Jenyns was basically a biblical fundamentalist, which meant a creationist. He would have gotten along famously with Captain FitzRoy, also a strong believer. Debates (after grace) over wine and meals would not have been about the origin and distribution of variation in plants and animals. But can we doubt that we’d have learned about evolution anyway? No, not at all.
At roughly the same time period, another not-so-wealthy naturalist was doing his natural history in remote parts of the world (first Amazonia, then Indonesia), and he developed a clear idea of the ‘transmutation’ of species on his own. In 1858 he sent a brief manuscript explaining his idea to a correspondent, one who had become well-known among British naturalists, the same Charles Darwin.
This stunned Darwin who had been working ploddingly on his own theory of evolution. But with very good grace, he hastily assembled some bits and pieces to show his ideas (and, perhaps not so incidentally, his priority) which along with Wallace’s manuscript were read to the Linnaean Society. The world had been told, but hardly anyone was listening until the following year when Darwin published his lengthy assertion of the idea that the diversity of life arose through a gradual historical process—his Origin of Species.
Both Darwin and Wallace were famously influenced by economist Thomas Malthus’ book arguing the inevitable pressure of growing population on available resources, and that idea led to the idea that it was competition for such resources in Nature that inevitably favored (selected) those better competitors in terms of their future reproductive success. Adaptation by natural selection was the process that they argued explained the diversity and functional traits of species.
But the two ideas were rather different
Darwin and Wallace placed very different stress on how this process worked. Darwin stressed competition among individuals for survival or mates, so that in a given location the better-endowed individuals would have all the fun at the expense of their less-suited contemporaries. Since traits of organisms were at that time viewed as caused by the deterministic effects of some causal elements (that, in his way, the Moravian monk Gregor Mendel was studying, unbeknownst to Darwin and Wallace). The most successful competitors would transmit these elements to their offspring, and the elements would thus proliferate over time to replace less-successful elements.
Differential success was also important to Wallace. He recognized that, of course, individuals proliferate well or not, but his stress was more on competiton among groups or species, and/or of groups against the limits of their environment. Some groups would do well and modify as successfully adapted species while others would wane. It was the group characteristic, even though of course comprised of individual members, that told the tale.
Now, if Darwin had stuck to his guns, so to speak, we would be talking today of Wallacian, not Darwinian, evolution. Whatever we would have discovered about the nature of inheritance, whether or not by now we had discovered DNA and its functions in the cell, we may very well not have developed our ferocious obsession with individual competition, an obsession that often drives us to view genes as if they themselves, rather than the whole individuals or whole populations or whole species, were the central competitors in the evolutionary race.
I think things today might be very different, and we might not be trying to enumerate individual genes in individuals’ genotypes when it came to accounting for genetic causation, genomic and even adaptive evolution. The reason isn’t that individuals and their genotypes are unimportant, nor that some mysterious function unrelated to individual genes reifies the concept of population to give one population an edge over another. The reason would simply be a different way to understand that the dynamics of both individuals and their genes are fundamentally aggregate phenomena. And we’d have very different ideas on the role of populations and context.
In Part II, I’ll consider the collective nature of genomes in populations and how that affects their evolution in group-contextual ways. Then in Part III, I'll try to show that individuals are themselves similarly context-driven populations of genotypes.