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So, in adaptive evolution, there are two types of causal links.

There is:
(1) environmental change ---------> evolutionary change

There is also:
(2) evolutionary change ---------> evolutionary change.

The elementary fact that the outcome of (2) is the same as its input, provides an element of feedback.
This feedback may well account for long term macroevolutionary trends.

(By the way, in (2) I mean evolutionary change of the population under consideration, not of the species around it, which fall under environmental change.)
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