Biology 101
Life On Planet Earth
23 February, 1998

Principles of Evolution

The History of Evolutionary Thought

• What is a species?

• The philosophies of Plato and Aristotle influenced early Christian beliefs.


• Evidence supporting evolution was discovered even before Darwin's time.


• Charles Darwin's voyage on the beagle sowed the seeds for his theory of evolution.


• Darwin and Wallace both proposed that evolution occurs by natural selection.


• Evolutionary theory arises from scientific observations and conclusions based on them.

• The fossil record provides evidence of evolutionary change over time.


• Comparative anatomy provides structural evidence for evolution.


• Embryological stages of animals can provide evidence for common ancestry.

Comments & corrections to Chapter 16 from Audesirk & Audesirk Biology 101 Text:

• page 289 - "...To explain the origin and diversity of life on earth, nearly all the peoples of the world historically turned to hypothesis of creationism [sic]. The most common of these hypothesis is that a supernatural being created each type...." This is a bit misleading (at best!) Really, I think the authors are referring to the widely held beliefs in England, at the time of Darwin (1850s), but this is a pretty unique time in history - for most of the past 3000 years or so, Western science (and religions, including Christianity!) adhered to the belief in spontaneous generation.


The History of Evolutionary Thought

• page 290 - "Creationism, the idea that each species was created individually by God and never changed thereafter, reigned unchallenged for nearly 2000 years..."
The word "species" wasn't even coined until a hundred years or so before Darwin - so how could this idea "reign unchallenged for 2000 years"?? The authors are just simply wrong here... perhaps they meant that most people had a theological belief - that God created life through spontaneous generation - before then. But lots of people STILL have a theological belief today - so I'm not sure this is a completely valid point, either....


• page 291 - "As European naturalists explored the newly discovered lands of Africa, Asia, and America..." The time under consideration is the early 1800's - I don't think AFRICA & ASIA (nor America, for that matter!) were "newly discovered lands..."


• page 292 - "This concept, called uniformitarianism, satisfies a scientific axiom often called Occam's Razor: The simplest explanation that fits the facts is probably correct." But what "facts" existed for saying how old the earth was, or that it never had a beginning??


• page 302 - "...As predicted by the principles of evolution, the pale moths are making a comeback in these areas, and the black form is becoming increasingly rare." Is this really evolution, or mere selection?


• page 305 - "Direct comparison of Nucleotide Sequences" The best way to do this is to compare the entire genomic DNA sequences, which is becoming possible through the human genome project. This is what bioinfomatics is all about...

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