How does evolution change over time?
The basic evolutionary process themselves have not changed in over 3 billion years.
The broad direction of evolution consists of millions of species who are either adapting to changing environments via genome changes that give them more adaptive traits or if unsuccessful, become extinct.
For example, bivalves like clams and oysters have been around for over 500 million years now and broadly speaking have been very adaptive in oceans, although not all species of clams and oysters are still alive today. Similarly, dinosaurs were around for over 135 million years, but were not able to adapt to the massive environmental changes brought on by the giant asteroid that hit Earth 65 million years ago.
Major environmental changes, like super volcanic eruptions, asteroid impacts, glaciations tend to dramatically change the course of evolution by creating losers unable to adapt and winners who are able to adapt and subsequently take over the losers niches.