https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8/Head https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8 http://www.nanopub.org/nschema#hasAssertion https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8/assertion https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8 http://www.nanopub.org/nschema#hasProvenance https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8/provenance https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8 http://www.nanopub.org/nschema#hasPublicationInfo https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8/pubinfo https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8 http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.nanopub.org/nschema#Nanopublication https://w3id.org/np/RATofTrC9VvYtdd1NynYc1FSWYT7Gug6W5y_Z0aYu1dD8/assertion https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test http://purl.org/dc/terms/description All 79,166 accepted Metazoa genera were fetched from the PBDB taxa API; genera without ages or family were dropped. A family was taken as extinct when none of its genera is flagged extant and none has a last appearance at 0 Ma. Each genus ranges through from firstapp_max_ma to lastapp_min_ma; genus diversity D(t) was counted on a 0.1 Myr grid between the family's first origin and final extinction, and the centre of gravity CG of D over relative time (0 = origin, 1 = extinction) was computed for the 1,866 extinct families with >= 5 genera and >= 10 Myr duration. The median CG, the share below 0.5 and a one-sided Wilcoxon signed-rank test of CG - 0.5 were compared with the pre-registered thresholds; families ending within 2 Myr of the five big mass extinctions and families by era of origin are reported separately. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/delphi/ontology/Assessment https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test http://www.w3.org/2000/01/rdf-schema#comment Measured: 0.477 median centre of gravity of range-through genus diversity of extinct animal families (0 = origin, 1 = extinction; < 0.5 = slow decline) (n = 1866, Wilcoxon one-sided p (CG < 0.5) = 1.06e-18; IQR 0.409-0.547). Interpretation: Darwin's 'complete extinction of the species of a group is generally a slower process than their production' is read through clade shape (Gould et al. 1977): if production is fast and extermination slow, the diversity trajectory rises steeply and tapers, giving a centre of gravity in the first half of the clade's duration. Groups are extinct animal families as classified in PBDB (Darwin's 'groups' of genera and families); diversity is counted in genera, because Darwin's species are rarely resolved in the fossil record. Range-through ranges from database first and last appearances are used without sampling correction; the Signor-Lipps effect pulls last appearances earlier and can shorten or lengthen the tail, so the test measures the record as compiled. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test http://www.w3.org/2000/01/rdf-schema#label Claim test of darwin1859-ch10-08: supports, confidence 0.6 https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test http://www.w3.org/2000/01/rdf-schema#seeAlso https://github.com/fractastical/delphisci/blob/bf2af6ee0a84e23ffa6414ad7a0a50a8c276506e/test-data/claim-tests/darwin-origin/darwin1859-ch10-08/result.json https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test http://www.w3.org/ns/prov#wasAttributedTo https://w3id.org/delphi/resource/agent/delphisci-claim-tester-claude-opus-5-5 https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/admissibleDatasets A community fossil occurrence database giving first and last appearance ages for genera with family classification, compiled independently of Darwin; open access; at least 100 extinct families with five or more genera. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/assessmentType claim-test/0.1.0 https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/dataKind biological https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/disconfirmingObservation Extinct families are symmetric or top-heavy (median centre of gravity at or above 0.5). https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/evidenceAgainst As Darwin himself noted for ammonites, families ending at the big five mass extinctions are the exception: their median CG is 0.523 and only 41% are below 0.5 (n = 359), against 0.468 and 64% for families ending at other times (n = 1,507). https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/evidenceAgainst Families are PBDB's classification, which includes paraphyletic families; Darwin's 'group' could also be read at the order or class level, which was not tested. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/evidenceAgainst Genus first and last appearance ages are taken at the outer bounds of the first and last intervals (firstapp_max_ma, lastapp_min_ma), which lengthens every genus range by up to one interval at each end symmetrically. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/evidenceAgainst No sampling correction was applied. Range-through ranges from database first and last appearances are affected by the Signor-Lipps effect (last appearances drawn earlier); the 'pull of the Recent' does not apply because only extinct families are used. The grok assessor warned that sampling bias can manufacture slow-looking declines; the opposite bias (late-Lazarus truncation) also exists, so the direction of net bias is not known. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/evidenceAgainst PBDB is a live database; re-running reproduces the method but counts drift as records are added. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/evidenceAgainst The asymmetry is real but small: median CG 0.477 (IQR 0.41-0.55), 59% of families below 0.5. It holds in every large phylum (Chordata 0.485, Arthropoda 0.473, Mollusca 0.462, Brachiopoda 0.489, Echinodermata 0.456, Cnidaria 0.473) and in Paleozoic-, Mesozoic- and Cenozoic-originating families (0.477, 0.482, 0.475). The test passes the pre-registered thresholds, but 'generally a slower process' is supported only as a modest tendency, not a strong rule. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/expectedObservation Most extinct families have a diversity centre of gravity below 0.5 of their duration (early peak, longer decline). https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/failCriterion Pre-registered: REFUTES if the median CG >= 0.5. Any other outcome is MIXED. Fewer than 100 qualifying families: inconclusive (underpowered); PBDB API unreachable: inconclusive (data-unavailable). Descriptive secondary statistics: median CG and share below 0.5 for families ending at the five big mass extinctions (end-Ordovician 443.8, Late Devonian 372.2, end-Permian 251.9, end-Triassic 201.4, end-Cretaceous 66.0 Ma, within 2 Myr) versus all others, and for Paleozoic-, Mesozoic- and Cenozoic-originating families. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/hasConfidence 0.6 https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/hasEvidence https://w3id.org/delphi/resource/evidence/darwin1859-ch10-08--claim-test--dataset-1 https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/hasVerdict supports https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/hypothesis Extinct animal families in the fossil record are bottom-heavy: their genus diversity peaks early in their history and tapers over a longer decline, so the centre of gravity of the diversity trajectory lies in the first half of the family's duration. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/inferenceMethod Range-through genus diversity per family on a 0.1 Myr grid; centre of gravity relative to family duration; one-sided Wilcoxon signed-rank test against 0.5 with p < 0.01, median < 0.5 and share below 0.5 >= 55% for support; median >= 0.5 refutes. https://w3id.org/delphi/resource/assessment/darwin1859-ch10-08--claim-test https://w3id.org/delphi/ontology/passCriterion Pre-registered: from the Paleobiology Database taxa API, all accepted animal (Metazoa) genera with first and last appearance ages and family assignment. A family is extinct if none of its genera is flagged extant and every genus has lastapp_min_ma > 0. Each genus ranges from firstapp_max_ma to lastapp_min_ma; the family's range is the union. Diversity D(t) = number of genera ranging through t on a 0.1 Myr grid. Centre of gravity CG = sum(D(t) * tau(t)) / sum(D(t)), tau = (family origin - t) / (family origin - family end), so CG < 0.5 means diversity is concentrated early and decline is slower than rise. Families qualify with >= 5 genera and duration >= 10 Myr. 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