• Final Breakup of Pangaea• Australia and Antarctica split

– Antarctica froze– Then warmed– Then froze again

• Northern polar ice cap formed which lead to multiple ice ages...how?

• Subduction along the West and East coasts of North America

• Hot spots in Yellowstone National Park caused by subduction event

• Formation of Mt. Everest and the Swiss Alps• Bye bye Tethys Sea (African and Eurasian continent

collisions)

Break-up of Pangaea During the early Jurassic, Pangaea began to

breakup (174 Mya) and formed Laurasia and Gondwana ( aka Gondwanaland)

By the Cretaceous, Gondwana split up into what has become Africa, S. A., India, Antarctica and Australia

_______________________________________Bottom Line: The final splitting of Laurasia into

N.A. And Greenland happened during the Cenozoic Era

Australia and Antarctica split up As Australia and Antarctica split up,

Earth’s climate started to cool because of new ocean current dynamics (distribution of energy)

India and Australia began to move northward

Formation of the Polar Ice Cap As Antarctica localized around the

magnetic south pole cold current paths developed leading to the formation of glaciers

Around the mid-Cenozoic (Pliocene Epoch) water within the Arctic Ocean began to freeze and formed the first northern polar ice cap

Since then, glacial activity can be measured in the abundance or lack of sea ice extent in the north pole.

This process has traditionally taken thousands of years

Implications of having a North Pole Blocks warm water and air from

reaching the poles May significantly impact the albedo

positive or negative feedback loop Oppositely, having a continental

landmass above a magnetic pole decreases the likelihood of an ice age as it blocks the development of glaciers and icebergs

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Formation of the Rocky Mountains North American tectonic activity lead to

the formation of the modern day Rocky Mountains

Orogenic activity during the Mesozoic moved sediment inland and filled the Rocky Mountains. This made for exceptionally well-preserved fossils

Phareodus; Fossil Fish found in Wyoming

Subduction on the East and West Coasts of N.A. Oceanic plates from the West began to

subduct the North American plate during the latter end of the Eocene Epoch

= Volcanic Activity in California and the San Andreas Fault

Evidence of this may be seen in the geographic make up of the south-western USEX. Basin and Range Province

Hot Spots in Yellowstone National Park Subduction from the early and mid

Cenozoic influence the geology of inland regions (hot spots)

Yellowstone National Park is famous for active geologic activity Geysers, Hot Springs and extrusive rhyolitic

rock with a characteristic yellow colour

Morning Glory Pool

Formation of the Swiss Alps and the Himalayan Mountains Movement of India into Eurasia caused

intense folding (and still does to this day)

Rock found atop found Mt. Everest are Ordovician marine limestones

Africa moved northward into Europe and formed the Swiss Alps in much the same way

The Tethys Ocean Disappearance Existed between Laurasia and Gondwana

and closed up as India and Africa moved Northeast into their current positions

Some species had become extinct, but some survived and evolvedWhales and dolphins

Grass Importance of the Pliocene ice age

(Savannah creation across North America) Primates; features and characteristics Hominoids -> Hominids -> Homo Sapiens

Successful Life in the Cenozoic Aquatic mammals first appeared (whales

and dolphins)Evolved from land dwellersLarge size, hydrodynamic bodies,

thermoregulatory adaptationsCharismatic megafauna (large animal species

with widespread popular appeal that environmental activists used to achieve conservation goals well beyond just those species)○ Lions, tigers, Wolves, Bald Eagle, Giant Panda

Successful Life in the Cenozoic Most current groups of mammals were

established by the Eocene Epoch

Grass

Sod: Grass and soil complex

The Pliocene Ice Age aka Quarternary Ice Age Repeated glaciation leading up to the Repeated glaciation leading up to the

last glaciation event caused savannahs last glaciation event caused savannahs (grassland ecosystems) to become dry (grassland ecosystems) to become dry and allowed new forms of life to flourish and allowed new forms of life to flourish as those adapted to the savannah as those adapted to the savannah ecosystem died off or adapted.ecosystem died off or adapted.

1977: Dima found in Siberia

Radiometric dating estimates that Dima died 40 000 years ago

Development of Primates Opposable thumbs; stereoscopic vision; non-specialized teeth (generalist eating

behaviour);and a relatively high body to brain ratio

separate primates from other mammals

- Opposable thumbs are purposed for grabbing, carrying, tool making and ‘creative interactions’

Maxilla (jaw bone) of various hominoids

-Development of the occipital lobe (back of brain used in visual processing)- Development of the cerebellum (‘little brain’ traditionally thought to play a role in motor control

Hominoids -> Hominids -> Homo

sapiens Hominids are

characterised as bipedal (walking on two legs)Sexual selection

hypothesis

Significant differences between Homo neanderthalensis (extinct) and Homo sapiensNeanderthals had a

flared ribcage and large gait (stride)

Homo sapiens had larger brains and slender hands

Neanderthals had ‘thick-walled’ bones relative to Homo sapiens

The ‘Out of Africa’ Hypothesis:Human Evolution Presents that modern humans evolved in

Africa ~200 000 years ago and started to migrate out ~60 000 years ago

Displaced/replaced other homo species in Europe and Asia

Genealogy trees based on mtDNA (mitochondrial DNA) concludes that all homo sapiens descended from Mitochondrial EveMitochondrial DNA in Africa is the most diverse

relative to other populations

Hominoids -> Hominids -> Homo

sapiens