If you could visit a theme park that offered you a chance to view and even interact with real-life dinosaurs, would you go? I think I might. Who wants to swim with dolphins when you can hang out with dinosaurs? Maybe even ride one?

Well, if legendary paleontologist Jack Horner has his way, we just might get our wish—and, it could be much sooner than any of us realize. Horner is a champion of the scientific proposal to resurrect dinosaurs from extinction. And it looks like this idea might have a real chance at success.

Horner’s not taking the “Jurassic Park/World” approach of trying to clone dinosaurs from ancient DNA (which won’t work for myriad technical reasons). He wants to transform birds into dinosaur-like creatures by experimentally manipulating their developmental processes in a laboratory setting.

The Evolutionary Connection between Birds and Dinosaurs

The basis for Horner’s idea rises out of the evolutionary paradigm. Most paleontologists think that birds and dinosaurs share an evolutionary history. These scientists argue that shared anatomical features (a key phrase we’ll return to) between birds and certain dinosaur taxa demonstrate their evolutionary connection. Currently, paleontologists place dinosaurs into two major groups: avian and nonavian dinosaurs. Accordingly, paleontologists think that birds are the evolutionary descendants of dinosaurs.

So, if Horner and others are successful, what does this mean for creation? For evolution?

Reverse Evolution

In effect, Horner and other interested scientists seek to reverse what they view as the evolutionary process, converting birds into an evolutionarily ancestral state. Dubbed reverse evolution, this approach will likely become an important facet of paleontology in the future. Evolutionary biologists believe that they can gain understanding of how biological transformations took place during life’s history by experimentally reverting organisms to their ancestral state. Reverse evolution experiments fuse insights from paleontology with those from developmental biology, molecular biology, comparative embryology, and genomics. Many life scientists are excited, because, for the first time, researchers can address questions in evolutionary biology using an experimental strategy.

Proof-of-Principle Studies

The first bird that researchers hope to reverse-evolve into a dinosaur-like creature is the chicken (Gallus gallus). This makes sense. We know a whole lot about chicken biology, and life scientists can leverage this understanding to precisely manipulate the embryonic progression of chicks so that they develop into dinosaur-like creatures.

As I described previously (see Resources for Further Exploration), in 2015 researchers from Harvard and Yale Universities moved the scientific community one step closer to creating a “chickenosaurus” by manipulating chickens in ovo to develop snout-like structures, instead of beaks, just like dinosaurs.¹

Now, two additional proof-of-principle studies demonstrate the feasibility of creating a chickenosaurus. Both studies were carried out by a research team from the Universidad de Chile.

In one study, the research team coaxed chicken embryos to develop a dinosaur-like foot structure, instead of the foot structure characteristic of birds.² A bird’s foot has a perching digit that points in the backward direction, in opposition to the other toes. The perching digit allows birds to grasp. In contrast, the corresponding toe in dinosaurs is nonopposable, pointing forward.

Figure 1: Dinosaur Foot Structure. Image credit: Shutterstock

Figure 2: Bird Foot Structure. Image credit: Shutterstock

The researchers took advantage of the fact that vertebrate skeletons are plastic, meaning that their structure can be altered by muscle activity. These types of skeletal alterations most commonly occur during embryonic and juvenile stages of growth and development.

Investigators discovered that muscle activity causes the perching toe of birds to reorient during embryonic development from originally pointing forward to adopting an opposable orientation. Specifically, the activity of three muscles (flexor hallucis longus, flexor hallucis brevis, and musculus extensor hallucis longus) creates torsion that twists the first metatarsal, forcing the perching digit into the opposable position.

The team demonstrated that by injecting the compound decamethonium bromide into a small opening in the eggshell just before the torsional twisting of the first metatarsal takes place, they could prevent this foot bone from twisting. The compound causes muscle paralysis, which limits the activity of the muscles that cause the torsional stress on the first metatarsal. The net result: the chick developed a dinosaur-like foot structure.

In a second study, this same research team was able to manipulate embryonic development of chicken embryos to form a dinosaur-like leg structure.³ The lower legs of vertebrates consist of two bones: the tibia and the fibula. In most vertebrates, the fibula is shaped like a tube, extending all the way to the ankle. In birds, the fibula is shorter than the tibia and has a spine-like morphology (think chicken drumsticks).

Figure 3: The Lower Leg of a Chicken. Image credit: Shutterstock

Universidad de Chile researchers discovered that the gene encoding the Indian Hedgehog protein becomes active at the distal end of the fibula during embryonic development of the lower leg in chicks, causing the growth of the fibula to cease. They also learned that the event triggering the increased activity of the Indian Hedgehog gene likely relates to the depletion of the Parathyroid Hormone-Related Protein near the distal end of the fibula. This protein plays a role in stimulating bone growth.

The researchers leveraged this insight to experimentally create a chick with dinosaur-like lower legs. Specifically, they injected the amniotic region of the chicken embryo with cyclopamine. This compound inhibits the activity of Indian Hedgehog. They discovered that this injection altered fibula development so that it was the same length as the tibia, contacting the ankle, just like in dinosaurs.

These two recent experiments on foot structure along with the previous one on snout structure represent science at its best. While the experiments reside at the proof-of-principle stage, they still give scientists like Jack Horner reason to think that we just might be able to resurrect dinosaurs from extinction one day. These experiments also raise scientific and theological questions.

Do Studies in Reverse Evolution Support the Evolutionary Paradigm?

On the surface, these studies seemingly make an open-and-shut case for the evolutionary origin of birds. It is impressive that researchers can rewind the tape of life and convert chickens into dinosaur-like creatures.

But deeper reflection points in a different direction.

All three studies highlight the amount of knowledge and insight about the developmental process required to carry out the reverse evolution experiments. The ingenious strategy the researchers employed to alter the developmental trajectory is equally impressive. They had to precisely time the addition of chemical agents at the just-right levels in order to influence muscle activity in the embryo’s foot or gene activity in the chick’s developing lower legs. Recognizing the knowledge, ingenuity, and skill required to alter embryological development in a coherent way that results in a new type of creature forces the question: Is it really reasonable to think that unguided, historically contingent processes could carry out such transformations when small changes in development can have profound effects on an organism’s anatomy?

It seems that the best the evolutionary process could achieve would be the generation of “monsters” with little hope of survival. Why? Because evolutionary mechanisms can only change gene expression patterns in a random, haphazard manner. I would contend that the coherent, precisely coordinated genetic changes needed to generate one biological system from another signals a Creator’s handiwork, not undirected evolutionary mechanisms, as the explanation for life’s history.

Can a Creation Model Approach Explain the Embryological Similarities?

Though the work in reverse evolution seems to fit seamlessly within an evolutionary framework, observations from these studies can be explained from a creation model perspective.

Key to this explanation is the work of Sir Richard Owen, a preeminent biologist who preceded Charles Darwin. In contemporary biology, scientists view shared features possessed by related organisms as evidence of common ancestry. Birds and theropod dinosaurs would be a case in point. But for Owen, shared anatomical features reflected an archetypal design that originated in the Mind of the First Cause. Toward this end, the anatomical features shared by birds and theropods can be understood as reflecting common design, not common descent.

Though few biologists embrace Owen’s ideas today, it is important to note that his ideas were not tried and found wanting. They simply were abandoned in favor of Darwin’s theory, which many biologists preferred because it provided a mechanistic explanation for life’s history and the origin of biological systems. In fact, Darwin owes a debt of gratitude to Owen’s thinking. Darwin coopted the idea of the archetype, but then replaced the canonical blueprint that existed in the Creator’s Mind (per Owen) with a hypothetical common ancestor.

This archetypal approach to biology can account for the results of reverse-evolution studies. Accordingly, the researchers have discovered differences in the developmental program that affect variations in the archetype, yielding differences in modern birds and long-extinct dinosaurs.

The idea of the archetype can extend to embryonic growth and development. One could argue that the Creator appears to have developed a core (or archetypal) developmental algorithm that can be modified to yield disparate body plans. From a creation model standpoint, then, the researchers from Harvard and Yale Universities and the Universidad de Chile didn’t reverse the evolutionary process. They unwittingly reverse-engineered a dinosaur-like developmental algorithm from a bird-like developmental program.

Why Would God Create Using the Same Design Templates?

There may well be several reasons why a Creator would design living systems around a common set of templates. In my estimation, the most significant reason is discoverability.

Shared anatomical and physiological features, as well as shared features of embryological development make it possible to apply what we learn by studying one organism to others. This shared developmental program makes it possible to use our understanding of embryological growth and development to reengineer a bird into a dinosaur-like creature. Discoverability makes it easier to appreciate God’s glory and grandeur, as evinced in biochemical systems by their elegance, sophistication, and ingenuity.

Discoverability also reflects God’s providence and care for humanity. If not for the shared features, it would be nearly impossible for us to learn enough about the living realm for our benefit. Where would biomedical science be without the ability to learn fundamental aspects about our biology by studying model organisms such as chickens? And where would our efforts to re-create dinosaurs be if not for the biological designs they share with birds?

Resources for Further Exploration

Reverse Evolution

• “The Creation-Evolution Controversy in ‘Jurassic World‘” by Fazale Rana (article)

Shared Biological Designs and the Creation Model

• “Archetype or Ancestor? Sir Richard Owen and the Case for Design” by Fazale Rana (article)
• “Why Would an Infinite Creator Employ the Same Designs?” by Fazale Rana (article)
• “Does Old-Earth Creationism Make God Deceptive?” by Fazale Rana (article)
• “Duck-Billed Platypus Venom: Designed for Discovery” by Fazale Rana (article)

A common question that we receive at Reasons to Believe is, “Why did God create dinosaurs?” One obvious answer: God likes big animals. Consider the blue whale at up to 190 tons—more than twice as big as the largest dinosaur! As Psalm 104 describes, God has created animals in the greatest imaginable diversity. As I demonstrate in my book Improbable Planet, God has always packed Earth with as much and as diverse life as the physical conditions on Earth permitted.

Today, the physical conditions of Earth do not allow a land animal any larger than an elephant to thrive. During the ages of the dinosaurs, shallow seas and tall trees on the continents permitted land animals as large as the dinosaurs.

Less obvious reasons for why God created dinosaurs and elephants is to increase the global availability of nutrients and to permit a greater diversity of life to survive. Two papers published within the past two weeks, and several more within the past few years, describe both observational field studies and theoretical biological models that establish large-bodied herbivores have played and continue to play a much more important role in increasing the global availability of nutrients critical for maintaining abundant and diverse life-forms than previously acknowledged.

Large-bodied herbivores, like the sauropod dinosaurs that roamed the continents 145–66 million years ago and weighed up to 60 tons, and elephants that roam tropical Africa and Asia today weighing up to nearly 7 tons, move from region to region as they forage for food. They retain their food for tens of hours or more. They don’t efficiently assimilate their food. They typically defecate far from where they harvest their food. Thus, ecologists have presumed for the past century that large-bodied herbivores play a role in dispersing vital nutrients throughout Earth’s ecosystems.

Christopher Doughty of the School of Informatics, Computing, and Cyber Systems at Northern Arizona University has been actively developing ecosystem models for the past decade. In a paper published in Nature Ecology & Evolution, he used the U.S. Geological Survey’s COALQUAL database to empirically verify the degree to which large-bodied herbivores geographically distribute nutrients.¹

Doughty compared remnant plant material from coal deposits from the Cretaceous period (145–66 million years ago) with those from the Pennsylvanian subperiod (323–299 million years ago). Plant material nutrients measured 136% more concentrated in the Cretaceous than during the Pennsylvanian. The difference between the two periods was that the Cretaceous had large-bodied herbivores, namely the sauropods, whereas the Pennsylvanian had none at all. Doughty ruled out nonbiotic processes, such as weathering rates, for the cause of the 136% difference by noting that aluminum (a non-nutrient and mildly toxic element for plants and animals that weathers at the same rate as the plant material nutrients) showed no difference between the two periods.

In a paper published just days ago in Palaeontology, a team of four ecologists noted that the Cretaceous dinosaurs spanned a 4-million-fold range in body sizes, ranging from 15 grams to 60 tons. In analyzing the biomechanics of the largest dinosaurs the four ecologists concluded that these animals would have very long food passage times.² That is, the time between one of these dinosaurs eating plant material and defecating the nutrient-rich wastes from what they had eaten would be days, not hours.

This conclusion of very long food passage times for these dinosaurs was affirmed in a a separate study. A team of sixteen biologists showed that the very long necks and small heads of the sauropods meant that little mastication could take place in the mouth.³ The only possible compensating factor would be very long food passage times. Such long food passage times and the enormous sizes of these dinosaurs imply that they were defecating far from where they were eating. Thus, these dinosaurs would have efficiently distributed nutrients throughout their environments.

Three decades ago, environmental zoologist Paul Rees showed that what is true for the sauropod dinosaurs is also true—to a somewhat lesser degree—for the largest herbivores on Earth today. He showed that the food passage times for African Bush elephants (see figure) ranges from 21–46 hours.⁴ In the same study, he determined that the food assimilation efficiency was only 22.4%. Given that African Bush elephants move tens of miles per day, like sauropod dinosaurs before them, they efficiently transport nutrient-rich material throughout their environments.

Figure: Male African Bush Elephant
At up to 13,400 pounds body weight the male African bush elephant ranks as the largest terrestrial animal on Earth. Source: https://commons.wikimedia.org/wiki/File:African_Bush_Elephant.jpg.

The very important role that large herbivores play in distributing nutrients in current habitats was affirmed in a study of the impact of megafauna extinctions on nutrient availability in Amazonia.⁵ Three ecologists pointed out that during the late Pleistocene (20,000–11,700 years ago), 97 genera of large animals went extinct. They showed that this extinction event reduced the lateral flux of the limiting nutrient phosphorus in Amazonia by more than 98%!

Doughty closed his recent research paper with a call to conserve the remaining large animals on our planet. He cited data showing that the removal of the largest animals likely would reduce nutrient concentrations in their habitats by an additional 130% or more. Evolutionary models show that the increase in maximum biovolume of a factor of 100,000 times that has occurred since the Cambrian explosion 543 million years ago “could not have emerged from a random process” and that this pattern of dramatically increasing body sizes “does not reflect a simple scaling up of widespread and persistent selection for larger size within populations.”⁶

In other words, God made a major investment in creating large herbivores to create large herbivores. He created them to benefit all life, and humanity in particular. We need to thank God for the large herbivores and do everything we can to not only preserve them, but also restore them to near the population levels they manifested at the time of Eden.

From Jerry in Los Angeles, CA

Only during the last few decades have scientists recognized the many mass extinction and speciation events throughout life’s history. Psalm 104:29–30, however, described these events thousands of years ago:

My daughter’s dinosaur phase lasted about 10 years. At age 4, she dressed up as a paleontologist for Halloween. Imagine a 4-year-old in a pith helmet knocking on your door.

Children are often curious about when dinosaurs lived, what happened to them, and whether they were on Noah’s ark. But many parents struggle to answer these questions. Christian parents contact RTB regularly looking for resources—books or videos—to teach their children about dinosaurs from a Christian perspective.

Unfortunately, most Christian books on dinosaurs are written from a young-earth perspective and promote scientifically untenable ideas. These two guidelines can empower educators to more effectively use the wide variety of resources available.

1. Encourage your child’s curiosity about God’s world.

Modern science was birthed largely because people were curious about exploring and learning as much as they could about the Creator’s world. Public libraries offer a treasure trove of information—all just waiting to be explored by your child. My daughter used to check out two or three books on dinosaurs each week. It seemed like there was a never-ending supply of options.

The advice I offer parents is to give their children some freedom in selecting topics that interest them. This autonomy is more likely to help them stay engaged over the long-term than if parents try to coax them along. And using mainstream books and videos will provide students access to the great body of knowledge from scientific research.

2. Don’t stress about evolution.

Many parents are concerned about the evolutionary content in secular books. In my experience, however, young children don’t possess the developmental ability to grasp the complexities surrounding the creation-evolution debate. I found that I was far more stressed about evolution than my kids were. To them, it was just another word in a book. It’s appropriate to begin addressing the evolution controversy in middle school, when kids generally are developmentally ready to start philosophical issues. Until then, it’s best to focus attention on fostering the child’s curiosity.

Even though the resources in a library or on television are written from a naturalistic point of view, the overwhelming majority of scientific data in them is correct. As you read or watch science-related material with your kids, engage them in a discussion about God’s creation.

Look at that dinosaur! It’s so unusual looking. Isn’t God imaginative?
What does this dinosaur eat? God designed its teeth to eat that.

The most important resource in any discussion with children about dinosaurs is you. No book or video can substitute for the ongoing discussions that can take place between parents and their children. For this reason, it’s absolutely vital that Christian parents equip themselves to be conversant on a range of science-faith issues, including dinosaurs, so they’ll be ready to give their children a response for the reason that’s within them.

For more on this topic, listen to Krista’s four-part podcast with her daughter Emily: “Dinosaurs and Kids.”

In last Monday’s article, I discussed the conclusions drawn by a panel of 41 scientists from their careful review of over twenty years’ worth of research findings concerning the cause of the Cretaceous-Paleogene (K-Pg) mass extinction event.¹ They determined beyond any reasonable shadow of doubt that a huge asteroid colliding in the Yucatán Peninsula of Mexico 65.5 million years was indeed the culprit behind the demise of the last remaining ecosystem of dinosaurs and, along with it, over half of all other species. In the second and last part of the series I will describe the panel’s conclusions concerning the effects brought about by the collider and what those effects imply for the creation/evolution debate.

Taking advantage of the latest measurements of the crater size and the ejecta deposits, and using updated models for the dynamics of the asteroid-Earth collision event, the team calculated the physical and chemical effects of the collision event. Hitting as it did on the Atlantic seashore, the collider generated megatsunamis reaching up to several hundred feet high.² The impact induced earthquakes exceeding magnitude 11 (more than 10,000 times the magnitude of the recent quake in Haiti).³ The collision event ejected and distributed around the globe the especially sulfate-rich sediments that existed at the collision site. Very conservatively, at least 100 to 500 billion metric tons of sulfur were released into the terrestrial atmosphere within minutes after the impact.⁴ This sulfur, rapidly transforming into sulfur aerosols, cooled Earth’s surface by up to 10° centigrade (18° Fahrenheit) and kept it that way for many years, even several decades. It generated global acid rains, which ,along with soot and dust, led to severe respiratory distress for all large-bodied land-dwelling animals. “Instantaneous (days to months) destruction of diverse forest communities coincident with deposition of ejecta from the Chicxulub impact” occurred.⁵ To quote from a previous study on the consequences of a large asteroid collision, “The combination of all these physical effects would surely represent a devastating stress on the global biosphere.”⁶ The stress was all the more devastating given that Earth’s life had already been traumatized by the 1.5 million years of on and off super-volcanic eruptions occurring on the Deccan plateau just prior to the collision event.

Darkness, pervasive cold, and suffocating dust and aerosols suppressed photosynthesis, thus bringing about plant and animal extinction. Creatures (like the dinosaurs and animals relying on plankton) dependent on primary producers disappeared. But detritivores (creatures feeding on dead organisms) flourished.

This compression of nearly all the K-Pg extinctions into one near instantaneous, globally pervasive event poses a challenge to non-theistic models for the history of life. It’s difficult enough for Darwinian evolution to explain the appearance of new sets of species from several relatively minor, time- and geographically-separated extinction events. It is far more challenging to explain the appearance of new species from a single mass extinction disaster of such catastrophic proportions as the Chicxulub collision event.

Explaining the rapidity with which mass speciation events followed the K-Pg mass extinction presents another challenge for non-theistic models. Darwinian evolutionary mechanisms are inherently slow and inefficient. Yet in some cases dramatic mass speciation events are measured to have taken place within just thousands of years or less after the K-Pg mass extinction event.⁷

Furthermore, the growing recognition that giant asteroid/comet collision events on Earth over life’s history cannot be rare also creates problems for non-theistic models. Over the past several decades, geologists have discovered evidence for many ancient impact craters measuring in excess of 100 kilometers (62 miles) in diameter. Astronomers have confirmed that two much larger belts—the Kuiper belt and the Oort cloud—complement the main asteroid belt in our solar system. They also have discovered even bigger belts of asteroids and comets orbiting nearby stars.⁸ Additionally, as the Sun orbits about the center of the Milky Way Galaxy, close stellar encounters disturb the dynamics of the solar system’s three belts of asteroids and comets. Thus, several large impact collision events on Earth throughout life’s history were inevitable.

It now appears that the solar system is relatively deficient in asteroids and comets. The deficiency level, however, reveals fine-tuning. In fact, some astronomers argue that the quantity, size, and placement of asteroids and comets should be incorporated into the anthropic principle, which states that the universe, Milky Way Galaxy, and solar system manifest many fine-tuned properties that make the existence of life and humans in particular possible. They point out⁹ that if Earth receives too few asteroid/comet collision events, the planet surface would lack sufficient amounts of the volatiles, refractories, and metals that advanced life requires. On the other hand, too many asteroid/comet collision events would be hazardous to advanced life.

Another manifestation of the fine-tuning design of the rate and intensity of asteroid/comet collision events concerns the faint Sun paradox.¹⁰ As the Sun’s nuclear furnace fuses hydrogen into helium, its core density increases. This increase causes more efficient nuclear fusion, which makes the Sun shine with increasing brightness. Today, the Sun is about 15 percent brighter than it was 3 billion years ago. But a particular ecology of life pulls the just-right quantities of greenhouse gases from Earth’s atmosphere to keep the planet’s surface at the ideal temperature for life.

Mass extinction and mass speciation events must be carefully designed and timed. Anything less fine-tuned would have left Earth with the wrong life at the wrong time and places to make the necessary adjustments to Earth’s atmosphere, continents, and oceans to compensate for the changing physics of our planet, galaxy, Sun, and Moon. For the same reason life’s history on Earth cannot be a mindless process. Someone must be exercising a guiding hand to ensure that biology does not get out of sync with astronomy, physics, geology, and chemistry. The marvel of life on Earth is that it has lasted as long as 3.8 billion years and for virtually all of that long epoch has existed at an extremely high level of abundance and diversity.

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Part 1 | Part 2

In 1980, Luis Alvarez, winner of the 1968 Nobel Prize in physics, and his geologist son, Walter, touched off a controversy when they suggested they had discovered what killed the dinosaurs.

They claimed their detection of iridium enrichment at the Cretaceous-Paleogene (K-Pg) boundary (65.5 million years ago) implied that an asteroid, approximately 10 kilometers (6 miles) in diameter, struck Earth and led to the demise of the dinosaurs¹ and over half of all other species on Earth. During the thirty years since Alvarez’s announcement, scientific opinion has remained divided over whether this mass extinction was caused by an asteroid or by a series of super volcanic eruptions spread over 1.5 million years that occurred on the Deccan plateau (now west central India).

Theological implications complicate the debate and certainly fuel much of the emotion behind it. Volcanic eruptions spread over 1.5 million years would be much less of a shock to life than a single giant impactor releasing, within a few hours, the energy equivalent to more than ten billion Hiroshima-sized atomic bombs. If more than half of Earth’s species were suddenly wiped out only to be replaced shortly thereafter with radically different life-forms designed to more efficiently remove greenhouse gases from the atmosphere and perfectly compensate for the Sun’s increasing luminosity,² then it is difficult, if not impossible, to avoid concluding that God’s hand was behind it all. It is also difficult to get around concluding that the Bible accurately predicted future scientific discoveries when the psalmist, in reference to Earth’s life, declared:

When you take away their breath, they die and return to the dust. When you send your Spirit, they are created, and you renew the face of the earth.³

Recently a panel of 41 scientists from 12 countries and 10 different scientific disciplines has carefully reviewed over 20 years worth of research findings to finally settle the row.⁴ That an asteroid collision occurred approximately 65 million years ago was never in doubt. An ancient impact crater dated at that time lies buried underneath the Yucatán Peninsula in Mexico (see image below). It measures between 180 to 200 kilometers (112 to 124 miles) in diameter.⁵ In analyzing data from more than 350 known K-Pg boundary sites the team demonstrated that all these sites “show a distinct ejecta distribution pattern related to distance from the Chicxulub crater.”⁶ In response to the assertion that the Chicxulub impactor preceded the K-Pg mass extinction event by about 300,000 years,⁷ they note that “orbital cycles in deep-sea sites demonstrate that there is neither a proposed global 300-thousand-year gap nor a hiatus between the Chicxulub impact and the K-Pg boundary.”⁸ On the other hand, the Deccan flood basalt volcanism predominantly takes place during the several hundred thousands of years before the K-Pg event.

The research panel also disputed the claim that multiple time-separated impacts brought about the K-Pg extinction event. In their words, “The pattern of decreasing ejecta-layer thickness with increasing distance from the impact crater is consistent with the Chicxulub impact as the unique source for the ejecta in the K-Pg boundary event deposit.”⁹ An independent study led by geologist Kenneth MacLeod concluded, “Sedimentological, geochemical, and paleontological changes across the boundary closely match patterns expected for a mass extinction caused by a single impact. …There are no other spherule layers in the section.”¹⁰

In their exhaustive review of the evidence, the international panel swept away any remaining doubt about the cause of the K-Pg mass extinction event. The culprit, as Alvarez claimed, was an asteroid measuring at least 10 kilometers in diameter. The physical and chemical effects of this collision event, what those effects mean for Earth’s life, and the debates over creation and evolution will be discussed in part 2 of this series.

Part 1 | Part 2