The question pretty much sums it up. How do animals/plants change for each: Spring, Summer, Autumn, and Winter?
A detailed explanation on distinct behaviour and appearance changes would be nice.
There are various parameters that describe change of seasons such as day length, temperature, humidity. But it can be assumed that most of these parameters ultimately depend on one parameter- day length.
The response of plants towards the length of day/night cycle is called photoperiodism (which dictates spring flowering).
This article explains the effect of a gene called CONSTANS(CO) on spring flowering. CO is post transcriptionally regulated by cryptochromes and phyochromes.
However, my knowledge of plant molecular biology is not that great and I would advise that you refer the mentioned article and the cross references cited in that.