1) The four different kinds of fossils:
Intact (such as when the actual clam shells, etc. remain)
Compression (such as carbon films, left behind by leaves)
Cast (when the actual body or tree limb etc. rotted away & left a hole
     and then minerals filled in this hole, and have the shape)
Perminealized (for example, petrified wood; decays very slowly
       (and rock gradually fills in and hardens)

2) Geologic Periods: The Cambrian 500-600 million years ago

Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Tertiary=Cenozoic
Don't memorize all these later periods; just Cambrian
Pre-Cambrian fossils are rare and special, and the oldest fossils you are likely to find are cambrian.
At the "Cambrian explosion ", many multicellular life forms appear.

All modern phyla had already evolved by the start of Cambrian

3) Mass Extinctions: Geological periods were invented to correspond to patterns of common fossil plants and animals, as if the world had gone merrily along for 40, 50 or 65 Million years, and then had somehow gotten very different fairly quick.

You already knew that the dinosaurs became extinct at the boundary between the Cretaceous and the Tertiary. Many other kinds of animals also became extinct then;
including lots of marine invertebrates. ~65 million years ago
Almost everyone now believes these extinctions were caused by an small asteroid hitting the earth (at the Yucatan Peninsula!)

This was one of 5 mass extinctions since the Cambrian!
& the others were even bigger, in terms of # of kinds of animals that became extinct: By far the biggest was at the end of the Permian (That was at the beginning of the age of dinosaurs)
~230 million years ago to ~65 million years ago
the Triassic + Jurassic + Cretaceous = 163 million years
Dinosaurs were around for more than twice as long as it as been since they became extinct!!
Were all of these 5 mass extinctions caused by asteroids?No one knows! It could well be true.

4) What evolved when, in the history of the earth?

Earth itself formed ~ Four and a half thousand million years ago

First Life evolved: ~ Three and a half thousand million years ago

Multicellular animals and plants evolved
          ~ One (to one and a half) thousand million years ago

Cambrian radiation (and all phyla already evolved)
          A little more than half a thousand million years ago.

5) Global changes in the atmosphere, in relation to life forms

Not until less than a billion years ago did the atmosphere become 20% Oxygen , and that was because of photosynthesis.
The increase in Oxygen concentration began two billion years ago

Algae appear about 2 billion years ago, etc.

Deposits of iron ore are believed to have been laid down at times of early photosynthesis (and there are different ideas about this) The early photosynthesis produced more ferric salts that oxygen

And several other kinds of mineral deposits are believed to result from pre-cambrian bacteria, algae etc. biochemical metabolism.

Questions that you should be able to answer:

b) If you categorized fossils into 4 different kinds, according to the mechanism of their formation, what would the categories be?

*c) The youngest (most recent) fossils would be expected to fall into which of these categories? And explain your reasoning.

*d) Into which of the 4 categories would the oldest fossils probably belong? Why?

e) Has the earth's atmosphere always been pretty much the same as it is now? (no)
Was it like it is now when life first evolved? Where did all the additional oxygen gas come from?

f) For about how long as the atmosphere had as much oxygen as it does now?

g) What is now believed to have killed off all the dinosaurs?

h) Were the dinosaurs the only major group of animals that died off at that time?

i) Have there been any other mass extinctions, comparable (or even larger) that the one that occurred at the end of the Cretaceous period? * About how many? (5, altogether, at least)

**j) Would you guess that any asteroids hit the earth before the Cambrian? Why might we not know about mass extinctions that had occurred earlier than that?

k) About how old is the earth itself believed to be?

l) Life is believed to have evolved about how long after the formation of the earth?

m) For about how long were all life forms still unicellular?

n) About how long ago are multicellular animals and plants believed to have evolved?

o) What is meant by the Cambrian radiation?

p) Did evolution of new life forms have anything to do with deposition or iron ore beds?

*q) Science fiction sometimes includes the idea of "terraforming" planets: which means changing their atmosphere and other features to make them habitable by humans. In what sense did evolution terraform the earth itself?

**r) Which is your favorite kind of dinosaur?