Phanerozoic Eon

Cambrian Explosion What is meant by “Explosion”:

• Adaptive radiation of animals

• Morphological diversification

• Development of hard-part skeletons

• Global expansion of the fauna in the ocean

Burgess Shale (cambrian rock)

A representative Cambrian rock deposit in British Columbia, Canada.

What is significant about Burgess Shale?

• Rock that is evidence for the cambrian explosion

• Many specimens preserve soft-body parts

Break up of Pannotia:

• Six major continents (incl. Laurentia & Gondwana)

  • Expansion of well-circulated shallow seas

  • Warmer climate & oceanic crust than today

    • Crust was warmer than today because it rotated faster

    • Higher sea level

Abundant oceanic invertebrates & first vertebrates:

• Archaeocyathid (Cambrian)/ Bryozoan (Ordovician) reefs

• Brachiopods

• Mollusks (e.g., nautiloids)

• Arthropods (e.g., trilobites)

• Jawless fishes

What happened at the end of early Paleozoic (Cambrian-ordovician) and what did it lead to?

Major glaciation -> Mass extinction

what are Archaeocyathid (Cambrian)/ Bryozoan (Ordovician)?

reefs

What are Brachiopods?

are marine invertebrates with two shells hinged at the back. They are filter feeders and have a rich fossil record dating back over 500 million years.

what are Mollusks (e.g., nautiloids)?

are soft-bodied invertebrates with a muscular foot, visceral mass, and a mantle that often secretes a calcium carbonate shell.

What are Arthropods (e.g., trilobites)?

are invertebrate animals with exoskeletons, segmented bodies, and jointed appendages. Trilobites are an extinct group of marine arthropods.

Extensive shallow season continued in what phase

mid-paleozoic

What are Tabulate & rugose corals

reef builders

First jawed fishes happened when

Silurian [Ordovician]

what was the devonian known for

“Age of Fishes”

What animals existed during the age of fishes

Placoderms, early ‘sharks’ & bony fishes

What emerged during the mid-paleozoic

First land plants during silurian but possibly ordovician

What did the first land plants cause

Thickened ozone layer

What did the thickened ozone layer cause

First land animals (e.g., arthropods)

When did the first tetrapod occur

late devonian

When was there a mass extinction in mid-paleozoic

Devonian cause(s) still in debate

Evolution of land plants in mid-paleozoic

• Bryophytes (non-vascular plants; mosses)

• Tracheophytes (vascular plants: plants with stems (+ roots + leaves) = ‘most plants’)

  • Rhyniophytes (first tracheophytes without roots or leaves)

Evolution of land vertebrates in mid-paleozoic

• Tiktaalik (= ‘transitional form’ between fishes and tetrapods during the late Devonian)

  • Appendicular bones (basic limb architecture of tetrapods have already evolved)

  • Pectoral girdle still attached to skill (this is still a fish characteristics)

• Tetrapods (amphibians & reptiles diversified during the ‘late’ Paleozoic)

Bryophytes

non-vascular plants; mosses

Tracheophytes

vascular plants: plants with stems (+ roots + leaves) = ‘most plants’

Rhyniophytes

first tracheophytes without roots or leaves

Tiktaalik

‘transitional form’ between fishes and tetrapods during the late Devonian

Appendicular bones

basic limb architecture of tetrapods have already evolved

Pectoral girdle still attached to skull

this is still a fish characteristics

Tetrapods

amphibians & reptiles diversified during the ‘late’ Paleozoic

‘Late’ Paleozoic

Carboniferous-Permian

What happened during the late paleozoic

Gathering of continents (Carboniferous)

• Formation of Pangaea & Panthalassa Ocean (Permian)

late paleozoic climate

• Carboniferous:

  • Major glaciation (Gondwana)

  • Warm & humid (other regions)

• Permian:

  • Widespread arid condition

Carboniferous climate

• Major glaciation (Gondwana)

• Warm & humid (other regions)

Permian climate

Widespread arid condition

Marine life in Late paleozoic

• Brachiopods

• Mollusks (e.g., nautiloids)

• Arthropods (e.g., trilobites)
  Echinoderms (e.g., crinoids)

• Jawed fishes

land life late paleozoic

• Coal swamps & forest (e.g., ferns, lycopods, & seed-bearing trees)

• Insects

• Amphibians gave rise to ‘amniotes’ that lay shelled eggs (e.g., ancestral reptiles & ‘mammal-like’ reptiles)

Mass extinction in paleozoic

• The greatest mass extinction in the Earth’s history 

  • Over 90% of life disappeared

  • Cause(s) still in debate but likely intense volcanism & poor oceanic circulation

When did Archaeocyathid happen

Cambrian

when did bryozoan occur

Ordovician

what are Brachiopods

are marine invertebrates with two shells that are hinged at the back. They are filter feeders and have a unique feeding structure called a lophophore.

what are Mollusks

are soft-bodied invertebrates with shells, like snails, clams, and octopuses. They have a muscular foot and a mantle that secretes the shell.

what are Arthropods

are invertebrate animals with segmented bodies, exoskeletons, and jointed appendages. They include insects, spiders, crustaceans, and millipedes.

What are Echinoderms

are marine animals characterized by radial symmetry, a water vascular system, and spiny skin. Examples include starfish, sea urchins, and sea cucumbers.

When did mass extinctions occur

• end of pleistocene

• end of cretaceous

• end of triassic

• end of permian

• End of devonian

• end of ordovician

What is the Mesozoic Era known as

age of reptiles

What happened during mesozoic era

Breakup of pangaea:

• Laurasia (north america, greenland, eurasia)

• Gondwana (south am., africa, india, australia, antarctica)

  • Tethy and Atlantic Oceans

what was the climate like in mesozoic era

• Triassic: Dry in low-mid latitude and wet in high latitude

• Cretaceous: Equably warm worldwide

What was the plants like in mesozoic era

• Seed-bearing trees (conifers: Triassic-Jurassic)

• Flowering plants (Cretaceous-Today)

Invertebrates in Mesozoic era

• Mollusks (ammonoids, bivalves, & gastropods)

• Echinoderms (e.g., sea urchins)

• Crustaceans (crabs & lobsters)

Mammals (evolved from mammal-like reptiles) mesozoic

• Egg-laying mammals

• Multituberculates

• Live-bearing mammals (marsupials and placentals)

Reptiles mesozoic

• Turtles, lizards and snakes

• Ichthyosaurs & plesiosaurs

  • Mesozoic marine reptiles (thrived during this time)

• Archosaurians:

  • Crurotarsans (incl. crocodiles)

  • Pterosaurs (= flying reptiles)

  • Dinosaurs (one lineage gave rise to birds)

Mass extinction mesozoic cause

asteroid impact near Yucatan peninsula

What was the cenozoic era known as

Age of mammals

what was the tectonic activity like in cenozoic

   Present-day arrangement of continents & oceans

• Expanding Pacific and Atlantic Oceans

• India-Eurasia collision & closure of Tethys Ocean

  • Formation of Indian Ocean

• Orogenic belts:

  • Circum-Pacific Belt (so-called “ring of fire” because of extensive volcanism)

  • Alpine-Himalayan Belt

Circum-Pacific Belt

“ring of fire”

Climate of cenozoic

• History:

  • Paleogene: tropical

  • Neogene: Cool

  • Pleistocene: Series of ice ages and warm periods

• Causes (natural):

  • Plate tectonics and volcanism

  • Milankovitch theory

    • Just know its the idea that explains how the ice age occurs

  • Variation in solar energy

  • Organism

paleogene climate

tripical

neogene climate

cool

pleistocene climate

series of ice ages and warm periods

causes of climate cenozoic

• Plate tectonics and volcanism

• Milankovitch theory

  • Just know its the idea that explains how the ice age occurs

• Variation in solar energy

• Organism

Cenozoic life:

• Flowering plants (incl. grasslands: Oligocene-Today)

• Scleractinian corals, mollusks, and echinoids

• Birds and placental mammals (incl. humans)

Milankovitch Theory

explains how changes in Earth's orbit and axial tilt influence climate change over long periods of time.

India-Eurasia collision & closure of Tethys Ocean

Formation of Indian Ocean

orogenic belts in cenozoic era

• circum-pacific belt

• alpine-himalayan belt

Archosaurians

• Crurotarsans

• Pterosaurs

• Dinosaurs

What is significant about dinosaurs mesozoic

one lineage gave rise to birds

pterosaurs

flying reptiles

crurotarsans

are a group of archosaurs that includes crocodiles and their extinct relatives. They have a unique ankle joint structure.

Triassic climate

Dry in low-mid latitude & wet in high latitude

cretaceous climate

Equably warm worldwide

Laurasia

[North America, Greenland, Eurasia]

Gondwana

[South Am., Africa, India, Australia, Antarctica] → tethys and atlantic oceans

Warmer climate & oceanic crust than today caused what

higher sea levels