Punctuated Equilibrium
Niles Eldredge & Stephen Jay Gould · 1972
"Species don't typically evolve at a smooth, constant rate — the fossil record shows long periods of near-stasis punctuated by relatively rapid bursts of change, usually tied to speciation events, rather than continuous gradual transformation."
The fossil record has an awkward feature Darwin himself worried about: it's full of gaps rather than smooth transitions. In 1972, two paleontologists argued the gaps weren't missing evidence — they were the actual pattern.
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Nothing in Biology Makes Sense Except in the Light of Evolution
"By the mid-20th century, genetics (Mendel's discrete units) and natural selection (Darwin's mechanism) had been fused into a single coherent framework — the Modern Synthesis — that made evolutionary theory the organizing principle underneath every other branch of biology."