by Richard William Nelson | Jan 20, 2026
Adaptation is the fifth of the five principles of natural selection introduced by Charles Darwin in The Origin of Species. The long-necked giraffe once served as a popular example of adaptation. Darwin explained –
“The structure of each part of each species, for whatever purpose it may serve, is the sum of many inherited changes, through which the species has passed during its successive adaptations.”
Two twentieth-century contributors, Ernst Mayr and Yuri Filipchenko, however, developed our modern understanding of adaptation in Earth’s biosphere.
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by Richard William Nelson | Aug 20, 2025
Time is the fourth principle driving Charles Darwin’s theory of evolution, “by means of natural selection.” As with the other four principles, time—specifically, the timeframes of Earth’s history—challenges Darwin’s theory of “slight, successive” changes.
The theory of natural selection is contingent on extended periods of time. In The Origin of Species, Darwin wrote –
“I do believe that natural selection will generally act very slowly, only at long intervals of time.”
The evolution of biological timeframes offers fascinating insights into the history of evolutionary theories. “Timeframes” are interchangeable with modern concepts of “timelines” and “timescales.”
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by Richard William Nelson | Feb 19, 2025
Time is the fourth of the five principles of natural selection introduced by Charles Darwin in The Origin of Species. Darwin viewed long periods as essential for the theory of natural selection to even work, writing –
“I do believe that natural selection will generally act very slowly, only at long intervals of time.”
Estimates of Earth’s “long intervals of time” since the nineteenth century have increased exponentially. At the time, most popular estimates were on the order of several hundred million years.
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by Richard William Nelson | Sep 7, 2024
Selection is the third of the five principles of natural selection introduced by Charles Darwin in The Origin of Species. Darwin wrote –
“Over all these causes of Change I am convinced that the accumulative action of Selection, whether applied methodically and more quickly, or unconsciously and more slowly, but more efficiently, is by far the predominant Power.”
To explain selection, Darwin drew a parallel between a breeder’s selection process and natural selection, using pigeon breeding (pictured above) as one example. At the time, breeding pigeons was a prestigious pastime for the elite.
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by Richard William Nelson | Jul 13, 2023
Concepts of biological evolution center on species, the central agent of evolution. This centrality is demonstrated in the title of Charles Darwin’s bestseller —
“On the Origin of Species by Means of Natural Selection”
One of modern biology’s principal functions includes the naming, grouping, and defining of species. However, exploring the history of the term opens a fascinating window into the checkered history of Darwin’s theory of natural selection.
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Adaptation is the fifth of the five principles of natural selection introduced by Charles Darwin in The Origin of Species. The long-necked giraffe once served as a popular example of adaptation. Darwin explained –
