Living In An Entirely Different Physical As

Two Forms Or Species Are Sympatric, If They Occur Together, That Is If Their Areas Of Distribution Overlap Or Coincide. Two Forms (or Species) Are Allapatric, If They Do Not Occur Together, That Is If They Exclude Each Other Geographically. The Term Allopatric Is Primarily Useful In Denoting Geographic Representatives.

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.

Anyone Who Writes About "darwin's Theory Of Evolutionin The Singular, Without Segregating The Theories Of Gradual Evolution, Common Descent, Speciation, And The Mechanism Of Natural Selection, Will Be Quite Unable To Discuss The Subject Competently.

It Seems To Me That For Darwin The Pulsing Of Evolutionary Rates Was A Strictly Vertical Phenomenon.

Definitions Are Temporary Verbalizations Of Concepts, And Concepts- Particularly Difficult Concepts- Are Usually Revised Repeatedly As Our Knowledge And Understanding Grows.