Jack, you still don't get it. Eldridge questions gradualism. Instead, he champions punctua
Jack, you still don't get it. Eldridge questions gradualism.
Instead, he champions punctuated equilibrium. Both approaches
advance theories to explain the fact of evolution.
The geologic column is divided into periods. Each period is
identified largely on the basis of the fossils it contains.
Eldridge's fossil "non-change" is restricted to periods. The
Silurian, as Eldridge might argue, exhibits fossil phyla which
show little change over the *period*. The phyla from the next
period, the Devonian, differ markedly from the Silurian, and so
on from period to period throughout the geologic column.
(The geologic column is illustrated in most good dictionaries).
So, Eldridge, like gradualists, sees great change in organisms
throughout the whole of geologic time - otherwise known as biological
evolution. He suggests, however, that gradualist theories cannot
account for what appear to him to be abrupt changes in organisms
from *period to period*. If organisms evolved gradually, Eldridge
would argue, then the boundaries between periods should be blurred.
But he says they aren't blurred. Eldridge (and others) therefore
counters with punctuated equilibrium, that is, lengthy periods of
"non-change" (actually minor genetic change), each period terminated
or "punctuated" by abrupt and major changes in living forms.
Eldridge proposes catastrophic events to explain abrupt change.
Gradualists argue that genetic changes accumulate slowly over great
periods of time, and that this best explains the evolutionary record.
Actually, neither is mutually exclusive. The battles between
"warring camps" are largely over the emphases each places on their
particular ways of explaining the fact of evolution.
Its that simple, but you have not exhibited such an understanding.
If you did understand, you would also understand why your cobbled
quote is at best meaningless and at worst dishonest. However, I
doubt you will ever extract you head from the sand.
Rich Fox, Anthro, Usouthdakota
E-Mail Fredric L. Rice / The Skeptic Tank