Dear—, and: Dear—, and: Continental Drift Theory

2020 ◽  
Vol 128 (3) ◽  
pp. 381-384
Author(s):  
Donika Kelly
1978 ◽  
Vol 11 (2) ◽  
pp. 130-150 ◽  
Author(s):  
Henry Frankel

Although there are numerous and significant differences between the theories of scientific growth and change proposed by Kuhn, Lakatos, and Laudan, they all hold that specific scientific theories should be viewed as constitutive of more comprehensive theories. Kuhn calls those more general theories ‘paradigms’, Lakatos labels them ‘research programmes’ and Laudan refers to them as ‘research traditions’. They all argue that scientists are much more willing to give up the specific theory within a given research programme rather than the programme itself, and that individual theories should be viewed as attempts to increase the overall explanatory power of the more general theories, since the ultimate concern of the scientist is with the success of the general rather than the specific theory. When a basic theory or research programme is confronted with severe criticism, proponents attempt to protect the hard core or central elements of their programme through the invention of auxiliary hypotheses. Good auxiliary hypotheses adequately answer the objections for which they are designed, and suggest new avenues of research. In 1928, Arthur Holmes provided proponents of continental drift theory with an auxiliary hypothesis which afforded them a badly needed account of the forces responsible for continental drift. Although Holmes' proposal was not ultimately correct, it was the first plausible alternative offered by an exponent of the continental drift research programme.


2019 ◽  
Author(s):  
Piotr Bajdek

Biogeographic distribution of infected plants and the continental drift theory allow a time calibration of the phylogenetic tree of Pospiviroidae. Viroids evolved in the late Early Cretaceous shortly after the appearance of angiosperms, which constitute their only known hosts. No decline in the estimated speciation rates of Pospiviroidae is observed during the Late Cretaceous but they abruptly decreased at the Cretaceous–Paleogene boundary. However, an adaptive radiation of Pospiviroidae which occurred in the late Paleocene may reflect a recovery from the K–Pg mass extinction. The evolutionary history of viroids has been in part shaped by radiation and extinction events of angiosperms. Herein, for the first time I show the probable impact of a mass extinction event on the speciation rates of subviral pathogens, which are the simplest known lifeforms.


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