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Earth and environmental Science > Earth Exam > Flashcards

Earth Exam Flashcards

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Biology 101 flashcards
1
Q

What are mass extinctions?

A

Are events in history where large numbers of species die out over a period of time. Typically over 50% of species die out. Mass extinctions refer to marcoscopic life which is large enough to be easily observed

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2
Q

What is the Permian Triassic extinction event?

A
  • Happened 251 million years ago
  • Resulted in 96% of all marine species and 70% terrestrial species to become extinct
  • only know mass extinction of insects, nearly all trees died
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3
Q

What is the theories for the Permian Triassic extinction?

A

Asteroid impact:

  • evidence rare grains of shocked Quartz in Australia and Antarctica
  • large deposits of iridium, can only deposited by extra terrestrial bodies

Volcano:

  • The emeishan traps in China covered millions of kilometres with lava
  • dust clouds form, blocking out sunlight disrupting photosynthesis
  • organisms boiled due to carbon dioxide in atmosphere
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4
Q

What is the K-T extinction ?

A
  • extinction event of 80% of all species of animals
  • responsible for death of dinosaurs
  • happened 66 millions years ago
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5
Q

What are the theories for the K-T extinction ?

A

Meteorite impact:

  • huge crater discovered buried beneath sediments of yultan in Mexico and second crater in Ukraine.
  • crater had large deposits of iridium
  • fossil markings, like ones found in wa and North America

Volcanic eruption-

  • lava to flow melting everything in path
  • caused dust clouds, blocking out sun for months and effecting photosynthesis
  • increase in carbon dioxide in atmosphere would cause animals and dinosaurs to boil
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6
Q

What is a radiation event/ explosion of species?

A
  • Rapid amount of species created after a mass extinction event, that wipes out all diversity.
  • after mass extinctions occur, they leave empty niches, so species with the right traits can take advantage of the space.
  • other species become isolated from each other and split, this creates diversity again
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7
Q

What is the Cambrian explosion?

A

Was a short evolutionary event beginning around 545 million years ago in the Cambrian period.
- lasting for millions of years, resulting in the divergence of modern animals.

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8
Q

What is heat flow?

A

The transfer of energy from a warmer object to a cooler object

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9
Q

How does heat from earths interior reach the surface?

A

By convection

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10
Q

How is energy from the sun transmitted to earth by?

A

Radiation

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11
Q

How does energy move ?

A

By convection, radiation and conduction

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12
Q

How does energy travel by radiation?

A

In waves called electromagnetic radiation.

  • electromagnetic waves contain a wide range of wavelengths, called the electromagnetic spectrum.
  • radio waves have the longest wavelengths and gamma rays have the shortest
  • Some radiation from the sun travels to the earth and is visible because it is in the visible range
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13
Q

How does energy travel with convection ?

A
  • Most energy on earth is moved by convection.
  • the uneven hearing of matter is what drives convection. Matter that is heated becomes hotter, and rises, but collier denser matter sinks.
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14
Q

What is a convection current?

A

The movement of matter due to difference in density.

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15
Q

What is conduction?

A

Is the transfer of energy from a warmer object to a colder object.
- This is because the particles in the hotter object are fast moving and transfer energy to the cooler object with slow moving particles.

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16
Q

Where is conduction present in the earth?

A

Energy can be transferred from the geosphere and the atmosphere by conduction.
- when earths surface is warm it transfers heat to the atmosphere, this can create winds due to hot air rising and cold air sinking.

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17
Q

Where is convection in the earth?

A
  • In the ocean differences in temperature and salinity cause differences in density.
  • convection currents in the atmosphere form when cold air sinks and warm air rises.
  • convection occurs in the geosphere in the mantle. The heated rock flows like putty, as it becomes less dense the heated rock rises towards the earths surface. The cooler denser rock sinks. This transfers heat to the crust
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18
Q

What are metamorphic rocks ?

A

Metamorphic rocks are formed when a previously existing igneous, sedimentary, or metamorphic rock is subjected to high heat and pressure. For this to happen the rock has to be beneath he surface, rocks can move down by subduction.

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19
Q

What is foliation?

A

Near parallel orientation of minerals within rocks.

E.g slate, gneisis, schist

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20
Q

What is granular texture?

A

Metamorphic rocks with a sugary or granular texture, because they have been under high pressure and not high heat. e.g marble and quartzite

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21
Q

What are BIF’s?

A
  • Huge deposits of the iron ore mineral hematite and goethite in rocks.
  • these rocks wee deposited as chemical precipitates on the floor of shallow water.
  • they formed from the great oxidation event, the over population of oxygen by photosynthetic organisms.
  • They are prevelant in north Australia.
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22
Q

What are BIF’s used to show ?

A

BIF’s are used to show that there was an increase in oxygen in the atmosphere.

  • BIF’s also give an insight into the past environments conditions
23
Q

What is the Coriolis effect ?

A

The air masses aren’t fixed to the ground.

  • When earn rotates the air masses in the northern hemisphere are deflected to the right.
  • The air masses in the Southern Hemisphere get deflected to the left
24
Q

How are winds generated ?

A

The incoming solar radiation heats the surface of the earth.

  • Then the warmer air rises because it is less dense, this creates low pressure.
  • When more air piles up on each other this crates high pressure, so the high pressure moves toward the low pressure to fill the space.
25
Q

What are soils composed of ?

A

Mixture of minerals, organic matter, gases, liquids, and countless other organisms

26
Q

Explain how soil is formed ?

A

Soil is formed by decomposed materials coming together by weathering and erosion and deposited onto land.
- Soil rises about 500 to 1000 years to make just 2.5 cm

27
Q

What are ripple marks ?

A

Are formed on the tip of unconsolidated sediments by action of currents.
- ripple marks allow scientists to enable the way up of the sedimentary structures

28
Q

What are mud cracks and how do they help scientists ?

A

Are fine gained silty and clay sediments, that are laid down on a surface, where there is little rainfall or it is hot.
- Mudcracks show scientists which is the uppermost surface of deformed stratum.

29
Q

How does graded bedding help scientists ?

A

Provides clues as to sediments original depositional environment.
- sometimes layers can be seen in sedimentary rocks in which the larger particles are at the bottom, indicating they settled our first.

30
Q

What is cross bedding ?

A

Is formed by the downstream migration of Bedford such a ripples or dunes.
- cross bedding allows scientists and geologists to see what direction the current was flowing because of the direction of tilt

31
Q

What is the theory of uniformitarianism ?

A
  • The present is key to the past

- e.g the atmosphere has changed and we know this because of volcanic outgassing

32
Q

What is cross cutting principle ?

A

Any younger igneous or sedimentary rock that cuts through any older rock.

33
Q

What is faunal succession?

A

How fossils of the same age can be found in different places

- indicating that the rock is that age

34
Q

What are the unconformities ?

A

Angular- tectonic plates have folded and then sediments have been deposited ontop

Disconformity- eroded layers have had sediments deposited ontop.

Non-conformity-
Sediments lay themselves over a pre existing rock

35
Q

What is a Hadley cell, and how does it work?

A

The Hadley cell is a large scale wind cell that moves air from the equator 30degrees south and north.
- The air is warmed by the ground, and rises and is pushed off to the sides, creating low pressure. The air is being piled ontop of each other so this creates high pressure. The high pressure moves towards the low pressure to fill the space.

36
Q

What are the normal conditions of whether in Australia and South America ?

A

Trade winds blow east to west, so cold water upwelling in South America (east). It rains on east Australia because of low pressure.

37
Q

What are Index fossils ?

A

Known as guide fossils and are fossils used to define and identify geological periods.
- They help find the relative age of the layer of rock, with carbon 14 dating

38
Q

What are the four features of index fossils ?

A
  • Widespread
  • Abundant
  • Easy to identify
  • present over a short geological timescale
39
Q

What are fossils ?

A

The remains of traces of animals or plants, preserved by natural means.
- They mainly occur in sediments rocks

40
Q

Why are fossils useful for finding out?

A

By studying fossil records we can tell how long life has existed on earth.

41
Q

What is a mineral ?

A

Naturally occurring inorganic, crystalline solid.

42
Q

What are the 5 properties needed to be mineral ?

A
  • naturally occurring as a solid
  • inorganically produced
  • crystalline solid
  • fixed compositions or limited range of compositions
  • atoms arranged in an orderly structure
43
Q

Explain how our early atmosphere was originally derived ?

A
  • The atmosphere is the later of gases surrounding the earth, and formed from volcanic outgassing, during the cooling and differention of the earth.
  • Giving us carbon dioxide, sulphur dioxide.
  • It was anoxic conditions
44
Q

Explain how the evolution of photosynthetic organisms changed out atmosphere?

A
  • Cyanobacteria were photosynthesising and producing oxygen and taking in carbon dioxide from the sun.
  • The oxygen accumulated in the shallow oceans and diffused into the atmosphere.
  • The oxidation of iron BIF’s added more oxygen to the atmosphere.
  • The ozone layer formed from the accumulation of oxygen and absorbs most f the Suns ultraviolet radiation.
45
Q

Explain the nitrogen cycle ?

A

Fixation- first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen to ammonium.

Nitrification- This is where ammonium is turned into nitrates by bacteria, for plants to be able to absorb.

Assimilation- This is how pants get their nitrogen. They absorb nitrates from soil into their roots. Nitrogen is then used in amino and nucleic acids.

Ammorification- The decaying process. When plants or animals die, decomposers like fungi and bacteria turn nitrogen back into ammonium
to continue the cyle

Detrification- excess nitrogen in soul gets put back out into the air by microbes.

46
Q

What are the layers of the atmosphere (in order) ?

A

Troposphere- starts at earths surface, this is where most weather occurs.

Stratosphere- Starts after the troposphere, this is where the ozone layer is.

Mesosphere- Starts above the stratosphere, meteorites burn up in this layer.

Thermosphere- The layer above the mesosphere

47
Q

What are El Niño conditions ?

A
  • Trade winds weaken
  • usually trade wind push warm water from east to west, so warm water creeps back towards South America
  • Rains in South America
  • Dryer than usual in Australia
  • Reduced upwelling at South America
48
Q

What are the conditions of a La Niña event ?

A
  • Like an extreme ‘normal event’
  • More upwelling in South America
  • Trade winds are stronger
  • Australia is wetter
  • Dries South America
49
Q

What are ocean currents ?

A
  • Relatively narrow channels of swift moving surface ocean water
  • Currents move clockwise in that northern hemisphere and anticlockwise in the Southern Hemisphere.
  • They are driven by prevailing winds
  • Move hear around the world
50
Q

How do ocean currents effect weather and climate ?

A
  • Air above cold currents carry little moisture which helps create desserts.
  • On shore winds blow over warm currents and transfer moisture.
51
Q

How does ocean currents effect the poles and the tropics ?

A
  • Warm currents flowing always from the tropics, carry heat to polar regions
  • Cold currents flowing from the poles help cool the tropics.
52
Q

What is thermohaline circulation ?

A
  • Refers to part of the large scale ocean circulation that is driven by global density gradients.
  • Temperature, and salt content determine the density of sea water
53
Q

What is the Leewin current ?

A

Transports warm tropical water southwards in Autumn and Winter.
- They are driven by westerly winds

54
Q

Why is THC referred to as the great ocean conveyor ?

A

Because it is a large scale conveyor of ocean currents.

  • temperature and salinity effect the density of the water, which in turn effects circulation.
  • THC replaces sea water at depth with sea water from the surface.
  • Transports cold water from the poles to the topics and vice verser

Earth and environmental Science (5 decks)

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