Advanced Concepts

Question 0

Main Driving Force of Plate Tectonics

Answer 0

1. Slab Pull - sink oceanic plate, subduction zone, pulls other plates in.
2. Convection Currents - earths mantle, moving crustal plates on top.
3. Magma Upwelling - at surface [mid ocean ridge, rift valleys] push old crust away.

Question 1

Younger Dryas

Answer 1

. Big Freeze
. 1300 year period
. Drought 12,000 yBp
. Caused by collapse of N.American Ice Sheets
. Draw graph

Question 2

Major GHE. What other anthropogenic products contribute?

Answer 2

1. Water Vapour
2. CO2
3. CH4
4. N2O

Anthropogenic

. Burning fossils fuels
. Deforestation - change in land usage. CO2 is released from vegetation & locked up in soils.
. F - gases
. Agriculture - cows, farmland etc

Question 3

Snowball Earth. When & Why?

Answer 3

. Most recent - 650Mya, 3/4 periods knows as Cryogenian Earth.
. Reduction in CO2 & CH4.
. Reduction caused by: continents in tropics thus O2 rise [Oxygenic Photosynthesis], global silicate weathering high, CO2 & CH4 levels fell thus decrease in temp, climate stabilised at a colder state.

Evidence
Bed lay within tropics when deposited, they contain sedimentary structures.
Alternatively structures were created only by glacial activity.

Question 4

Sun brightness varies with age. How and Why?

Answer 4

. 11 - year cycle [sunspot cycle]
. Sun spots correlate to change in brightness
. Sun spot - dark intense magnetic area inhibiting convection cooling the photosphere. Faculae form around the spot elevating the temperature to return to regular flow thus solar variation occurs.
Draw graph.

Question 5

Definitions
Lithosphere
Hydrosphere
Asthenosphere

Answer 5

Lithosphere - rocky crust, inorganic composed of minerals, primarily silica.
Hydrosphere - all water on earth. 97% is ocean.
Asthenosphere - highly viscous, ductile forming region of upper mantle of Earth. Below lithosphere. Depth - 80-200km.

Question 6

When were mammal like reptiles dominant? What replaced them?

Answer 6

. 260Mya
. Mammals
. Peaked in Permian. Decline in Late Triassic.

Question 7

Evolution by natural selection.

Answer 7

. Traits enhancing survival/reproduction become more common in successive generations of a population.

. Follows 3 facts [self-evident mechanism]

1. Variation within population with respect to morphology, physiology and behaviour. [Phenotypic Variation].
2. Varying rates of fitness/survival. [Differential Fitness].
3. Traits passed from generation to generation. [Heritability of Fitness].

Question 8

Main theories explain origin of life.

Answer 8

1. Natural Selection - Evolved by common descent from single primitive life form 3900 Mya. In accord with naturalism.
2. Deep Sea Vents - Hydrogen rich molecules, rocky nooks have concentrated molecules providing minerals catalysts for critical reactions. Present day vibrant communities thrive in this environment.
3. Abiogenesis [RNA World] - natural life process arising from non-living matter such as simple organic compounds [ooze]. Life descends from an RNA World [DNA & RNA need each other to form RNA can store DNA info as an enzyme like protein thus forming DNA].
   Earliest evidence - 3.5 Bya as microbial mat fossils. EoArchean Era hence sufficient crust had solidified following the Hadean Era.
4. Panspermia - life came from space. Martian meteorites brought microbes as they hitchhiked on comets from other star systems.

Question 9

Hyperthermophiles. Where are they found? What conditions?

Answer 9

. Organism that thrives in extremely hot environments. 60 degrees and upwards.
. Optimal conditions 80 degrees.
Commonly found at sea vents, environments of high acidity and radiation.

Question 10

Faint Young Sun

Answer 10

Apparent contradiction of early water in Earths history.
The astrophysical expectation that the Sun’s output be only 70% as intense during that epoch compared to modern day epoch.

Question 11

Pole of Rotation. How are they located?

Answer 11

Known as Euler Pole.
Movement of a rigid body on surface of a sphere can be described as rotation about a fixed axis relative to the chose reference frame.
They’re located by Paleomagnetic data. Plate motion from magnetic strips found at seafloor spreading areas and geometric matching of continental borders/boundaries.

Question 12

Who wrote Principles of Geology? Chief concept to discuss geological history of Earth?

Answer 12

Charles Lyell

Uniformitarianism

Question 13

History of atmosphere/ocean during Pre-Cambrian focusing especially on evidence for atmospheric oxygen.

Answer 13

Only algae present in ocean, single celled bacteria.
Atmosphere primarily nitrogen before ecological crisis.
Molecular oxygen not significantly present till after photosynthetic life forms evolved/began to produce large quantities of oxygen as a byproduct of their metabolism.
Radical shift from inert to oxidising atmosphere [ecological crisis].
Oxygen quickly combined with iron, as oxidisable surface ran out, oxygen accumulated in atmosphere to modern day levels.
Evidence - huge. BIF’s laid down as iron & oxygen first combined.

Question 14

Factors likely to shape future usage of fossil fuels?

Answer 14

Alternative fuel source - renewables [electric & hydrogen]
Growing population
Growing emissions - “global warming”
Shale gas
Population Opinion
Global supply affected by politics & conflict
Economic welfare of the economy & people

Question 15

Uniformitarianism

Answer 15

Scientific observation that same laws and processes that operate in the universe now, have always operated in the universe in the past and apply everywhere in the universe.
Key principle of geology.

Question 16

Komatites

Answer 16

Ultra mafic mantle derived rock. 
Extremely high Mg content.
Archean Age.
Restricted in distribution to Archaen shield areas.
They occur in Archaen Greensand belts.
Low Si, K, Al content.

Question 17

Methanogens

Answer 17

Microorganisms that produce CH4 as a metabolic byproduct in anoxic conditions.
They’re classified as archaea, a domain distinct from bacteria.
Commonly found in wetlands and digestive tracts of animals and humans.

Question 18

Role of Apoptosis in Eukaryotes Evolution

Answer 18

Apoptosis - process of Programmed Cell Death [PCD].

PCD kills pre cancerous cells, viruses, pathogenic bacteria to allow development of the multi-cellular organism.

Question 19

Palaeocene - Eocene Thermal Maximum. Evidence?

Answer 19

Extreme changes in the carbon cycle
Marked by prominent negative excursion in carbon stable isotope delta 13C.
Large decrease in 13C/12C ratio of marine and terrestrial carbonates and organic carbon.
Ocean Acidification