Comparison of Theories
| Theories of Evolution |
|
| Darwinism | Orthogenesis | Lamarckism | |
| Mechanism | 1. Short-sighted Natural Selection sorting random genetic variation, no other guidance or aim. 2. Selected traits are adaptive, i.e. have some survival value. |
1. Driven by some internal mechanism, but not towards a goal. 2. Natural selection unimportant. 3. Characters produced may be totally non-adaptive, i.e. have no survival value. |
1. Intrinsic drive towards perfection 2. Inheritance of acquired characteristics (both are Lamarckian principles) 3. Natural selection adopted by some in latter years. |
| Common descent | Yes New species coming into existence by speciation events. |
No Speciation rejected or considered unimportant in long term trends; spontaneous generation of new species resulting in parallel evolution. |
Depends upon source quoted Signs that species shared a common ancestor were detected before Darwin, but in absence of a mechanism some still rejected the idea. |
| Status | Prevailing in modified form as modern evolutionary synthesis. | Refuted by Charles Darwin's Origin of Species and the modern evolutionary synthesis. | Declined after the Origin, though the mechanism was not refuted until the modern evolutionary synthesis in which it was established that the mechanism does not exist. |
Read more about this topic: Orthogenesis
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