Evidence
Jablonski found that the extinction rate of marine invertebrates was significantly higher in the stage (major subdivision of an epoch – typically 2–10 million years' duration) following a mass extinction than in the stages preceding the mass extinction. His analysis focused on marine molluscs since they constitute the most abundant group of fossils and are therefore the least likely to produce sampling errors. Jablonski suggested that two possible explanations deserved further study:
- Post-extinction physical environments differed from pre-extinction environments in ways which were disadvantageous to the "dead clades walking".
- Ecosystems that developed after recoveries from mass extinctions may have been less favorable for the "dead clades walking".
"Dead Clade Walking" has since appeared in other scientists' writings about the aftermaths of mass extinctions.
Read more about this topic: Dead Clade Walking
Famous quotes containing the word evidence:
“Analysis is more likely to adjust evidence than to adjust itself.”
—Mason Cooley (b. 1927)
“I believe that no characteristic is so distinctively human as the sense of indebtedness we feel, not necessarily for a favor received, but even for the slightest evidence of kindness; and there is nothing so boorish, savage, inhuman as to appear to be overwhelmed by a favor, let alone unworthy of it.”
—Marcus Tullius Cicero (106–43 B.C.)
“I don’t know what it is about fecundity that so appalls. I suppose it is the teeming evidence that birth and growth, which we value, are ubiquitous and blind, that life itself is so astonishingly cheap, that nature is as careless as it is bountiful, and that with extravagance goes a crushing waste that will one day include our own cheap lives.”
—Annie Dillard (b. 1945)