Darwin did not properly understood laws of inheritance (although somewhere Mendel was founding the law of factors from pea experiments). Darwin's theory had big challenges: inability to deal with blended inheritance as suggested by Jenkins (which would cancel out mutatic variation across generations), and it required far more evolutionary time period than Kelvin's age of the Earth estimate.
The age of the Earth—a quantity of importance in theology, geology, biology and physics—was first estimated using scientific methods by Kelvin. His estimate was based on uniform heat conduction and solid homogeneous interior. Geologists (believers of uniformitarianism) and biologists (Darwinism) required a much bigger estimate. Perry proved the age of earth could be much bigger than Kelvin's estimate if one assumed a partially fluid interior and allowed the mantle to convect.
Discovery of radioactivity and nuclear reactions provided new energy source; major revisions were now required for Kelvin's estimate of the age of the Sun.
Pauling gave alpha helix structure of proteins. Avery and his group established that DNA is responsible for turning nonvirulent bacteria into virulent ones; however, other scientists (including Pualing) did not believe that DNA had anything to do with heredity, rather they believed proteins are the inheritance units. While Franklin achieved good x-ray diffraction photos of DNA, Pauling was bent on convincing peeps about the alpha helix structure of proteins. Soon, Pauling got interested in DNA and published a triple helix structure of the DNA.
Pauling had poor access to x-ray diffraction photographs of DNA and made no special effort to see Franklin's photographs. His three-strand model was wrong—it wasn't even an acid—for it could not release hydrogen when dissolved in water.
Hoyle explained the evolution of stars and nucleosynthesis. Heaver elements upto iron are formed within the stars and are scattered in the cosmos following supernova. However, Gamow wanted most elements to have been created within minutes of big bang. The current accepted picture is Hoyle's.
To account for the expansion of the universe (an implication of Hubble's discovery), Hoyle and others proposed steady state theory. On the other hand, Gamow and others advocated a big bang theory. Much evidence accumulated for a big bang theory (such as cosmic microwave background of Penzias-Wilson); Hoyle was convinced, and he proposed quasi steady state theory. Hoyle did not believe the universe's age would allow biology and complex life to originate.
Einstein's original equations predicted a changing universe. To allow universe to be static (in the sense of steady state), he added the cosmological constant