then, the Ediacaran taxa weren't impediments but the drivers of the evolution that was eventually to lead to all the rich animal diversity we see today.

Call it the "Come and Get It" theory of the Cambrian explosion. The Ediacarans set the table, put the nutritious food on it, and called out, "Come forth, Animalia!" It's honestly hard not to describe it any other way. The Ediacarans gave their permission? They created opportunities? They became "drivers of the evolution" of animals? The main paper merely states the same ideas with the addition of jargon: "The Ediacaran biota thus played an enabling role in bilaterian evolution similar to that proposed for the Savannah environment for human evolution and bipedality."

It shouldn't be necessary to belabor the point. This hypothesis fails to address the main problem that Stephen Meyer emphasized in Darwin's Doubt: What was the source of the information required to build new complex body plans and integrated organ systems at multiple hierarchical levels? Won't someone please address that question?

Oxygen Again

Let's try two more recent papers. Another paper in Nature Communications looks to oxygen as the cause of animal evolution:

Neoproterozoic (1,000-542 Myr ago) Earth experienced profound environmental change, including 'snowball' glaciations, oxygenation and the appearance of animals....Overall, increased ocean oxidation and atmospheric O2 extended over at least 100 million years, setting the stage for early animal evolution.

The news release from the Birkbeck University of London repeats this theme, implying that oxygen gives permission for animals to evolve: "It took 100 million years for oxygen levels in the oceans and atmosphere to increase to the level that allowed the explosion of animal life on Earth...."

We've already dealt with the just-add-oxygen theory (here and here).

Molecular Clock Again

Last, a dispatch in Current Biology comments on the Yang paper about the molecular clock (see our response here). That paper cast doubt on the precision of molecular clock measurements; here, Pisani and Liu agree:

This imprecision of the molecular clock deep in the history of life is frustrating. While the clock provided hope that divergence times for lineages could be dated in the absence of fossil information, it is now clear that the only way to increase its precision is to improve our knowledge of the fossil record itself, via the discovery of new fossils, resolving the affinities of existing ones, and accurately dating fossil occurrences. With genomic data now available our focus should return to palaeontology, and particularly to the investigation of the early and middle Neoproterozoic. It is evident that in isolation, neither fossils nor molecular data can derive the precise and accurate timescale of life so essential to our efforts to robustly test proposed correlations between the history of life and that of planet Earth.

Obviously this is not helpful to Darwinians either, so it's not surprising that they, too, ignore the information problem.

Space Jams?

Jehovah God's warning to the nations:The Watchtower Society's commentary.

Questions From Readers:

What is causing “the desirable things of all the nations” to come into the “house” of true worship?—Haggai 2:7.:

Through the prophet Haggai, Jehovah foretold: “I will rock all the nations, and the desirable things of all the nations must come in; and I will fill this house with glory.” (Haggai 2:7) Is the rocking “of all the nations” causing “the desirable things” of the nations—honesthearted individuals—to embrace true worship? The answer is no.

Consider what rocks, or shakes, the nations and what this shaking leads to. The Bible says that “the nations [have] been in tumult and the national groups themselves kept muttering an empty thing.” (Psalm 2:1) The “empty thing” they keep “muttering,” or meditating on, is the continuation of their own sovereignty. Nothing shakes them more than any threat to their rulership.

The worldwide preaching of the established Kingdom of God done by Jehovah’s Witnesses has become just such a threat to the nations. After all, the Messianic Kingdom of God in the hands of Jesus Christ is going to “crush and put an end to all [man-made] kingdoms.” (Daniel 2:44) The message of judgment included in our preaching work is sending out a tremor among the nations. (Isaiah 61:2) And the shaking gets more severe as the preaching work increases in scope and intensity. Of what is the rocking foretold at Haggai 2:7 a portent?

At Haggai 2:6, we read: “This is what Jehovah of armies has said, ‘Yet once—it is a little while—and I am rocking the heavens and the earth and the sea and the dry ground.’” Quoting from this verse, the apostle Paul wrote: “He has promised, saying: ‘Yet once more I will set in commotion not only the earth but also the heaven.’ Now the expression ‘Yet once more’ signifies the removal of the things being shaken as things that have been made, in order that the things not being shaken [the Kingdom] may remain.” (Hebrews 12:26, 27) Yes, the entire present system of things is going to be shaken out of existence to make room for the new world of God’s making.

Honesthearted people are drawn to true worship but not because the nations are rocked, or shaken. The action that is drawing them to Jehovah and his worship is the same action that is causing the nations to rock, namely the worldwide preaching of the established Kingdom of God. The declaration of the ‘glad tidings of everlasting good news’ draws rightly inclined individuals to the worship of the true God.—Revelation 14:6, 7.


The Kingdom message is one of judgment and of salvation. (Isaiah 61:1, 2) The results of preaching it worldwide are twofold: the rocking of the nations and the coming in of the desirable things of the nations to Jehovah’s glory.

The Watchtower Society's commentary on 'the Nations'.

NATIONS:

In the broad and general sense, a nation is made up of people who are more or less related to one another by blood and who have a common language. Such a national group usually occupies a defined geographic territory and is subject to some form of central governmental control. According to the Theological Dictionary of the Old Testament, “Hebrew evidences a tendency for goy to describe a people in terms of its political and territorial affiliation, and so to approximate much more closely to our modern term ‘nation.’ ʽam [people], conversely, always retains a strong emphasis on the element of consanguinity as the basis of union into a people.” (Edited by G. J. Botterweck and H. Ringgren, Vol. 2, 1975, p. 427) The Greek terms eʹthnos (nation) and la·osʹ (people) are used similarly. In the Scriptures the plural forms of gohy and eʹthnos usually refer to Gentile nations.

Origin. The first notice of the forming of separate nations appears in the post-Flood period, in connection with the building of the Tower of Babel. Those sharing in this project were united in their opposition to God’s purpose. The principal factor facilitating united action was that “all the earth continued to be of one language and of one set of words.” (Ge 11:1-4) Jehovah took notice of this and, by confusing their language, “scattered them from there over all the surface of the earth.”—Ge 11:5-9; MAP Vol. 1, p. 329.

Separated now by communication barriers, each linguistic group developed its own culture, art, customs, traits, and religion—each its own ways of doing things. (Le 18:3) Alienated from God, the various peoples contrived many idols of their mythical deities.—De 12:30; 2Ki 17:29, 33.

There were three great branches of these nations stemming from the sons and grandsons of Noah’s sons Japheth, Ham, and Shem, and these were reckoned as the founding fathers of the respective nations called by their names. The listing in Genesis, chapter 10, therefore might be termed the oldest tabulation of nations, 70 in number. Fourteen were Japhetic, 30 Hamitic, and 26 Shemitic in origin. (Ge 10:1-8, 13-32; 1Ch 1:4-25) For more information regarding these national groups, see CHART, Vol. 1, p. 329, as well as articles on each of the 70 descendants of Noah.

Many changes, of course, came with the passing of time. Some nations were absorbed by their neighbors or disappeared altogether, because of weakness, disease, or war; others came into existence through new migrations and population increases. The spirit of nationalism at times became very strong among certain groups, and this, coupled with great military exploits, gave ambitious men the necessary thrust to build world empires at the expense of weaker nations.

A Father of Nations. God told Abram to leave Ur and move to a land He would show him, for as He said, “I shall make a great nation out of you.” (Ge 12:1-4) Later, God enlarged on his promise, saying, “You will certainly become a father of a crowd of nations. . . . And I will make you very, very fruitful and will make you become nations, and kings will come out of you.” (Ge 17:1-6) This promise was fulfilled. Abraham’s son Ishmael fathered “twelve chieftains according to their clans” (Ge 25:13-16; 17:20; 21:13, 18), and through the six sons of Keturah, other nations traced their ancestry back to Abraham. (Ge 25:1-4; 1Ch 1:28-33; Ro 4:16-18) From Abraham’s son Isaac sprang the Israelites and Edomites. (Ge 25:21-26) In a much larger, spiritual sense Abraham became “a father of many nations,” for persons of many national groups, including those of the Christian congregation in Rome, by reason of their faith and obedience could call Abraham their father, “the father of all those having faith.”—Ro 4:11, 16-18; see ISRAEL No. 2.

How God Views the Nations. As the Creator and Universal Sovereign, God is within his absolute rights in setting the nations’ territorial boundaries (if he chooses to do so), as he did with Ammon, Edom, and Israel. (De 2:17-22; 32:8; 2Ch 20:6, 7; Ac 17:26) The Most High and Lofty One over all the earth is not to be compared in greatness with nations of mankind. (Jer 10:6, 7) Actually the nations are as but a drop from the bucket in his sight. (Isa 40:15, 17) So when such nations rage and mutter against Jehovah, as when they put Jesus to death on a torture stake, He only laughs at them in derision and confounds and destroys their presumptuous counsel against Him.—Ps 2:1, 2, 4, 5; 33:10; 59:8; Da 4:32b, 34, 35; Ac 4:24-28.

Yet for all of Jehovah’s superlative greatness and power, no one can rightly charge him with being unjust in his treatment of national groups. It makes no difference whether God is dealing with a single man or a whole nation, he never compromises his righteous principles. (Job 34:29) If a nation is repentant, as were the people of Nineveh, he blesses them. (Jon 3:5-10) But if they turn to doing bad, even though in a covenant with him, he destroys them. (Jer 18:7-10) When an issue arises, Jehovah sends his prophets with a message of warning. (Jer 1:5, 10; Eze 2:3; 33:7) God is not partial toward any, great or small.—De 10:17; 2Ch 19:7; Ac 10:34, 35.

Therefore, when whole nations refuse to recognize and obey Jehovah, or they cast him out of their minds and hearts, Jehovah executes his judgments upon them. (Ps 79:6; 110:6; 149:7-9) He devotes them to destruction and turns them back to Sheol. (Ps 9:17; Isa 34:1, 2; Jer 10:25) In descriptive language God says that the wicked nations will be turned over to his Son, the one called “Faithful and True . . . The Word of God,” to be dashed to pieces.—Ps 2:7-9; Re 19:11-15; compare Re 12:5.

The New Nation of Spiritual Israel. For centuries Jehovah God dealt exclusively with natural Israel, time and again sending his prophets to the nation so that the people might turn from their wayward course. Finally he sent his Son, Christ Jesus, but the majority rejected him. Therefore, Jesus said to the unbelieving chief priests and Pharisees: “The kingdom of God will be taken from you and be given to a nation producing its fruits.”—Mt 21:33-43.

The apostle Peter clearly identified that “nation” as one composed of persons who had accepted Christ Jesus. (1Pe 2:4-10) In fact, Peter applied to fellow Christians the very words that had been directed to natural Israel: “You are ‘a chosen race, a royal priesthood, a holy nation, a people for special possession.’” (1Pe 2:9; compare Ex 19:5, 6.) All of them recognized God as Ruler and his Son as Lord and Christ. (Ac 2:34, 35; 5:32) They possessed heavenly citizenship (Php 3:20) and were sealed with the holy spirit, which was an advance token of their heavenly inheritance. (2Co 1:22; 5:5; Eph 1:13, 14) Whereas natural Israel was constituted a nation under the Law covenant, the “holy nation” of spirit-begotten Christians became such under the new covenant. (Ex 19:5; Heb 8:6-13) For these reasons it was most appropriate that they be called “a holy nation.”

When God’s spirit was first poured out upon about 120 disciples of Jesus (all natural Jews) on the day of Pentecost in the year 33 C.E., it became evident that God was dealing with a new spiritual nation. (Ac 1:4, 5, 15; 2:1-4; compare Eph 1:13, 14.) Later, beginning in the year 36 C.E., membership in the new nation was extended to uncircumcised Gentiles, who likewise received God’s spirit.—Ac 10:24-48; Eph 2:11-20.

Regarding the preaching of the good news to all nations, see GOOD NEWS.


Gog and Magog. The Bible book of Revelation (20:7, 8) states that, after Christ’s Thousand Year Reign, Satan “will go out to mislead those nations in the four corners of the earth, Gog and Magog.” Evidently such nations are the product of rebellion against Christ’s administration.—See GOG No. 3.

On how Darwinism is taught

Darwinism vs. the real world. XXX

You Are What You Eat: The Beginnings of the Digestive Process:
Howard Glicksman February 21, 2016

Editor's note: Physicians have a special place among the thinkers who have elaborated the argument for intelligent design. Perhaps that's because, more than evolutionary biologists, they are familiar with the challenges of maintaining a functioning complex system, the human body. With that in mind, Evolution News is delighted to offer this series, "The Designed Body." For the complete series, see here. Dr. Glicksman practices palliative medicine for a hospice organization.


Take a good look at yourself. Everything you see (and can't see) is made up of chemicals that had to be taken into your body before they could be formed into organs and tissues. These chemicals are things like water, glucose and other sugars, amino acids, cholesterol, sodium, potassium, calcium, iron, and vitamins, just to name a few. In fact, other than molecular oxygen (O2), which is used for energy and is taken in through the lungs, all the other atoms and molecules the body needs to live, grow, and work properly enter through the gastrointestinal system. In other words, you are, quite literally, what you eat.

Since the body is made of matter, it must follow the laws of nature. Many of the nutrients the body needs are chemically locked up inside more complex molecules that cannot enter the body through the gastrointestinal system because they are too big. These include carbohydrates, which consist of chains of sugar molecules; proteins, which are made up of many different types of amino acids joined together; and fats, which consist of fatty acids and glycerol. To procure what the body needs, the gastrointestinal system must use enzymes to first breakdown these complex molecules into smaller ones in a process called digestion. Then it absorbs these simpler molecules so the body can use them to construct the complex molecules it needs to survive.

The gastrointestinal system depends on many different parts to digest and absorb the necessary nutrients for life and excrete what is not needed. These include the mouth, teeth, tongue, salivary glands, pharynx, esophagus, stomach, intestine, pancreas, liver, gall bladder, colorectum, and anus. Here's how it all works. The gastrointestinal tract is basically a long, muscular, hollow tube that contracts to push its contents along. Food and drink enter the mouth and are swallowed into the tract. The contents are then slowly transported at a speed that allows for optimal digestion.

Fluids, containing various chemicals and different enzymes to help breakdown the complicated chemical structures within its contents, are secreted into the lumen. These fluids break down the molecules into simpler ones, like glucose, amino acids, free fatty acids, and cholesterol. Once the complex molecules have been broken down, the cells that line the lumen of the gastrointestinal tract absorbs them into the body and places them in the blood. From here they are transported to where they are needed. Let's consider how the body follows the rules and takes control to begin this process.

The process of digestion is similar to how a pulp and paper mill works. The mill uses mechanics and chemicals to take huge logs and chop and mash them into pulp for paper and other products. Similarly, the first job of the gastrointestinal system is to use mechanical and chemical means to take in complex molecules and unlock the nutrients within them so the nutrients can be absorbed into the body. However, the equipment and the chemicals at the mill don't do anything unless there are actually logs to be processed, otherwise it would be wasting energy and other resources. So too, the gastrointestinal system begins the process of digestion in earnest only when you eat or drink.

There are many different sensors in the body that stimulate the hunger center, which is the integrator that analyzes the data, and then notifies the conscious mind to take in calories. By responding to this urge the body activates the gastrointestinal system, the effector that actually does something about the situation. The process of digestion begins as soon as food enters the mouth. Its presence, along with its taste and smell, are detected by the nervous system, which stimulates the release of saliva from glands in the mouth. Saliva is a fluid that contains many different chemicals that not only help oral and dental health, but also the swallowing of food. Saliva also contains digestive enzymes, like amylase and lipase, which are the first enzymes to start working on the complex molecules that have been ingested. Amylase breaks the chemical bonds between sugar molecules, like glucose, that are joined together in large carbohydrate molecules, like starch. And lipase breaks the chemical bonds between molecules, like fatty acids and glycerol that are joined together in large fat molecules.

As the contents of the mouth mixes with saliva, it is mashed by the teeth and the tongue, formed into a small mushy lump called a bolus, and moved back toward the throat (pharynx). Up until this point everything the body has done, bringing in food and drink, chewing, and moving it into the pharynx, has been voluntary. But once the bolus reaches the pharynx, the body must automatically take control to be sure that it goes into the esophagus and not the lungs. Sensors in the pharynx detect the bolus and send information to the brain where it is integrated. The brain then initiates the swallow reflex by sending out nerve messages that cause coordinated muscle contraction to propel the bolus into the esophagus. The esophagus is a muscular passageway that propels the bolus in a wave-like movement, called peristalsis, down through the chest cavity toward the stomach that is located within the abdomen.

Anyone who has ever had something "go down the wrong tube" can attest to the extremely sensitive cough reflex that prevents accidental aspiration (inhalation). If enough food or water goes down the trachea toward the lungs, instead of the esophagus, this can quickly lead to respiratory failure. So, merely trying to explain how all of the above parts came together, as evolutionary biologists claim to do, without explaining how coordinated swallowing developed, is not sufficient to explain the systems development. After all, once the bolus goes over the precipice of the pharynx and by the power of gravity and muscular action moves downward, there is only so much time available for the body to react.

While looking in a mirror, if you gently place your fingers on the front of your neck just below the jaw and swallow a few times, you will see and feel the tissue in the neck move up and down. What you are feeling and seeing are the upper parts of your respiratory system being moved up and out of the way so the airway can be protected from what is being sent down into your esophagus. This requires about twenty-five different pairs of muscles under the direction of the swallow center in the brain, and is carried out in about a second, usually a thousand times a day.


Because some people with neuromuscular conditions (like brainstem stroke, Multiple Sclerosis, Lou Gehrig's disease) have problems with swallowing, they are at high risk for aspiration. Clearly, for our earliest ancestors to survive would have required them to have had all of the right parts working in a coordinated fashion. But we have only shown how the body is able to safely move what it eats and drinks from the mouth to the esophagus. What then? Next time we will look at what happens within the stomach and beyond to complete digestion and allow for the absorption of the nutrients the body needs to live, grow, and work properly.