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Prehistory 1:
Geologic
Timeppt. by Robin D. Seamon
Resource: TEXTBOOK:
Prentice Hall Earth Science
notes
http://home.earthlink.net/~tran
qbase/images/fossils.jpg
HOOK VIDEO- COSMOS: “Lost
Worlds of Earth” (45 min)
HIGHLIGHTS:
• Earth: 4.5 billion years old
• ¾ of the geologic timeline holds life
• Life forms changed Earth’s chemistry
• Catastrophes affected the evolution of life-
extinctions
• New weedy species thrives & takes over after
an extinction
VIDEO: How Much is A Million?
EXTINCTIONS: widespread & rapid decreases in
amount of life on Earth.
5 major Extinctions:
65
myaK-Pg Extinction 75% extinct
(killed
dinosaurs)
Mammals &
birds survive
200
myaTriassic-Jurassic
extinction event75% extinct Dinos & birds
survive
251
myaPermian-Triassic
extinction event95% life extinct
“Great Dying”
Archosaurs
survive
375
myaDevonian
extinction70% extinct Marine life
changed
450
myaOrdovician-
Silurian extinction70% extinct X 2 2 events
***CC Video: Mass Extinctions (12 min)
Mass extinctions:
• Long-term stress compounded by short-term
shock (2 things)
POSSIBLE CAUSES
• Flood basalt events (LIP)
• Sea level falls
• Impact events (asteroid/comet)
• Sustained & significant global cooling
• Sustained & significant global warming
• Anoxic events: (lack of O in oceans-warming)
• Oceanic overturn (disruption of thermohaline
circulation)
• Plate tectonics
• Initiate/end Ice Ages
• Change ocean & wind patterns
• Close off or open land bridges
• Decrease continental shelf
• Arid interior
• OTHER:
• New disease
• Out-competition
• Man-made extinction of species
EFFECTS & RECOVERY
• Weedy species- species that can quickly adapt
to the environment; becomes dominate
• Reproduce quickly
• Disperse widely
• Live in a variety of habitats
• Establish populations in strange places
• Resist eradication once established
• 5-10 million years before re-diversification
Geologic Timeline CALENDAR LAB
If Earth’s whole history was
compressed into 1 year, each
day would represent 12.5
million years.
According to this calendar,
animals & plants didn’t
evolve on Earth until the
late Fall.
First fish started crawling
onto land, evolving into
amphibious creatures with
legs in early December
Primates (group that today
contains lemurs, monkeys,
humans) only appeared in
the last week of December.
CC Video: History of Life on Earth (12 min)
PH1 UNIT CHECK1
1. Age of the Earth according to geologists
2. How many major extinctions has Earth experienced?
3. How long does it take for biological re-diversification to
happen on Earth?
4-5. Name two supercontinents that were once on the Earth.
6. What is the species that is able to withstand the
environmental changes and resulting mass extinctions? They
repopulate Earth.
A- Mesozoic Era
B- Paleozoic Era
C- Cenozoic Era
D- Precambrian
1. Era in which we live
2. Era in which dinosaurs were dominant
3. Era in which fish and marine animals
were dominant
4. Earliest time period- only bacteria
4.5 billion years old
5
5-10 million years
Rodinia, Pangaea
Weedy species
CA
B
D
Precambrian Era: Vast and Puzzling
4.5 Billion years ago to the Cambrian Period
3.4 bya: microscopic bacteria
Atmosphere: water vapor, CO2 , Nitrogen,
NO OXYGEN
Ozone layer protects from UV: water protects
Later, primary plants (cyanobacteria) evolved,
used photosynthesis which created oxygen
Oxygen accumulates 2.5 bya
CC VIDEO: Big History- Life Begins (12 min)
Precambrian Era: Vast and Puzzling
Fossils:
* stromatolites: layered mounds and columns of
calcium carbonate (material deposited by algae)
* 600 mya 1st multi-celled organisms
EXTINCTION
Remnants of Precambrian Rocks
After Precambrian Era, time is divided into 3
other eras:
* Paleozoic Era
(Invertebrates Fish Amphibians)
* Mesozoic Era
(Reptiles)
* Cenozoic Era
(Birds & Mammals)
Early Paleozoic Era: Life Evolves
540 mya
Divided into 6 time periods:
* Cambrian Period
* Ordovician Period
* Silurian Period
* Devonian Period
* Carboniferous Period
* Permian Period
Paleozoic Era
LIFE EVOLVES
early life began in the seas
shells, trilobites
Early Paleozoic Era: Life Evolves
Land masses:
* First: Gondwana ( S. Amer, Africa, Australia,
Antarctica, Asia) MAP
*Then another mass is raised: Laurasia
(N. Amer, Eurasia) MAP
* Then in Permian Period, there was: Pangaea
(all continents together) MAP
ADVANCE
BACK
Cambrian Period: “Age of Invertebrates”
first organisms with shells, trilobites dominate
Ordovician Period: first fish
Silurian Period: “Age of Fishes”
first land plants
Devonian Period:
fish dominate, first insect fossils
Carboniferous Period: “Age of Amphibians”
amphibians abundant, large coal swamps,
Permian Period: extinction trilobites & other marine
animals; first reptiles
Periods of the Paleozoic Era
Late Paleozoic Era
At the end of the Paleozoic Era, (400mya)
plants adapted to water’s edge to inland
Amphibians diversified
Greatest of 5 mass extinctions
(Climate became seasonal)
ADVANCE
Silurian Period
BACK
BACK
Ordovician Period
Armor-Plated Fish
BACK
Model of a Pennsylvanian
Coal Swamp
BACK
Permian Period Reptiles
ADVANCE
Mesozoic Era: “Age of Reptiles”
350 mya
Divided into 3 time periods:
* Triassic Period
* Jurassic Period
* Cretaceous Period
Dinosaurs were land-dwelling reptiles that
were dominate during Mesozoic Era
Major event: breakup of Pangea
Mesozoic Era: “Age of Reptiles”
Life:
* gymnosperms:
“Naked seeds”- plants produce seeds without
covering; rely on wind for pollination
* Canadian Rockies formed
* shelled egg: adaptation favoring land birth
IMPORTANT EVOLUTIONARY STEP
* Reptiles dominate
ADVANCE
BACK
The Flying Reptile Pteranodon
ADVANCE
Fossil Skull of an Extinct Crocodile
Periods of the Mesozoic Era
Triassic Period “Age of Reptiles”
Dinosaurs dominate
Jurassic Period
First birds, dinosaurs dominate
Cretaceous Period
First angiosperms (flowering plants that trick
animals into pollination & seed dispersal)
ADVANCE
Jurassic Period
BACK
Cretaceous Period
MASS EXTINCTION!!!
K-Pg Boundary- Earth struck by 6-mile wide asteroid,
resulting in mass extinction: 65 mya
End of the Mesozoic Era:
Badlands, SD
Cenozoic Era: “Age of Mammals”
65 mya
Considered the “Age of Mammals”
Divided into three periods
* Paleogene Period
* Neogene Period
* Quaternary Period
Plate movement led to much mountain building,
volcanism, earthquakes
Cenozoic Era: “Age of Mammals”
Angiosperms replace gymnosperms as
dominate land plants
Mammals (animals that bear live young,
maintain steady body temperature & produce
milk for their young) replace reptiles as
dominate animal
adaptations such as insulating body hair, more
efficient heart & lungs, allow mammals to lead
more active lives
Fossils from La Brea Tar Pits
Cenozoic Era: “Age of Mammals”
Life
Large mammals & extinction:
* In N. America, mastodon & mammoth
(huge relatives of elephant), saber-toothed cats,
giant beavers, large ground sloths, horses,
camels, giant bison become extinct
???? WHY???
Cenozoic Era: “Age of Mammals”
Mastadon
Wooly mammoth
Cenozoic Era: “Age of Mammals”
Saber-toothed tiger
Giant ground sloth
Cenozoic Era: Human Ancestors
2 mya – 10mya humans?
***CC VIDEO: Big History: Evolutionary Epic (12 min)
42
1. Layered mounds and columns of calcium carbonate (remains of ancient bacteria)2. large reptile of the Mesozoic Era3. ‘naked seed’, plant produces seed in cone4. warm-blooded animal that has hair/fur & produces milk5. flower-producing plant6. early, extinct arthropod of the Cambrian-Paleozoic periods
7. angiosperms or gymnosperms?8. stromatolites or single-celled organisms?9. water plants or land plants?10. squishy-egg producers or shelled-egg producers?
a. gymnosperm b. stromatolite c. trilobite d. angiosperm e. dinosaur f. mammal
A
PH1 UNIT CHECK2
Which was first:
B
C
E
D
Reader’s Theater:
North American History
Character
LINK
Script
LINK
LAB:
Geologic Beaded
Timeline
LAB Activity:
Group Timeline Project
Precambrian Paleozoic Mesozoic Cenozoic
Cambrian
Your timeline should include in pictures and words the following: (use
color)
Time ( - )
Era _____________, “Age of _________” Period
Geology
Atmosphere & weather
*New adaptations
plants, animals
Extinctions?
RESOURCE:
TEXTBOOK: Prentice Hall Earth Science
notes 6th grade
