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Thursday 26 May 2016

The design debate through the looking glass


Design through the Looking Glass


You don't have to hold an amino acid up to a mirror to see its mirror image. Amino acids (except for one, glycine) come in pairs, like gloves, on the real-world side of the looking glass. So do the sugars used in DNA and RNA; they are assigned a "handedness" based on conventional rules of describing their orientation in 3-D space. In all other physical respects, chemical and thermodynamic, they are identical in their activity. This makes them difficult to separate.
The phenomenon is known as chirality. The chiral "isoforms" are called enantiomers of each other. Left-handed enantiomers are preceded byL- (from Latin levo) as in L-alanine, while right-handed enantiomers are preceded by D- (fromdextro) as in D-ribose. A mixture of both hands is said to be racemic, or heterochiral. A pure mixture of one hand is called homochiral.
With only rare exceptions, all living things use just one "hand" of these molecular gloves: left-handed amino acids in proteins, and right-handed sugars in nucleic acids. How this came about has long been a mystery, as four Chinese scientists from Tsinghua University in Beijing explain in Nature Chemistry:
Despite biology's seemingly limitless diversity and the vastness of its territories that permeate into virtually every corner of the Earth, at the fundamental level of biochemistry, all known forms of life are narrowly deļ¬ned by a single version of molecular machinery based on L-amino acids and D-ribose nucleic acids. Although rare examples of the use of D-amino acids, such as D-aspartic acid in animal brains, and L-sugars, such as L-arabinose in plants, do exist, the central dogma and most of the biological macromolecules have followed the homochirality established by life's earliest ancestorsProcesses that led biology onto this particular chiral path have remained largely elusive, even though experimental evidence for breaking the mirror symmetry has been reported and many theoretical models have been proposed.[Emphasis added.]
As it stands, no experimental or theoretical model explains the origin of life's homochirality by natural processes. Some experimenters have produced a slight enantiomeric excess of one hand or the other, but usually with non-biological chemicals, and nothing approaching the purity of life's chiral molecules. Proteins and nucleic acids cannot work with mixed handedness. A single wrong-handed building block is enough to destroy DNA, RNA, and proteins. As we saw last year, checkpoints ensure that life's building blocks remain homochiral.
This purity of handedness baffles materialists, because their causal toolkit only includes natural law and chance. The probability of getting a single-handed polymer from racemic ingredients is comparable to getting a string of coin tosses coming up all heads. The longer the sequence, the more improbable it becomes -- quickly swamping the chance hypothesis. Yet as Wang et al. state, our knowledge of natural laws isn't helping solve the problem.
Recently, an in vitro selected catalytic RNA capable of incorporating nucleotides in a cross-chiral fashion without enantiomeric cross-inhibition was reported. The fact that no known laws of physics and chemistry preclude biology's use of either of the two chiral systems, mirror-image twins of one another, has led to an intriguing question as to whether a parallel mirror-image world of biology running on a chirally inverted version of molecular machinery could be found in the universe or be created in the laboratory.
Turning from origins to application, they describe their initial attempts to create mirror-image life:
We reasoned that towards synthesizing a mirror-image biological system, an imperative step would be to reconstitute a chirally inverted version of the central dogma of molecular biology with D-amino acid enzymes and L-ribose nucleic acids--although reconstituting a mirror-image, ribosome-based translation systemthrough the total synthesis of all the ribosomal RNA (rRNA) and protein building blocks is still beyond the current technology, the totalchemical synthesis of (small enough) mirror-image polymerases might be feasible. Here we set out to synthesize such a mirror-image polymerase and to test if two steps in the central dogma, the template-directed polymerization of DNA and the transcription into RNA, can be carried out in a synthetic mirror-image molecular system (Fig. 1a).
(For present purposes, we won't dispute the central dogma, although biologist Jonathan Wells has written extensively on its problems.)
These scientists did, in fact, succeed in getting some template-driven polymerization and transcription of opposite-handed amino acids. It was very slow, but it demonstrates that, in principle, life could exist in a mirror image of itself. Alice through the looking glass would appear identical to her mirror image, but would not be able to eat opposite-handed food!
Commenting on this work for Nature, Mark Peplow explains why synthetic mirror-image biomolecules have desirable properties:
In principle, looking-glass versions of these molecules should work together in the same way as normal ones -- but they might be resistant to attack by conventional viruses or enzymes that have not evolved in a looking-glass world.
That makes mirror-image biochemistry a potentially lucrative business. One company that hopes so is Noxxon Pharma in Berlin. It uses laborious chemical synthesis to make mirror-image forms of short strands of DNA or RNA called aptamers, which bind to therapeutic targets such as proteins in the body to block their activity. The firm has several mirror-aptamer candidates in human trials for diseases including cancer; the idea is that their efficacy might be improved because theyaren't degraded by the body's enzymes. A process to replicate mirror-image DNA could offer a much easier route to making the aptamers, says Sven Klussmann, Noxxon Pharma's chief scientific officer.
Wang et al. took the smallest known polymerase enzyme, just 174 amino acids long, and laboriously constructed a right-handed counterpart. They succeeded in getting it to extend a primer from 12 nucleotides to 18 nucleotides in 4 hours. Getting it to 52 nucleotides took 36 hours -- a "glacial pace," Peplow remarks. Nevertheless, it was an important discovery. Both the normal and mirror-image enzymes worked independently, without interference, when mixed in the same test tube.
The Design Inference
The researchers admit it would be a "daunting task" to build a mirror-image version of a ribosome where translation could take the left-handed RNA and translate it into a right-handed protein. Building a "looking glass cell" is a far-off dream. At this stage, though, we can draw some conclusions about chance and design.
Peplow confirms that homochirality remains a vexing problem. He surely would have said otherwise if a likely non-random cause were known.
In their research paper, the Tsinghua researchers also present their work as an effort to investigate why life's chirality is the way it is. This remains mysterious: it may simply be down to chance, or it could have been triggered by a fundamental asymmetry in nature.
But Steven Benner, at the Foundation for Applied Molecular Evolution in Alachua, Florida, says it's unlikely that creating a mirror form of biochemical life could shed any light on this question. Almost every physical process behaves identically when viewed in a mirror. The only known exceptions -- called 'parity violations' -- lie in the realm ofsubatomic physics. Such tiny differences would never show up in these biochemical experiments, says Benner.
Benner and Peplow just conceded that natural law cannot explain homochirality. To a materialist, that leaves chance. For a short polypeptide of 100 amino acids to have formed by chance would be ½ x ½ x ½ ... 100 times: 1 chance in 2100, which is approximately 1 in 1030. There aren't enough probabilistic resources to make this likely to happen in a primordial soup of racemic amino acids. But then, even if it did, homochiral DNA or RNA would have to form independently out of its own racemic building blocks. There's just no realistic chance of success in a materialistic world. Intelligence, by contrast, can easily select one hand over the other; consider how quickly an eight-year-old could sort a pile of coins into heads and tails.
Another conclusion from this paper is that homochirality as observed in life is contingent: i.e., it could exist in the opposite mirror-image form. There is no chemical or thermodynamic reason why proteins must be left-handed as opposed to right-handed, or why nucleic acids must be right-handed as opposed to left-handed. The experiments show that chemical reactions can proceed just as well in a mirror-image world. When a choice has been made one way to the exclusion of other possibilities, and it is beyond the reach of chance, it gives indication that intelligence has embedded information into the system.
Finally, these researchers demonstrate empirically how intelligence can embed information into a system. They purposefully selected building blocks of one hand to construct their polymerase. They had a goal, and a means of reaching it. If we rightly judge their work as a product of intelligent design -- as glacially slow as it was -- how much more the products of a cell that work rapidly and accurately, using machinery at a level of sophistication beyond our ability to imitate?
It's logical. If a system on the far side of the looking glass is intelligently designed, then the system on the near side is also intelligently designed. Only a fun-house mirror could distort that conclusion.

Tuesday 24 May 2016

Universal common ancestry in the hotseat II

The Vitellogenin Pseudogene Story: Unequally Yolked

Monday 23 May 2016

Universal common ancestry in the hotseat.

Functional Pseuodogenes and Common Descent

Saturday 21 May 2016

The pink slip for Mendel?

Teach students the biology of their time
An experiment in genetics education reveals how Mendel’s legacy holds back the teaching of science, says Gregory Radick.


Historians study the causes and consequences of past events, but also consider alternative scenarios. What might have happened, for example, if Britain had stayed out of the war in Europe in 1914? Science historians also ask such counterfactual questions, and the results can be surprisingly instructive.Take genetics. The past year has seen prolonged celebrations of the work of Gregor Mendel, linked to the 150th anniversary of the paper that reported his experiments with hybrid peas. Mendel’s experiments are central to biology curricula across the world. By contrast, the criticisms levelled at Mendel’s ideas by W. F. R. Weldon, Linacre professor at the University of Oxford, UK, are a footnote.

From 1902, Weldon’s views brought him into increasingly bad-tempered conflict with Mendel’s followers. In basic terms, the Mendel­i­­­­ans believed that inherited factors (later called ‘genes’) determine the visible characters of an organism, whereas Weldon saw context — developmental and environmental — as being just as important, with its influence making characters variable in ways that Mendelians ignored. The Mendelians won — helped by Weldon’s sudden death in 1906, before he published his ideas fully — and the teaching of genetics has emphasized the primacy of the gene ever since.The problem is that the Mendelian ‘genes for’ approach is increasingly seen as out of step with twenty-first-century biology. If we are to realize the potential of the genomic age, critics say, we must find new concepts and language better matched to variablebiological reality. This is important in education, where the reliance on simple examples may even promote an outmoded determinism about the power of genes.

But what if Mendelism had never come to dominate genetics in the first place? What if Weldon’s perspective had emerged as the winner in that historical battle, and his interactionism, allied to his vivid sense of how variable the real characters of real organisms are (never just yellow or green, round or wrinkled, or any other Mendelian binary), had become the core of the subject? This is where I, and colleagues, have tried to run an experiment.

In a recent two-year project, we taught university students a curriculum that was altered to reflect what genetics textbooks might be like now if biology circa 1906 had taken the Weldonian rather than the Mendelian route. These students encountered genetics as funda­mentally tied to development and environment. Genes were not presented to them as what inheritance is ‘really about’, with everything else relegated to ignorable supporting roles. For example, they were taught that although genes can affect the heart directly, they also affect blood pressure, the body’s activity levels and other influential factors, themselves often influenced by non-genetic factors (such as smoking). Where in this tangle, we ask them, is a gene for heart disease? In effect, this revised curriculum seeks to take what is peripheral in the existing teaching of genetics and make it central, and to make what is central peripheral.Our experimental group consisted of second-year humanities undergraduates. First-year biologists, who were taught the conventional approach, acted as our control. We saw a difference — those students taught the Weldon way emerged as less believing of genetic determinism, and, I suspect, better prepared to understand the subtleties of modern genetics. (The difference was statistically significant, but I hesitate to make much of that, given that numbers were small and there were differences between the groups. I am mindful, too, that it was Weldon who first drew attention to Mendel’s own problems with exaggerated statistics.)

With such experiments — bringing insights from the archive into the science classroom — the scientific past can inform and maybe even improve the scientific future. In turn, they suggest a broader vision of collaboration. To advance scientific knowledge, historians and philosophers of science should work in close proximity to scientists, not actually in the lab but right down the corridor. Then, investigations into neglected phenomena and debates that were shut down too soon might provide the spark to serve creative science.

What of Mendel? Some might complain that it is a poor anniversary gift to jettison him from his place of honour in the genetics curriculum. Let me suggest that this grumbling, although understandable, is misguided. If we want to honour Mendel, then let us read him seriously, which is to say historically, without back-projecting the doctrinaire Mendelism that came later. Study Mendel, but let him be part of his time.

Likewise, let our biology students be part of their time, by giving them a genetics curriculum fit for the twenty-first century. If we teach them about Mendel, we should do so not to fill them with slack-jawed wonder at his foundational achievement, but to help them to appreciate how even the most imaginative and rigorous science — and Mendel’s was first rate on both counts — bears the stamp of the historical circumstances of its making. To learn that lesson about past science is to bring a welcome level of self-awareness and critical self-reflection to the present.

On the evolution of a Darwinist.

The Evolving Dr. Schafersman (Again)
John G. West

Dr. Steven Schafersman, self-proclaimed "secular humanist" and head of Texan Citizens for Science, is once again insisting that "language by the anti-evolutionists about doubt or weaknesses or controversy involving evolution is just rhetoric. Doubts or weaknesses don't exist among scientists." Poor Dr. Schafersman needs to recheck some of his previous public statements, for despite what he says now, during the 2003 biology textbook adoption process in Texas he ultimately conceded that there are plenty of scientific controversies in modern evolutionary theory. As I pointed out in a podcast in January, Schafersman in 2003 did initially assert that there were no scientific controversies over evolution for textbooks to cover. But then he began to...well... evolve. By the time the adoption process was finished, Schafersman was admitting that there are in fact many scientific controversies raised by modern evolutionary theory, only he thought that students were too stupid to study them. Recounting Dr. Schafersman's evolving statements is a great way to expose the sham claim we've been hearing throughout this week that evolution has no weaknesses.

Below is a step-by-step account Dr. Schafersman's amazing evolution in 2003:

1. In his written testimony submitted to the Texas State Board of Education on July 9, 2003, Dr. Schafersman asserted categorically:

All the biology texts are factually accurate and free of errors concerning evolution; the books do not misrepresent any details of the modern scientific understanding of evolution, nor do they omit scientific information critical of evolution, because there isn't any such information, contrary to what you have led to believe. (emphasis added)
2. In his oral testimony before the Board on July 9, 2003, Dr. Schafersman made the same general point but added a slight, unexplained qualification:

There is no scientific controversy about the fact of evolution and, thus, no weakness concerning its occurrence. There are also no weaknesses about the theory of evolution at the level it is presented in these textbooks. [Transcript of Hearing on July 9, pp. 112-113] (emphasis added)
3. In the web version of Dr. Schafersman's written testimony of July 9, 2003, a more extensive qualification suddenly appeared (which was not in the version of his testimony he actually submitted to the Board). In his revised written testimony, Dr. Schafersman explicitly acknowledged that there are in fact "disagreements and controversies ('weaknesses') concerning evolutionary theory," but he implied they are only appropriate for professional researchers and graduate students to hear about:

There is no scientific controversy about the fact of evolution and thus no scientific weaknesses concerning its occurrence. There are also no weaknesses about the theory of evolution at the level it is presented in these textbooks. Disagreements and controversies ("weaknesses") concerning evolutionary theory are found at the frontiers of research and graduate education, not at the level of introductory biology textbooks. [originally posted at http://www.txscience.org/files/testimony.htm] (emphasis added)
4. Finally, in the web version of Dr. Schafersman's written testimony submitted to the Board for the Sept. 10, 2003 hearing, Dr. Schafersman acknowledged that there are in fact "many disagreements among scientists" about evolution, and he even conceded that learning about these disagreements need not be limited to just graduate students and researchers, but also some upper-division undergraduate students might be able to study them. Dr. Schafersman also provided a detailed list of what he regarded as the genuine scientific controversies over evolution. Notably, Schafersman's list included some of the key controversies previously raised by critics of evolution (such as the sufficiency of microevolution to explain macroevolution, and questions about the primacy of natural selection):

There are many disagreements among scientists about the correct nature or explanation of the evolutionary process. These should be studied in a university evolution class, usually taught in the senior year because of the great amount of prior biological knowledge needed to understand the issues. Their existence indicates that evolutionary science is a very healthy, active, and productive field. Here are some of them, including all the most contentious ones:
A. The sufficiency of microevolution to explain macroevolution v. the existence of specific macroevolutionary processes such as mass extinction, species selection, macromutation, etc.

B. Disagreements about the tempo and mode of evolution under different circumstances: slow v. fast, gradual v. punctuated, before and after a mass extinction event, background evolution v. adaptive radiation, etc.

C. Adaptation of all features in evolution via natural selection v. features resulting from non-adaptive events and processes, such as correlation of growth, body constraints, neutral theory, genetic drift, etc.

D. The role of contingency and non-progression in evolutionary history v. evolutionary progress, improvement, and repetition due to convergent evolution.

E. Disagreements about the primacy of natural selection of individuals compared to other levels of the evolutionary hierarchy, such as gene selection, group selection, and species selection.

F. Nature v. Nurture, Genes v. Environment--this is the most divisive controversy. There are at least three positions: blank slate/human potential proponents v. sociobiologists and evolutionary psychologists v. biological determinists and IQ and race investigators.

G. The extent to which evolutionary theory can explain or account for human morality, religion, behaviors, self-awareness, free will, etc.

H. The reality or not of memes in the human population; memes are similar to genes, but are actually ideas or concepts that evolve throughout the human population and are affected by similar processes that affect genes, such as natural selection, genetic drift, founder effect, etc. Memes affect cultural evolution in the same way that genes affect physical evolution.
[originally posted at http://www.txscience.org/files/icons-revealed/index.htm ] (emphasis added)

5. So Dr. Schafersman eventually conceded that there are many scientific controversies over evolutionary theory, and he was even willing to allow some undergraduate students to study them. But he continued to oppose the right of high school students to learn about them. Why? To be blunt, he seemed to think that high school students are too dumb to understand scientific controversies. So in his view, even "Real scientific problems, controversies, etc., should not be included in introductory science textbooks." It's better for high school students to simply accept existing theory and learn not to question:

Scientific theories are too massive and established to expect any high school student to critique or question. The vast majority of high school students would not be able to perform such critiques in a scientific way. Scientific theories should be accepted as reliable knowledge in K-12 classes, and not made the object of questioning until they have the educational training necessary to do so, which consists of years of graduate study at universities.
Real scientific problems, controversies, etc., should not be included in introductory science textbooks, because they are almost always too difficult to understand and their presence would only lead to student confusion and frustration.

There are certainly problems, controversies, difficulties, and knowledge gaps with the modern theory of evolution--the explanation of how the mechanism of the evolutionary process operates over time--but for the reasons stated above, these topics are just too complex to be dealt with in high school. They almost never are, and the textbooks need not and usually do not cover them.

The concept of students learning about the 'strengths and weaknesses' in scientific 'hypotheses and theories' in high school is unscientific and pedagogically useless.

[originally posted at http://www.txscience.org/files/icons-revealed/index.htm] (emphasis added)


6. So who are the ones trying to "dumb-down" how biology texts cover evolution? Those who want textbooks to cover evolutionary controversies, or Darwinists like Steve Schafersman who think allowing students to learn about the strengths and weaknesses of existing theories (as mandated by Texas law) is "unscientific and pedagogically useless"?

Darwinism vs.the real world XXX

Calcium: Maintaining the Right Proportions
Howard Glicksman


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.

Evolutionary biology is historical science. But that I mean it tries to explain the origin of life by looking only at what is needed to live and explaining it by guessing at historical circumstances. In contrast, physiology is operational science, in that, by looking at how what is needed to live functions within the physical and chemical laws of nature, it tries to explain how life actually works. But when it comes to question of the origin of life, non-operational science is important as well. In other words, it is important to consider what happens when what is needed to live is not functioning well enough to survive. Pathophysiology is "the physiology of disordered function," or the science that explains how the body malfunctions and dies. It is representative of non-operational science.

Natural history museums often display human skeletons alongside those of other animals. Without any discussion of the physiology and pathophysiology of bone and calcium metabolism, these exhibits seek to convince the unwary that life must have come about by chance and the laws of nature alone. In contrast, museums of science and technology display the skeletal remains of different inventions with the intermediate models that led up to the modern versions. By discussing the science behind the technology and the problems and failures encountered along the way, they demonstrate the intelligence used to create them. When it comes to how bones fit into the origin of life, natural history museums only use historical science to show how life looks, whereas when it comes to human ingenuity, museums of science and technology add operational and non-operational science to show how inventions work and don't work to prove their point.

My last article in this series showed that the molecular and cellular structure of bone is complex and that its relationship with the calcium metabolism makes it absolutely vital. The bone cells live within the bone they form. They include the osteoblasts, which take calcium from the tissue fluid surrounding the bone cells to form bone, and the osteoclasts, which break down and remove calcium from bone and deposit it into the bone tissue fluid. Ninety-nine percent of the body's calcium is within its bones and ninety-nine percent of the calcium within the bones is in a crystalline form called calcium hydroxyapatite.

The remaining one percent of bone calcium is dissolved as calcium phosphate in the tissue fluid that surrounds the bone cells. Since this bone tissue fluid is in direct contact with the capillaries, it acts as a bridge by which calcium can move between the circulation and the bone. Through the bone tissue fluid, the body is able to not only supply the bone with its calcium needs, but also provide for its ongoing calcium needs. In other words, through tissue fluid and circulation, the bones act as a reservoir for the calcium metabolism of the body. Let's look at the roles that non-bone calcium plays within the fluid inside and outside of the cells.

Just as sodium (Na+) and potassium (K+) become positively charged ions when dissolved in water, calcium becomes positively charged Ca++ ions in solution. The amount of Ca++ ions within a given amount of fluid is called the Ca++ ion concentration. Of the one percent of calcium outside the bones, only ten percent is present as Ca++ ions in solution outside the cells. This extracellular fluid includes the interstitial fluid, which surrounds the cells and the plasma in the blood. The remaining ninety percent of calcium outside the bones resides in the cells. However, most of this intracellular calcium is not dissolved in the cellular fluid (cytosol) but stored in many of its organelles. In fact, the concentration of Ca++ ions in the cytosol is about ten thousand times less than in the fluid surrounding the cells and in the blood. Since the kidneys constantly filter fluid, with its content of Ca++ ions, out of the circulation, if none of it could be brought back, the body would lose its total calcium content in about two months.

In addition to providing the calcium the bones need to protect the organs from injury and attachment for muscles so we can breathe, move around, and manipulate things, the Ca+ ions in the extracellular fluid are also vital for clotting. Without Ca++ ions in the blood, clotting would be impossible and every day injuries would be much more serious threats. However, there is another very important role the Ca++ ions outside the cells play, which affects all nerve and gland function, heart, and all other muscle function.

Nerve cells produce neurohormones and gland cells produce fluids, enzymes, and hormones. Under a controlled setting, these are released in response to an appropriate stimulus. For example, as noted previously, when the core temperature rises above normal, the sympathetic nerves release acetylcholine , telling the sweat glands to perspire. And when the blood glucose drops too low, the alpha cells in the pancreas release glucagon, telling the liver to release glucose from glycogen. Each of these actions takes place because of a specific signal. This signal is the sudden and massive movement of Ca++ ions into the nerve and gland cell through Ca++ ion channels caused by original stimulus (the rise in core temperature and the drop in blood glucose). This controlled, sudden, and massive influx of Ca++ ions into the cell is the universal signal telling the nerve cells to release their neurohormones and gland cells to release fluids, enzymes, and hormones.

Heart and other muscle cells work by contracting. This involves the contractile proteins within them interacting with each other in a specific way. When adequately stimulated, massive amounts of Ca++ ions enter the cytosol of the heart muscle cells from the surrounding fluid and are released from Ca ++ ion storage units (sarcoplasmic reticulum). This sudden rise of Ca++ ions allows the contractile proteins to interact and bring about contraction. The other muscle cells of the body work in a similar way. With adequate stimulation, they release massive amounts of Ca++ ions into the cytosol from the sarcoplasmic reticulum, making their contractile proteins interact to cause contraction. Just like for nerve and gland cells, it is this controlled, sudden, and massive influx of Ca++ ions into the cytosol that is the universal signal that brings about heart and other muscle cell function.

Controlled nerve, gland, heart and all other muscle function require that the ten thousand-fold difference between the Ca++ ion concentration outside and inside the cell be maintained. But, in trying to maintain this difference in Ca++ ion concentration, the laws of nature present the body with a dilemma. Diffusion is a law of nature that says chemicals in solution are always in motion and tend to move from an area of higher to lower concentration. Since Ca++ ions can diffuse across the plasma membrane, this means that diffusion tends to make Ca++ ions enter these cells. This movement into the cells would significantly increase the Ca++ ion concentration within them and if not opposed would make them non-functional.

If you read some of the earlier articles in this series you may have noticed that the dilemma that diffusion presents to the cell for Ca++ ions is similar to the one it faces for Na+ and K+ ions. The body solves that problem through millions of sodium-potassium pumps in the plasma membrane, which use energy to pump Na+ ions out of the cell while bringing K+ ions back in, against their natural tendency to go in the opposite directions. The innovation the cells use to overcome the natural force of diffusion so they can keep the Ca++ ion concentration in their cytosol ten thousand times less than what it is outside of them is the calcium pump.

There are calcium pumps within the plasma membrane of all of the cells of the body and within the sarcoplasmic reticulum of the heart and other muscle cells, which use energy to actively pump Ca++ ions out of the cytosol. In this way, the body maintains normal nerve, gland, heart, and all other muscle function.

Don't you think it would be good for natural history museums to include in their displays on human skeletons information about the cellular and molecular make-up of bones, their relationship with the calcium metabolism, and the importance of Ca++ ions inside and outside the cell? Then, when they use the similarities between human skeletons and the ones of other animals to claim that life must have come about by chance and the laws of nature alone, the accompanying questions will be apparent. Where did the osteoblasts and osteoclasts come from and in which order? Where did the calcium pumps come from and how do they know how much calcium to send out of the cell to allow for nerve, gland, heart and all other muscle function? That would be educating the public about how life works instead of just how it looks.


Next time we'll look at how the body acquires calcium. The process isn't as easy as it is for water, glucose, and salt. In fact, the mechanism involved is just one more reason to wonder how evolutionary biologists can continue to claim that life has come about by chance and the laws of nature alone.