Cephalopods are probably the best subject to use as an example of the evolution of memory. Octopuses and squids, for example, have developed highly specialized, dedicated memory centers that enhance their ability to learn and remember. As a result, they modify their hunting techniques based on past experiences.
What makes them a good study subject is the availability of their close relative, the primitive nautilus. The nautilus, while having a similar albeit simpler brain structure, lacks the dedicated memory centers present in the more developed species of cephalopods. Despite this handicap, it appears the nautilus still has developed a rudimentary capacity for temporally separated short and long term memory (about 1 hour short term, and roughly 6-12 hours long term). This suggests that a very basic ability to recall recent past events developed in ancestral cephalopods. As new species emerged, brains with more pronounced and sophisticated memory centers contributed to their success and therefore became a trait favored by natural selection.
An interesting assertion, but for it to be so it would have to follow that species with greater memory capacity are more successful at survival. That would tend to form an inverted pyramid of life with those having the best memory forming the top layer and so on. Such is not the case.
Comparing the nautilus and squid, why is one having less memory than the other a handicap if both survive and are successful?
More evolutionary assumptions and materialist poofery.