I will sketch out several pre-Darwinian conceptions of human evolution, but I think it's important to note that the perceived relationship between atheism and evolutionary belief (or, the antithetical relationship between science and religion) is, at the very least, a twentieth century concept. The theological rejection of evolution that precipitate the Scopes trial, for example, originated with fundamentalism that crystallized as late as 1910, and even here there are some rather curious figures: the geologist George Frederick Wright was a professor at Oberlin Seminary and contributed an essay to The Fundamentals, while subscribing to Darwinism and later theistic evolution as a geologist. Charles Darwin refers both to God and 'the Creator' in The Origin of Species, and was even trained to be a country parson.

The oppositional framework of religion and science seems untenable to me and several scholars, including Peter Bowler and Martin JS Rudwick, have convincingly shown that religion has in fact had a quite valuable influence on scientific inquiry and the formation of knowledge.

The Comte de Buffon posited in the mid-18th century that species may gradually change (but did not conceptualize particular mechanisms); Darwin's grandfather, Erasmus Darwin, postulated in Zoonomia that the earth is both ancient (on a magnitude of millions of years) and that species have changed remarkably, even posing the existence of the Last Universal Common Ancestor.

Jean-Baptiste Lamarck, a student of Buffon, posed the first widely disseminated theory of evolution, that of acquired characteristics. If it is advantageous for a giraffe to have a long neck, and the animal stretches out its neck over the course of its pre-reproductive life in order to consume more leaves, its offspring will be born with a longer neck.

Now, Lamarck was wrong (though recent epigenetics research is an interesting complication), but his theory underscores the general interest in the 19th century surrounding past life, the recognition of the historicity of the earth and the existence of fossils (variously interpreted as theological 'tricks,' evidence of the deluge, or spontaneously created forms in stone mimicking their organic counterparts).

There were religious accusations against natural history; most immediately William Paley comes to mind, who accused anyone who rejected the watchmaker analogy of atheism, but even then Darwin professed to greatly enjoy Paley's book and that he had nearly had it memorized. More common was the integration of natural theology and transmutation, such as Robert Chambers' Vestiges of the Natural History of Creation.

As for the origin of life itself, nearly all natural historians did adopt a religious point of view. Denis Diderot was one of few professed atheists, and he postulated a quite intriguing vitalist matter; Diderot's metaphysical conception of matter is somewhat unwieldy--one of the more well-known thought experiments holds that a marble statue, ground and mixed into earth, will become the plants that are eaten by the animals that are eaten by humans, so what does it really mean to say the statue is not alive but the human is? What distinguishes the forms of matter? Similar ideas pop up later for Goethe in Elective Affinities - but Goethe was more or less religious, as a 'pantheistic' Spinozist.

Pre-Darwinian concepts of evolution are really quite wonderful, and highlight the the diversity of Early Modern scholars and the intellectual heritage that bleeds into even contemporary sciences.