The idea that all species are descended from common ancestors had not only been suggested by Darwin, but also Jean-Baptiste Lamarck. Their idea basically was that inheritable differences among individuals result in different chances of survival and reproduction. For some those inheritable differences resulted in death, others resulted in significant changes in shape, size, strength, armament, color, biochemistry, and behavior.
During anagenesis a single species is transformed. The genetic changes sometimes accumulate within a isolated species, but not throughout the whole thing, and those isolated species adapt to local conditions. It eventually goes on its own way and becomes a new ecological niche.
http://66.114.0.13:9797/MuseSessionID=cfed6c22f8876829a51e732f1acd83a/MuseHost=www.accessscience.com/MusePath/content.aspx?id=475150&searchStr=anagenesis
The splitting-and-specializing phenomenon was the "principle of divergence"
Most of his evidence fell into 4 categories:
1. Biogeography
-the study of the geographical distribution of living creatures
2. Paleontoogy
-investigates extinct life-forms, as revealed in the fossil record
3. Embryology
- examines the revealing stages of development that embryos pass through before birth or hatching
4. Morphology
- the science of anatomical shapes and design
A part of the evolutionary process in which a single species is transformed.The evolutionary process whereby one species evolves into another without any splitting of the phylogenetic tree- "http://www.biochem.northwestern.edu/holmgren/Glossary/Definitions/Def-A/anagenesis.html"
Evolution can take place by anagenesis, in which changes occur within a lineage, or by cladogenesis, in which a lineage splits into two or more separate lines. Anagenetic evolution has doubled the size of the human cranium over the course of two million years; in the lineage of the horse it has reduced the number of toes from four to one. - "http://www.britannica.com/eb/topic-22328/anagenesis"
