palaeontology Flashcards

1
Q

trace fossils

A

fossil records of biological activities

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2
Q

ethologic classification

trace fossils

A

traces of…

  • resting
  • locomotion
  • grazing
  • feeding
  • dwelling etc.

-> representing evidence of animal behaviour

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3
Q

2 type of body fossil

A
  • mould -> mineralised impression of organism left in sediment
  • cast -> mineralised sediment that fills mould recreates shape of remains
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4
Q

micropalaeontology divided into 4 areas…

A
  1. Calcareous -> eg. coccoliths
  2. Phosphatic -> eg. conodonts
  3. Siliceous -> eg. diatoms, radiolarians
  4. Organic -> eg. pollens, spores
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5
Q

what are fossils?

A
  • physical evidence of prehistoric life
  • may be preserved remains / other traces
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6
Q

palaeontology

A

study of fossils and evolution of life on Earth

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7
Q

main characteristics of trace fossils

A
  • same organism may produce >1 ichnotaxon & same ichnotaxon may be produced by >1 organism
  • trace fossils commonly preserved in rock units that are otherwise unfossiliferous & rarely transported
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8
Q

type of trace fossil:

bioturbation

A
  • bioturbation structures are biogenic sedimentary structures reflecting disruption of sedimentary layers
  • by activity of an organism, inc tracks, trails & burrows
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9
Q

coprolites

trace fossils

A

fossilised faeces -> giving evidence of animal’s diet

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10
Q

stromatolites

A
  • layered sedimentary formations that are created by photosynthetic cyanobacteria
  • are trace fossils that record interaction between microbial communities & sediments
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11
Q

sedimentary rocks

A
  • layered rocks formed by the accumulation / deposition of mineral / organic particles
  • that are transported to place of deposition by water, wind, ice & mass movement
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12
Q

taphonomy

A

study of how organisms decay & become fossilised

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13
Q

Konservat-Lagertätten (conservation Lagerstätten)

A
  • deposits known for exceptional preservation of fossilised organisms / traces
  • which are crucial in providing answers to important moments in history & evolution of life.
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14
Q

exceptional preservation examples

A
  • Burgess Shale- type fossils
  • amber fossils
    -> when animal was alive, quickly trapped in tree sap -> stops scavengers/bacteria decomposing body
    -> only small animals trapped in tree sap, bigger can get away so not often seen
  • frozen fossils
    -> eg. baby mammoths
    -> in cold temps, specific mud burial env keeps baby mammoths flesh
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15
Q

palaeontological kit

A
  • hard helmet -> broken rock in quarries might fall
  • geological hammer
  • geological notebook
  • boots
  • hand lens -> helps you identify rocks & fossils
  • binocular microscope
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16
Q

palaeontological techniques

A
  • essential kit
  • field collection
  • fossil preparation-> use needles to remove sediment covering fossil to reveal fossil details
  • acid preparation -> to dissolve sediment
    -> takes 1-2 yrs!!! limited damage to fossil
    -> also used to separate microfossils from matrix
  • microfossil picking -> looks like sand so use microscope & small paint brush to find valuable fossils for study
  • advanced technology -> eg. SEM to show high magnification image of fossil
    -> eg. synchrotron -> have a particle accelerator which reveals 3D image of microfossils
  • reconstruct fossils (everything else has lead to this!!)
    -> use computer reconstruction & drawings of what we thought animals looked like
17
Q

example of fossil that synchrotron helped us identify

A

Markuelia
(from early Cambrian->early Ordovician)

  • fossil embryos -> each fossil like a grain of sand
  • when you put them under SEM, each grain is actually tiny worms
  • using synchrotron facilites, can see internal structures
18
Q

(in)vertebrate palaeontology

A

concentrates on (in)vertebrate fossils

19
Q

Palaeobotany

A

studies fossil plants

20
Q

Micropalaeontology

A

focuses on microfossils of all kinds

21
Q

Ichnology

A

interprets trace fossils

22
Q

Palaeoecology

A

examines interactions between…

  • diff ancient organisms
  • organisms & their env
23
Q

Biostratigraphy

A

uses fossils to work out chronological order in which rocks were formed

aka…

focuses on correlating & assigning relative ages of rock strata by using fossil assemblages contained within them

24
Q

Palaeoclimatology

A

focuses on history of Earth’s climate

25
Q

5 classic subdivisions of palaeontology

A
  • Vert. Palaeontology
  • Invert. Palaeontology
  • Palaeobotany
  • Micropalaeontology
  • Ichnology

-> largely focused on individ. fossils/organisms

26
Q

principle of faunal succession

A
  • sedimentary rock strata contains fossilised flora & fauna
  • & these fossils succeed each other vertically in specific, reliable order that can be identified over wide horizontal distances
27
Q

radiometric dating

A
  • technique used to date rocks …
  • based on comparison between abundance of naturally occurring radioactive isotope & its decay products
28
Q

examples of radiometric dating

A
  • radiocarbon dating -> for recent fossils
  • potassium argon dating
  • uranium lead dating -> for ancient fossils
    -> often find uranium in volcanic ash
29
Q

evidence of evolutionary history

A
  1. providing time scale of evolution
    -> faunal succession
    -> radiometric dating
    -> biostratigraphy
  2. revealing evolutionary pathways
    -> fossils unique morphological combos reveal links between extant taxa
    -> eg. Archaeopteryx: oldest bird BUT recently suggested non-avialan dinosaur instead
  3. reconstructing macroevolution
    -> Sepkoski Curve
30
Q

macroevolution

A
  • encompasses biggest trends & transitions in evolution
  • especially with regard to evolution of whole taxonomic groups
  • over long periods of time
31
Q

classical “Sepkoski” Curve

A
  • Jack Sepkoski plotted no. of marine invert. fossil taxa in each interval of Phanerozoic…
  • which revealed no. of interesting patterns inc. Cambrian, Paleozoic & Modern “Evolutionary Faunas”…
  • as well as identified “ Big Five “ mass extinctions of marine inverts.
32
Q

evidence of palaeoecology

A
  1. interaction between sp
    -> eg. fighting dinosaurs preserved (Velociraptor vs Protoceratops)
  2. organisms & env
    -> trace fossils can reveal interaction between organism & env.
33
Q

continental drift theory proposed in 1912

A
  • earth’s outer shell divided into several plates & they move around over geological time
  • fossils are evidence of this:
    -> similar plant & animal fossils found around shores of diff continents (S.America, Africa, India, Antarctica, Australia)
    -> suggests continents were once joined together
34
Q

palaeoclimatology

A
  • new field of study focusing on past climates
  • fossils with continuous stratigraphic ranges can be exploited for climate proxies to reconstruct climate change, such as diatoms, foraminifera, corals, shells & pollens
  • most widely used method based on variations in oxygen isotope composition of biogenic marine carbonate, from which the broad pattern of change in marine temps has been reconstructed
35
Q

evidence of env changes

A
  1. plate tectonics
    -> similar fossils found around shores of continents suggest they were once joined
  2. palaeoclimatology
36
Q
A