THE PRECAMBRIAN: Part 1 of 3

SCIENCE AND THE BIBLE TALK ABOUT THE EARLY EARTH

 

INTRODUCTION

How does one relate the standard scientific model to that presented in the Bible for the history of the Universe and Earth? This does not have an easy answer, but the Geoscience Research Institute will be addressing the question in several blogs outlining the different parts of the geologic column. The standard divisions are: Precambrian with little life, Paleozoic with old life, Mesozoic with intermediate life, and Cenozoic with recent life. This blog begins with the Precambrian and is based partly on Biblical Research Institute Science Council presentations and a field trip that occurred in 1993 at Glacier View Ranch south of Rocky Mountain National Park in Colorado.

In the standard chronology of Earth’s geologic history, the Precambrian part covers by far the largest fraction of time – 88% of the total. This spans the time from 4.56 Ga to about 0.54 Ga, where “Ga” stand for giga annum or billions of years ago. The standard scientific timeframe is included because many conservative Seventh-day Adventist academics are comfortable with long ages for inorganic matter and believe that only life was created recently.

Because this article attempts to cover so much material, the discussion is split into three parts. The first two parts present the standard scientific model, where in some cases various models are being suggested for one set of data. Design examples and creationist ideas are interspersed throughout these first two sections. The third part presents some additional creationist perspectives, although not much science is available. (To date young-age creationists have spent little time trying to explain the Precambrian in terms of a recent creation, with little speculation and less scientific research.) Here are the three sections:

  • This first section summarizes the standard model for formation of the Universe, Solar System and Earth, Moon, oceans, continents, and plate tectonics. Brief references to the Universe, Sun, and Moon are included because what happens beyond Earth sets the stage for what happens on Earth during the Precambrian and in the Genesis 1 account.
  • The second section describes Precambrian rock exposures, as well as the atmosphere, climate, and Precambrian life. Many illustrative pictures are included.
  • The third section provides two perspectives suggested by creationists: (1) a young universe and life and (2) old inorganic material, but young life.

Some of the terms and concepts addressed here are too complex to do them justice in a single article. For this reason, many web links and references are included to provide more detail and a more complete understanding. The outline of the standard model is based especially on The Story of Earth by Hazen (2012). Additional information is available from a scholarly volume on Earth’s Oldest Rocks edited by Van Kranendonk et al. (2007). The web provides additional resources such as Encyclopedia Britannica, Michigan State University, Live Science, an historical geology textbook website, a journal devoted to Precambrian Research, a YouTube video, a good summary timescale, and a few cartoons.

UNIVERSE

This is no supermodel spiral

The NASA/ESA Hubble Space Telescope observes some of the most beautiful galaxies in our skies —  This little spiral, known as NGC 4102, has a different kind of appeal, with its tightly-wound spiral arms and understated, but charming, appearance. NGC 4102 lies in the northern constellation of Ursa Major (The Great Bear). 

In the standard scientific model, the universe began at a Big Bang about 14 billion years ago. When an expanding universe was first suggested in about 1930, it was rejected by the scientific community because it seemed to suggest an effect without a cause pointing to an outside force like God. By the 1960s the Big Bang came to be accepted after the observation of microwave background radiation that could be explained by an initially hot, dense universe; however, scientists are still wondering (January 25, 2016) how the universe began and what came before the Big Bang. One creationist suggests that there is a crisis in cosmology (January 26, 2016).

The Big Bang created quarks, which coalesced into protons and neutrons that then formed atoms such as hydrogen and an environment where light could travel through space. These hydrogen atoms clustered into stars which became hot under gravitational pressure and started burning by nuclear fusion, just as in a hydrogen bomb. The “burning” meant combining four protons or hydrogen nuclei (1H) together into helium (4He).

After the hydrogen had been converted to helium, the helium started combining so that three helium nuclei would combine to form carbon (12C), but carbon must have a certain excited-state resonance energy for this to work. Before this resonance energy was experimentally observed, it was predicted by Fred Hoyle as a necessary fact for nature to produce carbon by stellar evolution. Now that this resonance energy has been discovered, it has been suggested as an evidence for the intelligent design of the carbon nucleus, but the argument must be used with caution.

After 12C is produced, heavier elements were formed by the addition of more 4He nuclei to make such elements as oxygen (16O), magnesium (24Mg), silicon (32S), and iron (56Fe). Atoms heavier than iron require an input of energy, so did not form until the extra energy from a supernova explosion was available to produce atoms of iodine, platinum, gold, mercury, lead, uranium, etc. These stellar explosions seeded space with these elements, many of which are just exactly the elements necessary for life.

SOLAR SYSTEM AND EARTH

Remnants of these stellar explosions formed clouds of gas and dust. One such nebular cloud with its mass all rotating in the same direction developed into our Solar System with a large central bulge forming the Sun and the remainder coalescing into planets.

This Sun is the ideal size for life on earth: if it were ten times larger it would burn too fast, and if it were ten times smaller it would not provide enough energy. During Earth’s early stages, the Sun had only about 70% of its current light output. This might suggest a much colder early Earth, but evidence for liquid water at that time indicates that that was not the case. This warmer-than-expected Earth has been explained by a greenhouse effect and by the Earth absorbing a much higher percentage of the Sun’s energy in the past.

A solar wind blew the lighter gases away from the Sun to where the gas planets of Jupiter, Saturn, Uranus, and Neptune now orbit. The heavier material remained closer to the Sun and accreted into meteorites and planetesimals (small planets) and eventually into the rocky planets of Mercury, Venus, Earth, and Mars. This formation of Earth occurred during the period of “heavy bombardment” by meteors in the Hadean (4.5-4.0 Ga). During this time the Earth differentiated into a denser iron/nickel core and less dense silicate mantle. A recent article (January 28, 2016) summarizes a book on the accretion and differentiation of the early Earth.

About 10% of meteorites are iron that once formed the cores of planetesimals and 90% are silica rich chondrites that once formed their mantles. Present day examples of these early meteorites are most easily found in the Earth’s Antarctic ice fields and the Sahara desert. The largest known iron-nickel meteorite is the Hoba meteorite displayed near Grootfontein in Namibia.

MOON

In the standard scientific model, the Moon formed within fifty million years after the development of the Solar System. It was once thought that the Moon formed by the breakup of the Earth, or by being captured from a solar orbit, or by accretion just as the Earth had. New data from Moon rocks in the early 1970s however, indicated that these theories were not satisfactory. The Moon lacked an iron core and volatiles like water, so its composition was too different from that of Earth.

A new model that developed in the mid-1970s postulated that a small planet called Theia once occupied the same orbit as Earth, until it was captured by Earth and annihilated. The collisional debris thrown into space coalesced to form the Moon (see: Slattery, 1995; Choi, 2015). The impact from Theia was just right – not a miss, not too glancing, and not too head-on – and may have caused the Earth’s tilt of 23 degrees. Similar collisions may have caused Venus to rotate backwards and Uranus to rotate sideways. However, a recent article (January 29, 2016) suggests that the Moon was produced by a head-on collision.

Initially the Moon is thought to have orbited the Earth at a distance of about 15,000 miles. At that time the Earth would have rotated on its axis every five hours, a solar eclipse occurred every 84 hours, and the Earth had monster tides. As the Moon moved away from the Earth at about 4 cm per year, the Moon orbited the Earth faster and the Earth’s rotation slowed due to conservation of angular momentum.

OCEANS

Water is ubiquitous in our Solar System in moons and planets, underground oceans and volcanoes. The Moon has subsurface ice and its rocks are 750 parts per million water. Venus had water early in its history, but it was lost due to heat from a runaway greenhouse effect. Mars has a metal core, a silicate mantle, an atmosphere, and a subsurface global ocean hundreds of feet deep. It lost its surface water, but evidence for its past existence is found in water-rich clay, braided stream channels, river valleys, and minerals formed from the evaporation of water. Earth is between these two planets at the ideal distance from the Sun, or “Goldilocks Zone.”

Since the Earth is assumed to have formed from meteorites, the volatiles found in chondrites are expected to have existed in the early Earth – nitrogen, carbon dioxide, sulfur gases, and water. However, a large fraction of the expected volatiles seem to be missing, either lost to space from impacts such as Theia or deeply buried.

Over the last thirty years it has been suggested that Earth’s deep interior may hold prodigious amounts of water. The mantle transition zone may contain as much water as nine times the Earth’s oceans and the lower mantle as much at sixteen times as much. Under the high pressures and temperatures deep in the earth, minerals incorporate hydrogen which, along with their oxygen, can produce water. This water content is evident in granitic magmas that commonly contain 1-4% water and volcanic lavas that cause explosive volcanism as at Mt St. Helens due to the explosive release of pressurized water vapor.

According to the standard model, Earth’s early water came from the volatiles spewed out of volcanoes, so that shallow seas formed within a few tens of millions of years and oceans developed within 100 to 200 million years after Earth’s formation. The early oceans were saltier than today and apparently that salt has precipitated into salt deposits and evaporites – minerals formed from the evaporation of water.

Water has the unique chemical properties necessary for life (Hazen, 2012). Among other properties, it is a solvent; it has high surface tension making capillary action in vascular plants possible; and it splits into hydroxyl (OH) and hydronium (H3O+) ions important for acid/base pH reactions. Its high heat capacity decreases Earth’s temperature fluctuations to a range acceptable for life. Unlike most substances, water expands on freezing; thus ice has a lower density than water and will float. If this were not the case, ocean basins would fill with ice from the bottom up. It is a basic ingredient in biochemical reactions in our bodies that are more than half water.

 

 

CONTINENTS AND PLATE TECTONICS

Over the Earth’s history it has differentiated into a core, a mantle, and oceanic and continental crusts. The crustal plates are formed as magma rises from the mantle at spreading centers and volcanic arcs and destroyed as the tectonic plates descend back into the mantle at subduction zones. The differentiation and movement is due to gravitational effects on different density rock depending on their heat content and the arrangement of atoms in their minerals.

The Earth’s rocks are made up of minerals and the minerals are composed primarily of six types of atoms: oxygen, silicon, aluminum, magnesium, calcium, and iron. One usually thinks of the oxygen in the atmosphere, but 99.99999% of it is in the Earth’s minerals. Silicon is to inorganic rocks what carbon is to organic life, since both form four bonds with surrounding atoms. These oxygen and silicon atoms together (SiO2 silica) are the primary constituents of the Earth and its silicate minerals.

The early Earth was a hot magma ocean with the heat coming from the collision of meteor fragments, from gravity-induced tides, and from radioactive elements. The magma oceans cooled by conduction, convection, and radiation. The hot, early Earth differentiated based on density (in g/cm3) which is related to silica content. Higher silica content means lower density rocks, so rocks nearest the Earth’s surface are generally highest in silica. The differentiated Earth consisted of an iron core with negligible silica and a density of 10-13, a mantle with 45% silica and density of 3-4, and eventually a basalt crust with 50% silica and density 2.8-3.0. For comparison, later granitic rocks have a silica content of 60-75% and a density of 2.6-2.7. Seismology, the study of earthquake waves, is today able to identify a lower mantle made of the mineral perovskite with a density of about 4, a transition zone, and an upper mantle made of peridotite with a density of 3.1-3.4.

During the first 50 to 100 million years, a basalt crust formed from 5% partial melting of the peridotite upper mantle. Rocks don’t have a single melting temperature and the first parts to melt have a higher silica content and a lower density than the remainder. The lower density basalt was more buoyant than the mantle and rose to the surface forming black volcanic islands in the Earth’s shallow seas.

During the Archean from 4.0 to 2.5 Ga, plate tectonic activity began and the first small pieces of granitic continental crust called cratons formed. Life requires atmosphere, oceans, and land, but “You can’t have continents without granite, and you can’t have granite without taking water deep into the Earth … So at some point plate tectonics began and started bringing lots of water down into the mantle. The big question is when did that happen?” (see January 21, 2016 article). John Baumgardner suggests that catastrophic plate tectonics began at the Genesis flood.

The heat energy driving tectonic activity came from convection in the mantle, but the trigger may have been an asteroid impact. This differentiation to granite is part of the trend of elemental separation and concentration: the six major elements separated from hydrogen and helium by the solar wind; Earth’s silicate mantle separated from the iron core; basalt crust separated from mantle; water and other volatiles separated from rock; and now granite separated from basalt. The final result is low density continental crust made up of granitic rocks rich in silica, sodium, potassium, water, and trace elements. Its major minerals are quartz which eventually forms sandy beaches and feldspar which eventually breaks down to clay-rich soil.

The Proterozoic from 2.5 to 0.5 Ga is marked by the onset of modern plate tectonics, including volcanoes and earthquakes. Plate tectonic activity (Condie, 1998; Rino et al., 2004; Hawkesworth et al., 2010) caused the cratons to move around and combine to form the continents and at times a single super-continent. Pangea that formed at about 0.3 Ga is the most familiar example of a super-continent, but is more recent than the Precambrian. Older examples in the Precambrian include Rodinia (1.0-0.6 Ga), Columbia/Nuna (1.9-1.4 Ga), and a more conjectural Kenorland (2.7-2.5 Ga) and Vaalbara (3.1-2.8 Ga). Of these, Andrew Snelling briefly discusses Rodinia in his plate tectonic flood model. The supercontinent cycles are the subject of ongoing study.

REFERENCES

  • Charles Q. Choi (2015). “How the Moon Formed: Violent Cosmic Crash Theory Gets Double Boost.” April 8, 2015.
  • Kent C. Condie (1998). “Episodic continental growth and supercontinents: a mantle avalanche connection?” Earth and Planetary Science Letters, v.163, p.97-108.
  • J. Hawkesworth, B. Dhuime, A. B. Pietranik, P. A. Cawood, A. I. S. Kemp, and C. D. Storey (2010). “The generation and evolution of the continental crust.” Journal of the Geological Society, London, v.167, p.229-248.
  • Robert M. Hazen (2012). The Story of Earth: The First 4.5 Billion Years, from Stardust to Living Planet. Penguin Group: Viking; see also, https://eos.org/articles/new-nova-tv-show-explores-coevolution-of-rocks-and-life
  • Rino, T. Komiya, B. F. Windley, I. Katayama, A. Motoki, and T. Hirata (2004). “Major episodic increases of continental crustal growth determined from zircon ages of river sands: implications for mantle overturns in the Early Precambrian.” Physics of the Earth and Planetary Interiors, v.146, p.369-394.
  • Wayne Slattery (1994 sic). “Where Did the Moon Come From? Part I.” Geoscience Reports, n.18, p.1-3.
  • Wayne Slattery (1995). “Where Did the Moon Come From? Part II.” Geoscience Reports, n.19, p.1-3.
  • Martin J. van Kranendonk, R. Hugh Smithies, and Vickie C. Bennett, eds. (2007). Earth’s Oldest Rocks. Elsevier.

 


Benjamin Clausen, PhD Physics,

Geoscience Research Institute

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What Is Biology? Part 4 of 4

How Life is Defined:

There is no simple clear definition of what life is. This is appropriate as life is a wonderful, complex, beautiful, enigmatic phenomenon that defies any effort to over-simplify it. Still, most people have no difficulty recognizing living things and differentiating them from non-living things.

The best that we can do as scientists is list out characteristics that all living things share. If something lacks these characteristics, it is not living, but if it has them, it probably is alive. Here are some characteristics of living things:

  1. Cells – All living things are comprised of cells, ranging from the smallest single-celled bacteria to multi-celled organisms containing trillions of cells, like mature elephants or oak trees
  2. Reproduction – Organisms make copies of themselves
  3. Development and growth – Newly produced living things go through a series of changes, including growth, before they reproduce and continue the cycle of life
  4. Homeostasis – Living things maintain a relatively constant internal environment; not too hot or cold, not to acidic, not too salty, not too dry and so on
  5. Adaptability – This characteristic is sometimes called responsiveness or sensitivity. It means that organisms can detect changes in their environment and respond, within limits, so that they can continue to live
  6. Metabolism – Energy is taken in by living things and used for development, growth, maintenance of homeostasis, reproduction and to adapt to environmental changes.

Most scientists can think of things they would like to add to this list. A molecular biologist might observe that life is complex, an ecologist that life is interdependent, an ornithologist that life is elegant and so on. All these things are true, so why are they not on this list? One reason is that the list could be overly long if everything was on it and verification of every characteristic in every organism could be a daunting task. In addition, some of these things, such as elegance, are judgment calls. Not everyone can agree on what is or is not elegant.

Life is beautifully complicated;reductionism is a commonly used strategy when studying it. Reductionism is the idea that we can better understand things by reducing them to their simplest components. Scientists practicing reductionism are like someone who takes apart machines to see how they work, leaving a trail of irreparable devices scattered in pieces around their home. Imagine trying to understand a bicycle using reductionism. Bikes are wonderfully efficient transportation devices and understanding that may be enough for some people, but reductionists believe that taking bikes apart to examine the wheels, pedals, chain, frame, ball bearings, handlebars and so on will give a better understanding.

The problem with reductionism is that with living things – as with bicycles and other machines – the property we are interested in is the result of all the parts working together, not of the individual parts. In other words, understanding every detail of handlebars really doesn’t tell you how a bike works; it is the arrangement of the handlebars along with the other parts that actually makes them function as handlebars. Off a bike, handlebars are just a bent metal tube.

The phenomenon we call life is an emergent property, something that only exists as a result of a combination of many parts. The parts of a cell are not all a little bit alive. They are no more alive than a rock, just as handlebars are not a little bit a transportation device. They only become part of a transportation device when combined with all the necessary parts of a bike arranged together in exactly the right way.

Biologists have a big problem; life is complicated and hard to understand. Practicing reductionism – taking organisms apart and getting down to their simplest components – seems to be the only way of learning how they work. But life is a product of the complicated interaction of many components, so there is no way of getting down to a few fundamental parts that let us understand how life works or what life is. In other words, life is nothing like as simple as physics or chemistry, in which a few forces or fundamental particles explain a lot. Biology is a whole lot more interesting!

Summary:

Biology is the scientific study of the profound mystery we call life. Life is so amazing that it defies definition and is recognized on the basis of its characteristics, which include: reproduction, development, cellular structure, metabolism, homeostasis and adaptability. Our worldview strongly influences how we see life, the questions we ask about it and the theories we will consider to explain it.

Scientists agree that all theories about nature are subject to empirical data, and can usually agree on what the data are, but science is limited to the data available. Logic sometimes gives multiple interpretations and approaches like reductionism are imperfect. Rules like Ockham’s razor can help, but it should not be surprising that sometimes multiple different conclusions are arrived at based on the same data.

Even with its limitations, and a metaphysical foundation that not everyone would agree to, science, and particularly biology, has proven to be an extraordinary tool for discovery as we seek to understand life and the world in which we live. For those who embrace the biblical worldview, it opens vast new opportunities to see and appreciate the brilliant wisdom of the Creator.


 

Timothy G. Standish, PhD

Senior Scientist, Geoscience Research Institute


 

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What Is Biology? Part 3 of 4

The scientific method uses inductive reasoning to generate theories that explain data. Deductive reasoning is used to generate testable hypotheses that must be true if a theory is true. When the hypothesis is tested, it may fit well with the new data generated, thus supporting the theory (but not proving it true). If the hypothesis is inconsistent with data, then the theory is inconsistent with data and needs to be modified in some way, or completely replaced with a new more comprehensive theory.

The Scientific Method

All scientific endeavors begin with a question. The questions we ask are typically influenced by our worldview. For example, a Darwinist may ask, “How did the appendix evolve?” While a Bible-believer might ask, “What was the appendix created for?” The questions we ask determine the answers we seek. Imagine being a scientist who wonders; “What does the appendix do?” How would you proceed?

Discovering what data are already available about the appendix would be a good start, so from books you learn the appendix is about the size of a finger and dangles off the large intestine. Sometimes it becomes inflamed and, if it is not removed, can kill a person. However, if the appendix is removed, people can still live healthy lives.

Charles Darwin looked at this evidence and interpreted it this way:

Charles Darwin enthroned – Natural History Museum London 2013

“That this appendage [the appendix] is a rudiment, we may infer from its small size, and from the evidence … of its variability in man. … Not only is it useless, but it is sometimes the cause of death, …”[1]

A logical inference from data, like this, is commonly called a “theory.” Theories are one of four components of the scientific method:

  1. Data – observations that are relevant to the question being asked
  2. Theory – An explanation of data addressing the initial question
  3. Hypotheses – logical deductions from theories. These must be true if a the theory is true
  4. Experiment – an empirical test of a hypothesis. This generates more data (and frequently more questions)

 

Interpreting organs like the appendix as rudiments or vestiges of once useful organs inherited from our ancestors may work within a Darwinian evolutionary framework, but not very well.

The problem is that from a logical perspective, Darwin’s interpretation of the evidence is unsatisfying. It can be construed as relying on an argument from ignorance: “I don’t know what this does, so it must do nothing.” If the appendix does nothing and sometimes kills people, natural selection should have eliminated it as it has, according to Darwinian thinking, in other organisms such as squirrels and chinchillas [2]

This assumption may also work within a biblical framework, if it is assumed that Adam had a functional appendix and that function has been lost in modern humans. From a biblical perspective, why would God create an organ with the potential to kill humans unless it performs some important function? Both Darwinism and the biblical worldview offer unsatisfying explanations for a useless appendix. The theory that the appendix actually does something seems simpler, thus more likely to be true if Ockham’s razor is used.

A “hypothesis” is logically derived from a theory, although this term is loosely defined and can mean a hunch based on one or a few observations. In the sense I’m using “hypothesis” here, it basically says, “If theory X is true, then Y must be true.” To be scientific, a theory must generate testable hypotheses. The theory that the appendix is functionless generates testable hypotheses. For example, “If the appendix is functionless, then removing it should make no difference.” “Experiment” is simply another word for the kind of test that can be done based on this hypothesis. So the functionless appendix theory is definitely scientific, but that does not necessarily mean that it is true.

The kinds of hypotheses that a scientist comes up with may be strongly influenced by their worldview. For example, a Darwinist might hypothesize that if the appendix is functionless, then there should be a clear pattern of its evolution when “related” organisms are compared. In fact, this hypothesis has been tested and the “pattern” is not what would be expected. The presence and absence of the appendix in different mammal groups requires that it evolved and disappeared multiple times, hardly a simple clear pattern [2]

The Bible says that humans are “fearfully and wonderfully made” (Psalm 139:14), which seems at odds with the existence of functionless and dangerous organs. Someone who embraces the biblical worldview is probably going to have a problem with the functionless appendix theory, even if they lack a theory about what its function is. They are more likely to ask, “What does the appendix do?” Instead of having a clearly testable hypothesis, they may simply go and look at the appendix a little more closely before dismissing it as functionless.

Human appendix

Human appendix

It turns out that those who have looked a little harder at the appendix have developed the theory that the appendix functions as a reservoir of beneficial bacteria that are necessary for human health. When people suffer from acute diarrhea, they may flush out harmful organisms or substances along with the beneficial bacteria and, when that happens, the gut is rebooted with beneficial bacteria from the appendix.

The theory that the appendix functions to reboot gut bacteria is consistent with more data than the theory that it is functionless. But even good theories are commonly in tension with at least some observations. If the appendix is so important, why can it be removed without killing a person? The explanation lies in the fact that widespread appendix removal coincided with the rise of modern medicine and public health practices. Rates of acute diarrhea have declined due to better sewer systems and safe water supplies. In addition, antibiotics and other medicines have greatly helped in the treatment of some formerly common causes of diarrhea. Less diarrhea means less dependence on the appendix to reboot the gut.

Is the theory that the appendix reboots gut bacteria true? That is a hard question to answer. A good scientist will be a little skeptical no matter how well a theory appears to explain the relevant data. We can never have all the data and, even if we did, there may still be multiple logical theories that explain it. What if Ockham’s razor is wrong and a more complex explanation is actually the correct one? How can we be absolutely sure that another scientist has not become so carried away by their worldview that they only recorded data consistent with it, dismissing other data as irrelevant or unimportant?

There are many reasons a theory may be wrong, but generally a theory that is consistent with logic and data, not ignoring data that are in tension with it, is a valuable starting point in understanding nature. The scientific method is not a way of proving a theory true in the same way that postulates can be used in a geometric proof. It is a way of testing a theory by seeing if hypotheses derived from it hold up under testing with experiments, analyzing the logic and comparing it to new data. The objective is not to prove the theory true, it is to discover how robust the theory is and, if it fails in some way, to replace it with a new theory that better explains the data.

At this point the scientific method may seem a little muddled, imprecise and confusing. This is because in practice it can actually be that way. A simplified diagram of how the scientific method works can be found in the figure below. Reality is never quite this simple.

The scientific method uses inductive reasoning to generate theories that explain data. Deductive reasoning is used to generate testable hypotheses that must be true if a theory is true. When the hypothesis is tested, it may fit well with the new data generated, thus supporting the theory (but not proving it true). If the hypothesis is inconsistent with data, then the theory is inconsistent with data and needs to be modified in some way, or completely replaced with a new more comprehensive theory.

 

 

Timothy G. Standish, PhD

Senior Scientist, Geoscience Research Institute


 

Footnotes

[1]Charles R. Darwin, The Descent of Man, and Selection in Relation to Sex 2d edition. (London: John Murray, 1882), p 21.
[2] Smith HF, Fisher RE, Everett ML, Thomas AD, Bollinger RR, Parker W. 2009. Comparative anatomy and phylogenetic distribution of the mammalian cecal appendix. Journal of Evolutionary Biology 22(10):1984-99. doi: 10.1111/j.1420-9101.2009.01809.x. Epub 2009 Aug 12).

 

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What Is Biology? Part 2 of 4

 

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Image Credit: clipart.co

 

Rules of Science:

 

If we embrace the metaphysical assumptions listed in the previous blog:

 

  1. The material world exists
  2. The universe is logical
  3. Our senses provide reliable information about the world
  4. Our minds allow us to understand at least some aspects of reality

 

There are still some rules that we have to follow if we are to do any science, including biology. The first is that empirical data is the authoritative test of all ideas in science. This reliance on empirical data differentiates science from belief systems like Atheism, Hinduism, Christianity or other religions. Many would argue that for atheists, human reason is the ultimate authority. Hinduism and Christianity also embrace reason, but in both cases the ultimate authority lies in books; the Vedas, Bhagavad Gita and other texts for Hindus, the Bible for Christians. Whether or not data, books, individuals or some other authority is used, interpretation is always necessary. If an interpretation is inconsistent with the authority it claims to be interpreting, it is generally rejected. So, if an explanation – commonly called a theory in science – is inconsistent with data, it is judged to be unscientific..

 

A second rule is honesty. Scientists can only report exactly what they observed; otherwise their conclusions will not be empirically based. The results of experiments must be reported exactly as they occurred. There is no such thing as “wrong data,” if it is an honest report of what was actually observed. Unfortunately, fabricated data can exist and may mislead other scientists.

 

The rules of logic must be used when interpreting data, but sometimes there are multiple equally logical interpretations. When explaining the origin of biological structures, Darwinists and Bible-believers logically interpret data differently. For example, the “arms” of a whale, frog, horse, lion, human and bird have essentially the same pattern of bones. Darwinists interpret this as evidence of a common ancestor because, within their worldview, it is best explained as the result of these animals inheriting a common genetic program for their body parts from a common ancestor. Those who believe one God created these diverse kinds of organisms may explain these common structures as the result of a common Designer, but also point out that generally speaking other potential limb designs are not as functional and that Darwinism does a questionable job of explaining the origin of limbs in the first place.

 

“Ockham’s razor” is a rule that scientists use to differentiate likely explanations from equally logical, but less probable explanations. It is named after a brilliant 14th Century English philosopher monk named William of Ockham. Ockham’s razor can be stated as, “The simplest explanation is the most likely to be true.” Scientists from the time of Aristotle until now have used this rule. Here is how Albert Einstein stated it:

 

“[T]he supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.”[1]


 

Timothy G. Standish, PhD

Senior Scientist, Geoscience Research Institute


 

Footnotes

[1]Albert Einstein “On the Method of Theoretical Physics” The Herbert Spencer Lecture, delivered at Oxford (10 June 1933); also published in Philosophy of Science, Vol. 1, No. 2 (April 1934), pp. 163-169, p. 165.

 

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What Is Biology? Part 1 of 4

Anemone and clown fish - cc Tim Sheerman-Chase

Anemone and clown fish – cc Tim Sheerman-Chase

 

Biology is the scientific study of life. But what is “science?” And what is “life?” Most of us use these words all the time and have a general idea of what we mean by them, however, it is common for scientists themselves to not have a clear understanding of what science is and this is not as surprising as it sounds. Philosophers of science struggle to define their own area of study, with different and incompatible ideas of exactly what is and is not science holding some sway. Defining life has proven to be equally enigmatic. Instead of definitions of life, it is common to settle on a set of characteristics that life exhibits. Having said that, there are major ideas about science and life that most scientists and other people agree on. In this series of blogs, we will examine science and metaphysics, rules of science, the scientific method, and finally how life is defined.

Science and metaphysics:

A common misconception is that science provides irrefutable explanations of reality that only the mentally unstable would question, but consider this recent quote from a paper about the reproducibility of published results in papers dealing with psychology:

“After this intensive effort to reproduce a sample of published psychological findings, how many of the effects have we established are true? Zero. And how many of the effects have we established are false? Zero. Is this a limitation of the project design? No. It is the reality of doing science, even if it is not appreciated in daily practice. Humans desire certainty, and science infrequently provides it… Scientific progress is a cumulative process of uncertainty reduction that can only succeed if science itself remains the greatest skeptic of its explanatory claims.” [1]

“The Thinker” Rodin Museum, Paris, France

Science is a way of gaining understanding of the natural world through the logical interpretation of information taken in through our senses. This sensory information is called “empirical data.” Commonly, machines like microscopes, thermometers, sound recorders and other technologies are used to extend our senses when collecting data.

Scientific knowledge has given us vaccines, antibiotics, men on the moon, abundant food and many other blessings. Most people agree that the scientific method is a powerful tool for understanding our world, but no one believes it is the only way of understanding. In fact, science can’t be done without making certain assumptions that are untestable using science. These are called “metaphysical assumptions” and they are purely philosophical. For example, to do science, it is assumed that information acquired through our senses accurately represents reality. That makes sense to most Western people, but it has been argued that what we take in through our senses is actually an illusion, not real at all. The Hindu Yoga Vāsistha puts it this way:

“Just as the world and its creation are mere appearances, a moment and an epoch are also imaginary, not real.” [2]

Four metaphysical underpinnings of science are:

  1. The material world exists
  2. The universe is logical
  3. Our senses provide reliable information about the world
  4. Our minds allow us to understand at least some aspects of reality

Each of these metaphysical underpinnings is consistent with the biblical worldview. The material world exists as a reality because the True God created it. God, who is the same “yesterday, today and forever” Hebrews 13:8 sustains the creation, so it is consistent and logical. God created humans with senses to perceive our world and encourages us to understand it with the minds He gave us.


 

Timothy G. Standish, PhD

Senior Scientist, Geoscience Research Institute


 

Footnotes

[1]Swami Venkatesananda (translator). 2010. The Supreme Yoga: Yoga Vasistha. Motilal Banarsidass Publishers Private Limited: Delhi, India. pg 47.
[2] Open Science Collaboration. 2015. Estimating the reproducibility of psychological science. Science 349(6251):943, aac4716-1-8. DOI: 10.1126/science.aac4716

 

Posted in Biology, Philosophical and Historical Perspectives | Tagged , , , , , , | 1 Comment

Mineralogy: A World of Law and Beauty

Amethist, a variety of quartz

Amethyst, a variety of quartz

When you think of minerals, you may think of the breakfast components you read on the back of the cereal box. This blog however, is a discussion about minerals like garnet, amethyst, diamond, emerald, ruby, sapphire, opal, topaz, turquoise, and many others. These gemstone minerals are beautiful because of the way they are cut, faceted, and polished, but minerals in their natural habitat can be quite beautiful as well.

This article will provide an introduction to mineralogy and outline the different mineral categories, discuss some interesting features about minerals, describe the formation of minerals in different environments, and mention some minerals referenced in the Bible. For those interested in additional information, and especially illustrations, hyperlinks are included below. Also, here are several related books and websites:

What is a mineral? It is a naturally occurring solid with a specific chemical composition and a distinctive internal crystal structure, in contrast to a rock that has a variable mixture of minerals. In the following discussion, chemical formulas will be given for some of the simpler minerals using the standard chemical abbreviations for the elements. A mineral’s chemical formula indicates which atoms are present in the mineral and in what proportions. For example, ice (H2O) contains hydrogen and oxygen in a two-to-one ratio.

Why is mineralogy important? Aesthetically, it is important because of the beauty of gemstones and because of a general interest in how the laws of nature work. Practically, it is of interest because minerals are the source of many natural resources and the extraction of minerals such as gold, silver, and copper goes back thousands of years.

Mineral Categories

Crystal systems. Mineral crystals can be categorized into several systems based on their symmetry properties with respect to a plane or axis; a plane of symmetry divides a crystal into two mirror images; whereas, an axis of symmetry is a line about which the crystal can be rotated by 180° (diad), 120° (triad), or 90° (tetrad) to give a replica of itself. The six crystal systems in order of decreasing symmetry are: isometric/cubic (4 triad axes), trigonal/hexagonal (1 triad axis), tetragonal (1 tetrad axis), orthorhombic (3 diad axes or 1 diad axis and two planes), monoclinic (1 diad axis and/or 1 plane), and triclinic (no axes or planes). Common minerals exemplifying each of these systems are: isometric garnet, trigonal tourmaline, hexagonal emerald, tetragonal zircon, orthorhombic topaz, monoclinic micas and clays, and triclinic turquoise.

Groups. In the 1800s, minerals were classified into groups by the Christian geologist, James Dwight Dana; these groupings are still used today. The native elements include gold and copper. The sulfides include iron sulfide (pyrite) better known as fool’s gold. The sulfates include gypsum (CaSO4) commonly used for plaster board. Common examples of the oxides are hematite (Fe2O3), an ore mineral for iron, and magnetite (Fe3O4), which is easily identified because it acts as a magnet. Ice (H2O) is perhaps the most common example of an oxide mineral at the surface of the earth.The halides are salts with the most common being halite (NaCl).

The largest group of minerals is the silicates, since silica is to the inorganic world what carbon is to the organic world. Silicon is the significant element because it forms four bonds just as carbon does. The resulting silica tetrahedra can form 3D networks, sheets, chains, rings, double tetrahedra, and independent tetrahedra. Minerals consisting of 3D silica networks are some of the most common and include quartz and the feldspars. Minerals made up of silica sheets include the micas, clay, and talc (as used in talcum powder). An example of a silica ring mineral is beryl.

The different silica bond structures have increasing densities with increasing oxygen-silicon ratios as follows: 2 for networks, 2.5 for sheets, 2.75 for double chain amphiboles such as hornblende, 3 for single chain pyroxenes such as augite, 3 for rings, 3.5 for double tetrahedra, and 4 for independent tetrahedra. The densities are significant because the higher density forms crystallize under the high pressure conditions deep in the mantle of the earth; whereas the lower density forms crystallize in the lower pressure conditions in the crust. The ratios are important because the low ratio networks have a high viscosity in lavas which trap gases that can be explosive and result in volcanoes like Mt St Helens; the high ratio independent tetrahedra have a low viscosity in lavas which can flow much more easily, as from Hawaiian volcanoes.

Non-crystalline substances. Some substances similar to minerals do not have definite compositions and crystal structures, but are often discussed in association with the minerals. Amorphous glasses and gels form when a melt is cooled too rapidly to form crystals. Pearl is formed by clams. Amber is formed from tree sap.

Identifying Minerals

Many guides are available for an amateur wanting to identify and collect different minerals in nature. Some simple mineral characteristics used for identification are color and streak, hardness, luster, cleavage and fracture, habit, density, twinning, and mineral association.

At times color can be diagnostic, e.g., yellow sulfur, silver galena, purplish iridescent bornite, pistachio green epidote, and green or blue copper minerals such as malachite, azurite, and chrysocolla. In some cases color is due to impurities and is not diagnostic; for example, quartz can occur in many colors; however, when the streak is colored, it is generally not due to impurities.

Hardness can be a useful diagnostic property with the use of Mohs scale of hardness which classifies minerals according to how easily they can be scratched — talc (1), gypsum (2), calcite (3), fluorite (4), apatite (5), orthoclase feldspar (6), quartz (7), topaz (8), corundum (9), and diamond (10). For comparison, a fingernail is 2½ and a pocket knife is 5½. Those with a hardness of 1 feel greasy and those with a hardness of 6 and over will scratch glass.

Luster can be distinctive for metallic pyrite, vitreous biotite, and resinous sphalerite; chatoyant tiger’s eye is an especially spectacular luster with luminous bands of light that appear to move as the specimen is rotated. Octahedral cleaveage is diagnostic for fluorite and conchoidal fracture (like a broken pop bottle) is typical for quartz. Habit can be diagnostic for columnar tourmaline, fibrous asbestos, prismatic actinolite, foliated mica, and dendritic pyrolusite (MnO2). A high density is noticeable for galena. Twinning is especially useful for identifying staurolite “fairy crosses” and in distinguishing between orthoclase and plagioclase feldspars.

Other features useful for identifying some minerals are magnetic properties for magnetite, radioactivity for uraninite, fluorescence for scheelite, taste for halite salt, birefringence for calcite, and the hydrochloric acid test for calcite and other carbonates. Birefringence for calcite is displayed when a clear crystal is available, in which case two duplicate images can be seen when viewed through the crystal (see hyperlink for example). The acid test on carbonates results in the liquid fizzing like soda pop. The chemical reaction is CaCO3 + 2HCl à CaCl2 + H2CO3 with the carbonic acid breaking up into water and the carbon dioxide that causes the fizzing.

For the identification of some minerals, especially small ones, their observation in thin sections under a petrographic microscope is required. Such observations add several identifying characteristics as the mineral is rotated between two polarizing filters. Some minerals such as garnet remain dark during rotation; whereas, others show distinctive interference colors and become dark (extinguish) at 90° intervals upon rotation. Refractive index (or relief) is high for zircons and apatite in comparison with quartz and feldspar. The extinction angle (or angle at which the mineral becomes black), which is the angle between crystallographic direction and extinction, can be diagnostic between amphiboles and pyroxenes. Color (pleochroism) can change during rotation of the stage with respect to one polarizing filter.

The most common minerals in granitic rocks are quartz, potassium feldspar, plagioclase, biotite, and hornblende. These can usually be distinguished on a fresh surface in a hand sample, especially with a hand lens. Quartz is translucent white with conchoidal fracture (like a broken pop bottle). Potassium feldspar is often pink; whereas, plagioclase is white. Biotite mica is vitreous black and is sheeted. Hornblende is prismatic black.

Interesting Mineral Features

Polymorphism and Varieties. Some minerals have a single composition with a variety of forms. At low temperature, carbon forms graphite as used in pencil “lead” and in lubricants, but at high temperatures and pressures 100 km deep in the earth carbon forms diamonds instead. White prismatic andalusite, bladed blue kyanite, and white fibrous sillimanite are metamorphic minerals that occur at increasing temperatures and pressures, but with the same composition (Al2SiO5). Corundum has a unique chemical formula (Al2O3), is next in hardness to diamond, and is used as an abrasive; sapphire and ruby are two gemstones with the same composition, but with a significantly different appearance.

Perhaps the widest variety of forms occurs for silicon dioxide (SiO2) or quartz, with some of the more common varieties mentioned here. Amethyst is purple quartz that contains some manganese impurities. Citrine is yellow quartz. Chalcedony forms at low to moderate temperatures. Agate is a banded form of chalcedony formed by intermittent deposition in cavities, with a geode being a typical example. Onyx is agate banded in dark and light planes. Jasper is an opaque red chalcedony. Chert and flint, once used as cutting tools, are light to dark gray massive opaque chalcedony. Silicified wood is wood replaced by silica. Yellow brown tiger’s eye forms when silica replaces asbestos, but the fibrous structure is retained. Common glass is just amorphous quartz. Opal is an amorphous form of quartz containing 3-10% water and often displaying a rich iridescent play of colors.

Twinning. Sometimes when minerals crystallize, two crystals grow together as twins. A classic example is staurolite, where the two crystals cross at 60° or 90° forming fairy crosses. Orthoclase feldspar twins by the Carlsbad law to form two parallel crystals easily distinguished in granite in bright sunlight. Plagioclase feldspar twins by the albite law forming striations in microscope thin sections. In microcline feldspar, the albite and pericline laws combine to form two sets of perpendicular twins displaying a diagnostic grid structure in microscope thin sections.

Substitution. Often minerals do not have an exact composition because different atoms can substitute for each other in the crystal lattice. This occurs when two atoms have the same ionic charge and radius. In solid solutions, the components may vary in a predictable way; for example, iron and magnesium may substitute for each other in olivine, (Fe,Mg)2SiO4.

The feldspars provide the typical example of substitution. Since they are the most abundant of all minerals, here is a brief description of them in granitic rocks. Calcium feldspar or anorthite (CaAl AlSi2O8) grades into sodium feldspar or albite (NaSi AlSi2O8) which can grade into potassium feldspar or orthoclase/microcline (KSi AlSi2O8). The calcium-sodium feldspar solid solution series, where NaSi substitutes for CaAl, is generally known as plagioclase with the different percentages of sodium being given different names: 0-10% as anorthite, 10-30% as bytownite, 30-50% as labradorite, 50-70% andesine, 70-90% as oligoclase, and 90-100% as albite. The sodium-potassium feldspar solid solution series is more complicated and only occurs at high temperatures; at temperatures below about 600°C the two forms are unstable during slow cooling and separate to form parallel lamellae. An increasing amount of sodium and potassium and a decreasing amount of calcium generally indicates a more evolved magmatic system that has gone through more stages of melting and crystallization.

In garnet minerals (Fe,Mg,Mn,Ca)3Al2(SiO4)3, where iron, magnesium, manganese, and calcium atoms substitute for each other, aluminum can be replaced by the rare earth elements. Aluminum is preferentially replaced by the large ionic radius lanthanum at low pressures and the small ionic radius ytterbium at high pressures. The difference in replacement between lanthanum and ytterbium can be as much as a factor of one thousand and can be used to suggest the pressure at the source depth of granitic magma. Granitic rocks that have a high lanthanum/ytterbium ratio come from deep-source magmas that retained more lanthanum, but left the ytterbium behind in garnet. Granitic rocks that have a low lanthanum/ytterbium ratio come from shallow-source magmas that retained more ytterbium. Similarly, the amount of aluminum versus silicon in hornblende can be used to estimate the depth of crystallization of the mineral.

The potassium-40 isotope of the element potassium is radioactive and can be used in potassium-argon age dating. Several common minerals containing potassium that can be used for age dating are biotite mica, hornblende, and potassium feldspar. Rubidium-87 is another radioactive isotope; since rubidium has very similar chemical properties to potassium, it substitutes for potassium in the above minerals and can be used for rubidium-strontium age dating. Uranium and thorium substitute for zirconium in the zircon mineral (ZrSiO4) and for yttrium in xenotime and monazite (YPO4), so these minerals can be used for uranium/thorium-lead age dating.

Mineral Formation

Minerals form in several different types of environments: igneous from hot liquid magma, sedimentary from water solutions, and metamorphic in hot plastic rock.

Igneous Environment. Many minerals crystallize from liquid magma to form igneous rocks. The most common are the silicates — olivine, pyroxenes, amphiboles, micas, the feldspars, and quartz. These are in order from the first to form peridotite rocks at the highest temperatures and pressures in the mantle, to the intermediate gabbros in the lower crust, to the last-to-form granitic rocks at lower temperatures and pressures in the upper crust.

Slow growth of crystals due to slow cooling of magma in underground magma chambers yields larger crystals than those formed above ground due to rapid cooling of volcanic rock. However, volcanic rock can have two crystal sizes due to two stages of cooling — slow cooling underground yielding large crystals and later rapid cooling of the remaining lava after eruption to give a matrix with unobservable crystals.

The final liquid magma to crystallize yields pegmatites, often as dikes in rock fractures. These pegmatites often include exotic minerals like tourmaline, beryl, and lepidolite (lithium) mica because they contain all the left over elements that do not fit in the standard minerals. High water content such as in pegmatites also enables larger crystal growth. The final hot liquids can ascend from a magma chamber into the surrounding country rock through veins, yielding hydrothermal ore deposits with unique minerals such as those in copper deposits.

Sedimentary Environment. Precipitates and evaporite minerals can form in a sedimentary environment. Precipitates would include secondary quartz varieties such as agate and calcite precipitating from fluids moving through the sediment. Evaporite minerals such as halite and gypsum form from saline water bodies as the water evaporates and leaves the salts behind.

Metamorphic Environment. Many unique minerals form at higher pressures and temperatures than experienced in a sedimentary environment, but not as high as an igneous environment. The types of metamorphic minerals that form are determined by pressure, temperature, and chemistry, so that mineral assemblages can indicate the pressure/temperature conditions of formation. Typical metamorphic minerals include: sillimanite, staurolite, talc, serpentine, chlorite, garnet, actinolite, and epidote. The igneous minerals, albite, potassium feldspar, and biotite, also form under metamorphic conditions.

Minerals in the Bible

A number of minerals are mentioned in the Bible, although it is not always clear from the ancient Hebrew and Greek words exactly which of today’s known minerals are being referred to. Sulfur is referred to as brimstone (e.g., Gen 19:24; Isa 34:9; Rev 9:17). Other Bible examples include the minerals in the high priest’s breastplate (Ex 28:15-20; sardius, topaz, carbuncle, emerald, sapphire, diamond, jacinth, agate, amethyst, beryl, onyx, and jasper) and the foundations of the New Jerusalem (Rev 21:19-21; jasper, sapphire, agate, emerald, onyx, carnelian, chrysolite, beryl, topaz, chrysoprase, jacinth, and amethyst). According to tradition, the tablets of stone for the Ten Commandments are made from sapphire or lapis lazuli (see Ex 24:10,12; Eze 1:26; 10:1; Rev 4:3).

King Solomon’s copper mines with chalcocite, chrysocolla, and malachite are associated with granitic and sedimentary rocks at Elat and Timna in southern Israel. This area, where dozens of old furnaces to smelt copper have been found, may be the oldest location for copper production in the world. Originally the mines were thought to have been worked by the Egyptian empire in the 14th to 12th century BC using metal chisels and hoes to excavate tubular shafts to as deep as 30m. More recent radiocarbon dating suggests that the age is the 11th to 9th century BC during the time of David and Solomon.

The beauty, variety, and order in the mineral kingdom display some facets of God’s character and his laws for governing the world. The Bible speaks of the difficulties of finding gold, silver, iron, copper, onyx, sapphire, and topaz in dark mines underground, but notes that wisdom can be even harder to find, for it is in the fear of the Lord (Job 28).

 

Benjamin L. Clausen

Geoscience Research Institute

Loma Linda, CA

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Is Homo naledi your “relative,” “ancestor,” or “part of the human family tree”?

On September 10 2015, an open-access article on the journal eLife (downloadable at http://elifesciences.org/content/4/e09560) presented to the scientific community the newest addition of a species to the hominid fossil record: Homo naledi [1] (Fig. 1). A well-orchestrated unveiling of the discovery included release of an almost 2-hours long documentary produced by PBS and National Geographic entitled “Dawn of Humanity” and the classic amplification by major media outlets of the sensational finding.

F1.large

Figure 1: The fossil material used to establish the new Homo naledi species This view is foreshortened; the table upon which the bones are arranged is 120-cm wide for scale.
See more at: http://elifesciences.org/content/4/e09560#sthash.ieLGn8Va.dpuf

The fossil material described in the paper is indeed remarkable for several reasons. First and foremost, the sheer number of skeletal and dental remains recovered (over 1500, with scores more waiting to be excavated from the same site) makes this “the largest collection of a single species of hominin that has been discovered in Africa so far” [2]. A minimum of 15 individuals is represented in the assemblage, spanning different age groups, from infant to old adult. The remains are fairly well preserved, with some breakage and superficial abrasion, and are generally disassociated except in a few notable cases (e.g., the bones of a hand and those of a lower limb still in articulation) (Fig. 1). The second aspect triggering attention in the news is the mixture of human-like and australopithecine-like anatomical traits exhibited by different recovered parts (e.g., “human-like hands and feet” and “australopith-like pelvis”[3]). Finally, the context in which the fossils are preserved is also extremely intriguing. The remains were found in the top 20 cm of fine sediment covering the floor of a deep chamber in a cave system (called Rising Star) near Johannesburg (South Africa), presently accessible only through narrow passages (down to 20-cm in diameter) with vertical drops of more than 10 m (Fig. 2). It does not appear that the cave chamber had different accesses in the past nor that water transported the remains in the chamber. In addition, the assemblage consists exclusively of hominid remains, with no remains of other animals mixed in (with the exception of the bones of an owl and a few rodent teeth). This setting has led to speculation that the carcasses might have been intentionally disposed in this deep, completely dark recess, as discussed in an accompanying paper on eLife (downloadable at http://elifesciences.org/content/4/e09561) [4].

cave diagram1

Figure 2: Cross-sectional view of the rising star cave,
indicating the site where fossils were found.
http://elifesciences.org/content/4/e09561#F2

For those who treasure knowledge, science, and the Word of God, discoveries like this always elicit an ambivalent reaction. We are excited for a new piece of evidence brought back from the past but saddened in seeing it invariably presented to the masses with an unfiltered endorsement of Darwinian evolution. For example, in the space of a few paragraphs a CNN piece on Homo naledi [5] uses expressions like “new species of human ancestor,” “a new addition to our family tree,” and “new species of human relative.” The implicit message in this use of language is that humans are not the result of an intentional act of divine creation but are just one of the many branches of the tree of universal common descent from ancestral forms. This view contrasts with the alternative model of God creating distinct types (including humans) that might have modified with time. Language is a powerful tool that can be used to advocate specific interpretations of data. Generally, however, data themselves can be compatible with multiple hypotheses. The aim of this blog is to use the example of Homo naledi to illustrate the distinction between data and interpretations, and to discuss some of the questions a biblical creationist might have in relation to this new discovery.

Understanding the limitations of data

The Homo naledi fossil assemblage is an excellent example of the limitations intrinsic to the practice of historical sciences. We can only work with what is preserved and available, and build plausible scenarios based on the most logical inference, excluding unsupported hypotheses. Here are a few examples to illustrate the point:

1) Completeness. In terms of quantity of fossil remains and representation of different body parts from one single site, the discovery at Rising Star cave is very impressive. However, even amidst this abundance, the record is still fragmentary. For instance, remains of at least 15 individuals have been recovered so far, but only five partial crania and a few other cranial fragments are represented. Some parts of the cranium are not preserved or are documented only by one specimen. Given these limitations, traits that are presented as diagnostic for the Homo naledi skull are still based on a relatively limited database. The paper specifies that when different specimens preserve the same part of the cranium, they “agree closely in all morphological details” [6]. However, it also mentions exceptions, where differences between crania are interpreted “as related to sex” [6], that is due to variability between male and female individuals. Unfortunately, the paper does not provide a detailed discussion of the hinted differences.

2) Figures. It is important to understand the way in which some quantitative information is obtained from fossils. For example, in Table 1 of the paper [7] the cranial capacity (a measure of brain size) of Homo naledi is indicated as 513cc. In the methods section of the paper a good explanation is offered of how this figure was obtained. The process involved merging two sets of cranial remains on two different 3D models, interpolating areas where no data were available, and then making an average between the two calculated volumes (Fig. 3). This process of calculation gives a fair indication of the average brain size that seems representative of at least 4 individuals, but it is not a number obtained from direct measurement of a complete specimen. Another example is the estimate of body mass. The paper estimated the body mass of Homo naledi from bones of eight individuals, obtaining a range between 39.7 kg and 55.8 kg [8]. These numbers were calculated by measuring the breadth of femur bones at standard locations and applying to the measurements a regression equation based on modern human samples, where the body mass and femoral breadth of human individuals can be accurately established and correlated. This is standard procedure, but it is clear that the estimated body mass will vary if different modern human samples are used as reference and depending on the specific femoral measurements used. For example, using one of the same measurements adopted in the paper [9] but with a regression equation based on a different human sample [10] a range between 33.09 kg and 40.05 kg is obtained, which is less than the body mass values presented in the paper. Moreover, the assumption that the correlation between femoral breadth and body mass in modern humans is the same as in anatomically different fossil hominids is obviously not testable and probably an approximation at best.

F3

Figure 3: The two reconstructed crania of Homo naledi, viewed from the side (left) and from the top (right). The darker shaded area in both reconstructions is the endocranium (outer surface of the brain). A): composite formed from specimens DH3 and DH4. This is the smaller virtual cranium, with an estimated cranial volume of 465 cm3. Scale not provided in the original image. B): composite formed from specimens DH1 and DH2. This is the larger virtual cranium, with an estimated cranial capacity of 560 cm3. Scale bar in cm. Image credit: Berger et al. 2015, available at http://elifesciences.org/content/4/e09560

3) Attribution. Because most of the remains were not found in articulation (but see an exception in Fig. 4), it is difficult to establish which bones belong to the same individual. Paradoxically, if only one skeleton had been represented in the assemblage, even partial remains could have been used for direct measurement of actual body proportions. Having abundant disassociated material allows for a better understanding of the range of morphological and size variability in a population, but reconstructions of body proportions can be more complicated. Another possible complication with disassociated remains could be treating a mixture of two distinct types of hominid (e.g., one more human-like another more australopith-like) as if they belonged to one single type. The authors of the paper make a good case to exclude this possibility. They note that “in all cases where elements area repeated in the sample, they are morphologically homogeneous, with variation consistent with body size and sex differences within a single population” and that “distinctive morphological configurations,” including “traits not found in hominin species yet described,” are identical in the recovered specimens. Their conclusion is that “these considerations strongly indicate that this material represents a single species, and not a commingled assemblage” [11]. However, even if this reasoning is indeed compelling, the theoretical possibility of mixing of two types remains, and was indicated in commentaries of the discovery by renowned paleoanthropologists Jeffrey Schwartz (University of Pittsburgh) and Ian Tattersall (American Museum of Natural History) [12].

F4

Figure 4: The bones of this hand are one of the notable exceptions where Homo naledi remains were found in articulation. A) View from below (left) and above (right) of the assembled hand bones. Scale bar in cm. B) View of the articulated hand bones during excavation. Image credit: A) Berger et al. 2015, available at http://elifesciences.org/content/4/e09560; B) Dirks et al. 2015, available at http://elifesciences.org/content/4/e09561#F2

4) Behavior. A final demonstration of the gap between data and interpretations relates to the setting in which Homo naledi fossils were found. The remoteness of the cave chamber (Fig. 2) and the fact that only hominid remains were found there has resulted in the assertion that this is an example of intentional disposal of carcasses. However, this scenario is only a possibility and cannot be established with certainty. In fairness to the authors, their conclusions acknowledge that other scenarios are possible: “Both the mass mortality or death trap scenario […] and deliberate disposal hypothesis are considered plausible interpretations and require additional investigation,” although the authors do express a preference for the deliberate body disposal inference [13]. Unfortunately, the caution and balance expressed in the paper did not translate in the remarks made by the authors to the media, where biased statements like these were released: “We have just encountered another species that perhaps thought about its own mortality, and went to great risk and effort to dispose of its dead in a deep, remote, chamber” [14]; “We can tell that this wasn’t a social group that died through some sort of catastrophe in the cave” [15]; “We have, after eliminating all of the probable, come to the conclusion that Homo naledi was utilising this chamber in a ritualised fashion to deliberately dispose of its dead” [16]. Claims of ritualistic behavior, thoughts about own mortality, and assertive exclusion of the mass mortality scenario of a social group not only represent a stretching of the available evidence but in the latter case are also in plain contradiction with the conclusions of the paper.

The Homo agenda

The word Homo carries high significance, because it is part of the scientific name of humans. If an extinct type is placed within the genus Homo, it means that it shares closer similarity to humans than to any other known group of organisms, including australopithecines. Therefore, the choice of a name is not just a trivial technicality but conveys a sense of how the discoverers of a fossil would like it to be perceived. For evolutionists, something called Homo automatically takes a certain place in the alleged evolutionary sequence from australopithecines to humans. For creationists, something called Homo automatically falls within the morphological variations of a certain original created type. Both groups would want to avoid calling Homo something that is not.

The discoverers of the Raising Star cave fossils had to address two questions when choosing how to name the remains: 1) do these fossils represent a new type? 2) If so, to what is it most similar? By choosing the name Homo naledi, they answered the first question in the affirmative, and suggested humans as the answer to the second question. Although this choice might be legitimate, it is important to understand that it represents a specific interpretation of data and that other interpretations may suggest different conclusions to both questions. On the subject of this being a different type, for example, paleoanthropologist Tim White (University of California, Berkeley) considers, at an early stage of assessment, that these remains could be included within the variability of the already established species Homo erectus [17].

On the choice of the attribution to the genus Homo, the authors base their decision on human-like anatomical aspects described from the lower limb, hand, and teeth, as well as on the general shape of the cranium [18]. However, emphasis is deliberately placed on these characters while many other skeletal traits (e.g., pelvic area, shoulder region, ribcage) are more australopith-like than human-like. Estimated brain size, for example, is not only small in absolute value when compared to modern humans but also its relative proportion to estimated body mass (a measure known as encephalization quotient) is about half that of modern humans and similar to that of australopithecines [19]. In some of the presentation of the results, it seems that the authors of the paper wanted to deliberately emphasize a link with humans rather than australopiths. For example, the paper states that “H. naledi has a range of body mass similar to small bodied human populations” [20], but an equally true statement would have been that the range of body mass for H. naledi is similar to body mass estimated for large australopiths [21]. The emphasis on intentional disposal of cadavers is also framed as a supportive argument to highlight behavioral complexity currently seen only in humans. In theory, attribution of fossil remains to a genus should be based on statistical treatment of different skeletal and dental measurements that unequivocally group specimens with distinct anatomical traits. In practice, the procedure is complicated by the lack of agreement on which skeletal traits should be considered diagnostic for Homo and by the fragmentary nature of the fossil record [22].

Human evolution: A linear progression or a tangled mess?

One of the most significant aspects emerging from the study of Homo naledi is its combination of anatomical features, some more similar to Australopithecus, others to Homo. This mosaic distribution of characters is seen at the level of the whole skeleton, with the trunk, shoulder, pelvis, and proximal femur being australopith-like and the lower limb and dentition being more human-like. However, mosaicism is also apparent in specific regions of the skeleton. For example, the hand shows an overall Homo-like morphology in the wrist bones but relatively long and markedly curved fingers (Fig. 4) . Teeth are small, like in humans, but with molar size proportions found in australopiths. Skull shape is more rounded, like in Homo, but cranial capacity and encephalization quotient are small, as for australopiths. A similar mosaic distribution of characters has been documented in other fossil hominids, such as Australopithecus sediba [23] and Homo floresiensis [24].

In addition to the mixture of skeletal traits observed at the level of an individual skeleton, recent discoveries from eastern Europe have revealed that a suprising amount of morphological variability was also present among different individuals within the same hominid population [25]. When considered together, these findings present a significant challenge to the classic scenario of sequential human evolution, popularized by the iconic procession of silhouettes gradually rising from ape-like to human stance. No simple, congruent, linear trajectory can be established for the development of individual human skeletal traits (Fig. 5) . On the contrary, human-like functional complexes appear with almost “random” distribution in conjunction with australopith-like characters in different organisms and among individuals in the same population. This paradigm shift is being acknowledged in important review papers. Antón et al., for example, maintain that “dynamic environments favored evolutionary experimentation and the coupling and uncoupling of biological variables, which governed against any simple transition from Australopithecus to Homo[26]; they also talk of “intriguing shuffling of derived and plesiomorphic traits and biological variables that likely characterized the early evolution of Homo[27], meaning a puzzling mixture of modern and primitive traits from an evolutionary perspective. Similarly, Schwarz & Tattersall, conclude that “in contrast to Mayr’s austere linearity, we may find that human evolution rivaled that of other mammals in its evolutionary experimentation and luxuriant diversity” [28]. Words such as “intriguing,” “experimentation,” “shuffling,” and “luxuriant diversity” are strong indicators of a new unexpected trend and an implicit acknowledgement of how little is really known with precision about certain aspects of the hominid fossil record.

Fig. 5: Crania attributed to different species of Homo illustrate the concept of mosaic distribution of characters. Several anatomical features (indicated with their technical name in the figure) appear with different combinations in the different specimens. Image credit: Stringer 2015, available at http://elifesciences.org/content/4/e10627

Fig. 5: Crania attributed to different species of Homo illustrate the concept of mosaic distribution of characters. Several anatomical features (indicated with their technical name in the figure) appear with different combinations in the different specimens. Image credit: Stringer 2015, available at http://elifesciences.org/content/4/e10627

What could be the origin of this variability and mosaic distribution of characters in fossil hominids? As is often the case in historical sciences, only suggestions can be made. However, Antón et al. hint at three possible processes: 1) morphological and developmental plasticity related to environmental conditions. For example, availability of food and low risk of mortality can extend growth and delay puberty in humans, resulting in larger body size and slower maturation; 2) hybridization between different groups, meaning the generation of offspring from individuals belonging to distinct types that can interbreed; and 3) vicariance, meaning diversification of groups as a result of isolation due to migration or geographical barriers [29]. It is interesting to realize that these same mechanisms would work very well also within a creationist framework, where australopith and human types would be expected to diversify in a post-flood dispersal.

There is a final important corollary of the pattern of mosaic distribution of traits that needs to be highlighted. As pointedly remarked by Berger et al., because of the non-predictable combinations of characters apparent in different fossil hominids “we must abandon the expectation that any small fragment on the anatomy can provide singular insight about the evolutionary relationship of fossil hominins” [30]. In other words, a reconstruction of alleged evolutionary relationships built on comparisons of just one element (e.g., the cusps of a tooth, the shape of a mandible, the prominence of a brow ridge) would lead to contradictory results if entire skeletons were available.

Lessons to learn

The publicity given to the H. naledi discovery will certainly raise questions on the subject of human origins. This great opportunity for deeper reflection on the subject will be beneficial if misconceptions can be avoided. Here are some important points that should be considered by and for those sharing a creationist perspective:

1) Is Homo naledi the “missing link” between australopithecines and humans? Irrespectively of what the media would like us to believe, the answer is no. First of all, the Homo naledi fossils have not been dated and their stratigraphic placement is unknown. They could very well be a relatively recent hominid group, therefore irrelevant in the alleged evolutionary emergence of Homo. Even if their stratigraphic position was determined to be between australopithecine and Homo fossils, H. naledi does not present a transitional arrangement of morphological traits, but, as we have seen, a mosaic combination, therefore not exemplifying a hypothetical pathway of gradual sequential changes expected in Darwinian evolution. A most significant gap still remains in the fossil record of hominids, making the transition from australopithecines to humans an interpretation of very scanty data.

2) What was H. naledi? A human or an australopith? As discussed earlier, this is a matter of interpretation. Probably, creationists will be inclined to see it as an australopith-type variant, especially in light of its small brain size, with adaptations for bipedalism and diet-driven modifications in dentition [31]. The reality is that we just don’t know. There are several viable options from a creationist perspective. H. naledi could be a hybrid between two types, a different type of primate, or an environmentally-driven variant of either the australopith-type or the human-type.

3) What was H. naledi not? A new discovery is also an excellent opportunity to remind what has NOT been discovered. H. naledi is not an anatomically modern human. So far, we have not discovered remains of modern-looking humans except toward the very top of the geologic column. H. naledi is not a giant human fossil. Unfortunately, hoaxes about giant human fossil discoveries continue to be popular among well-meaning but poorly informed Christians [32], and great skepticism should be exerted when presented with some sensational news on the topic. H. naledi is not likely to represent an antediluvian fossil. Its deposition within the surficial sediments of a cave places its existence at the very end of the sequence of geological events that formed the present landscape.

4) What larger lessons can be learnt from this amazing discovery? Certainly, the most instructive lesson is that every seeker of knowledge will always benefit from a clear understanding of the difference between data and interpretations. Biblical creationists need to be aware of the powerful philosophical presuppositions at work when presenting new discoveries, often rooted in an evolutionary worldview. This might lead to intentional or unintentional bias in the presentation of results or in the popularization of their implications. As we sharpen our critical eye, we should continue to work confidently towards the construction of models that are compatible with a biblical worldview, maintaining a humble attitude in areas of incomplete understanding.


Ronny Nalin, PhD

Geoscience Research Institute


Footnotes

[1] Berger, L.R., et al., Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife, 2015. 4.

[2] Ibid., p.3.

[3] Ibid., pp.3,24.

[4] Dirks, P.H., et al., Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa. eLife, 2015. 4.

[5] McKenzie, D. and Wende, H., Homo naledi: New Species of Human Ancestor Discovered in South Africa. CNN, September 10, 2015, http://www.cnn.com/2015/09/10/africa/homo-naledi-human-relative-species/.

[6] Berger et al., p.6.

[7] Ibid., p.11.

[8] Ibid., p.18.

[9] AP subtrochanteric breadth, Table 3, p.18 of Berger et al.

[10] Grabowski, M., Hatala, K. G., Jungers, W. L., & Richmond, B. G., Body mass estimates of hominin fossils and the evolution of human body size. Journal of human evolution, 2015. 85, 75-93.

[11] Berger et al., pp.4,5.

[12] As reported in Barras, C., New species of extinct human found in cave may rewrite history. New Scientist, September 10, 2015, https://www.newscientist.com/article/mg22730383-700-new-species-extinct-human-found-in-cave-may-rewrite-history/.

[13] Dirks et al., p.30.

[14] Reported in McKenzie and Wende.

[15] Reported in Johnson, M.A., and Jackson, H., ‘Mind Blown’: Is Human Ancestor Discovery the Long-Sought Missing Link? NBC News, September 10, 2015, http://www.nbcnews.com/science/science-news/mind-blown-human-ancestor-discovery-long-sought-missing-link-n425406.

[16] Reported in Sample, I., Homo naledi: new species of ancient human discovered, claim scientists, The Guardian, September 10, 2015, http://www.theguardian.com/science/2015/sep/10/new-species-of-ancient-human-discovered-claim-scientists.

[17] Reported in Sample and in Hartley, R., Some bones to pick, Times Live, September 18, 2015, http://www.timeslive.co.za/thetimes/2015/09/18/Some-bones-to-pick.

[18] Berger et al., p.23.

[19] Using the body mass and brain size estimates of Berger et al. and data end equations in Ruff, C.B., Trinkaus, E. and Holliday, T.W. (Body mass and encephalization in Pleistocene Homo. Nature, 1997. 387, 173-176) the estimated encephalization quotient for H. naledi is about 2.4, whereas for modern humans it is about 5.3.

[20] Berger et al., p.18.

[21] For example, when the same equations and measurement types used to estimate body mass in Berger et al. are applied to AL 333-131 (a femur bone of Australopithecus afarensis) the value obtained is ~61kg, which exceeds all the body mass estimates for H. naledi. Using multivariate statistical analysis, Grabowski et al. calculate average male mass for A. afarensis as 49.5 kg, which also overlaps with the estimates for H. naledi.

[22] See, for example, Schwarz, J.H. and Tattersall, I., Defining the genus Homo. Science, 349/6251, pp.931-932.

[23] Berger, L. R., de Ruiter, D. J., Churchill, S. E., Schmid, P., Carlson, K. J., Dirks, P. H. and Kibii, J. M., Australopithecus sediba: A new species of Homo-like australopith from South Africa. Science, 2010. 328/5975, pp.195-204.

[24] Brown, P., Sutikna, T., Morwood, M. J., Soejono, R. P., Saptomo, E. W. and Due, R. A., A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature,2004. 431/7012, pp.1055-1061.

[25] Lordkipanidze, D., de León, M. S. P., Margvelashvili, A., Rak, Y., Rightmire, G. P., Vekua, A. and Zollikofer, C. P., A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo. Science, 2013. 342/6156, 326-331.

[26] Antón, S. C., Potts, R., and Aiello, L. C., Evolution of early Homo: An integrated biological perspective. Science, 2014. 345/6192, p.1236828-10.

[27] Ibid.

[28] Schwarz and Tattersall, p.932.

[29] Antón et al.

[30] Berger et al., p.23.

[31] This is, for example, the position taken by E. Mitchell on an Answers in Genesis blog on the H. naledi discovery: Is Homo naledi a New Species of Human Ancestor? September 12, 2015, https://answersingenesis.org/human-evolution/homo-naledi-new-species-human-ancestor/

[32] The latest fabrication to which I was recently pointed by a friend, who had some hopes of its credibility, can be found at http://worldnewsdailyreport.com/5-meter-tall-human-skeleton-unearthed-in-australia/

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