After midterm Flashcards
French developments
George Cuvier and Alexander brongniart developed ideas of faunal succession
Who was the first person to go beyond faunal succession and develop a modern concept of biostrigraphy?
Alcide dorbigny
What did dorbigny study?
Studied the Jurassic fossils and strata in southern France
Albert Oppel
Completed the modernization of bio stratigraphy
What makes a good biostratigraphic indicator fossil?
Distinctive Abundant Widespread geological distribution Not facies specific Rapid evolution Short temporal range
Reasons why local first and last appearance data isn’t globl
Biogeopgraphic: all species are geographic in origin, may immigrate to other places, suffer local extinction
Preservation
Facies specificity
Uncomformites: no rocks of that age in local sections
Classification of grace fossils
Ethnologic or taxonomic
Ethologic
Trace fossils are primarily evidence of animal behaviour
Seilacher established a small number of ethologic categories
Categories of ethologics
Resting trace: cubichnia Locomotion trace: Repichnia Grazing trace: pascichnia Feeding traces: Fodinichnia Dwelling traces: domichnia Traps/farming traces: agrichnia Escape traces: Fugichnia Equilibrium traces: equilibrichnia Predation traces: praedichnia Nesting traces: calichnia Fixation/ anchoring traces: fixichnia Death traces: mortichnia
Bio stratigraphy
The art and science of telling time from rocks
Based on faunal succession which was first discovered by William smith
Ichnofacies
Trace fossil association that recurs throughout geologic time in response to a set of paleoenvironmental conditions
Food resource paradigm
Limiting factor of distribution of trace making organisms in shallow marine water
Brackish water trace fossil model
- Reduced diversity of trace fossils in many cases mono specific
- Reduced size of trace fossils compared to their fully marine counterparts
- Predominance of simple trace fossils
- Sparse bioturbation
Ediacaran kimberella
In Russia probably a mollusk
Graphic correlation
Quantitative method of biostratigraphy developed by Alan shaw. Works by correlating multiple stratigraphic sections
If correlation is 45 degrees then sections had identical fossil distribution and rock accumulation
If different then one section had sediment accumulating faster then the other section
Biostratigraphic resolution
Ideally when using biostrigraphy for correlation we would like to do so with the greatest detail. Subdivide rocks into shorter zones this allows us to discriminate between events that happen closer together in time
Precision
+ or - error of an age
Dual biostratigraphy
Attempts to take in the spatial distribution of fossils as well as the temporal distribution
Bio facies
Biotic stratigraphic unit of environmental significance. How these are identified is you look at the different genera in your fossil collection
Paleoecology
Study of the interactions of fossils with each other and with the environment they lived in the geological past
Paleoautecology
Relationships of individual organisms to their environment
Palesynecology
Relationships of groups of organisms to each other and to their environment
Information potential
Life habits of extinct organisms
Nature of ancient communities and ecosystems
Paleoenvironmental reconstruction
Sea level changes
Pelagic
Live in the water column
Can be subdivided into plankton (floaters) and nekton (swimmers)
Plankton
Usually passive and goes where the current takes them
Plant plankton (diatoms) are called phytoplankton and are mostly microscopic
Animal plankton are called zooplankton and are mostly microscopic
Include foraminifera and jellyfish
Nekton
Mostly invertebrates like fish but can also be vertebrates like Cephalopods
Benthos
Epifauna (animals)
Epiflora (plants)
Infauna (living in and moving through the sediment)
Sessile
Stay in one place
Mobile
Move around or in the sea floor
Primary producers
Autotrophs
Manufacture their own food
Consumed by primary consumers which are usually suspension feeders
Secondary consumers
Consumer primary consumers so are predators
Tertiary consumers
Consume secondary consumers
Transformers and decomposers
Break down the dead that haven’t been consumed into organic material that can be recycled
Tiering
Prominent in rain forests. Competition for suspension food leads suspension feeders to grow taller then their substrate
K strategists
Slow reproductive and growth rates
Large bodies
Long lived
R strategists
Fast reproductive and growth rates
Small bodies
Short life spans
Limiting factors in species distribution
Light Food supply Oxygen Salinity Energy Temperature Substrate Water depth
Light
Promotes photosynthesis
Limiting factor in deep sea
Food supply
Food greatest at photic zone or near shorelines
Limiting factor in deep marine environments
Oxygen
Increase in need of oxygen with increase in size almost all metazoans need oxygen
Limiting factor on continental slope and in stagnant zones in the deep ocean
Salinity
Lower diversity with higher salinity
Limiting factor in hypersaline and brackish environments
Energy
High energy conditions promote suspension feeders because the wave currents keep organic material suspended within the water
Limiting factor in subtidal and coastal areas
Temperature
Most fish don’t regulate their body temperature but are the same temperature as the water
Limiting factor for nearshore environments where the water is subject to seasonal changes in temp
Substrate
Composition, mobility, and degree of consolidation play a major role in benthic Faunas
Water depth
Effects experienced through increase in hydrostatic pressure
Limiting factor in deep marine environments
How do trace fossils differ from body fossils
- Trace fossils usually represent evidence of behaviour
- The same organism may produce more then one ichnotaxon
- Same ichnotaxon may be produced by more then one organism
- Multiple arichtects may produce a single structure
- Producers are usually soft bodied animals that don’t preserve as well
- Trace fossils are commonly preserved in rock units that are otherwise unfossiliferous
- The same biogenic structure may be differentially preserved in various substrates
- Trace fossils commonly have long stratigraphic ranges
- Trace fossils commonly have narrow environmental ranges
- Trace fossils are rarely transported
Ichnology
Study of traces produced by organisms on or within a substrate
Cambrian explosion
Raid diversification
Origin of many body plans
Fauna: Arthropods trilobites
But also echinoderms brachiopods and molluscs
Cambrian explosion simple artifact or real event?
Physical changes in the environment
Biological changes
Reflecting intrinsic evolutionary change
Physical changes in the environment
Increase in oxygen levels
Widespread transgression
Aftermath of snowball earth
Biological changes in the environment
Biotic feedbacks that caused or aided the explosion
Evolutionary changes underway in the ediacaran
Coupling of benthos and plankton
Ordivician radiation
Diversification of early bryozoans, brachiopods and stalked Crinoids
As well as bivalves and Gastropods
4 major taxonomic components of ordivician
Bryozoans
Brachiopods
Corals
Echinoderms
Timing of ordivician radiation
Even lasted 25 myr
Maintained global diversification characteristic of the Cambrian
Diversification of Paleozoic started in the late arenig
Ordivician radiation seems to have slowed down by the llanvirn
Alpha diversity
Refers to the richness of taxa within a habitat
Increased during ordivician radiation
Example brachiopods went from having 10 genera within a community in the late Cambrian to 30 by the late ordivician
Beta diversity
Refers to taxonomic differentiation within among habitats
Also increased during ordivician
Gamma diversity
Records the total (alpha plus beta) for a landscape
Alpha and beta increased so the overall diversity increased
Tiering in ordivian
Was an increase in this during this time
Carbonate dominated facies (ordivician)
Dominated by articulate brachiopods and sponges
Siliclastic dominated facies
Dominated by trilobites and molluscs
Ordivician vs Cambrian
Cambrian was more for body plans
Whereas ordivian diversified within groups and families
Carboniferous world
Ice world Continents were all one mass Large forests source of coal Tropics were wet and warm where the coal swamps were No flowering plants
What tree dominated most in the coal swamps of the carboniferious?
Lycopods were over 30 m tall possibly 50 m
They dominated because they were mostly pole like for their lives and grew their branches last so it allowed them to grow taller then other plants
First plants in carboniferious to make an appearance
Seed plants- earliest type was a group called seed ferns
First conifers
Carboniferous environment
All of the trees would have led to decreased levels of co2 in the environment
This would have led to global cooling
Would have led to relative increase in oxygen
About 50% higher then it was today
Arthropds in the carboniferious
Arthropods in the carboniferious were very large
Largest terrestrial Arthropods ever known
Why this happened has long been a question
Some think it is due to the increase in oxygen levels
Or the absence of predators could have attributed to the size
Arthropleura
Large millipedes probably 2.5 m long.
Trace fossils are found more then their body fossils
Found in eastern North America and Scotland
Carboniferious
Meganeura
Largest insect ever
Wing spans of 65 cm
carnivores ate insects and possibly small amphibians
Carboniferious
Amphibians
Large increase in the terrestrial vertebrates
Early carboniferious they were pretty diverse and ranged in size from small mouses to pretty large
Late carboniferious there was another great radiation. Some became large predators that looked like crocodiles
Evolution of amniotes
Group of amphibians known as reptilomorphs
Evolved the ability to lay eggs
Earliest known amniotes
Hylonomus from Nova Scotia
Ammoniotes started in the carboniferious but don’t start appearing in great numbers until the Permian
Mazon creek
Upper carboniferious
Illinois
Mazon creek fossilization
Fossils preserved in siderite concretions
Fossils are small
When these are broken open see 3d moulds
The fact that the fossils are 3d and the surrounding siltstone is compressed suggest early formation of the concretions
Also since the concretions mirror the shape of the organism suggests the organism played a role in the concretion formation
MaZon creek biota
Northern (braidwood biota) terrestrial and freshwater in composition and dominated by plants
Southern (Essex biota) fully marine in composition and dominated by invertebrates
Terrestrial and aquatic animals for Mazon creek
Terrestrial: Arthropods, insects, arachnids, mryiapods
Aquatic: bivalves, jellyfish, tully monster swimming invertebrate predators
Joggins
Nova Scotia
Incredible tides expose more and more fossils
Trees in upright positions
Plants and fauna of joggins
Plants: lycopods and spore trees like that in the coal swamp
Fauna: hylonomus found in stumps of trees
Many amphibians: crocodile sizes predators
Arthropods: horse shoe crab traces, whip spiders
Permian
Synapsids became the most dominant
Synapsids broken up into paraphyletic pelycosaur and therapsids later
Sails
Spines were connected by tough layering of skins and that there were many blood vessels in the sails
Been suggested that these were used for thermoreagulation by giving them an advantage in cool mornings, and also needing to cool down later in the day
Cynodonts
In the Triassic became more and more mammal like
What is one of the key evolutionary transitions for mammal like synapsids?
The reduction of the number of bones in the lower jaw and their migration to the inner ear
Mesosaurs
First fully aquatic amniotes
Teeth suggest they ate fish or Arthropods
Protolophonids
Late Permian to late Triassic anapids
Either herbivores or insectivores
Triassic beginning vs end
Beginning was Dominanted by synapsids but by the end was dominated by diapsids most popular of which are archosaurs
Archosaurs
Group of dilapidated amniotes which include non avian dinosaurs, pterosaurs, birds and crocodiles
Two divisions of archosaurs
Crurotarsi- lead to crocodiles and their ancestors
Avemetatarsalia- lead to dinosaurs and birds
Permo triassic mass extinction
83% of all genera disappeared
Marine invertebrates suffered the most losses
Terrestrial plants see reorganization
Why were the basal archosaurs so successful?
Posture: moving from a sprawling position to an upright stance
Uris acid rather then urea: different mechanisms for excretion of ammonia favored by diapsids during the Triassic
Archosaurs posture
Having an erect posture is metabolically expensive and requires more energy
Suggests that they had higher metabolism and higher body temperatures and would need more food and oxygen
Waste removal
Triassic was arid compared to the Permian
Archosaurs had a different mechanisms for excreting ammonia (uric acid) rather then synapsids (urea)
After permo Triassic extinction
Archosaurs diversified after this, and took over niches that were formerly occupied by synapsids
Archosaurs were probably endothermic, meaning crocodiles reverted back to ectothermy
Birds retain endothermy
Ophiacodon
Synapsids
Permian
First large amniote
Carnivore
Caseids
Synapsid
Largest herbivore
Permian
Sailed back two division
Edaphasuarids: herbivores
Sphenacodonids: carnivores
Dinocpehalians
Permian
Therapsids
Herbivores and carnivores
Dicynodonts
Herbivores
Therapsids
Gorgonopsians
Therapsids
Carnivores
Phytosaurs
Archosaurs: crurotarsi
Mid late Triassic
Postosuchus
Erect gait
Largest of Triassic
Archosaurs: crurotarsi
Sphenosuchus
Archosaurs: crurotarsi
Late Triassic
Crocodiles
Jurassic to Cretaceous
Pterosaurs
Archosaurs: avemetatarsalia
Earliest known vertebrates to have evolved flight
Lagosuchus
Dinosauromorphs
Middle Triassic
Sister taxa to dinosaurs
Share many characteristic with them
Dinosauria
First arose in the late Triassic and dominated until the Cretaceous
Became successful in the Jurassic and Cretaceous before Going extinct at the Cretaceous/tertiary boundary 65 mya
Dinosaurs
Generally described as archosaurs with limbs held erect beneath the body
Ceratopsidae
Upper Cretaceous
Quadrupedal herbivores
Characterized by horns frills shearing teeth
Hadrosauridae
Known for duck bill
Skeleton adapt for running not swimming
Auditory signalling
Hadrosauridae
Resonating chambers to produce sound
Sexual signalling
Significant differences between males and females of the same species
Stegosauridae
Jurassic to Cretaceous
Characterized by plates on their back
Probably slow moving because their front legs were dramatically shorter then their back
Sauropods
Jurassic to Cretaceous
Neck elongated
Achieved size through air sacs and hollowing of bones
Theropods
Bipedal carnivorous dinosaurs
tyrannosaurids
Jurassic to Cretaceous Only found in asia and North America Alex predators Fastest of the large theropods Coelurosaurs
dromaesauridae
Raptors Travelled in packs Active fast predators Theropods Coelurosaurs
avialae
Containing their only representative: birds
Defined as all dinosaurs possessing feathers used in flapping flight
Coelurosaurs
Ornithischians
Hadrosaurs Ceratopsians Stegosaurus Ankylosaurus Pachycephalsaurus
Saurischians
Sauropods and theropods
Who used brooding? And what was it
Hadrosaurs, ceratopsians and theropods are to have cared for their young
Turtles
Triassic to recent
Bony shell
In diapsids
Turtles divided into two groups based on what
Necks
Cryptodires
Pleurodires
Plesiosaurs
Jurassic to Cretaceous Evolved from crocodile like ancestor Retained limbs that were modified into flippers Sauropterygia Reptiles
Ichthyosaurs
Triassic to Cretaceous
Air breathing, fast swimmers
Dolphin like body
Example of convergent evolution
Squamates
Lizards and snakes
Evolving in the Permian
Mobility
Venom
Mesosaurs
Cretaceous
Evolved form semi aquatic squamates
Apex predator outcompeting ichthyosaurs and plesiosaurs
