WEiT clearly expressed this process, which can be visualized as WEiT biological evolution “model,” in the following statements:
WEiT’s primary perspective of “Why Evolution is True”, it is concisely summarized as:
Now, when we say that “evolution is true,” what we mean is that major tenents of Darwinism have been verified. Organisms evolved, they did so gradually, lineages split into different species from common ancestors, and natural selection is the major engine of adaptation.[Page 223] [emphasis supplied]
WEiT then summarizes in the following statements the basic features that are essential for the foregoing statement to be plausible:
The theory of natural selection has a big job–the biggest in biology. Its task is to explain how every adaptation evolved, step by step, from traits that preceded it. This includes not just body form and color, but the molecular features that underlie everything. Selection must explain the evolution of complex physiological features—.[page 119][emphasis supplied]
But if we can see selection causing small changes over just a few generations, then perhaps it becomes easier to accept that, over millions of years, similar types of selection could cause the big adaptive changes documented in fossils.[Page 125] [emphasis supplied]
Thus, for WEiT to support its concept that evolution is “true,” the “why” must include the following critical components that are expressed as an “equation-like” model:
The components of this model establish the focal points for the analysis in this blog.
For the model to represent a plausible description of how animal forms developed, the nature of the model’s “consequences” (traits, new species, body plans) and “causes” (small changes) must, as expressed by WEiT, be explained.
Thus, the model is the cumulative expression into which all of WEiT’s explanations and examples must be incorporated as the process of Darwin’s gradualism.
