Geology 107 Exam - Queens University (2nd Half)

Milankovitch Cyclicity

(10's to 100's of thousands of years cycles) Relates to changes in the obliquity (tilting), precession (wobble) and eccentricity (ellipticity) of Earth's orbit.

Supercontinent Cycle

(Billion year cycles) -Studies of ice age deposits (tillites) provide a crude record over the past 3 billion years -4 major intervals of glaciation, three of which correspond to supercontinents -Early Proterozoic, 2 Ga (Nuna) -Late Proterzoic, 1 Ga (Rodinia) -Late Paleozoic, 300 Ma (Pangea)

Greenhouse-Icehouse Cycles

(Hundreds of millions of years cycles) -Greenhouse conditions warm over much of Earth, high sea levels -Icehouse conditions cold, low sea levels, ice sheets

Permian Extinction

- "The Great Dying" - Greatest extinction in Earth History - Due to ocean anoxia followed by a sudden release of CO2

Morganucodontids

- A group of early stem-group mammaliformes - late Triassic (225 Ma) - still had a cynodont jaw structure but other features were mostly mammalian -shrew- to mouse-sized, agile insectivores

Tetradium Thicket

- Analogous to modern fringing reef attached to shoreline - Metre-scale colonies of tabulate coral Tetradium - Fragile branching coral similar in habit to branching Porites corals - Edges of Tetradium thickets contain abundant broken corals and other fossils - Coral rubbble attracted scavengers, colonized by filter-feeders.

Monotremes

- Fur-covered partial endotherms; milk-producing but no nipples; lay eggs - Only two living genera, the platypus and echidna, both from Australia - Definitely known from the Early Jurassic onwards - Originated in Gondwana and been restricted to it ever since

Sub-tidal Seafloor

- Normal marine salinities, gently agitated by waves, well illuminated by sunlight -Ideal environment for animal and algal life - Diverse fossil assemblage includes most of the groups of the Ordovician Radiation - Trophic web includes most of the same elements of modern level-bottom shallow marine communities

Tidal Environments

- Occur in lower part of the Kingston rock section -Represent broad supratidal and intertidal flats - High salinity, periodic exposure and drying (desiccation) in a hot arid environment - Few modern organisms can stand these conditions, even fewer in the Ordovician -Abundant cyanobacteria in the form of stromatolites -Ostracods and trilobites, a few brachiopods in less exposed areas

Mass Extinction

- Significant and geologically instantaneous drops in diversity - Major (>50% family extinction; Permian), -Intermediate (10-50% family extinction; Ordovician, Devonian, Triassic, Cretaceous) -Lesser (3-10% family extinction; several events) - Followed by a burst of evolution Mass extinction is probably equal to natural selection in controlling the evolution of life on Earth.

Skeletal Innovations of Mammals

- upright stance - complex teeth - simplified lower jaw - multiple inner ear bones

Lizzie

-earliest stem-group reptiles 350Ma (latest Early Carboniferous) from Scotland include Westlothiana and other primitive forms

4 Solution to Cold-blooded/warm-blooded Dinosaur Debate

1) All dinosaurs were ectotherms ("overgrown lizards"). 2) All dinosaurs were full endotherms (Bakker's Delight). 3) Dinosaurs were a diverse group that contained ectotherms, partial endotherms, and full endotherms. 4) Large adult dinosaurs were gigantotherms. Juveniles and species with small adults may have been either endotherms or ectotherms.

Land Plant Effects

1) Binding of loose sediment by plant roots permanently changed patterns of erosion and sedimentation on the continents. 2) First appearance of a new type of river (meandering) due to the binding action of plant roots. 3) First appearance of a new rock-type (coal). 4) Dramatically altered carbon cycling. Massive drawdown of CO2. 5) Permanent rise in atmospheric oxygen to present levels. 6) permitted the origin and evolution of terrestrial animals.

Pre-Adaptations for Flight

1) Bone features in early theropods 2) Digit and body size reduction 3) Shoulder girdle and arm changes 4) Nesting behaviour and pubis orientation goes back 5) Feather development

Dinosaur Footprints

1) Brontosaur Trackways and Lifestyles - some of the largest tracks known -some random, but others may show herd behaviour 2) Dinosaur Speeds -noted that the distance between individual tracks increases with speed -can be used to calculate a relative stride length

Evolutionary Faunas

1) Cambrian Fauna - Trilobites, archaic molluscs, archaic echinoderms, and inarticulate brachiopods, mainly mudgrubbers 2) Paleozoic Fauna - Reflects the advent of armoured filter-feeders and pelagic predators during the Ordovician Radiation 3) Modern Fauna Gastropods, bivalves, crustaceans, echinoids, bony fish, all less armoured and more mobile than their equivalents in the Paleozoic Fauna.

Three main ways of recognizing global plunge in temperature as Earth moved from greenhouse to icehouse mode:

1) Leaf Shape Analysis Dramatic shift to serrate margins at Eoc-Olig boundary 2) Oxygen Isotope Analysis High 18O/16O ratios in seawater reflect large ice caps, proxy for temperature 3) Community Analysis Indicate a warm seasonable temperature with no frost or snow, yet we know this area to have been at 80 degrees Lat. with 4 months of total darkness in winter

3 Phases of Recovery

1) Lower Triassic lag phase (9 million years) immediately following extinction 2) Middle Triassic rebound phase (14 million years) 3) Upper Triassic expansion phase

The plate tectonic movement of biogeographic provinces through climatic zones has had a profound impact on the evolution of life:

1) Movement Through Climatic Zones = Pronounced decrease in diversity from tropics to poles 2) Plate Separation = Same latitude but changes degree of continental separation

2 Stages in Evolution of Mammals:

1) Pelycosaurids 2)Replaced by Therapsids

Later Evidence for Warmblooded Dinosaurs

1) Plate and Frills (Means of releasing excess heat) 2) Oxygen Isotopes 3) Bone Microstructure (Show typical endotherm bone structure) 4) Nasal Turbinates 5) Feathers (Modern endotherms are covered with hair or fur)

Bob Bakker Evidence

1) Predatory-prey ratios (Endothermy requires more energy) 2) Upright posture (All modern endotherms have upright posture) 3) Running Speeds (High speeds are typical of endotherms) 4) Polar Dinosaurs (Endotherms extend to polar regions)

The Triassic Takeover

1)Amphibians 2) Marine Reptiles 3)Terrestrial Diapsid Reptiles

Ginkgo

A"living fossil" that is unchanged since the Paleozoic. Important gymnosperm group throughout the Mesozoic but now reduced to a single species.

Carrier's Constraint

All amphibians, Paleozoic diapsids, and living lizards had a sprawling posture, fundamental problem is that animals with a sprawling posture cannot breathe and run at the same time. Evolution of semi-erect and finally erect posture freed the archosaurs.

Thre main Groups of Amniotes

Anapsid - no fenestra (earliest reptiles) Synapsid - one fenestra (mammal-like reptiles and mammals) Diapsid - 2 fenestrae (most modern reptiles, all dinosaurs, birds)

Biogeographic Provinces

Areas with distinct biotas, primarily reflect geography and climate

Bob Bakker

Argued that dinosaurs were warm blooded and presented several lines of evidence to back up his claim

Mesozoic Plants

Carboniferous and Permian landscapes were dominated by a late Paleophytic flora of ferns, seed ferns, and lycopods. Over the Triassic, this was gradually replaced by a Mesophytic flora of ferns, conifers and cycads

Belemnites

Cigar-shaped squid-like cephalopods also extremely common in Mesozoic marine ecosystems.

"Old Red Sandstone

Collision of Europe and North America in the Devonian produced mountain belts running up eastern margin of North America and western Europe produced a complex of mountains, lowlands with lakes and rivers, and shallow seas all preserved in ...

Comparative Anatomy

Comparisons of weight vs bone thickness for dinosaurs and living animals

Jehol (Liaoning)

Crown-group marsupials and placentals both first appear Liaoning beds in the Early Cretaceous of China

"The Age of Fishes"

Diversity of fishes probably higher now than at any point in the past, but the greatest disparity was undoubtedly back in the Devonian

Sepkoski

Divided all Phanerozoic marine animals into three overlapping Evolutionary Faunas.

Allosauroids

Dominant carnivores of the Mid-late Jurassic, Evidence for pack hunting.

Mesophytic Flora

Dominate by gymnosperms

Cenophytic Flora

Dominated by angiosperms, strong reliance on vector pollination and seed dispersal, lead to coevolution of angiosperms and animal vectors.

Triassic Extinction

Due to massive volcanism - Eliminated ornithosuchian diapsids and most synapsids who had been the direct competitors of the dinosaurs - Dinosaurs expanded from 2-3% to >85% of "reptiles" by the beginning of the Jurassic

Craniates

Early Cambrian from the Chengjiang Lagerstätten in China are more advanced than Pikaia, and imply that boneless fish arose early in the Cambrian Explosion

Fossil Forest

Eocene (40-45 Ma). Axel Heiberg Island in Canadian Arctic. -mummified forests, with trees and leaves perfectly preserved (still burn!) -assemblage of deciduous (swamp cypress, oak, hickory, ginkgo, etc.) and conifers (dawn redwoods, spruce, pine, etc.) typical of modern Georgia -animal fossils include turtles, alligators, hippo-like mammals typical of more tropical realms

Winton

Faster speeds are shown in the dinosaur stampede in Queensland, Australia. Thousands of small bipedal ornithopods and theropods trapped against water by a large carnosaur , true stampeding behaviour at top speed as they tried to run past the carnosaur

Mesozoic Era

First appearance of the animal groups that were characterize, after Upper Triassic

Confiers

First evolve in Permian, dominant group through the Mesozoic

Seed Ferns

First gymnosperms, plants bearing a naked seed, i.e. not encased in ovaries

Acanthodians

First jawed fish appeared in late Silurian

Marsupials

Give birth to immature young that then develop in the mother's pouch. originated in northern continents in the Jurassic or Cretaceous.

Placentals

Have a longer gestation period and give birth to more fully formed young

Coal Gap

Immense decrease in floral biomass

Undertracks

Impressions preserved some distance below the actual track

Osteichthyes

Jawed bony fish first appeared in the Devonian

Acme of Sauropterigians

Jurassic and Cretaceous were the acme of sauropterigians, large marine reptiles that had solved Carriers Constraint in the oceans.

Mososaurs

Large sea-going monitor lizards. Predators that ate fish, other reptiles, and ammonites. May have returned to land to lay eggs.

Siberian Traps

Largest Phanerozoic volcanic deposits on Earth -massive release of CO2 -Siberian volcanics also rich in S and heavy metals -most strongly affected groups were immobial marine filter feeders

Chondrichthyes

Mainly sharks and rays

Simpson Similarity Index

Measures degree of similarity between two biogeographic provinces, increases as they get closer and decreases as they move apart.

Pikaia

Middle Cambrian Burgess Shale is strikingly similar to living amphioxus and is regarded as one of the oldest fossil chordates.

Multituberculates

Most common Mesozoic mammals (Late Triassic-Early Cenozoic) named for the rows of cuspate teeth, similar to modern rodents in size and lifestyle but much more primitive

Rhipidistians

Now most commonly called tetrapodomorphs), an extinct group that evolved into tetrapods, and hence is on our direct evolutionary line.

Eoraptor

Oldest dinosaur early Late Triassic, small saurischian theropods.

Water World Environmental Zones

Ordovician Tidal Environments Tetradium Thicket Sub-tidal Seafloor

Cyads

Palm-like leaves with a prominent central seed-cone, important worldwide. Living cycads presently restricted to the tropics, but Mesozoic cycads range to near the poles.

Bryophytes

Polyphyletic group comprising liverworts, hornworts and mosses, have thin-walled, water-conducting cells but lack xylem.

3 Evolved Powered Flight

Pterosaurs Bats Birds

Al Fischer

Recognized that climate over the Phanerozoic has fluctuated at two or more scales between greenhouse and icehouse conditions

Epeiric Seas

Sea level was extremely high in the Ordovician, and effectively all of North America was covered by warm shallow seas

Glossopteris

Seed fern from Gondwana

Vascular Plants

Show more advanced features -xylem (elongate dead cells that form upwardly-directed pipes for water flow) -phloem (elongate cells that transport sugars made in photosynthesis to roots and stem) -intercellular gas transport tubes to bring O2 to roots and CO2 to leaves) -lignin (structural material that adds strength to xylem)

Ichthyosaurs

Small dolphin-like, agile, fish-eating reptiles. Gave birth to live young at sea

Agnatha

Species of jawless fish

Thecodonts

Stem group of the archosaurs that utilized all three postures

Paleobiology

Supercontinent of Pangea allowed dinosaurs to spread world wide o Its breakup in the early Jurassic likely after the origin of most clades o Most groups had large-global distributions o Clade extinction led to late Cretaceous differentiation in fauna into a distinct Gondwana and Laurasia faunas

Embryophytes

Terrestrial plant life is dominated by bryophytes + vascular plants

Thermoregulation

The ability to produce their own heat and control their body temperature, synapsids evolved the first thermoregulation, by enhanced solar heating in the pelycosaurs and partial endothermy in the therapsids.

Crylophosaurs

The first of the true "terrible lizards"

Ammonites

The most abundant swimming invertebrates, medium level carnivores (not as efficient as sharks or marine reptiles). Mesozoic cephalopods.

Cynodonts

The most advanced therapsids, (Permian-Triassic) directly traceable into the earliest mammals with innumerable intermediate forms

Triassic Recovery

Took 23 million years for the ecosystem to recover from the terminal Permian extinction

Urochordata and Cephalochordata

Two chordate-like phyla, on the way to fish.

Plesiosaurs

Up to 12 m long; long-necked with 4 paddle-like fins. Mainly fish-eaters that gave birth to live young at sea.

Three Stages of Large Theropods Diversity

o Late Jurassic as exemplified by the Morrison Fm. Here there are multiple species of mid to large sized carnivores representing all major clades, including the tyrannosaurs. o Early Cretaceous carcharodontosaurian dominated faunas world wide o The Late Cretaceous of Laurasia becomes dominated by a single group, the tyrannosaurs. These include famous names like Albertosaurus.

Non-skeletal features including:

· full thermoregulation · live birth · milk production

Evolving Mammalian Characters in the Skeleton

· increasingly complex teeth and tooth replacement · reduction in the number of bones in the lower jaw · simultaneous increase in the number of bones in the inner ear · fully upright stance