1. The Paleozoic Era!
Time for BIG changes!

2. Geologists divided the later strata into 3 major groups
Remember this?
Geologists divided the later strata into 3 major groups
Modern era
Ice Age
Cenozoic Era
Dinosaurs!
Mesozoic Era
We will explore the Paleozoic first…
Paleozoic Era
About 550 million years ago
Ediacaran
4 billion years of Earth history!

3. Paleozoic Era The more recent layers are subdivided into “PERIODS”
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Ordovician
Cambrian
Paleozoic Era
Trilobites
Brachiopods, Molluscs
Bi-valves, Arthropods
Ediacaran

4. The Early Paleozoic… Many new life forms with HARD SHELLS evolve…
A more diverse community is present!

5. A typical scene in the early Paleozoic Era.
Cephalopod
Trilobite
Crinoid
Brachiopod
Coral

6. From earlier animals with a “hint” of a backbone…
There evolved the first vertebrates!
Perm
Penn
Miss
Dev
Sil
Ord
Cam
By the early Cambrian…
…the first Fish swam the seas.

7. Ordovician New species continue to evolve… others become extinct… Perm
Penn
Miss
Dev
Sil
Ord
Cam

8. Silurian But…big changes are occurring!
New species continue to evolve… others become extinct…
Perm
Penn
Miss
Dev
Sil
Ord
Cam
But…big changes are occurring!

9. Starting possibly as early as the later Ordovician…
…land plants had been evolving!
(Probable SPORES have been found)
By the middle Silurian…
Perm
Penn
Miss
Dev
Sil
Ord
Cam
Early land plants looked like this…

10. By the start of the Devonian…
The ocean is filled with life…
…but the REALLY big story is elsewhere.
Near the shore, or in and along streams and coastal swamps, a major invasion is taking place…

11. …indicate that plant life had moved ashore!
Fossil stumps…
…and leaves…
…indicate that plant life had moved ashore!
Early Devonian landscape
Z. Burian (In: Špinar & Burian, 1972);

13. And by the end of the Devonian…
…the first real forests grew.
Perm
Penn
Miss
Dev
Sil
Ord
Cam
Archaeopteris dominates

14. THAT produced major changes in the landscape!
Earlier vegetation lacked the root systems of present-day vegetation…
…plants were apparently restricted to being near water
Those plants also produced little shade or leaf litter.

15. The evolution of new types of trees lead to a richer environment, creating more organic material…

16. …and probably changed stream channel morphology, and altered erosion and deposition.
Braided Streams
Overwhelming amounts of eroded material

17. Meandering Streams

18. Devonian
As always, new species continue to evolve, and other species become extinct…
Perm
Penn
Miss
Dev
Sil
Ord
Cam
Which sometimes seems like you’re watching the same play over and over with different actors! 

19. …but these more minor changes are overshadowed by MAJOR developments!
The first Fish evolved near the start of the Early Paleozoic…
Early Fish

20. Later…Armored Fish evolved! (Placoderms)
Some are small…
… Some reach AWESOME size!

21. Why would some fish evolve armor?
I wish he’d be more careful! 
Why would some fish evolve armor?
Why would they then become extinct?

22. And…perhaps, near those new forests…
Some fish evolve sturdy fins that may help them move through shallow water.
It proves to be a successful change

23. This is a Fish…
But what is this…?

24. …to animals that are at least partially terrestrial!
They are part of a series of fossils that show the transition from a “water animal”: a fish…
Icthyostega
Acanthostega
Tiktaalik
Pandericthyes
Eusthenopteron
…to animals that are at least partially terrestrial!

25. The newest find: Tiktaalik!

26. Obvious Amphibian!
Transitional Forms
Note Tiktaalik!
Obvious Fish!

27. So…during the early Paleozoic…
Hard shell animals evolve…
Trilobites, brachiopods, corals, cephalopods “rule the seas”
FISH EVOLVE…
Armored fish evolve…
…and then fade away.
The FIRST LAND PLANTS appear…
And at the end…a branch of fish evolve sturdy limbs and become the first AMPHIBIANS.

28. The late Paleozoic …
Amphibians had already moved ashore and taken over…
…and the first forests already existed…
…but before the end of the Paleozoic… new creatures evolved.

29. Mississippian In the oceans, new species continue to evolve… Perm Penn
Dev
Sil
Ord
Cam
In the oceans, new species continue to evolve…

30. Pennsylvanian But the action is NOT all in the ocean anymore! Perm
Miss
Dev
Sil
Ord
Cam

31. …by the Pennsylvanian, a vast diversity of plant life had evolved…
Perm
Penn
Miss
Dev
Sil
Ord
Cam
the land was covered by new species of plants.
Some of which now towered as much as 100 feet over the land…

32. …this is the time that great forests covered much of Illinois!
The Illinois Coal Forest: a great river delta where buried trees became coal.

33. It’s also the time of the Illinois State Fossil…
The “Tully Monster”!

34. During the Later Paleozoic, amphibians evolved into reptiles…
With hard-shelled eggs, Reptiles were “freed” from water…

35. …and reptiles evolved into many different types.
Early Mammals
…and reptiles evolved into many different types.
This diagram shows the transitional change in the jawbones from ancient Reptiles to early Mammals.
Early Reptiles

36. …Mammal-like Reptiles appear.
Near the end of the Paleozoic, as this evolutionary sequence continued…
…Mammal-like Reptiles appear.
Perm
Penn
Miss
Dev
Sil
Ord
Cam
Mammal-like Reptiles are reptiles with Mammal-like features.
(Obviously! : )

37. They do NOT look like “typical” reptiles.
They aren’t quite mammals, either…
…but one group WILL be!

38. But before this happens…
There is an enormous change: The “MOTHER of ALL EXTINCTIONS!”
For the Trilobites…
it’s the end!
Perm
Penn
Miss
Dev
Sil
Ord
Cam
For Brachiopods…
it’s never the same!

39. For other groups: extinction of many species!
…and for the Mammal-Like Reptiles…
Perm
Penn
Miss
Dev
Sil
Ord
Cam
…almost a total wipeout!

40. In the later Paleozoic…
Amphibians “ruled”…for a while
Insects filled the land…
Great forests covered the land… the “Coal Age” in Illinois
Reptiles evolved from Amphibians
Mammal-like Reptiles evolved…
…and then much was lost in the
“Great Extinction” at the end of the Paleozoic.

41. On to…
The MESOZOIC!
(Watch out for Dinosaurs!)

44. Same color = same bones
Ichthyostega
Notice the transitional changes from Eusthenopteron to Ichthyostega
Eusthenopteron

46. Remember: in the Early Paleozoic…
…life had moved from the ocean to the land…

47. The first land plants had evolved…
The first insects roamed the land…
And the first amphibians were evolving…