2. “explosion of life” “Explosion of Life” Paleozoic Era
After the Precambrian Era; time is divided into three (3) additional eras:
Paleozoic Era
(invertebrates >> fish >> amphibians)
Mesozoic Era
Cenozoic Era

3. “explosion of life” LIFE EVOLVES! –Early Paleozoic Era
Early Life began in the seas: shells; trilobites
540 Ma
Divided into six (6) time periods:
Cambrian Period
Ordovician Period
Silurian Period
Devonian Period
Carboniferous Period
Permian Period

4. “explosion of life” Two main land masses:
Gondwana (s.america; africa; australia; antarctica; asia)
Laurasia (n.america; asia)
Combined to form Pangea at the end of the Paleozoic Era!

5. “explosion of life”

6. “explosion of life” Cambrian Explosion! (cambrian period)
“life takes a big leap forward”
great number of different kinds of organisms evolved
“explosion” = many new life forms appeared within a relatively short period of time
Organisms…
had hard parts (exoskeletons; shells)
many were invertebrates
all animals lived in the sea
brachiopods/trilobites common

7. “explosion of life” Vertebrates Arise! (ordovician/silurian period)
ancestors of the modern octopus/squid appear
jawless fish evolved
first vertebrate (w/ backbone)
sucker-like mouth
common

8. “explosion of life” Life Reaches Land! (silurian period)
prior: only one-celled organisms lived on land
Plants: during Silurian Period:
plants became abundant
simple; low to the ground
grew in damp areas
Insects:
first insects appear

9. “explosion of life” Life Reaches Land! (devonian period)
Plants could grow in drier areas
Ferns adapted to dry areas
Organisms:
invertebrates/Vertebrates lived in the seas
invertebrates still more numerous
Devonian Period = “AGE OF FISHES”
most fish had jaws; skeletons; scales
sharks appeared in the late devonian
Animals Invaded the Land!!
First to crawl onto land were lungfish = first evolved amphibian (life on land/ life in water)

10. “explosion of life” Life Expands! (carboniferous period)
other vertebrates evolved from the amphibians
small reptiles developed
very large reptiles formed during the later paleozoic
winged insects evolved
huge dragonflies; cockroaches
giant ferns/ cone-bearing plants/ trees forme in swampy forests (“coal forests”)
The coal forest plants formed thick deposits of sediment that changed into coal over millions of years.

11. “explosion of life” The End! (permian period)
End of the Paleozoic Era (400 ma); plants adapted to water’s edge to inland
deserts become larger in tropical regions
pangaea forms
amphibians diversified
reptiles become dominant on land
warm-blooded reptiles appear
mass extinction occurs at the end of the permian period

12. “explosion of life” Mass Extinction! – Late Paleozoic Era
Greatest of Five (5) Mass Extinctions!
affected both plants/animals
on land/ in seas
no known reason as to the cause
possible: climate became seasonal
cause due to continental drift
Pangaea
Deserts expanded into the tropics
Ice sheets covered land near the south pole

15. “age of reptiles” “Dinosaurs!” Paleozoic Era Mesozoic Era
After the Precambrian Era; time is divided into three (3) additional eras:
Paleozoic Era
(invertebrates >> fish >> amphibians)
Mesozoic Era
(vertebrates >> reptiles)
Cenozoic Era

16. “age of reptiles” Survival! –Early Mesozoic Era
Life continues with some living things surviving the Permian Mass Extinction!
350 Ma
Divided into three (3) time periods:
Triassic Period
Jurassic Period
Cretaceous Period
Dinosaurs: land-dwelling reptiles that were dominate during the Mesozoic Era!
Major Event: the break up of Pangaea
Major Event: Another Mass Extinction

17. “age of reptiles” Life Highlights!: major plants: gymnosperms
shelled egg: adaptation favoring land birth
Reptiles dominate

18. “age of reptiles” Period Highlights! Triassic Period:
dinosaurs dominate
Jurassic Period:
first birds, dinosaurs dominate
Cretaceous Period:
first angiosperms (flowering plants)

19. “age of reptiles” Triassic Marks beginning of Mesozoic Era
Survived: fish; insects; reptiles; conifers
First dinosaurs and mammals appeared around 225 million years ago
Early mammals; evolved from warm-blooded reptiles; small in size
Dinosaur Ex: Eoraptor, Plateosaurus and Teratosaurus

20. “age of reptiles” Jurassic Middle aged dinosaurs appeared
Dominant! (several 100 different kinds)
Plant/animal eaters
Dominated for 150 million years
More diversity
More complex
Archaeopteryx – “ancient wing thing” = birds
Allosaurus
Stegosaurus
Diplodicus
Ceratosaurus

21. “age of reptiles” Creataceous Flowering plants emerge
Most advanced dinosaurs
Highly specialized (flying – adapted better)
Most successful of all dinosaur species
Most popular dinosaurs
Tyrannosaurs, Tricerotops, Ankylosaurus, Protocerotype, Velocoraptors, Pterodactyl

22. “age of reptiles” Mass Extinction! 65 Ma
Hypothesis: object from space struck Earth
Impact: threw huge amounts of dust and water vapor into the atmosphere
Sunlight blocked for years
Plants died; plant-eaters starved
Wiped out over ½ of all plant/animal groups; no dinosaurs survived
No 100% agreed upon as a theory
Climate change caused by increased volcanic activity

25. “explosion of life” “Mammals!” Paleozoic Era Mesozoic Era Cenozoic Era
After the Precambrian Era; time is divided into three (3) additional eras:
Paleozoic Era
(invertebrates >> fish >> amphibians)
Mesozoic Era
(vertebrates >> reptiles)
Cenozoic Era
(reptiles >> mammals)

26. “age of mammals” Age of Mammals! 65 Ma
Divided into two (2) time periods:
Tertiary Period
Quaternary Period
The Extinction of Dinosaurs create an opportunity for Mammals!
Life continues to explode on Land, in Water, and in the Air
Plate movement led to mountain building, volcanism, and earthquakes!

27. “age of mammals” Life! Angiosperms! Mammals!
Replace gymnosperms as the dominate land plants
Mammals!
bear live young
Maintain steady body temperature
Replaces reptiles as the dominate animal
Adaptations found:
Insulating body hair
More efficient heart/lungs
Mammals leading more “ACTIVE” lives

28. “age of mammals” Tertiary Period! Geology! Life!
Rocky Mountains/ Himalayas form
Continents continue to present day locations
Continental glacier covers Antarctica
Life!
Angiosperms thrive
First grasses appear
Modern animal groups appear

29. “age of mammals” Quaternary Period! (present day!) Geology! Life!
Earth’s Climate Cooled
Series of Ice Ages occurred
Thick glaciers advance and retreat over much of North America; Europe; Parts of S. America; and all of Antarctica
Earth’s Climate Warmed
Life!
Mammals; Angiosperms; insects dominate
Giant mammals of N. America/Eurasia become extinct when the Ice Age Ends about 10,000 years ago

30. how do we know; what we know?
Fossils from La Brea Tar Pits!

32. WHY? “age of mammals” Extinction! Large mammals
In North America: Mastodon/Mammoth; Saber-toothed cats; giant beavers; large ground sloths; horses; camels; giant bison become extinct.
WHY?