Entropy
Entropy is a measure of disorder in a system, first postulated by Lazare Carnot in 1803.
Creationist Henry Morris argues that the law of Entropy, also known as the Second Law of Thermodynamics, disproves evolution: "...the Second law, however, that wipes out the theory of evolution. There is a universal process of change, and it is a directional change, but it is not an upward change."[1]
However, the second law allows local decreases of entropy at the expense of an equal or greater increase elsewhere: in short, the second law is only violated where entropy decreased overall in a closed system, which the Earth is not, disproving Morris' argument. Furthermore, it is unclear that evolution requires even a local decrease in entropy: while the "order" of a species is subjectively greater due to evolution, this is not a thermodynamic concept. The second law is a precise, mathematically rigorous statement about heat flow, not a grand philosophical treatise on order and chaos.