Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Micropalaeo > Foraminifera > Flashcards

Foraminifera Flashcards

1
Q

What are Rhizaria?

A
  • formerly referred to as protista
  • unicellular eukaryotes
  • heterotrophic, symbiotic or parasitic
  • no test or skeleton
  • Radiolaria and Foraminifera (Cambrian to recent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are Radiolaria?

A
  • skeleton of opaline silica, organic and silica mix, or even strontium sulphate
  • 50 -200 microns
  • sometimes colonial assemblages 1m diameter
  • Cambrian to recent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a pseudopodia?

A

the tentral stream of cellular tissue from a radiolarian skeleton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are Foraminifera composed of?

A

CaCO3 skeleton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How long have Foraminifera existed and what is their nickname?

A
  • from the early cambrian to recent marine and brackish conditions
  • ‘armoured amoeba’ typically 0.5 -1mm in diameter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the Foram protoplasm divided into?

A
  • endoplasm (food vacuoles and nucleus)

- ectoplasm (pseudopodia fro eating organics)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why build a test?

A

Reduce biological pressure, physical and chemical stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What were the giant forams called?

A

Nummulites, 10cm diameter, 1 cell from the Eocene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name the Forams important features

A
  • wall structure
  • wall layering
  • chamber arragement
  • apertures
  • ornament
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name the types of wall structure:

A
  • Tectinous (organic, Allogromia)
  • Agglutinated (possibly organic, Texturlarina)
  • Porcelaneous (Milliolina)
  • Microgranular (Fusulinina, Globigerinina)
  • Hyaline (Rotallina)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why are Fusilinids important?

A

great biostratigraphic markers

  • rapidly evolving (esp. Carboniferous)
  • multilocular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe test morphology variables:

A
  • Diamorphism, change from sexual to asexual
  • Coiling direction, varies from sinistral to dextral usually related to temperature (goes back to 3Ma showing polar front and interglacials and glacials)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the main foram palaeoecologies

A
  • marine and brackish water

- planktonic, benthic and encrusting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What era are forams most useful for?

A

application of oceanography and climate in the cenozoic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Glutinated forams live…

A

below the CCD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the main foram applications?

A
  • Oceanography and climate

- Biostratigraphy

17
Q

What controls rotaliniid coiling?

A

ocean temperature, they help track thermocline and polar front

18
Q

the thermocline rises when?

A

at 0 degrees lattitude

19
Q

Why is plankton distribution not completely controlled by their lattitude (temperature)?

A

because the gulf stream interrupts it

20
Q

How are forams indicators of oceanic conditions?

A

looking at modern species using the transfer function of 18O/Mg/Ca however some specimens could have been dissolved or moved post mortem
- some are tropical (25 degrees C), seasonal (15) or polar and down in the thermocline (4-0)

21
Q

What are problems with using forams for predicting climate

A
  • some species could have changed their tolerances through time
  • bioturbation smears the signal
  • diagenesis
  • sample size
  • sediment accumulation is not constant
22
Q

Give an example of past climate reflected in foram record:

A

Palaeocene - Eocene Thermal maximum +5 degrees at the equator from greenhouse carbon increase! O2 foram isotopes spike as benthic foram extinction
occurs
- reefs were decimated expelling dinoflagellates and decreasing ocean alkalinity
- Large benthic forams (e.g. Nummulites) fill the niche
Another example in Eocene - Oligocene boundary

23
Q

How are forams used in oceanography?

A
  • O2 isotopes in benthic foram shells using a mass spectrometer
  • Example: Cenozoic cooling; recorded ratio of 18O: 16O as glacial and interglacial periods ensued
24
Q

Give an example for foram application in biostratigraphy:

A

Forams are widespread and short rangeing;

  • Eocene; Morozovella a planktonic foram are surface dwellers in the tropics and characteristic of palaeogene followed by a mass extinction in Mid Eocene ~38Ma
  • Possibly a response to eutrophication of surface waters and demise of symbiotic relationships with dinoflagellates that provided nutrients

Micropalaeo (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions