Irreducible complexity is the state of a biological mechanism being so complex that one missing element renders the entire organism being unable to pass on its genetic information. The concept of irreducible complexity is a challenge for the theory of evolution because if genetic mutation is the mechanism through which organisms evolve, how can these complex mechanisms have evolved and survived up until the present day when a gradual process of evolution would have rendered the organism unable to reproduce or survive without this complex biological structure fully intact? While many examples can be given, I will just list the ones I find the most compelling.
The process of metamorphosis, as seen in insects such as butterflies, is an incredibly complex reorganization of the catepillar. The larva disintegrates and rematerializes as a more complex flying insect. How did the catepillar avoid extinction when it has to first become a butterfly in order to reproduce? Without metamorphosis and then sexual reproduction, the catepillar could not have survived to the present day. How does metamorphosis evolve when it is a highly complex process of taking a non-reproducing organism and turning it into a reproducing one? The reproducing organism must first have existed in order for its larva to exist and acquire the ability to metamorphosize through genetic mutation according to evolution. But how can its reproducing stage exist without metamorphosis in the first place?
The flaggelum of the E. Coli bacteria is a biological motor and living piece of technology. The bacteria uses reversible motors that control shafts which rotate flagella that act as propellers. The entire process is powered by protons rather than electrons as in an electric motor. The motor uses rings, a bushing, a central rod, an S-ring, and a rotor which is the terminal ring. Diagrams of the bacterial motor can be found all over the internet for you to study further. How could the bacteria survive and reproduce without the ability to move using its flagella? How could such a device evolve over time through random mutations?
Sexual reproduction requires both a male and female partner who are genetically compatible with each other. How can a male and female pair have evolved independently of each other at the same time and at the same place? Extinction would set in unless all of the conditions for sexual reproduction exist at the same time. How could an asexually reproducing creature evolve into a sexually reproducing one? The ability to conceive and nurture unborn life must also have evolved at the same time for sexual reproduction to occur. The intricate process of fertilization is not fully understood even in our day. This is why even evolutionists can speak of the “miracle” of life.
The immune system is necessary for survival in order to fight off invading bacteria and viruses. The body’s defense network can keep track of invading organisms and learn from past victories over disease. But how could the genetic information that supports the immune system have evolved in the first place? An immune system is necessary for survival but existence is first required before the immune system could develop. The organism would have died before the immune system could have evolved. The genetic information for life to exist must have come into existence at once rather than through millions of years of random genetic mutations.
Other topics that could be discussed are: the human eye, photoreceptors, the cupped eye of marine limpets, the biochemistry of vision, the bombardier beetle, the making of proteins, amino acids, RNA, mRNA, DNA transcription, gene regulation, the binding of proteins to catalyze a chemical reaction, cilium, the fibrin protein network and blood clotting, the animal cell, mitochondria, vesicular transport, photosynthesis, antibodies, biosynthesis of the AMP, symbiosis of cells, cell membranes, protein structure, the four levels of nucleic acid structure, lipids, and polysaccharides. While not an example of irreducible complexity, I find it hard to believe that anyone can think that the leaf-tailed gecko, which might as well have “God Exists” painted on its body, could possibly evolve through random genetic mutation.
For more evidence of God’s existence based on the world around us, see Walt Brown’s book In the Beginning.