Introduction

Question 1

Name the major microfossil groups:

Answer 1

• Prokaryotes (cyanobacteria in PreCambrian);
• Protistants (acritarchs, radiolarians, foraminifera;
• Plants (spores and pollen);
• Animals (ostracods, conodonts, SSF)

Question 2

How long does the microfossil record extend to?

Answer 2

Archean (3.5Ga) - Eubacteria, cyanobacteria

Question 3

How can microfossils be characterised, give examples?

Answer 3

By their skeleton composition:

• calcareous (ostracods, foraminifera, nannoplankton)
• siliceous (diatoms, radiolarians)
• phosphatic (conodonts, SSFs)
• organics (chitinozoans, acritarchs, dinoflagellates, SCF)

Question 4

What are the environmental ranges of microfossil groups:

Answer 4

• use diagram*
• Pollen and spores from land to marine
• ostacods and diatoms in freshwater and marine
• acritarchs and benthic foraminifera in marine shelf and basin
• chitinozoans, nannoplankton, planktonic foraminifera, radiolarians in marine basin

Question 5

State the geological history of microfauna

Answer 5

Hadean: Prebiotic world
Archean: 3.8Ga origin of life
Proterozoic: 2.5Ga Earliest cyanobacteria
1.8Ga Early eukaryotes (acritarchs)
BORING BILLION
L. Proterozoic: SSF 
E.Cambrian: Forams
L.Cam.: Possible Ostracods, conodonts 
Mid. Ord.: Ostracods, Spores 
L.Dev.: Gymnosperm Pollen 
Triassic: Dinoflagellates, nannoplankton
Jurassic: Diatoms, Angiosperm pollen

Question 6

Why are microfossils important?

Answer 6

• Identifying the early evolution on earth, only fossil for about 3Ga
• Help explain some important feedback loops between early evolution of the planet and biosphere

Question 7

Whats the other name for organic walled microfauna?

Answer 7

palynomorphs

Question 8

name the organic walled microfauna:

Answer 8

• Acritarchs
• Chitinozoans
• Dinoflagellates
• Pollen and spores (terrestrial)

Question 9

What was the range for dinoflagellates and what forms do they come in?

Answer 9

Cambrian?
- Triassic to recent
Photosynthetic and heterotrophic forms, it is the cyst that preserves as a fossil
- expelled from coral in dying reefs

Question 10

Name the microfossils that contribute to the silica cycle

Answer 10

• Diatoms
• Radiolarians
• Silicoflagellates

Question 11

When do the silica based microfauna range?

Answer 11

• Radiolarians: Cam - recent, marine photic zone to abyssal depths
• Diatoms: Lower Jurassic - recent, Marine and freshwater
• Silicoflagellates: Lower Cret. - recent, marine photic zone

Question 12

How many species of diatoms are there?

Answer 12

100,000, responsible for circa 45% of primary production in the ocean - organics

Question 13

Which microfauna are important for the carbon cycle and palaeoclimate?

Answer 13

• Ostracods
• Foraminifera
• Nannoplankton

Question 14

When do the calcareous microfauna range?

Answer 14

• Ostracods: Ordovician - recent, abyssal planes to damp leaf litter
• Foraminifera: Lower Cambrian - recent, freshwater to deep ocean
• Nannoplankton: Triassic - recent, marine photic zone

Question 15

How many living species of ostracod are there?

Answer 15

65,000, most abundant arthropods in the fossil record, reflective of ecology

Question 16

How many species of foram are there?

Answer 16

38,151 fossil and 8981 living, providing the best record of deep time climate

Question 17

What microfauna are responsible for 45% of marine primary productivity?

Answer 17

Algae: Coccolithophores (calcareous nannoplankton) and diatoms (siliceous)