Some Biogeographers, Evolutionists and Ecologists:
Rosa had a distinguished career as an invertebrate zoologist (mostly studying polychaete and oligochaete annelids), but he would not be remembered today were it not for his theory of hologenesis ("ologenesi" in the original Italian). Rosa's model of evolutionary process was an orthogenetic one in which species were thought to change slowly on the basis of two kinds of forces: adirectional ones akin to natural selection that caused modifications over time (but not bifurcating speciation), and cladogenesis, or the splitting of one species into two. Among other things, the theory also projects that these processes are completely controlled by internal causes, and that new forms will emerge at a slower rate as time goes on, eventually ceasing to be added altogether. The theory is not well known to the English-speaking scientific community, and in any case contains some fairly apparent and perhaps fatal flaws. Still, it periodically continues to attract interest, as certain aspects of it are backed by some evidence, and some observers have noted that its unusual perspective may have contributed to the development of vicariance biogeography and panbiogeography approaches (Leon Croizat, for example, produced some defenses of it).
--born in Susa, Italy, on 29 October 1857.
For Additional Information, See:
--Dictionary of Scientific Biography, Vol.
Copyright 2005 by Charles H. Smith. All rights