Little kids love to ask, “Why?” So do skeptics; however, their “why” questions aren’t asked to gain insight. Instead, they are rhetorical—posed to highlight inconsistencies between the way the world actually is and the ideal that arises out of the Christian worldview. In this vein, skeptics object to the notion of creation and intelligent design by asking, “If God is responsible for creating life, why are there so many ‘bad designs’ in nature?”

Even though biological systems appear to be designed for a purpose, skeptics are quick to point out features that appear to be cobbled together by evolutionary processes from preexisting structures. They assert that poorly designed systems aren’t what anyone would expect if an all-powerful, all-knowing, and all-benevolent Creator brought life into existence. On the other hand, marginally designed systems—which appear to be kludged together—are exactly what one would assume if evolutionary processes are responsible for life’s origin, history, and design.

One example of intracellular biological structures that seem to be kludged together isorganelles, such as mitochondria and chloroplasts. Life scientists point to the genomes found in these organelles as evidence for their evolutionary origin. Each of these subcellular components possesses a small, circular piece of DNA housed within its interior (the lumen). Mitochondrial genomes are around 20,000 base pairs in size, encoding about 35 to 40 proteins. Chloroplast genomes are around 120,000 base pairs in size, encoding between 60 and 100 proteins. For reference, the smallest known genome—found in the bacterium Mycoplasma genitalium—is comprised of about 480,000 genetic letters, specifying around 500 proteins.

Evolutionary biologists believe that these two organelles originated through a process known as endosymbiosis. According to this idea, complex eukaryotic cells originated through a symbiotic relationship among single-celled microbes when free-living bacteria and archea were taken inside another cell as an endosymbiont. Presumably, mitochondria are derived from Rickettsiales, and chloroplasts from cyanobacteria. Once taken inside the host cell, these microbes established a permanent symbiotic relationship with the host, with one cell living inside the other. After this event occurred, the endosymbiont (engulfed microbe) and the host became mutually interdependent, with the endosymbiont producing food for the host cell. According to the endosymbiotic hypothesis, over time the endosymbionts evolved into organelles through a process referred to as genome reduction. This reduction resulted when genes from the endosymbiont’s genome were transferred into the genome of the host organism. Eventually, the host cell evolved the machinery to produce the proteins needed by the endosymbiont to transport those proteins into the endosymbiont’s interior. During the transformation from endosymbiont into organelle, the genome reduction was extreme. For example, a typical cyanobacterium has over 2,000 genes, easily 10 times the number of genes found in a chloroplast.

In light of these processes, the presence of reduced genomes in mitochondria and chloroplasts seemingly represents the vestiges of the evolutionary origin of these two organelles. This begs the question: Why haven’t all of the genes in these organellar genomes been transferred to the host genome? According to some evolutionary biologists, the partial genomes of these organelles could be viewed as transitional in nature. Given more time, the transfer will eventually become complete. In support of this view, they point to other organelles such as mitosomes and hydrogenosomes, which completely lack genomes. Presumably, the gene transfer process has been completed in these endosymbionts-turned-organelles. They also point to the fact that mitochondrial genomes from different organisms possess a differing number of genes, connoting that gene transfer is in differing stages in these organisms.

Maintaining organellar genomes is a costly prospect for the host cell. Typically, a couple hundred proteins are needed to support the production of proteins encoded in mitochondrial genomes. This appears to be an unnecessary feature of the cell’s chemistry because it would be more efficient to produce all the proteins in the cytoplasm and then transport them to the organelles. Evolutionary biologists take this inefficiency and waste as added support for the evolutionary origin of these organelles.

Skeptics versed in biology reasonably ask why an all-knowing, all-powerful, and all-benevolent Creator would produce organelles with genomes. Recent work by investigators from Sweden provides an answer to this question.¹ Their research supplies a reason for why organelles possess genomes and why these genomes must encode proteins—albeit, a limited number.

The researchers demonstrated that the proteins encoded by mitochondrial and chloroplast genomes have distinct structural features. (Namely, they are proteins associated with the organellar membranes, comprised of a large number of hydrophobic amino acids.) If these proteins were encoded in the nuclear genome and produced in the cytoplasm—instead of the lumen of mitochondria and chloroplasts, as they actually are—the proteins would be transported to the endoplasmic reticulum(ER) instead of the mitochondria and/or chloroplasts. The cell’s machinery that directs proteins to the ER can’t discriminate between the proteins of the ER and a select number that should be targeted to mitochondria and chloroplast because of the common structural features these two groups of proteins share. Therefore, to ensure that the appropriate proteins wind up in the membranes surrounding mitochondria and chloroplasts, these biomolecules must be produced in the interior of these organelles. This requirement entails that these organelles have genomes within their lumen to encode the information needed by the organelle’s machinery to make these specialized membrane proteins.

So, a biochemical logic undergirds the structure and function of mitochondrial and chloroplast genomes. The existence of this rationale makes it reasonable to view organelles, such as the mitochondria and chloroplasts, as the Creator’s handiwork. Like most biological systems, these organelles appear to be designed for a purpose. So when a skeptic asks why organelles have genomes, creation and intelligent design proponents now have a ready answer.

On May 25, 1961, President John F. Kennedy gave the United States of America a national goal of “landing a man on the moon and returning him safely to the earth.” The president went on to say, “This decision demands a major national commitment of scientific and technical manpower.” Among the numerous complexities surrounding this task, a critical question arose: How could a spacecraft navigate the 238,900 miles of empty space from Earth to the Moon?

In an airplane, one manner of navigating is called dead reckoning. With this technique, all that is needed is a map, a timepiece, a velocity indicator, and a compass (plus a compass angle or direction must be identified). However, the Apollo spacecraft needed a navigation system that could dead reckon without a compass. The task to create one was awarded to the MIT Instrumentation Laboratory of Dr. Charles Stark Draper, remembered as “the father of inertial navigation.”

Through careful research and experimentation, Draper’s laboratory developed inertial measurement units (IMUs) that used gyroscopes to measure rotation in each of the three orthogonal axes. Additionally, accelerometers were developed to measure translation through space in the same three axes. With three gyros to detect rotation in the three axes, plus accelerometers to detect linear acceleration (translation) along the same axes, and devices to quantify these measurements, you have an IMU. With these IMUs (redundant systems) integrated with the spacecraft’s flight computer, thrusters, engines, and data on the known positions of Earth and the Moon, you have a complete inertial navigation system (INS).

What is remarkable is that the same functional parts described above for the INS have biological counterparts in the human ear.¹ For the detection of linear acceleration (translation through space), humans have the utricle and the saccule, otolith organslocated in the inner ear. The utricle is capable of detecting movement along the horizontal plane (x- and y-axes). In the otolith organs, tiny hairs called stereocilia andkinocilia detect these deflections. The stereocilia and kinocilia are embedded in the cupula and produce differential electrical nerve signals. The signals are conducted along cranial nerves to the brainstem. The saccule similarly detects movement in the vertical plane (z axis), as when riding up or down in an elevator. Just as in an IMU, these parts are all closely associated and packaged together in the vestibular systemof the inner ear.

To get an idea of how this system works in humans, imagine that three lucky football fans are randomly selected to compete in a halftime contest of navigation. Each contestant in turn is seated in a golf cart on one goal line, facing the opposite goal line. They are then blindfolded and driven around the field for 30 seconds on a course that involves changes of accelerations and turns. At the end, they are awarded points for their ability to determine which side of the 50-yard line they are on, which sideline they are closer to, how many yards they are from the nearest goal line, and which direction they are facing. In other words, this is a test of inherent dead reckoning skill. How would a human accomplish this?

Since the lucky fans knew their starting point, they might be capable of imagining their stopping place by sensing their changes in position. Certainly, the path could be complicated enough to overwhelm their navigation system, but some individuals could likely do a very good job of it.

Spacecrafts’ INS have a tendency over time to accumulate small errors that could turn into larger errors unless there is some other intermittent input to provide occasional correction factors. These may come from a ground-based radio navigation system, satellite-based navigation (GPS or GLONASS), an uplink from ground telemetry, an integrity channel, or manual correction from a navigator on board using a sextant (as on the Apollo missions). Humans’ inherent INS also uses inputs to correct our sense of position and balance. These may include visual or auditory cues and somatic sensations.

Our system is also connected to muscles of the body that may respond with certain reflexes when we are out of balance or falling. The University of Rochester Medical Center Health Encyclopedia describes it this way:

For example, when you trip and fall, reflexes automatically command your hands and arms to reach out and break your fall. Muscles will contract throughout your body to minimize injury. But what if you were carrying a priceless object, say, a Ming vase [or an infant]? Would you drop the vase [or baby] in order to use your hands to break the fall? Not necessarily, experts say. Within 10 to 30 milliseconds after tripping, the conscious motor centers of the brain would take control of the fall, weighing the chances of breaking the vase versus breaking your neck. If the object in your hands is important enough to you, you can modify the reflex action and keep a grip on the vase [or baby, accepting the likelihood of greater personal injury].²

This ability to suppress our protective and “primitive” fall reflex is an unexpected capacity given the biochemical assumptions of the origin of life, or the neo-Darwinian accounts of the evolution of life. However, such a capacity would be expected given an intelligent cause for our existence.

When reflecting on the INS created to achieve a lunar landing, the skill, artistry, and ingenuity that went into the system may invoke awe and admiration. How much more astounding, then, is the fine-tuned system built into humanity? This system of systems that brings together locomotion, situational awareness, means to correct for out-of-balance situations, and an open-ended navigation system is truly remarkable and demonstrates tremendous intelligence in its design—referring, of course, to the human version that the mechanical one merely mimics.

Dr. Eddy M. del Rio

Dr. Eddy M. del Rio received his MD from Saint Louis University in 2004, and currently serves as a practicing physician for the Veterans Health Administration in the greater Springfield, MO region.

“NASA Finds Earth-like Kepler-452b: Discovery May Help Prove We’re Not Alone”

“What’s Life like on Kepler-452b? A Little like This, Maybe?”

“NASA Finds ‘Earth’s Bigger, Older Cousin’”

“Kepler-452b: What It Would Be like to Live on Earth’s ‘Cousin’”

So read the headlines based on a NASA press release about the most recent “habitable planet” discovery. Here’s what really happened:

NASA’s press release actually contained more circumspect language in claiming to have “confirmed the first near-Earth-size planet in the ‘habitable zone’ around a Sun-like star.” NASA did label Kepler-452b (the exoplanet under scrutiny) as Earth’s bigger, older cousin, but clearly stated that the find represents an important milestone in the journey toward locating another Earth. The discovery of Kepler-452b demonstrates for the first time that scientists have the capacity to detect something akin to Earth orbiting around a star like the Sun. Previous claims of potentially habitable planets involved objects closer in size to Earth, but these were orbiting M dwarfs—stars much smaller than the Sun.

According to an article published in the Astronomical Journal, the exoplanet in question orbits a G2 star with an estimated age of 6 billion years and a surface temperature of 5,757 K (kelvin). For comparison, our Sun is a G2 star, is 4.6 billion years old, and has a surface temperature of 5,778 K.¹ The exoplanet’s diameter measures 60 percent larger than Earth’s and orbits in a period of 385 days. Given the luminosity of its host star, the authors note that Kepler-452b always resided in the habitable zone (the more optimistic range) and will continue to do so for the next 3 billion years. The larger diameter of Kepler-452b puts it in the super-Earth category, but research indicates it has a better than even chance of being rocky.

While recognizing the importance of this find in the search for an Earth twin, a couple of caveats are in order regarding the potential habitability of Kepler-452b. Many super-Earths end up as giant gas balls depending on the environment in which they formed. According to the paper, this one has just under a 50 percent chance of accumulating so much gas that it has no rocky surface. Even if a rocky surface exists, other research shows objects like Kepler-452b usually acquire dense atmospheres with pressures that prevent life on the planet.² Even if Kepler-452b contains a rocky surface and a thin atmosphere, the development of biospheres may require so many rare events that it never happens.

Scientists continue to make steady, and sometimes spectacular, progress toward finding Earth-like planets orbiting stars other than the Sun. As they do so, they draw closer to answering the ultimate question of whether life exists beyond the confines of Earth. The more they discover exoplanets that resemble Earth, the greater our tools become to evaluate the rarity of Earth’s capacity to host abundant and diverse life.