October 9, 2023 | Jerry Bergman

See Intelligent Design in a Heartbeat

A heart starts beating in a
coordinated flash like a
marching band begins


by Jerry Bergman, PhD

A common argument for intelligent design is irreducible complexity. Irreducible complexity refers to any machine or system that requires two or more parts in order to function as it was designed to function. Examples of irreducible complexity include all molecules, proteins, mousetraps, organelles, and organisms such as humans. Although popularized by Michael Behe who used the concept to defend intelligent design, the irreducible complexity concept has been used by a wide variety of academic disciplines for centuries. [i]

One common example is the human body. As any anatomy student knows, when an organ is discussed, its components are detailed as to why they are critical for the system to function. The mammal heart will not function without all of its central parts, including the valves, the pacemaker, the walls, and its coronary arteries and veins. The fact of irreducible complexity, such as illustrated by this example, is a major problem for evolution.[2]

One argument against irreducible complexity that evolutionists use is “co-option”. Co-option is the idea that a trait supposedly evolved for one purpose, but then is subsequently co-opted for another propose. The most well-known example claimed by evolutionists is the

gas bladder, that “organ deluxe” for regulating buoyancy in teleost fishes…  In teleost fishes, gills have assumed all the burden of respiration, while the gas bladder has been sealed off from the gut and now functions in buoyancy. In the lobe-finned fishes, on the other hand, gills eventually disappeared as the gas bladder became increasingly modified to serve as a lung.[3]

This theoretical story is told as if the details of its evolution have been empirically and historically documented, which they haven’t. Co-option is often referred to as ‘pre-adaptation’. McLannan notes that

there is a glaring problem with the word “pre-adaptation” itself. It is teleological; that is, it implies there is a direction or purpose to evolution (to make the trait adaptive), when in fact it is impossible to predict with any degree of accuracy the future of a biological character based on its current state. Evolution does not solve future problems. It is a process of the here and now that has ramifications for the future that we can recognize only in hindsight.[4]

This is precisely why there exists much concern with the validity of “co-option”.

Adult zebrafish (Wiki Commons)

The Study of Zebrafish

New research of zebrafish provides some insight into irreducible complexity. Zebrafish are named after zebras because their bold black lines situated along their sides resemble those of a zebra. They are a favorite animal used for research because its entire genome has been sequenced, its genetic manipulation is comparatively easy, and it has high fecundity, external fertilization, and rapid development. Zebrafish eggs are fertilized and develop outside the mother’s body, thus it is an ideal model organism for studying the early development of an organism. A further advantage is that its embryo is nearly transparent.

Harvard University Professors Bloomekat and Chi’s zebrafish research concluded that the “heart cells in zebrafish start beating suddenly and all at once to form a synchronized heartbeat.”[5] When zebrafish hearts are developed, only 24 hours after it hatches, each cell can beat on its own.[6] Cell beating would not be selected by natural selection until the heart and circulatory system existed and were already functioning. As the authors say, “the first heartbeat occurs even before formation of the primitive heart tube (the first functional structure formed during heart development).”[7]

In other words, the fish’s heart is operational even before the tubes which carry the blood to the body have been formed. It is working even before it has a function in the fish in anticipation of the rest of the system. Unlike the adult zebrafish heart, the embryo heartbeat is not coordinated by specialized pacemaker cells.[8] The Harvard University researchers discovered that zebrafish “heart cells start beating suddenly and all at once as calcium levels and electrical signals increase. Moreover, each heart cell has the ability to beat on its own, without a pacemaker, and the heartbeat can start in different places.” Specifically, the researchers, using fluorescent proteins and high-speed microscope imaging

captured changes in calcium levels and electrical activity in heart cells of developing zebrafish embryos. To their surprise, they discovered that all the heart cells abruptly transitioned from not beating to beating — characterized by simultaneous spikes in calcium and electrical signals — and immediately began beating in sync… like somebody had flipped on a switch.[9]

The heart first keeps pace without a pacemaker clock, and the individual cells rapidly cooperate producing a regular heartbeat that “is organized very quickly at the start of life from what seems to be a total mess.”[10]

Zebrafish embryonic development (Wiki Commons)


The zebrafish cells were specifically designed to beat, which serves no life-giving purpose until later. This is an example of designed “preadaptation”. When only a few cells are beating, the electrical field they produce causes some coordination of the beating. This is a “useless” step which is only functional later when they aggregate and form a functional heart, a response that had been programmed into the cells to occur.

Next, the circulatory system has been designed to carry nutrients and oxygen to the heart to allow it to develop and function. The heart and circulatory system in turn supply nutrients and oxygen to the entire body. For the animal to live, all of these independent designs must exist, and, if any one of them is lacking, the zebrafish will die. The Bloomekat and Chi research has shown that the zebrafish cell design is required for its life.


The researchers had expected a gradual development of the Zebrafish from a fertilized cell to an adult. Instead, “Rather than individual cells gradually coming online, the researchers found that the cells suddenly go from silent to fairly regular beating… All of a sudden you see this big flash” when this happens, explained one of the study’s authors.[11] This unexpected sudden flash, the “abrupt transition from silence to tissue-wide activity intrigued the research team. It’s almost like you have to get a bunch of people to march in sync without them ever having walked before.”[12] Of course, the fishes’ behavior is not “like you have to get a bunch of people to march in sync without them ever having walked before” but it is actually like a bunch of people that march in sync because they have been programed by their DNA to march in sync on cue. They behave as they were programed to behave.

The cells were programmed by an intelligent designer to respond, to beat, then to respond to the electrical stimuli, and later in the aggregation to beat in sync. This is another example where the creation worldview has proven correct. When it was discovered, creationists such as myself were not in the least surprised.[13] In humans, pre-designed behavior enables the assembled heart to beat about three billion times in a typical human lifetime.[14]


[1] Bergman, Jerry. The Last Pillars of Evolution Falsified: Further Evidence Proving Darwinian Evolution Wrong. WestBow Division of Thomas Nelson and Zondervan, Bloomington, IN, 2022.

[2] Bergman, 2022.

[3] McLennan, Deborah. The Concept of co-option: Why evolution often looks miraculous. Evolution: Education and Outreach 1:247–258; https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-008-0053-8, 2008.

[4] McLennan, 2008.

[5] Caruso, Catherine. How the heart starts beating. Harvard Medical School;
https://hms.harvard.edu/news/how-heart-starts-beating, 27 September 2023.

[6] Bloomekat, Joshu, and Nel Chi. Coordinating the first heartbeat. Nature 622(7981):37-39; p. 37 https://www.nature.com/articles/d41586-023-02938-2, 27 September 2023.

[7] Bloomekat and Chi, 2023.

[8] Bundel, Shamini. The very first beat: how a heart starts to pulse. Hours of footage of zebrafish embryos let researchers capture and study this key moment in development. Nature;  https://www.nature.com/articles/d41586-023-03052-z, 27 September 2023.

[9] Caruso, 2023.

[10] Caruso, 2023.

[11] Gerhard, Danielle. Emerging from silence: Capturing the first heartbeat The Scientist;
https://www.the-scientist.com/news/emerging-from-silence-capturing-the-first-heartbeat-71396, 27 September 2023.

[12] Gerhard, 2023.

[13] Gerhard, 2023.

[14] Bloomekat and Chi, 2023. p 37.

Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,800 college libraries in 27 countries. So far over 80,000 copies of the 60 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.

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