Conditions For Life On Earth

Question 1

What is proper distance?

Answer 1

Earth is the perfect distance away from the sun which means it is formed in the habitable zone of the atmosphere. Liquid water can exist on earth

Question 2

What is the magnetic core?

Answer 2

Earth was a fireball that got bombarded by comets forming the core. Molten outer core means that iron and nickel forms the magnetosphere

Question 3

How was atmosphere formed?

Answer 3

Earth cooled fast
Gases were attracted by gravity and protected by earths magnetosphere
Greenhouse gases like methane created a strong greenhouse effect keeping earth warm.

Question 4

How was water formed on earth?

Answer 4

Water vapour condensed
Ice brought by comets and meteorites melts
Water covered almost entire planet (islands,no continents)
Microscopic life forms

Question 5

How was oxygen formed on earth?

Answer 5

Cyanobacteria in ocean creates first living things that produce oxygen during photosynthesis
(Although it was poisonous)
Reacted with methane reducing greenhouse effect so earth freezes causing ice age before current atmosphere.

Question 6

What we’re the key conditions that allowed early life to develop and survive on the planet?

Answer 6

-21% oxygen
-greenhouse gases like methane and carbon dioxide keeps earth warm
-magnetosphere protects against cosmic rays and solar winds
-distance from sun allows liquid water and regulates temp

Question 7

How has the position of solar systems allowed for the development of life on earth?

Answer 7

-Position of earth in solar system controls temp and allows presence of liquid water
-Earth is in the habitable zone of solar system (not to far or close to the sun)
-temp on most of earth is perfect for photosynthesis

Question 8

What is a magnetosphere?

Answer 8

The region around the planet that act as as a magnetic shield.

Question 9

Why is the magnetosphere important?

Answer 9

-protects earth from releasing greenhouse gases
-molten iron and nickel spins outer core generating a magnetic field
-protection from solar winds that could potentially destroy atmosphere
-protections from cosmic radiation (causes cancer)

Question 10

What is the importance of water?

Answer 10

-universal solvent
-provides habitats
-key transporter of nutrients and toxins in and out of cells
-essential for photosynthesis
-high specific heat capacity moderates temp and limits extremes of temp
-anomalous expansion

Question 11

What does the earths rotation around the sun determine?

Answer 11

-year length control
-frequency of seasons

Question 12

What does rotation on earths axis control

Answer 12

-day length
-extremes of temp eg: day= hot night=cold (small gaps in photosynthesis)

Question 13

What does tilt on axis control?

Answer 13

-seasons
-hibernation
-migration
-life cycles

Question 14

What is the Importance of Cyanobacteria?

Answer 14

-responsible for 20% of global oxygen supplies today
-most populous creature on earth
-evolved through photosynthesis
-evolution of eukaryotes

Question 15

How have Carbon Dioxide levels changed

Answer 15

-decreased in the atmosphere due to photosynthesis (uses carbon dioxide to produce energy in the form of glucose)
-carbon is now locked up in living things like soil and ice (carbon sequestration)

Question 16

Compare conditions in the early atmosphere to the current atmosphere.

Answer 16

Early
-More carbon dioxide
-Absence of oxygen
-more methane
-ammonia
-more water
-more sulphur dioxide

Current
-21% oxygen (aerobic respiration)
-79% nitrogen
-0.04% carbon dioxide

Question 17

How do living organisms affect the cycling of water?

Answer 17

-plants evaporate water through stomata in transpiration (without there would be arguably less water in atmosphere)
-during photosynthesis plants take up water from the ground into the body of the plant
-more vegetation=more interseption of water slowing the flow of water = less run off

Question 18

What other ways have living things changed the conditions on earth?

Answer 18

-Photosynthesis has reduced carbon dioxide and increased oxygen
-decomposition= soil formation
-food chains transfer nutrients and other substances
-nutrient cycling ( bacteria responsible for moving nitrogen into soil for plants)
-respiration
-carbon sequestration
-water cycle