So I was listening to a brief discussion of binomial nomenclature (blast from my intro bio past) when it dawned on me…doesn’t the very idea of aggregating species into families, species and so on, imply kinship? e.g. isn’t the idea of an evolutionary tree already present in the scheme that Linnaeus set out more than a century prior to Darwin?
I’m wondering if the Origin of the Species was not quite as revolutionary as it’s presented to be, if there was already a widespread inkling about evolution already.
In other words, do we carry the same kind of mythology about pre-Darwinian thought (that they didn’t “know” about evolution at all) that we carry about Columbus (that everyone thought the Earth was flat before him).
This may really be a GD thread, but since technically I’m asking a more fact-based “fight my ignorance” question, I’m going to put it here. I’m hoping somebody has a good enough understanding of the intellectual history to help me out.
No one familiar with the history of biological science would ever claim that Darwin created the first theory of evolution. What Darwin accomplished was to put together a description of the mechanism for the process of evolution, (lacking only the genetic component for the basic theory). His concept that natural selection was the process by which random variations were selected has proven to be a more accurate description than earlier concepts such as that a parent would acquirte characteristics through need or desire, passing on those traits to progeny.
It is not quite true, however, that the Linnaean model required an evolutionary tree. Nothing philosophically prevents all life forms to have been created in families. The fact is that the evidence conclusively points against that and seen in retrospect, the evolutionary origin of related species, etc. seems pretty clear–almost obvious–but the thinkers of the eighteenth century did not have the retrospective view available to them.
Linnaeus first proposed his binomial scheme at a time when his own views involved species being rather strictly fixed. He made it clear that he believed that all species that had ever existed must have been created by God at Creation. His scheme was thus an attempt - modest and provisional - to understand how God had ordered the world. And trying to order stuff by classifying into categories and sub-categories is a pretty natural scheme to suggest, even in circumstances that have nothing to do with descent. (Historians at this point usually get great mileage out of exploring the possible influence of all sorts of earlier classification schemes in other fields on him.)
Later on in life his views on the point softened and he discussed the possibilty that some species had come about at later times. The primary mechanism he considered was hybridisation, whereby new species could be formed by crossing primordial ones. At times he speculated that the divisions at the genus level might reflect the set of species originally created. But there’s little sense here that the process is creating anything new: it’s just doodling in the more minor details in the grander scheme of God’s conception.
On the wider history, this talk.origins article provides an intro to how pre-Darwinian thinking separately covered most of the individual components that went into the Origin’s “one long argument”. It is an extremely widespread myth that all pre-1859 thinking was dominated by the notion of divinely-created fixed species. That was already an old-fashioned way of thinking at the time, even at the level of popular culture.
Not only was Darwin not by far the first to introduce the notion of evolution; the basic principles were laid out by James Burnett and Pierre Louis Maupertuis, along with some general schemes that resemble very skeletal arguments for natural selection. Darwin’s own grandfather, Erasmus Darwin, presented theories of evolutionary mechanisms in his book on pathology, Zoönomia, although the more resembled those of the inheritance of acquired characteristics of Lamarck, who of course also preceded Darwin.
Even (Charles) Darwin’s true contributions–his theories of natural and sexual selection, and the decades of research supporting thereof–were not unparalleled among his contemporaries; his correspondence indicates that he was rushed to publish On The Origin of Species by the essay On the Tendency of Varieties to Depart Indefinitely From the Original Type by naturalist Alfred Russel Wallace, which Wallace had sent to Darwin to review, and which Darwin was shocked to read as it was essentially an abstract of his own work. While Darwin and Wallace differed on minor details of the overall theory and examples confirming it, the thrust of both theories were virtually the same.
So none of what Darwin presented was a great surprise to the natural scientists of the day, or indeed, to the general public who had a demonstrated appetite for revolutionary advancements in science that challenged conventional views. Species was a very popular book (with five editions IIRC and multiple printings of each), and while his later books (The Descent of Man, The Expression of the Emotions in Man and Animals) were more challenged and somewhat less well received, they were still quite popular, all the moreso for the controversies, interpretations, misconstruations, and attempts to define a specific mechanism by which inheritance could operate.
Of the latter, clues were put together by Gregor Mendel in his work with heredity and Swedish botonist Karl Wilhelm von Nägeli, but it wasn’t until August Weismann’s discovery of meiosis and his germ plasm theory that a method for transmitting inheretic characteristics was to be had. Walther Flemming should probably be mentioned somewhere in there as well, though he didn’t make the necessary connections and was apparently unaware of Mendel’s work. It was, of course, the famous discovery of DNA transcription and replication that gave a complete explanation, but despite the inference, Darwin’s theories were outstandingly apropos.
Natural scientists of the post-Enlightenment period were intent on finding the “meaning of God” through His creations, and were often dissecting and classifying in order to delve some deeper order or meaning. Linnaeus and his eponymous nomenclature were merely another effort in that vein, and he had no interest or belief in falsifying or debunking traditional fundamentalist religious belief; quite the opposite, actually. That’s okay, Max Planck never accepted that light was quantitized, either, and considered the physical law that bears his name to be “a purely formal assumption” with no physical reality; Einstein and Bose had to give his “formal assumption” a rigorous empirical model and formal derivation, respectively.
In addition, Linnaeun* classification wasn’t always cut and dried. Based purely on anatomy, the relationship of various species was sometimes debatable. For example, you might be forgiven for presuming that the aardvark is some sort of Edentate unless you get into very obscure technical details about teeth. A number of marine invertebrates are still of very doubtful relationship or have to be assigned into their own phyla. Still, what Linnaeus showed was that the living organisms of the world aren’t arbitrary in their features, which was an indispensible first step towards an evolutionary theory.
*mangled Latin? My apologies.