Criticisms of evolution by creationists/intelligent design theory includes irreducible complexity, lack of transitional fossils, the second law of thermodynamics, and complexity of DNA and information Theory. According to creation science and intelligent design theory, some biological systems are too complex to have evolved from simpler or less complete predecessors through natural selection. However, evolutionists argue that research has shown that complex systems can evolve from simpler ones through a series of functional intermediates. Examples include the evolution of the eye and the bacterial flagellum. However, this is simply false because other researchers have pointed out that this is not an example of a true increase in genetic complexity, but just a continuation of pre-existing genetic information rather than real evolution. The bacterial flagellum requires an interdependent relationship within its makeup to function properly and it could never have evolved in stages.

According to creation science and intelligent design theory, there are gaps in the fossil record, and transitional fossils do not exists because the fossil record is only decorated with variations of the same kinds of unique animals, which is not true evolution. However, evolutionists argue that numerous transitional fossils have been discovered, such as Archaeopteryx (a supposed transition between dinosaurs and birds) and Tiktaalik (a supposed transition between fish and tetrapods). However ,  creationists, intelligent design theorists, and some evolutionists  point-out that Archaeopteryx is a true bird with unique features because no direct ancestor or descendent has been confirm to be related to Archaeopteryx. Tiktaaliks are not transitional animals because their line of descent has never been confirmed by evolutionists or other researchers using fossil history. Therefore, the fossil record remains incomplete and it  provides no substantial evidence for an imaginary evolutionary process.  According to creation science and intelligent design theory,  evolution violates the second law of thermodynamics, which states that systems tend to move towards disorder. However, evolutionists argue that  the second law applies to closed systems, and the Earth is not a closed system; it receives energy from the sun, which drives the increase in complexity. However, creation science researchers and intelligent design theorists argue that this is simply not true because suppling energy to an open system cannot and never has driven evolution because energy being supplied to an open system needs a conversion factor or biological mechanism or system to increase information and cause true evolution.  According to creation science and intelligent design theory,   the complexity of DNA and the information it contains cannot arise by chance. However, evolutionists argue that natural selection is not a process of chance but one of non-random survival of randomly varying replicators. Mutations provide variation, and natural selection increases complexity over time. However, creation science researchers and intelligence design theorists argue that evolution is purely based on chance because there is no mind or intelligence directing the evolutionary process. Evolution is a religious philosophy based upon faith in naturalism and materialism.  The idea of evolution, present for the last 150 years and widely accepted, has profoundly impacted people’s perspectives on the world. It is a deception to say that they came onto this planet by chance and that they are a “species of animal.” The proposition is false. In addition to this, it teaches children that the sole law in life is a self-centered battle for survival and to maintain their own personal existence. This idea clearly manifested its effects in the nineteenth and twentieth centuries, leading to growing selfishness, moral degeneration in society, the rapid spread of self-interest, ruthlessness, and violence, the development of totalitarian and bloody ideologies like fascism and communism, and social and individual crises as people strayed further from the morality of the Christian and biblical worldview.