Belinda wrote: ↑Sun Oct 10, 2021 12:36 am
...
I enjoyed hearing he kept pigeons as a hobby and so was already au fait with artificial selection to change the characteristics of offspring. Speciation was something else (NB His published book was called "On The Origin Of Species").He noted populations of Galapagos finches differed significantly between one island and the next.
There were a lot of prepatory discoveries that he initially used from ...
(1)population studies of London(which showed that where more people struggled, they both had more children AND higher death rates.)
(2)fossils (which showed a lot of species no longer existing than exist suggesting that most species die off and where he recognized that death itself is a significant factor of the 'selection' process that weeds out those that do not (or no longer) 'fit' to the environement.)
(3)geological layers (that have a common universal set of patterns regardless of where one is in the world) [Although not well established yet, the geologists would notice the layering that we now use to define eras. For instance, the lowest levels would have no species, then simple ones, then more and more complex ones up to the dinosaurs showing a distinct cut of of their existence, etc.]
(4)geological mapping (that suggests land masses (continents) linked as though they once were together; this one was what may have suggested why he looked closer at a small scale version of this by the Galapalos islands.)
(5)geological age of Earth (whereby the layering mentioned above suggested Earth had to be much older than we used to think was much earlier)
The above are just some of the major notices from other areas of the then developing sciences which initiates his argument before proposing his theory as set out in "On the origin of the species". He thus postulated that
Variation was important where
population explosions occur and
pruning of life by Death as a selection mechanism. Then he argued for how we humans can affect other animals (
Artificial Selection) first to begin his theory. The latter part of the book then put all these together to show that
Nature Selects in the same way. [We are part of Nature but many would not accept this due to our religious bias of being 'special' with respect to other animals. So he had to argue Nature as an extension or 'generalized' Selector.]
I'm only going mostly on memory (but have the book if I want to check up the particulars). But the logical factors are relatively easy and most of what I mentioned above. This is just an outline though.
I asked what others know here because I am surprised THAT most who are critical of the theory from religious apologetics literally have not read the book and also do not know that Darwin was ONLY a start. What followed Darwin's version became more and more clear by post-Darwinian studies.
Mendel, for instance, had studied peas and where genetics suggested the
mechanism that Darwin would not know in his day.
Statistics and other math also contributed later; new
chemistry knowledge also contributed and so today,
"evolutionary theory" is well developed beyond Darwin.
[For odd reasons, many Christian apologists falsely assume that if you somehow discredit Darwin himself that it would suffice to discredit the theory when what followed him could remove Darwin's historical role and still have enough evidence to assure evolution is true. The theory is not reliant on who the historical contingencies themselves 'evolved' and are not based on personal virtues. Darwin could have potentially become the worst infamous character in the world and it would have no power to remove the evidence and logic used to argue for evolution.]