I Have The Honesty To

Paleontologists Had Long Been Aware Of A Seeming Contradiction Between Darwin's Postulate Of Gradualism, Confirmed By The Work Of Population Genetics, And The Actual Findings Of Paleontology. Following Phyletic Lines Through Time Seemed To Reveal Only Minimal Gradual Changes But No Clear Evidence For Any Change Of A Species Into A Different Genus Or For The Gradual Origin Of An Evolutionary Novelty. Anything Truly Novel Always Seemed To Appear Quite Abruptly In The Fossil Record.

Evolution Thus Is Merely Contingent On Certain Processes Articulated By Darwin: Variation And Selection.

The Reduced Variability Of Small Populations Is Not Always Due To Accidental Gene Loss, But Sometimes To The Fact That The Entire Population Was Started By A Single Pair Or By A Single Fertilized Female. These 'founders' Of The Population Carried With Them Only A Very Small Proportion Of The Variability Of The Parent Population. This 'founder' Principle Sometimes Explains Even The Uniformity Of Rather Large Populations, Particularly If They Are Well Isolated And Near The Borders Of The Range Of The Species.

Living In An Entirely Different Physical As Well As Biotic Environment, Such A Population Would Have Unique Opportunities To Enter New Niches And To Select Novel Adaptive Pathways.

Biology Can Be Divided Into The Study Of Proximate Causes, The Study Of The Physiological Sciences (broadly Conceived), And Into The Study Of Ultimate (evolutionary) Causes, The Subject Of Natural History.