Studies on evolution have made significant progress in multiple disciplines, but evolutionary theories remain scattered, complicated, elusive, and controversial. To address this issue, a novel evolutionary theory is deduced from thermodynamics in this article. As per the formula of Gibbs free energy, carbon-based entities (CBEs) on Earth tend to absorb more energy. This is the evolutionary driving force leading to organic synthesis of higher-hierarchy CBEs (HHCBEs). The organic synthesis raises the amount of HHCBEs and increases the structural complexity and hierarchy of CBEs. Increased structural complexity and hierarchy spontaneously offer complicated functions to HHCBEs. Genetic mutations, epigenetic changes, and uninheritable variations provide diversified HHCBEs for natural selection which is redefined as survival of the fit and elimination of the unfit, leading to increase of diversity and fitness of HHCBEs. Order in biology resulting from permanent natural selection is largely contrary to order in physics. Natural selection acts on the overall fitness involving all traits through the co-action of positive selection and negative selection. Natural selection can establish biological traits in short geological periods. Different combinations of traits can lead to sympatric speciation targeting the same niche. Altruism, collaboration, and obeying rules with balanced freedom are all important throughout the CBE evolution which harbors three overlapping phases including chemical evolution (abiogenesis), biological evolution, and group evolution. Altogether, this theory termed the CBE evolutionary theory (CBEET) suggests that evolution which favors fitness and diversity is driven hierarchy-wise by energy. It reveals the driving force of evolution and reestablishes the key role of natural selection. It integrates with advances from multiple disciplines and provides simple and rational answers to some evolutionary conundrums. It removes several elusive or erroneous views including the one regarding negative entropy. It bridges natural sciences and social sciences and sheds novel insights into harmonious development of human society.