5/19/2011 1 Cenozoic Life History Marine Invertebrates and Phytoplankton Terminal Mesozoic extinction took out Ammonites, Rudists, most planktic forams, much of the phytoplankton Survivors flourished and diversified – Foraminifera – large and small – Diatoms –great deposits of diatomite in Miocene – Corals form reefs in warm waters – Bryozoans (smaller and more ornate) thrive – Bivalves and Gastropods rule and become increasingly modern and familiar – Echinoids become more infaunal (Sand dollars) Cenozoic is quite provincial due to changing ocean currents and latitudinal temperature gradient
26
Embed
Cenozoic Life History - CCSF€¦ · 5/19/2011 1 Cenozoic Life History Marine Invertebrates and Phytoplankton Terminal Mesozoic extinction took out Ammonites, Rudists, most planktic
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
5/19/2011
1
Cenozoic Life History
Marine Invertebrates and Phytoplankton
Terminal Mesozoic extinction took out Ammonites, Rudists, most planktic forams, much of the phytoplankton
Survivors flourished and diversified
– Foraminifera – large and small
– Diatoms –great deposits of diatomite in Miocene
– Corals form reefs in warm waters
– Bryozoans (smaller and more ornate) thrive
– Bivalves and Gastropods rule and become increasingly modern and familiar
– Echinoids become more infaunal (Sand dollars)
Cenozoic is quite provincial due to changing ocean currents and latitudinal temperature gradient
5/19/2011
2
Cenozoic Vegetation and Climate
Angiosperms came to rule, but gymnosperms and
seedless vascular plants still numerous
Leaves with entire smooth edges and drip points
indicate high rainfall, warm conditions
– Paleocene of Colorado
– Oligocene Florissant Beds of Colorado
Leaves with incised margins indicate cool, dry
climates (Wolfe)
5/19/2011
3
Paleocene-Eocene Thermal Maximum
Abrupt warming trend 55 mya
Ocean circulation disrupted, deep warm
water, release of methane, greenhouse
effect
Subtropical plant fossils in western North
America indicate warmest period of Cenozoic
in Paleocene and Eocene – Pan-tropical
conditions
Plants and Climate
Oligocene drop in temperature
General decrease in precipitation in
midcontinent of North America
– Grasslands with scattered trees (Savannah)
– Grasslands (Steppe)
– Seen in the teeth of mammals
5/19/2011
4
Cenozoic Birds
Paleogene may be called the Age of Birds – 1st members of many modern groups evolved
– Large predatory birds took over that niche before mammals
Miocene saw songbird explosion
Pleistocene large, flightless birds e.g. Moas, elephant birds
Flying birds rule the sky
The Age of Mammals
140 my were small and not very diverse
(Mesozoic)
Exploited the niches left by the dinosaurs
and other reptiles – land, sea and air
Continued diversification at surprising speed
throughout the Cenozoic
5/19/2011
5
The Age of Mammals
Types of Mammals
– Monotremes –egg laying Mammals
– Marsupials – Carry embryo in pouch
– Placental mammals – Have Placenta, give birth to
live young
5/19/2011
6
Paleocene Mammals
Some holdovers from Mesozoic, soon extinct
Archaic Mammals: insectovores, marsupials and multituberculates
New Mammals: rodents, rabbits, primates carnivores, ancestors of hoofed animals
Most mammals small; some orders became extinct
No match for giant birds
Eocene and Oligocene Mammals
Larger
Ancestors of many living orders
Very large mammals included uintatheres
and titanotheres
Oligocene drying produced diversification to
more modern fauna
5/19/2011
7
Small mammals
Most mammals are small
Insectovores (including shrews, moles,
hedgehogs)
Rodents (largest are beavers and capybaras)
Rabbits
Bats – modification of the hand to wing and
flight
Carnivorous Mammals
Predators and meat eaters (some omnivorous)
Most have pointed, specialized teeth – carnassials
Uncommon as fossils because uncommon in life – represent 5% of warm-blooded population
Many are solitary animals (not all)
5/19/2011
8
Diversification of Carnivores
Began with creodonts and miacids; creodonts extinct in Miocene
Similarity of dogs and hyenas = convergent evolution
Saber-tooth cats repeatedly evolved through the Cenozoic