Every fall I am privileged to welcome a new General Biology class to Southern Adventist University. On the first day the students are nervous and excited to start their journey, discovering the inner workings and hidden depths of biological systems. Most students expect that success in General Biology requires memorizing the textbook’s detailed, comprehensive “facts.” They believe that most of the major questions in biology have been settled, and that they will succeed in learning if they can recite these “answers” on the exams. It doesn’t take long to show them that there are serious flaws in their thinking. They assume they can learn the textbook’s “facts” without examining the worldview they are using to understand them or the worldview of the authors. Even such seemingly simple questions as “What is an organism?” prove difficult to answer when we realize that the appearance and stability of complex, well-integrated biological systems demand an explanation. An explanation that likely changes when one allows Scripture to guide their worldview.
The textbook authors organize the chapters starting with the smallest biologically relevant organization, molecules, and progress to ever larger levels of organization, e.g., cells, tissues, organisms, ecosystems, and biomes. At face value this organization appears logical; it, however, is logical only if we assume that biological systems are built from the ground up rather than arising as well-integrated systems from the start. Why is answering the question “What is an organism?” challenging? And why does the answer depend on one’s worldview?
Let’s start with ourselves. We are organisms; we should be able to determine what an organism is, right? First, we are multicellular, i.e., composed of many distinct cell types that arise from a single cell during development. Our cells have a division of labor, yet they coordinate among themselves to produce a complete, integrated being. This phenomenon alone begins to blur the boundaries between where cells start and end. For example, our cells form sheets that are physically connected and may even share cytosol (the jellylike fluid inside a cell) through structures called gap junctions. Sharing the cytosol means signaling molecules produced in one cell can travel to adjacent cells, causing them to respond as if the signal originated there. Thus, we can think of our cells as distinct units and as a collective unit in which the individual ceases to have meaning, and the unit becomes the focus.
The duality between being composed of distinct units and well-integrated collective units is also evident in siphonophores (such as the Portuguese man-of-war) and even in ant colonies. Siphonophores are colonial organisms composed of distinct, specialized zooids. Each zooid is multicellular and resembles an entire organism in its organization. However, these zooids combine to form a larger conglomerate, which we typically regard as the organism. To a lesser extent, but strikingly similar, the entire ant colony can be regarded as an organism. Individual workers cannot survive or reproduce independently; collective effort is required. In this way, an individual ant functions more like a cell or zooid than as an entire organism, leading some to consider the colony the complete unit.[1]
Siphonophores and ant colonies may at first appear like extreme cases, but humans also share intriguing similarities. As with many other creatures, our bodies contain more non-self cells (i.e., cells that do not share one’s own genome; collectively referred to as our microbiome) than self cells (i.e., cells that share the same genome and originate from the same fertilized egg).[2] It turns out that our body is an entire ecosystem for such microscopic organisms as bacteria, protists, and fungi.[3] Not only do these organisms live in and on us—they are crucial to our development and function. They are necessary for proper immune function, play an important role in digestion, and even influence our nervous system’s development and function. And it is to the nervous system that we turn next.
Human action is required to achieve true completeness. We are not separate from nature, nor are we just one more example of it, and neither of us can reach our collective completeness without the other.
There is growing evidence that gut microbes have bidirectional interactions with our nervous system. The microbes produce chemicals (neurotransmitters, neuromodulators, and hormones) that influence the development and function of our cells, and, in turn, are bathed in the chemical signals that our body produces to coordinate its own activities.[4] This bidirectional, mutual relationship is so important that several diseases/disorders have been tied to its dysfunction, e.g., anxiety and depression, autism, and Parkinson’s disease.
Given how integral and integrated our microbiome appears to be, it becomes increasingly difficult to determine where we begin and end as an organism. Can a human develop and thrive without its microbiome? It appears that we are composed of many well-integrated parts (including both self and non-self cells) and, in turn, form part of a larger, well-integrated system (as we observed in siphonophores and ants).
Now let’s return to our question: “What is an organism?” Here is where a biblical worldview is useful! The creation stories in Genesis 1 and 2 provide a framework for understanding the concept of completeness. In Genesis 1 we see God end each day with the pronouncement that “it was good.” It was only after creation was completed, however, that God proclaimed it “very good.” Thus the totality gained something that each part lacked—true completeness. Further, God gave humanity a unique role: to act as God’s representative on earth. We are to ensure that the rest of creation can fulfill its God-given command to “be fruitful” and “fill the earth” (Gen. 1:28). Human action is required to achieve true completeness. We are not separate from nature, nor are we just one more example of it, and neither of us can reach our collective completeness without the other.
Scripture leads us to look at nature as a well-integrated system composed of other well-integrated systems. And we have ample biological examples that support this view. It may seem like a small difference whether someone assumes organisms are built from the ground up or that they originate as well-integrated systems, but I believe it makes a profound difference in how we approach biology, the questions we ask, and the discoveries that we will ultimately achieve. One of my greatest joys is seeing the next generation of scientists embrace a scriptural worldview and see how it can lead to new ideas capable of changing the world.
[1] C. Detrain and J. L. Deneubourg, “Self-organized Structures in a Superorganism: Do Ants “Behave” Like Molecules?” Physics of life Reviews 3, no. 3 (2006): 162-187; T. Miura, K. Oguchi, H. Yamaguchi, et al., “Understanding of Superorganisms: Collective Behavior, Differentiation, and Social Organization,” Artif Life Robotics 27 (2022): 204-212, https://doi.org/10.1007/s10015-022-00754-x.
[2] A. Mullard and A. Mandavilli, “The Inside Story: The Human Body Teems With Microbes,” Nature 453, no. 7195 (2008): 578+, https://link.gale.com/apps/doc/A183367689/AONE?u=anon~fc7fd0cc&sid=googleScholar&xid=cd46afe0
[3] M. Matijašić, T. Meštrović, H. Čipčić Paljetak, M. Perić, A. Barešić, and D. Verbanac, (2020). “Gut Microbiota Beyond Bacteria—Mycobiome, Virome, Archaeome, and Eukaryotic Parasites in IBD,” International Journal of Molecular Sciences 21, no. 8 (2020): 2668.
[4] L. H. Morais, H. L. Schreiber IV, and S. K. Mazmanian, “The Gut Microbiota—Brain Axis in Behaviour and Brain Disorders,” Nature Reviews Microbiology 19, no. 4 (2021): 241-255.
