Conditions For Life On Earth

Question 1

How does the mass of the Earth help life on Earth?

Answer 1

1. The mass and force of gravity retained an atmosphere.
2. Provided gases such as methane, ammonia and carbon dioxide.
3. High atmospheric pressure prevented all liquid water from boiling.

Question 2

How does distance from the Sun create conditions for life on Earth?

Answer 2

• ‘Goldilocks zone’
• Distance produces temperatures suitable for life to flourish.
• Being too close could cause liquid water to boil and cells to denature.

Question 3

How does orbital behaviour create suitable conditions?

Answer 3

• 24 hour rotations of the Earth prevent temperature extremes.
• Axis of rotation produces seasonal variations.

Question 4

How does the magnetosphere create suitable conditions for life?

Answer 4

Earths molten core produces a magnetic field which provides protection from radiation and solar winds which can be biologically damage to life.

Question 5

How does the presence of liquid water allow life to develop on Earth?

Answer 5

1. General physiological solvent.
2. Transport within organisms.
3. Temperature control - evaporation of water absorbs heat, reducing temperatures.
4. Aquatic habitats.
5. Absorption of UV radiation.

Question 6

How did atmospheric oxygen maintain stability for life on Earth?

Answer 6

2.7 billion years ago, archaea learned to photosynthesise in the oceans. Oxygen was released into the atmosphere, allowing the ozone oxygen cycle to develop. The absorption of UV light produced a dynamic equilibrium which made life possible.

Question 7

What are the steps of the ozone-oxygen cycle (the formation of ozone O3) ?

Answer 7

1. Oxygen (O2) molecule in atmosphere.
2. UV light spilts O2 into atomic oxygen (O)
3. Atomic oxygen reacts with O2 molecules to produce ozone.
4. Formation of ozone layer.

Question 8

How has carbon sequestration stabilised conditions on Earth?

Answer 8

Photoautotrophs absorbed CO2, helping to reduce atmospheric CO2 levels and reduce long-term global temperature rise.

Question 9

How have biogeochemical cycles helped stabilised conditions on Earth?

Answer 9

As a variety of organisms developed, so did interconnected biological processes. This helps prevent the build up of waste and resource shortages.

Question 10

What is paleo climatology?

Answer 10

The study of past climates

Question 11

What is glacial?

Answer 11

A period of time lasting thousands of years when the Earth had low average temperatures.

Question 12

What is interglacial?

Answer 12

A period of time lasting thousands of years when the Earth had high average temperatures.

Question 13

What is climate proxy data?

Answer 13

Preserved physical characteristics of the past sensitive to the climate so can indirectly tell us what the past climate was like.

Question 14

Examples of proxy data?

Answer 14

Dendrochronology and pollen analysis.

Question 15

What is dendrochronology?

Answer 15

Studying tree rings - the number of rings can be used to estimate the age. Thicker rings may indicate wetter and warmer climates where growth was higher.

Question 16

What is pollen analysis?

Answer 16

Drilling up a sediment core from the seabed and comparing ratios of differnt types of pollen in the layers.
Layers containing heat loving plant pollen could indicate a warmer climate.

Question 17

How can you use historical instrumental records to monitor past climate conditions?

Answer 17

Look at direct records of the weather made over the years at weather stations.

Question 18

What are some issues with using past climate research methods?

Answer 18

1. Data doesn’t extend very far into past.
2. Data could be affected by other factors.
3. Open to error.
4. Lack of sophisticated equipment used.
   5 Lack of coordination between researchers.

Question 19

What is involved with radioisotope composition dating?

Answer 19

Measure the ratio of carbon-12 to carbon-14. Carbon-14 denatures, carbon-12 persists, allowing scientists to determine the age of a sample.

Question 20

How can ice cores be used to research past climate conditions?

Answer 20

1. Studying oxygen isotope ratios from the frozen water - comparing O-16 and O-18 ratios. Tends to be more O-16 in glacial periods.
2. Studying gas composition of bubbles - layers with high concentrations of greenhouse gases may be from interglacial periods.

Question 21

How can studying the ratio of magnesium to calcium in ocean sediment cores predict past climates?

Answer 21

Compare ratios of magnesium to calcium in the calcite deposits within drilled up sediment cores. Layers containing more magnesium suggest a period of warmer sea surface temperatures as more magnesium is incorporated into calcite shell at higher temperatures.

Question 22

What remote sensing techniques can be used?

Answer 22

Using monitoring equipments such as helium balloons, aircrafts and satellites. We can carry out infrared imaging.

Question 23

Why are newer methods better?

Answer 23

1. Improved precision.
2. More precise dating of samples.
3. Wider variety factors can be tested.
4. Can monitor larger areas.
5. Can monitor older periods of time.