gould s.j. & eldredge n. 1977 punctuated equilibria: the tempo and mode of evolution...

• Gould S.J. & Eldredge N. 1977Punctuated equilibria: the tempo and mode of evolution reconsidered.Paleobiology 3: 115-151.

Herhaling

"most evolutionary change is concentrated in rapid events of speciation in small, peripherally isolated populations"

"the norm for a species … is morphological stasis"

"paleontologists have worn blinders … ignored gaps in the stratigraphic sequences … and evolutinaru stasis"


Herhaling

Verpersoonlijking van de "vijand"

John Wyatt Durham

Gryphaea

"…Trueman rejoiced in Gryphaea, but never mentioned the hundreds of Liassic species that showed no temporal change … "

Micraster

"…Rowe monographed Micraster but spoke not a word about its legion of static colleagues in the English chalk … "

"…Ziegler's celebrated study of the Silurian brachiopod Eocoelia … presents data for five characters. Three display a fluctuating pattern, one no trend at all, and the last a directional pattern. Only the last is graphed."

Lepidolina multiseptata

Tomowo Ozawa

"…Ozawa measures nine characters … Four exhibit gradual trends; five do not. The first four are either graphed or listed in tables; the remaining five are discussed in qualitative terms only."


Herhaling


Review van empirische testen

Studies op verkeerde schaal te kleine schaal ("neontologische" studies) te grote schaal (graduele series van soorten)


Herhaling


Review van empirische testen

Studies op verkeerde schaal Studies met ontoereikende data(-analyse)

"…most cases presented as falsifications are circular because they rely upon the gradualistic presuppositions they claim to test…"


Herhaling


Review empirische testen

Studies op verkeerde schaal Studies met ontoereikende data Mogelijks "ware" gevallen van gradualisme

ontworteling en reïnterpretatie


Herhaling



Studies op verkeerde schaal Studies met ontoereikende data Mogelijks "ware" gevallen van gradualisme Studies die punctuated equilibria ondersteunen


Herhaling



Nieuwe ideeën

Species selection


Herhaling



Nieuwe ideeën

Species selection relative ability to speciate, not morphological flexibility


Herhaling



Nieuwe ideeën

Species selection relative ability to speciate, not morphological flexibility "the need to translate micro to macroevolution guarantees that paleobiology shall provide essential theory"


Herhaling



Nieuwe ideeën

Politiek


• Gould S.J. & Eldredge N. 1993Punctuated equilibria comes of age.Nature 366: 223-227.

Overwinning !

"punctuated equilibrium has been accepted by most of our colleagues … as a valuable addition to evolutionary theory"



Overwinning !

"misunderstandings of colleagues … who failed to grasp …"



Overwinning !

"the need to reformulate macroevolution, notably the key phenomenon of trends, as an accumulation of discrete speciation events treated as entities rather than undefinable segments of continua"



Overwinning !

Macro-evolutie = species sorting

"Most macroevolution must be rendered by asking what kinds of species … did better than other (speciated more frequently, survived longer) … "



Overwinning !

Macro-evolution = species sorting

Implicaties "levende fossielen" "darwins" nonsensicaal Cope's rule : kleine soorten speciëren sneller gecorreleerde punctuaties



Overwinning !

Macro-evolution = species sorting

Implicaties

Empirische ondersteuning

Jaar

72 74 76 78 80 82 84 86 88 90 92 94 96 98

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Jaar

73-77 78-82 83-87 88-92 93-97 overall

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positief neutraal negatief

gould s.j. & eldredge n. 1977 punctuated equilibria: the tempo and mode of evolution...

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