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



[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

Posted in Geology | Tagged , , , , , , , , | Leave a comment

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.


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.

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.


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].


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


[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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Conserving Island Earth

The world must have seemed like a big place to Helga Estby, a Norwegian woman who walked across America in the year 1896. Helga immigrated to the United States with her parents in 1871 at the age of 11. On May 5, 1896, at the age of nearly 36, Helga and her 18 year old daughter Clara set out to walk across the United States. They started from Mica Creek, in far eastern Washington state, and walked an estimated 3500 miles to New York City, where they arrived on December 24. The mother and daughter may have been the first to walk intentionally across the United States on foot. Since then, numerous people have repeated the feat, usually requiring from five to seven months. From the point of view of a person living in 1896, the world would seem big and its resources virtually unlimited. But this view has changed.

We now recognize the world is not so big, and its resources very definitely are limited. Part of the credit for this comes from a photo known as “The Blue Marble.” On December 7, 1972, the Apollo 17 crew took a photograph of our planet, showing it to be a blue island in space. That photo has become known as “The Blue Marble.” Although it was not the first photo of the earth from space, it captured the attention of the American public in an unprecedented way. The photograph coincided with a surge in interest in environmental protection, and quickly became an icon of the environmental movement. Our view of the earth had shifted from one of unlimited potential to one of a fragile blue island in space.

Concern for the environment continues to occupy a place in current culture. We hear frequent warnings of global warming and its possible relationship to human use of fossil fuels, sunspot activity or variations in earth’s orbit. As the human population increases, other species are crowded out and lost to extinction. Fears of an ongoing “mass extinction” are often expressed, with varied estimates of how many species are threatened with extinction before we even discover their existence. Many voices oppose the expansion of human population at the expense of other species, sometimes resorting to reducing humans to the level of other species. At its extreme, some have even promoted the idea that animals such as chimpanzees should be regarded as “persons” in the same sense as humans. Fortunately, the courts have not agreed, perhaps aware that such a precedent could easily be applied to gorillas, then monkeys, dogs, horses, pigs, etc., with no obvious criteria to distinguish those with legal accountability for their actions from those without it. Meanwhile, poverty and pollution, both related to environmental degradation, reduce the quality of life for increasing numbers of humans, increasing human misery and threatening to destabilize society. Amidst the turmoil and challenges of caring for our world, what is an appropriate Christian response?

Fortunately, the biblical story of creation provides some important principles for responsible care of “Island Earth.” For example, Genesis indicates that God regards the animals with favor. After creating the animals and before humans were created, God considered the world to be “good. This shows that the creatures with which we share this world, along with their habitats, have value in themselves.

Another point from the creation story is that humans were put in charge of the world. God gave us “dominion” over the other creatures. The word “dominion” implies a kind of kingship, which means we are to function as kings on behalf of the other animals. Kings properly use their authority to manage their subjects for the common good. Our mandate from creation is to use our power to enhance the quality of life, not only for ourselves, but also for the other species that share the planet with us. It is true that we sometimes have to restrain or even kill other animals, but we do so with a sense of regret, looking forward to the promised new creation when such things will no longer be necessary. We should never cause unnecessary suffering, even to rats and other nuisance animals, because we serve and represent a Creator who values all creatures and intended them to live in harmony with one another.

Recognition of humans as created in the image of God is a third point that guides our care for the environment. Every human should be treated with respect and dignity out of respect to the One whose image they carry. Poverty, violence and suffering had no place in the “very good” earth originally created. These atrocities are the result of human choices, and all who recognize their calling as stewards of creation will work to oppose them.

From these biblical principles we can derive guidelines for managing our world and its resources. This includes our treatment of the physical environment, the diverse biota with which we coexist, and our fellow humans.

We may not be able to control some aspects of the physical environment such as sunlight and earth’s orbit, but we do have powerful effects on the quality of the water, soil and atmosphere. Waste management is a problem we have still not solved, as seen in the “garbage patches” of our oceans, the smog in the air of our cities, the industrial pollution in our soil and groundwater, and the problem of safely storing radioactive waste products. We can all see evidence of changes in the climate. Whether these are due to human activities, to natural cycles or both, we can carefully evaluate our use of resources and plan how to change our habits to respond to changes in climate. As individuals, we can reduce consumption, recycle materials, and properly dispose of household wastes. As citizens and tax payers we can support responsible efforts to manage waste disposal, maintain supplies of clean water, and work to eliminate pollution from industries and automobiles. Each of these methods is consistent with the biblical principle that we are given the task of being stewards of God’s creation.

There are many ways we can care for the other living organisms. Setting aside land in wilderness areas helps preserve diverse habitats, and also provides us with opportunities for healthful outdoor activities. Wildlife refuges provide safe resting places for birds in migration and habitats for the plants and animals of the region. Habitat corridors linking wildlife preserves improve the survival chances of threatened species. Animals used in research should be treated well, and not left to suffer. Domesticated animals should be treated with care, even when raised for food purposes. Pet predators can be spayed or neutered to prevent destruction of smaller creatures, such as by feral cats. Each of these activities, along with many others, is evidence that we take seriously our responsibility as stewards of “Island Earth.

Care for other humans should be a high priority for we who have been charged to exercise dominion in our world. This includes respecting the rights of others to the basic freedoms: freedom of speech; freedom of religion; freedom of the press; freedom of assembly; and freedom to participate in the political process. We should endeavor to provide opportunity to each person to work to support themselves and their families. We should provide means to reduce suffering from disease, poverty and environmental degradation. All humans are part of one family, and family members take care of one another.

Caring for the environment is a natural concern for those who accept the biblical teaching of a six-day creation, in which God created a good physical environment, filled the world with diverse kinds of plants and animals, created humans in His own image and gave them responsibility to act as stewards on His behalf. Our understanding of this responsibility has increased over the years as we have come to realize that our world and its resources are finite, and that we truly live on an island called Earth.

For further reading, consult Entrusted: Christians and Environmental Care. Available from http://adventus21.com/Producto.aspx?idProducto=457&idIdioma=1&idCategoria=25

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Patterns in the Fossil Record, Part 2

Balancing extremes

A general note of caution is necessary in the discussion of patterns in the fossil record. As with many other aspects of the natural world, the complexity that we find in this field of study tends to transcend our idealized categorizations. This needs to be kept in mind to avoid misrepresentations or the promotion of unbalanced perspectives. Here is a list of apparently contradictory aspects that coexist and emerge when looking at the study of fossils from different angles:

Time: instantaneous and prolonged. Fossils are often produced as evidence for rapid and cataclysmic sedimentation and in most cases this is correct. The process of fossilization generally requires rapid burial for preservation of body parts. At the same time, there are fossils that carry with them the implication of passage of a certain amount of time, such as encrusted and bored shells, organisms growing attached to a hard substrate, or tracks and traces of bioturbation.

Anatomy and Structure: different and similar. The fossil record is a rich archive of organisms that have gone extinct and exhibit morphological characteristics often extremely different from what we are used to in the modern world. It is also evident, however, that many fossil creatures have body plans that can readily be associated with basic structural plans still observed today. For example, in spite of all the alleged eons of evolutionary time, modern bacteria do not appear much different from microfossils interpreted as Precambrian bacteria (Schopf et al., 2015).

Geographic distribution: global and local. The sequential order of distribution of fossils in the geologic record appears consistent on a global scale. Dinosaur remains are found in all different continents and they always occur in Mesozoic layers. However, at higher resolution (e.g., going from the family to species level) very few fossil organisms appear to have a truly cosmopolitan distribution. This implies complications in the correlation of regional schemes of fossil distributions developed for non-overlapping areas of the world.

Stratigraphic distribution: ordered and disordered. We have already described the pattern of ordered distribution of fossil forms through the geologic column. Even in this case, however, it is important to acknowledge that at finer resolution the lowest and highest appearance of taxa are not always easily and univocally determined. Complications include reworking of older fossils in younger sediments, masking of the highest and lowest appearances due to erosion, lack of appropriate sediments for fossil preservation, offset in lowest or highest appearance at two locations due to lateral migration of a community. These factors can cause differences in the relative order of appearance of the same fossil species in different localities.

Quality of the record: complete and incomplete. The fossil record is often presented as a highly incomplete documentation of the variety of life forms that have inhabited the Earth. At the level of individual specimens, the incompleteness is evident in the preservation of only certain parts of the original organism, with others, usually the soft parts, not fossilized. At the level of the whole record, incompleteness is thought to result from discontinuous sedimentation, gaps created by erosion, and the random and infrequent nature of fossilization. Notwithstanding the validity of these points, it is also important to remark the incredible richness of the fossil record. Many fossil forms are preserved in great quantities (e.g., microfossils) and there are numerous instances of specimens with exceptional preservation, including fossilization of soft parts. As for the overall completeness of the fossil record, in many cases the available data appear more than adequate to extract trends and address the shortcomings of a discontinuous record (Foote, 2001).

Fossil record patterns and origins models

There is a fundamental difference between the biblical and Darwinian models on the origin of biodiversity. The biblical model clearly states that numerous distinct groups were created from the beginning, whereas Darwinian evolution sees all organisms as interlinked in a chain of descent with modification from a single common ancestor. In this respect, creationists find good support of their position in the scarcity of transitional fossils and the sudden appearance with high disparity of forms documented in multiple levels of the geologic column. There is, however, much work still to be done to develop an overarching comprehensive model accounting for other patterns in the fossil record. For example, explanations for the ordered distribution and increasing modernity of fossil forms have been addressed by creationists at a general conceptual level, but not always systematically investigated through detailed hypothesis testing. This is in part due to differing views on how much of the geologic record should be considered as formed by the biblical flood.

Those who view most of the Phanerozoic geologic record as the result of diluvial activity rely on a mixture of physical, ecological and behavioral processes to account for the patterns observed in the fossil record (e.g., Clark, 1946; Roth, 1998; Brand, 2009). Mechanisms invoked include sequential inundation of spatially segregated ecological systems of the pre-diluvial world (this hypothesis is known as ecological zonation or biome[1] succession theory), differences in animal mobility and behavior in the face of rising waters, and hydraulic sorting of floating organic remains.

Those who consider large parts of the Phanerozoic rock record as representing pre-flood or post-flood sedimentation, explain the succession of different fossil assemblages as an effect of biological change and migration with time of communities populating the Earth. This scenario appears similar to that proposed in the classic evolutionary interpretation of the fossil record, but there are two crucial differences. First, in the evolutionary model life diversifies from a single monocellular ancestor and evolution implies an overall increase in biological information. However, in the creationist model, modification affects pre-existing created lineages and does not require the generation of new complex biological information (Brand & Gibson, 1993; Wood & Murray, 2003). The second difference relates to the rate of change, which, in the creationist model, is assumed to be much faster than the traditional view of slow gradual accumulation of advantageous traits over millions of years (Brand & Gibson, 1993).

From the perspective of evolutionary models, certain patterns of the fossil record (such as increasing modernity and ordered distribution) are compatible or fit well with the standard paradigm. However, others present challenges to the conventional interpretative framework. The lack of numerous intermediate forms is the foremost challenge, which has been noted since Darwin’s times. A common response is to attribute this problem to the low sampling effectiveness of the fossilization process. However, this assumption has been dismissed by quantifications of the completeness of the fossil record. In the words of Wagner (2010, p.462), “we now have the sediments: but they do not yield what Darwin predicts they should yield.” It should also be noted that when several transitional forms are known along an alleged evolutionary lineage, their morphological traits may show incongruent and conflicting distributions. This implies that the alleged transitional fossils very often cannot be arranged in a sequence that consistently accommodates all the characters undergoing evolutionary modification (Luo, 2007).

The phenomenon of stasis is also a pattern partially counter-intuitive to the evolutionary scenario. The observation of limited or no net change through the entire stratigraphic distribution of a fossil species fits poorly with a model explaining the variety of life forms as the result of continuous modification.

Another pattern which is not straightforwardly accounted for in the evolutionary interpretation of the fossil record is the high disparity shown by new groups at their first appearance. As remarked by Valentine (2004, p. 444), “this record runs counter to what might be expected during the origin of phyla, which would be the divergences of two lineages form common ancestors, at first at the species level only. Then as time passed their differences would become more pronounced, the two lineages becoming as distinctive as average genera, and then as average families, then as orders, and so forth.” Therefore, one would expect disparity to progressively increase as new modifications are acquired, but this appears not to be the case.

Moving forward: areas for future research

The creationist viewpoint would benefit from research exploring more in detail possible mechanisms responsible for some of the patterns observed in the fossil record, especially if these are seen as the result of natural processes being at work before, during and after the flood.

One area deserving more focused attention is the testing of ecological zonation theory. This idea suggests that vertical trends in fossil distributions reflect more an original difference in spatial arrangements of biomes rather than an evolutionary sequence. Interestingly, a similar approach has been presented in the standard scientific literature to explain turnovers in Paleozoic fossil plant assemblages (DiMichele et al., 2008; Looy et al., 2014). Even major dominance shifts in Paleozoic tetrapods appear to be strongly correlated with the disappearance of the coal forest biome (Sahney et al., 2010) or with a switch in the geographic location of the preserved fossil record (Benton, 2012).

Another area deserving attention is the study of sea level fluctuations and their effect on fossil distribution and preservation. It is possible that some patterns in the fossil record are the result of physical processes of deposition rather than evolution through time. Sea level variations could trigger sedimentary processes controlling the appearances and disappearances of taxa (including extinctions and radiations), and replacement and repetition of fossil assemblages (Brett, 1995;1998). An important part of this process would be to consider the difference between transported fossil assemblages and assemblages indicative of minimal transport or fossilized in place.

Finally, studies exploring time implications from the fossil record would also be highly significant. Of particular interest would be an analysis of the relative proportion of fossil concentrations (e.g., shellbeds) formed through slow time-averaging or sudden event deposition.


Fossils represent a unique archive of past life forms. Opening windows in the history of life on Earth, they should be highly valued as sources of information by anyone interested in origin issues.

The significance of fossils is greatly enhanced when they are examined in their stratigraphic context. Acceptance of the geologic column as an empirical construct based on correlation of local observations is therefore essential for the study of general patterns in the fossil record.

Any of the emerging patterns is always undergoing discussion and refinement, but there is a solid base of empirical data that represents the common ground on which both creationists and evolutionists may test their models.

The discontinuities between major fossil groups fit well with the creationist paradigm of an original diversity of created species, and represent, together with high initial disparity and the predominance of stasis over gradual change, a problematic aspect for the evolutionary interpretation of the fossil record. On the other hand, patterns related to orderly stratigraphic distribution of taxa and increasing modernity are currently the less satisfactorily integrated in creationist models.

Treasuring our trust in Scripture and exploring the richness of nature, we should maintain an awareness of the complexity of the fossil record, highlight with balance its many facets, and contribute through rigorous research to a better understanding of some of its aspects.

Ronny Nalin

Geoscience Research Institute



[1] A biome is an ecosystem characterized by specific climatic and geographic conditions (e.g., tropical grassland biome, temperate wetlands biome, etc.)


Benton, M.J., 2012. No gap in the Middle Permian record of terrestrial vertebrates. Geology, 40, 339-342.

Brand, L., 2009. Faith, reason and Earth history. Andrews University Press, Berrien Springs, 508 pp.

Brand, L. & Gibson, L.J., 1993. An interventionist theory of natural selection and biological change within limits. Origins, 20, p. 60-82.

Brett, C.E., 1995. Sequence stratigraphy, biostratigraphy, and taphonomy in shallow marine environments. Palaios, 10, p. 597-616.

Brett, C.E., 1998. Sequence stratigraphy, paleoecology, and evolution; biotic clues and responses to sea-level fluctuations. Palaios, 13, p. 241-262.

Clark, H.W., 1946. The new diluvialism. Science Publications, Angwin, 222 pp.

DiMichele, W.A., Kerp, H., Tabor, N.J. & Looy, C.V., 2008. The so-called “Paleophytic–Mesophytic” transition in equatorial Pangea—Multiple biomes and vegetational tracking of climate change through geological time. Palaeogeography, Palaeoclimatology, Palaeoecology, 268, p. 152-163.

Foote, M., 2001. Estimating completeness of the fossil record. In: Briggs, D.E.G. & Crowther, P.R. (eds), Palaeobiology II. Blackwell Publishing, Oxford, p. 500-504.

Looy, C.V., Kerp, H., Duijnstee, I. & DiMichele, W.A., 2014. The late Paleozoic ecological-evolutionary laboratory, a land-plant fossil record perspective. The Sedimentary Record, 12/4, p. 4-18.

Roth, A.A., 1998. Origins – Linking science and scripture. Review and Herald Publishing Association, U.S.A., 384 pp.

Sahney, S., Benton, M. J. & Falcon-Lang, H. J., 2010. Rainforest collapse triggered Carboniferous tetrapod diversification in Euramerica. Geology, 38(12), 1079-1082.

Schopf, J.W., Kudryavtsev, A.B., Walter, M.R., Van Kranendonk, M.J., Williford, K.H., Kozdon, R., Valley, J.W., Gallardo, V.A., Espinoza, C. & Flannery, D.T., 2015. Sulfur-cycling fossil bacteria from the 1.8-Ga Duck Creek Formation provide promising evidence of evolution’s null hypothesis. Proceedings of the National Academy of Sciences, 112/7, p. 2087-2092.

Stanley, S.M., 2001. Controls on rates of evolution. In: Briggs, D.E.G. & Crowther, P.R. (eds), Palaeobiology II. Blackwell Publishing, Oxford, p. 166-171.

Valentine, J.W., 2004. On the origin of phyla. University of Chicago Press, Chicago IL, U.S., 608 pp.

Wagner, P.J., 2010. Paleontological perspectives on morphological evolution. In: Bell. M.A., Futuyma, D.J., Eanes, W.F., & Levinton, J.S. (eds.), Evolution since Darwin: the first 150 years. Sinauer Associates, Inc., Sunderland MA, U.S., p. 451-478.

Wood, T.C. & Murray, M.J., 2003. Understanding the pattern of life. Broadman & Holman Publishers, Nashville, TN, 231 pp.

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Patterns in the fossil record, part 1

Fossils are remains of organisms or traces of their activity preserved in the rock record. The scientific significance of fossils is truly remarkable, because they represent the only available archive of past forms of life. Through fossils, not only can we reconstruct the morphology of extinct creatures but also infer aspects of their ecology and environment. Fossils are also very relevant in discussions about the origin of the varieties of life forms seen on Earth today.

This blog is divided in two parts. In the first, we will review some of the patterns that emerge from a general look at the fossil record. In the second, we will discuss the patterns in the light of naturalistic and biblical models of origins.


Fossils and the geologic column

In order to extract general patterns related to the distribution of fossils, it is first necessary to establish a spatial relationship between the rocks that contain them. Geologists have created a framework, called the geologic column, to serve the purpose of ordering rocks from various locations in an idealized succession of units and events. Imagine the geologic column as a layered cake, so that rocks at any given locality can be readily assigned to a specific layer of the column and their relationship with others rock units become self-evident. The geologic column is the outcome of scores of local observations, measurements and correlations between outcrops from all over the world. It is continually being refined, but its basic subdivisions are well established.[1]

In spite of skepticism from some creationists about the reliability of the geologic column as a valid construct, many endorse it as an effective tool to organize spatial information in the rock record.[2] In this paper, most of the patterns discussed assume the validity of the geologic column as a necessary foundation for their reconstruction.

In standard geologic practice, the geologic column is tied to a chronology of hundreds of millions of years. However, creationists generally do not agree with such long chronology for the formation of the many intervals of the column. Therefore, creationists who accept the geologic column keep the stratigraphic[3] data (i.e., order and correlation of rock units) separate from the absolute chronology (i.e., the numerical age) assigned to the rock units.


Review of some patterns in the fossil record 

Ordered distribution

One of the most prominent features of the fossil record is that every fossil species consistently occurs within a specific interval of the geologic column. Some taxa[4] may have a very restricted distribution, whereas others may be found in larger portions of the column. The interval of distribution for a taxon is sometimes called its stratigraphic range. For example, the stratigraphic range of human fossils corresponds to the Quaternary (the uppermost portion of the geologic column) whereas the stratigraphic range of dinosaurs is restricted to the Mesozoic (lower in the geologic column). Therefore, the distribution of fossils of these two groups does not overlap and they are never found together at the same site.

The stratigraphic range of fossil taxa is obtained through collection of samples from many localities. If numerous specimens are available (such as with microfossils, which can be collected by the thousands per sample) the stratigraphic range can be very precisely defined. On the contrary, when only a few specimens of a taxon are known, the upper and lower boundaries of its stratigraphic range can be expanded by new discoveries.

From exclusively marine to marine and terrestrial

Determining the mode of life of extinct organisms is not always straightforward, but it is usually possible to at least infer whether a fossil lived in a marine or terrestrial habitat. A remarkable feature of the fossil record is that all organisms found fossilized in the lower part of the geologic column (up to the Silurian) have generally been interpreted to be adapted for life in fully marine conditions. This implies a lack of terrestrial organisms among the millions of fossils of the lower Paleozoic. The Silurian-Devonian represents the first interval where fossils of terrestrial affinity begin to appear. What is particularly notable is that very different groups such as plants (Edwards & Burgess, 1990), invertebrates (Selden, 1990) and vertebrates (Milner, 1990) all present their first terrestrial representatives in this interval of the geologic column. Some of these forms, such as the lowermost occurring tetrapods[5] (Carroll, 2005), seem to have been adapted for life in coastal or riparian environments, at the interface between water and land. From the Devonian upwards, marine and terrestrial organisms are both widely represented in the fossil record.

Increasing modernity

Many of the fossils preserved in the rock record pertain to groups of organisms that are now extinct. Some fossil groups however, have representatives still living in modern times. One can estimate what percentage of the fossil taxa found in a specific interval of the geologic column is still living today. This exercise could be done at the species level or at a higher taxonomic category (such as genus or family). This analysis of similarity between present and fossil faunas and/or floras shows that as we move lower in the geologic column the similarity decreases (or, said in other words, fossils in the upper part of the geologic column are more similar to living organisms than those in the lower part of the column).


Disparity is a measure of the morphological difference between two organisms. When examining the fossil record, we could look for the degree of disparity between forms found in a specific interval of the geologic column. It is particularly interesting to estimate disparity at the appearance of new groups, because we want to see if they are relatively homogeneous or already differentiated when they first occur as fossil. The general trend emerging from the fossil record is one of high disparity right from the first appearance of a new group. A classic example of high initial disparity is the Cambrian “explosion” of metazoans[6], where very disparate organisms belonging to essentially all the animal phyla appear for the first time in Cambrian strata (Marshall, 2006).

The fossil record of many groups begins with few but morphologically very distinct organisms and is followed, in overlying strata, by an increase in diversity but as variations of already established themes.

Coordinated disappearance (mass extinction)

When no living representatives of a fossil taxon are known, the group is considered extinct. The great majority of fossil species is extinct, but the position of their highest occurrence in the geologic column varies greatly. However, some species disappear at the very same level (coordinated disappearance) and when the lost groups are numerous and belong to different categories of organisms the term “mass extinction” is applied. At least five distinct intervals of mass extinction have been recognized in the Phanerozoic (Sepkoski, 1986). The largest is the P-T (Permo-Triassic) extinction, where an estimated 54% of all marine families and 83% of all marine genera present in underlying strata disappear (Erwin, 1990). The most renowned is probably the K-Pg (Cretaceous-Paleogene) extinction because of its association with the disappearance of dinosaurs and its possible link with a high-energy meteorite impact (Alvarez et al., 1980). Beside these five major extinctions, there are several other examples of coordinated disappearances involving smaller numbers of taxa or geographically restricted provinces (Sepkoski, 1986).

Coordinated appearance (radiation)

The pattern of coordinated appearance (often referred to as radiation) basically represents the opposite phenomenon of coordinated disappearance. It relates to the occurrence in the same restricted portion of the geologic column of numerous taxa which were not present in underlying layers. Classic examples of radiations are the Cambrian “explosion” of metazoans (Marshall, 2006), the Ordovician diversification of marine faunas (Miller, 2001), the Cretaceous radiation of angiosperms (Friis et al., 2006), and the Eocene-Oligocene radiation of modern mammal orders and families (Bowen et al., 2002).

Stasis and gradual change

In a very influential paper, Eldredge and Gould (1972) proposed that fossil species show little morphological variation during the entire range of their stratigraphic

distribution. This hypothesis, called stasis, contrasted with the previously popular idea of a fossil record showing gradual and directional morphological change between species arranged in stratigraphic order. Several attempts have been made at clarifying which of the two patterns (stasis or gradual change) is truly represented in the fossil record. Some studies strongly suggest the reality of stasis (e.g., Cheetham, 2001) but others illustrate gradual morphological change (e.g., Arnold, 1983). A third modality, named “random walks,” is also possible and consists of appreciable change through the layers of the column but not in a definite direction. Statistical studies on the relative importance of these patterns of morphological change in the fossil record indicate that examples of gradual change are much less common than stasis or random walks (Hunt, 2007; Grey et al., 2008).

Intermediate forms between major groups

Since the publication of Darwin’s Origin of Species, one of the most sought after patterns in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. Of particular interest are morphological intermediates (or “links”) between major categories of living organisms (such as fish and amphibians, dinosaurs and birds, terrestrial and marine mammals). These connecting forms would represent the nodes between branches of an alleged evolutionary tree of life. However, such transitional forms are very scarce in the fossil record. Discussing the origin of higher taxa, Kemp (1999, p.246) states that “in virtually all cases a new taxon appears for the first time in the fossil record with most definitive features already present.”

It should be noted, however, that some forms with transitional characters or a mosaic of characteristics from different groups are indeed preserved in the fossil record. Representatives include Devonian tetrapod-like fish (Daeschler et al., 2006; Long et al. 2006; Ahlberg et al., 2008), upper Paleozoic-lower Mesozoic mammal-like reptiles (Kemp, 1999; Luo, 2007), Lower Cretaceous theropod dinosaurs with bird-like characters (Qiang et al., 1998; Xu et al., 2003), and Eocene terrestrial and amphibious cetaceans (Thewissen et al., 2001, 2007).

Other patterns

There clearly are numerous other patterns which could be investigated from the fossil record which are not discussed in this blog. These include trends in diversity, complexity, body size, specialization, preservation, trace fossils, and nature of embedding deposits. For a creationist commentary on most of these patterns the reader is referred to Gibson (1996).

Ronny Nalin

Geoscience Research Institute


[1] For a standard version of a chart showing the subdivisions of the geologic column (some of which are mentioned later in this article) see http://www.stratigraphy.org/index.php/ics-chart-timescale.

[2] For an example of differing creationist views on the geologic column, see Reed & Oard, 2006.

[3] Stratigraphy is a branch of geology which aims at subdividing the rock record into discrete units characterized by specific combinations of observable parameters (such as rock type, fossil content, magnetic properties, isotopic composition, etc.).

[4] The nomenclatural scheme of biology has different hierarchical levels to rank organisms from the general to the specific (e.g., phylum, family, genus, species). Taxon (pl.: taxa) is the general word used to refer to any of these categories (the word taxon, for example, could equally be applied to a species or a family).

[5] The term tetrapod is used to indicate four-limbed vertebrates, a group including amphibians, reptiles, mammals and birds.

[6] Metazoan is a technical term used to refer to multicellular animals.

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Teeming Creatures of the Sea!

The number of different kinds of living organisms is one measure of biological diversity, or what has become known as “biodiversity.” Our world’s oceans have the highest known biodiversity, second only to the number of species found in the tropical rainforest.

The small, white shell is a dead giveaway for the snail, Cyphoma gibossum on Caribbean coral reefs. The actual flesh of the animal is cream-colored with bright yellow spots. It feeds on polyps of gorgonian sea fans (a type of coral).

The small, white shell is a dead giveaway for the snail, Cyphoma gibossum on Caribbean coral reefs. The actual flesh of the animal is cream-colored with bright yellow spots. It feeds on polyps of gorgonian sea fans (a type of coral).

However, if we consider the potential number of undiscovered species in marine systems, it’s likely that our oceans would come out on top as the environment with the greatest number of species on the planet.

While more than 70% of Earth is covered with water, much of the vast expanses of ocean have relatively few species. Instead, much of the known biodiversity in our oceans is found in special areas that cover less than one percent of the ocean’s floor – coral reefs[i]. This is because although the vast areas of the ocean have plenty of space, they’re a little like deserts when it comes to the nutrients animals at the lowest level of the food chain need to survive and grow. In contrast, coral reefs are like oases, where nutrients are plentiful, but space is hard to come by. With so many organisms, from microscopic bacteria and algae to sea turtles

The ornately colored Caribbean Spiny Lobster, Panulirus argus, is found in crevices during the day throughout the Caribbean, and comes out to hunt and feed at night. It’s numbers are decreasing because of overfishing.

The ornately colored Caribbean Spiny Lobster, Panulirus argus, is found in crevices during the day throughout the Caribbean, and comes out to hunt and feed at night. It’s numbers are decreasing because of overfishing.

and hammerhead sharks, reliant on these important nutrients, there’s always lots of competition for places to live in coral reefs. But, there’s cooperation, too! Among other things, both competition and cooperation provide us with spectacular views of so many species of organisms (that high biodiversity) in these coral reef oases.

Still, we know relatively little about the number of species in coral reefs, and only very recently about the biodiversity of the deep ocean floor. For instance, we know of about 7,200 species[ii] of single-cell marine algae (known as phytoplankton), many of which are caught and eaten by microscopic predators (known as zooplankton, some of which are the larval, or baby, stages of larger animals), of which there are an estimated 50,000 species![iii] We know something about a great number of the groups of animals that live in and around coral

Although brightly colored, the hermit crab, Paguristes cadenati, is sometimes difficult to find because of its small size and shy demeanor. It uses the left over shell of a snail to hid in and protect its soft abdomen.

Although brightly colored, the hermit crab, Paguristes cadenati, is sometimes difficult to find because of its small size and shy demeanor. It uses the left over shell of a snail to hid in and protect its soft abdomen.

reefs, as well. For example, there are about 11,000 known species of corals (which are animals, not plants) and their relatives (the jellyfishes and anemones) in existence today[iv].

One of the largest known groups of ocean organisms is the Molluscs (the snails, sea slugs, chitons, and octopuses) of which there are some 100,000 described species (although not all of these live in the ocean), along with another 70,000 that are now only known from the fossil record[v]. There are several groups of marine animals that are made up of large numbers of species. One of these is the Superclass Crustacea, with a whopping 42,000 living species[vi], including the crabs, lobsters, shrimp, and the barnacles[vii].

The Indigo Hamlet, Hypoplectrus indigo, is rare in many parts of the Caribbean sea, and is one of the many brightly colored fish that make up the rainbow of colors on tropical coral reefs.

The Indigo Hamlet, Hypoplectrus indigo, is rare in many parts of the Caribbean sea, and is one of the many brightly colored fish that make up the rainbow of colors on tropical coral reefs.

With so many species living in our oceans (and many more which have yet to be discovered)[viii], we can see that our oceans are places of amazing diversity, beauty, and discovery. However, humans are taking a toll on these ocean systems with our input of chemical and plastic pollution. There are some places in our oceans where plastic fragments now make up a large amount of materials zooplankton and small fish are eating every day[ix]. Plastic pollution in our oceans and washing up on our beaches has become so wide-spread, it now accounts for the death of many marine animals and oceanic birds, even in places where no humans live[x].

It’s time for each one of us to stand up for our fellow creatures that live in the oceans. As stewards of the creation, let’s not simply talk about believing in creation, but work together to care for creation in ways we’ve been entrusted to do so from the beginning[xi]

This species of hydroid (a relative of corals and anemones) is the Christmas Tree hydroid, Halocordyle disticha, captures plankton with its toxic tentacles. In this photograph, individual polyps with their ring of stinging tentacles can be seen extended from the “tree.”

This species of hydroid (a relative of corals and anemones) is the Christmas Tree hydroid, Halocordyle disticha, captures plankton with its toxic tentacles. In this photograph, individual polyps with their ring of stinging tentacles can be seen extended from the “tree.”


Stephen Dunbar

Loma Linda University


[i] http://www.noaa.gov/features/economic_0708/coralreefs.html

[ii] Castro, P. & Huber, M.E. 2010. Marine Biology, 8th Ed. McGraw-Hill New York, NY.

[iii] Ibid

[iv] Pechenik, J. A. 2015. Biology of the Invertebrates, 7th Ed. McGraw-Hill New York, NY.

[v] Ibid

[vi] Ibid

[vii] Yes! Barnacles are closely related to crabs and shrimp, even though they were once thought to be more closely related to snails, and were classified as molluscs up to 150 years ago.

[viii] Some recent estimates place the number somewhere between 700,000 – 1 million. See, for instance, http://blogs.nature.com/news/2012/11/hundreds-of-thousands-of-undiscovered-marine-species-await-discovery.html

[ix] http://www.ted.com/talks/capt_charles_moore_on_the_seas_of_plastic?language=en

[x] http://pacificvoyagers.org/midway-atoll-the-plastic-plight-of-the-albatross/

[xi] Genesis 2: 8 – 15

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