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remains or evidence of organisms preserved in sediments or sedimentary rocks.
Where do we find fossils?
in sedimentary and low grade metamorphic rocks
they may act as a nucleus and create concreations
trace contenental drift by means of fossils. e.g. fresh water fish cant swim across ocean.
4 possible movements of species dispersion
- land bridge
- island hop
- cont. drift
why are fossils imporntant to evolution?
they are the only direct evidence of the history of life
what is biostratigraphy?
use of fossils in deducing succesion and age relations
qualifications of index fossisl (6)
- easily recognizable
- short strat range
- easily preserved
- worldwide distribution
- rapid evolution
why do we study fossils? (6)
- simple fascination
what is taphonomy?
taphonomy is the studdy of fossil preservation
what is the oldest frozen fossil we could have on earth?
quaternary was the last ice age
how deep is the photic zone?
200m that light can penetrate for photosynthetic animals
pelagic zone above the shelf as opposed to oceanic palagic
3 types of preservation
- body fossils
- molds and casts
how are body fossils preserved?
what is perminerlization?
it is petrification, pores fill with calcium or silica fluids
original material not removed
added matter makes fossils much heavier than original
what is recrystilazation
the hard parts grow in grain size or revrt to a more stable form
what is replacement
hard parts are disolved and replaced by other minerals like calcite silica pyrite or iron
what is carbonization?
all elements are removed exectp carbon
what is a mold?
a cavity with the shape of bone shell or organism
what is a cast?
a cast is the filling of a mold by minerals or sediments
what are ichnofossils?
trace fossils, evidence of organisms with no actual remains
name ichnofossils from bathyal to shore
vertical burrow in rocky shore
burrowing in wood or peat
vertical in unconsolidated sediments
vertical burrow in ssandy offshore
locomotion trails shallow marine shelf (sublitoral)
feeding traces in low energy muds on outer shelf
little bore holes in shell and bone from predation
what is an ichnofacies
a set of trace fossils associated with a particular envoirnment
what are the 7 components of structure?
- calcium carbonate / arragonite
- calcium phosphate
- chitin (crab shell)
- cellulose (tress/plants)
- ressistant organics (pollens)
what are molecular fossils
the chemical signiture is preserved with no idication of the structure
bones preserved vs teeth
theeth are hard calcium phosphate = recrystalize
bones porus = permineralized
what are the components of taphonomy (3)
what is necrolysis?
the death break up and decay and decomposition phase
what is biostratinomy?
aftre necrolysis but beofre burrial process of altering the remains
what is diagenisis?
the physical and biological changes that take place after burrial
what is elvis taxa
- taxa that is mis identified as being an extinct species...
- 1 dies and 2 looks like 1 but its not
what is the zombie effect, zombie taxa?
when an old fossil appears in much younger sediments due to reworking of the origanal older rock
what is lazarus taxa
taxa that temporarily disaperas from fossil record
how complete is the fossil record?
97% not preserved
classification for animals vs plants
- phylum ---- division
how does a paleontological species differ froma true species?
based on simalr geomorphology not ability to breed
what is ontogenisis
change in morphology within an individuals life span
how do populations vary? (4)
- ecophenotypic variation - changes due to envoirnment
- taphonomic varibility- distortion aftre death
- sexual dimorphism - diferences between males and females
- copes rule - body size enlarges throughout evolution
what is the taphonomioc filter (7 levels)
a graph showing amount of preservation through stages
- life assembalge
- death assemblage
- total fossil assemblage
principals to sexual dimorphism
males females 1:1 ratio
similar morphology in early stages
late stage diffreences amonites = larger femal and males with lapplets
four types of skelatal growth
addition skelatal growth
adding of discrete growth layers over time
addition skelatal modification
adding of discrete new parts which grow little after formation
what is molting
the shedding of an exoskeleton
modification skelatal growth
the continual remodeling and adding to exsisting elements
the study of sedimentary rock strata
5 most important steno laws to paleo
- super position - oldest lower
- original horizontality - deposit flat
- original continuity- extend until enviro Δ
- fossil succession - oldest fossil found in lowest layer
- fossil correlation - similar asemblages are similar age
quaternary / tertiary age
devonian/ carboniferous age
ORDAVICIAN / SILURIAN AGE
PC / Cambrian age
archean proterozoic age
hadean / archean age
3 principals pieces of evidence for PC life
- morhologiocal fossils - black cherts
- chemical fossisl
all show photo synthesis
stromatolite vs oncoid
- oncoids are sphereical around a nucleus
- stromatolites are columnar
describe growth of stromatolite
- thin threads of cyanobacteria trap calcareous sediment
- clacaerous mud builds up
- cyanobacteria grows through mud
- repition makes layering
artifial organic walled phytoplankton is a
what organism had first bilateral symetry
spriggina - centipede like thing ediacara
what is the oldest fossil of the precam
charina, deep water filter feeder
first organism with hard shell
cloudina tube worm
4 advantages to having hard body parts
- protection from uv
- prevents drying out
- protection predators
when did hard body parts become common?
all but _________ phyla existed in some form since the cambrian
what is effacement?
evolutionary addaption related to burrowing in mud
what is spinosity
eveloutionary trend of evolving spines to stick in mud
evolutionary trends in benthic triloobites
effacement, spinosity, lack of eyes, addition of body segments
eveloutionary trends in pelagic trilobites
- large eyes point downward
- elongate streamlined bodies
what fossil is representative of the earlies chordate
pikia a worm like thing
high spread rate make __ seas
low spread makes_______
- high spread = calcite seas
- low spread = arrogonite
what is the similaritie between braciopoda and bryozoa?
the lophore feeding breeting tube
inarticulata vs articulata morphology
inarticulata CaPO4, anus, no muscle, no teeth
articulata CaCO3 no anus, yes muscle, yes teeth
umerous sub parellel teeth
small simple teeth
very large teeth either sid eof central ligment
two or three cardianl tewth
what was prominet cretacious reef builder
what is palynology?
the study of pollens and spores
when was the first land plants?
plants evolved from ?
what was an early land plant? what did it have?
cooksonia had vascular titue and soprangia (spore bearing organs)
photosynthetic wonderplant of the silurian?
when was the first tree?
archeoteris in the late devonian
what time ranges where major coal and what made them
carbiniferous and permian host alot of coal from clalmites the large rush like trees
plant dispersal in the devonian
- 1) only near water
- 2) plants spread out through devonian, pollen very flamable fires
- 3) swamps of dead burnt trees lead to coal of carboniferous
what where the big reef builders in the cretacious and whqat class are they
rudists where major reef builders , made the chalk cliffs in UK, there was no middle cretacious and they are coclithopores
what is the red queen hypothesis
theory that organism must constantly adapt, evolve and proliferate to avoid extinction
back ground extinction vs mass extinction
backround exticntion is gradational over long time period, mass extinction is a very sudden change often due to catastrophy
what is the only way to correlate terrigenous to aquatic rocks?
what is an aproxuimate number to define mass extinction?
if >10 fmailies/1mya years qualifies a mass extinctions
5 general reasons for mass extinctions
- bolide impacts (meteors)
- climate change
- sea level change
- ocean chemistry change
10 major steps in the diversification of life?
- origin of life
- eukaryotes and reproduction
- reef building
what defines the cambrian fauna? how long was it
what defines the paleozoic fauna? how long did it last?
what defines modern fauna? how long?
- defined by gastropds
when and what caused the ordavician extinction
when what caused the devonian extinction?
what/when causes of the P/T extinction
- 250 mya
- sealevel and siberian traps
what/when of the triasic extinction
- 200 mya
- sub aqueous volcanics break up of pangea
6 keys to an idex fossils use in biostrat
- easily ID
- large geographic range
- wide range of enviornemnts
- narrow strat range
- easily preserved
what is the telizone
range between LFAD/LRAD localized
what is the taxon range
range between GRAD/GLAD global
what is the concurrent range zone
when the fad and lad is blended between two localitys using lads and fad
what is an assemblage zone?
charecterized by 3 or more taxa
what is an abundance zone
subset of the telizone where there is an abundace of an index fossil
what 4 ways describe the test of bryozoa and describe in geral
- discoid- hi energy = discs
- fenistrated- spiral
- encrusting - all over
- branching - low e - tree like
what four terms describe the symetry of bivalves?
- equi valve, inequivalve (x-sec view)
- equi latteral / inequilateral (plan view)