Sounds like fun! Mayr's book is right in front of me, so I'll just copy
from it...
Ernst Mayr, _One Long Argument_, Harvard U. Press, 1991, p.36
...However, when later authors referred to Darwin's theory, they invariably
had a combination of some of the following five theories in mind:
1) Evolution as such. This is the theory that the world is not constant
nor recently created nor perpetually cycling but rather is steadily
changing and that organisms are transformed in time.
2) Common descent. This is the theory that every group of organisms
descended from a common ancestor and that all groups of organisms, including
animals, plants, and microorganisms, ultimately go back to a single origin
of life on earth.
3) Multiplication of species. This theory explains the origin of the
enormous organic diversity. It postulates that species multiply, either
by splitting into daughter species or by "budding," that is, by the
establishment of geographically isolated founder populations that evolve
into new species.
4) Gradualism. According to this theory, evolutionary change takes place
through the gradual change of populations and not by the sudden
(saltational) production of new individuals that represent a new type.
5) Natural Selection. According to this theory, evolutionary change comes
about through the abundant production of genetic variation in every
generation. The relatively few individuals who survive, owing to a
particularly well-adapted combination of inheritable characters, give rise
to the next generation.
[....]
Mayr then gives a table of various evolutionary theorists, indicating which
of Darwin's theories they held to.
Table 1, p. 37:
Common Species Natural
Descent Multiplication Gradualism Selection
Lamarck NO NO YES NO
Darwin YES YES YES YES
Haeckel YES ? YES In Part
Neo-Lamarckians YES YES YES NO
Huxley YES NO NO (Ambivalent)
de Vries YES NO NO NO
Morgan YES NO (Ambivalent) Unimportant
> When Dawkins says that evolution is true, what is he saying? (Divide it up
> into sub-statements so we can ascertain what is true, what may be false,
> and what is indeterminate).
Richard Dawkins, _River out of Eden_, Basic Books, 1995, p. 3:
"The world becomes full of organisms that have what it takes to become
ancestors. That, in a sentence, is Darwinism. Of course, Darwin said
much more than that, and nowadays there is much more we can say, which is
why this book doesn't stop here."
(Many more substatements availabe there and elsewhere ;-))
-Greg