By the mid-1870s, most scientists accepted evolution, but relegated natural selection to a minor role as they believed evolution was purposeful and progressive. The range of evolutionary theories during "the eclipse of Darwinism" included forms of "saltationism" in which new species were thought to arise through "jumps" rather than gradual adaptation, forms of orthogenesis claiming that species had an inherent tendency to change in a particular direction, and forms of neo-Lamarckism in which inheritance of acquired characteristics led to progress. The minority view of August Weismann, that natural selection was the only mechanism, was called neo-Darwinism. It was thought that the rediscovery of Mendelian inheritance invalidated Darwin's views. COUNT 5
QSN1 Why did most scientists accept the validity of evolution by the 1870s, but considered natural selection a minor part of it? ANS1 they believed evolution was purposeful and progressive. QSN2 What was meant by the term saltationism? ANS2 new species were thought to arise through "jumps" rather than gradual adaptation QSN3 What is the term for the belief that species have a tendency to change and adapt in a certain direction? ANS3 orthogenesis QSN4 What was the minority view on evolution that was believed by August Weismann? ANS4 neo-Darwinism QSN5 What rediscovered inheritance was thought to invalidate Darwin's views on evolution? ANS5 Mendelian inheritance