“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

“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

“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!

“explosion of life”

“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

“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

“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

“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)

“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.

“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

“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

“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

“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

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

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

“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

“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

“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

“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

“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)

“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!

“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

“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

“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

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

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?