A few topics I had less knowledge of...

Trilobites; First known evidence in the early cambrian eon dating back to 540-250 million years ago. They were among the early arthropods which are hard shelled creatures with multiple body segments. Their name literally means three lobes. Trilobites are so notable due to their diversity making them the most most diverse group of animals preserved in fossil record.

Flowering plants; The first evidence of early flowering plants began in the Cretaceous period, Mesozoic era. Soon after was the climax of dinosaurs existence. The first flowering plants, also known as angiosperms attract insects and other organisms resulting with pollination and and development of fruit. Much of our food supply including fruit, wheat and rice come from angiosperms. This occurred about 142 million years ago.
Learn how the appearance of flowering plants greatly influenced mammalian evolution on the Science Channel's "Mammals vs. Dinos."

Coal depositing plants; Coal is compressed plant matter that transformed into a high-carbon material. The period from 350 to 275 million years ago is known as the Carboniferous period and during this time much coal formation began. This was a period of globally warm temperatures, which were fertile for plant growth.
At the end of the Carboniferous period and for about 135 million years thereafter, coal formation in the Northern Hemisphere greatly diminished. But with the onset of the Cretaceous period around 135 million years ago, plant growth and coal formation resumed, although by this time more complex vegetation, including plants and trees with protected seeds, had begun to dominate the landscape. Thus, the coal that we use today developed over hundreds of millions of years from a wide variety of vegetation.
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When did Pangea form and begin to break up?

The separate continents of the Paleozoic, after having drifted apart through the fragmentation of the super-continent of Rodinia eventually drifted together again during the Paleozoic, colliding to form the super-continent of Pangea during the Devonian and Carbonfierous periods, some 350 million years ago. Finally by the end of the Triassic the classic Pangea configuration was produced.

Pangea began to rift apart almost immediately. However, the process of separation was prolonged for some 250-300 million years, resulting in roughly the modern series of separate continental blocks in the Cretaceous, some 130-100 million years ago.

When did the Appalachian mountains form?
During the Paleozoic period more specifically the Ordovician period, around 480 million years ago.