Vernor Vinge had an excellent novel named "A Deepness in the Sky" that dealt with the development of intelligent life on a planet whose star would extinguish and re-ignite itself predictably. Something like 3 decades of ignition and then 7 or 8 decades of darkness. The dominant life form was a spider-like being that could hibernate and ride out the darkness by creating a "deepness" (essentially a den).

Great book, with interesting insights about unusual planetary configurations with life. I highly recommend it to anyone who likes hard science fiction.

The on-off star spent 215 years off, according to Wikipedia.

A Fire Upon the Deep, set in the same universe, is excellent too.

The answers can be inferred on Earth. Most photosynthetic organisms on Earth are not deciduous trees and don't have seasonal cycles. All of them do maintain circadian cycles to cope with the much faster and more dramatic day/night cycle.

Or most? I know the cyanobacteria do and I'm pretty sure the purple bacteria do. The bacteriorhodopsin-users might not. If you call that photosynthesis.