CENOZOIC LIFE AND EXTINCTIONS

•  Age of the Mammals

 
•  Geochronologic units:
•  Paleogene Period : Paleocene, Eocene, Oligocene Epochs
•  Neogene Period: Miocene, Pliocene, Pleistocene, Holocene Epochs
•   Modern faunas (no dinosaurs or marine reptile monsters or ammonites or rudists)

 
•   Neogene floras include grasses (Age of the _______________). Glaciation.

•   ______________ plants dominants after the Cr extinction.
•   Emergence of _________________ (in swamps only until continued growth evolved) Why?

 

 
 
 
 
 

•   Ng: cooler drier climates favor Compositae family plants (______________ & asters)

Marine Invertebrates and Protists

•   Survivors: sea urchins, crabs, corals, snails.

•   Diversification

      calcareous nannoplankton (after being almost eliminated during the Cr extinction)
     ___________________ (Neogene guide fossils).
 
•   _____________ build reefs after rudist extinct .

  Relationship between Mg/Ca ratio and ocean abundance:

•  Ea Pg: calc nannopl.= calcite (Low Mg/Ca ratio = _________________ MOR activity)
•  Olig: corals = aragonite (High Mg/Ca ratio = ________________ MOR activity)

•   Sand dollars (evolve from _________ ______________)

Diversification of Mammals

•  Differentiated teeth; identified by the molars

 
•   Living Orders: Monotreme, ____________________ & Placental

 
•   Few new orders (Pc) =>   giant mammals (Ec) =>  old orders extinct  (Olig) =>  others evolve into modern mammals...

 
•   Cr Survivors: marsupial __________________, multituberculates. ( They are primitive mammals)

 
•   Rodents, rabbits & bats appear in Pc

  Primates

•    Pc: Present
•    Ec: larger forms
•    Olig: Monkeys (S.Am & Afr)
•    Mc: hominids

•   Carnivores: speed and __________________

                                                    hyenas, cats
                 Miacyds                     dogs, bears, pandas
                                                    marine: walrusses, seals, sea lions

•   Ungulates: _______________ and limb adaptation
•    Even toed:  camels, pigs, ruminants
       cattle
       sheep
       deer
•    Odd toed:     ____________
                rhinoceros ( Extinct: Titanotheres & Chalicotheres)
                tapirs
•    Herbivore adaptations
•       molarization

                            Grazers: high crowns. Why?
                            Browsers: crowns regular height
•       limb         for ______________
•       long palm & toe bones
•       reduction of toe number
•       hoof

 
                       for  ______________
• thick limb (rhyno, elephant)

•   Giant Mammals:

   ______________ whale (teeth). Ec
   ______________whale (filter feeder). Olig.

 Elephants (Proboscideans)
           Widespread in CZ, only 2 genus & 2 sp remain today
          Appear in Ec.
          Divergence Mammoth/elephants Plio-Pleistocene

Birds
Paleogene diversification
            Ea Paleogene: __________________ birds = Dyatrimas, ostriches and rheas. Penguins
            Neogene: song-birds and flyers
            Diversity enhanced by the _________________ and __________________ expansion

Frogs and Snakes
Eocene: Evolution of frogs in the Eocene
Neogene:___________ evolved into snakes
                                                constrictor, poisonous snakes, Colubridae family
 

CENOZOIC EXTINCTIONS
Paleogene

• Extinctions in the second half related to         cooling

                                                                        drier climates

• Eocene: Warm climates => no polar ________ => deep sea anoxia => extinction of ____________ foraminifera

 
• 3 pulses of cooling after the Eocene warm spell,
•         glaciation in Antarctica, formation of the __________________current
•         Many N Am and Eu mammals become extinct because of changes in the flora
                    Affected tree climbers and those with soft leaf diets

• 10,000 y a; Only terrestrial forms larger than 40 kg.
• More severe in N Am, S Am & Australia.
• Causes
• Climatic change at the end of the glacial Age?

 

 
 
 
 
 
 
 

• Prehistoric overkill by humans?

 

 
 
 
 
 
 
 

Completed outline