chapter 1 - conditions for life

Question 1

4 elements needed for life

Answer 1

carbon, hydrogen, oxygen and nitrogen

Question 2

why is water important for living organisms

Answer 2

it’s a general physiological solvent in which most biological reactions take place (temp regulation / transport)

Question 3

what does the magnetic field do

Answer 3

deflects solar wind and stops damaging radiation reaching Earth

Question 4

when did life first develop?

when did Earth form?

Answer 4

3. 5 billion years ago

4. 6 billion years ago

Question 5

7 things water does

Answer 5

solvent water, transport within organisms, temp control, anomalous expansion on freezing, high specific heat capacity, aquatic habitats, absorption of uv rays

Question 6

what is the temp range

Answer 6

0C - 35C

Question 7

CO2 & nitrogen uses

Answer 7

CO2: photosynthesis, synthesis of carbohydrates, proteins and lipids
nitrogen: protein synthesis

Question 8

what does solar insolation do

Answer 8

energy for photosynthesis, water cycle and warms the earths surface & oceans

Question 9

when did atmospheric oxygen start to develop

Answer 9

2.6 billion years ago, concentrations started rising 2.45 billion years ago

Question 10

what did atmospheric oxygen do?

Answer 10

absorbed uv light, produced dynamic equilibrium

Question 11

carbon sequestration example

Answer 11

photosynthetic organisms, photoautotrophs, absorbed CO2 and some got stored in rocks and fossil fuels

Question 12

analytical techniques that have been developed to estimate past climate (4)

Answer 12

radioisotope composition - ratio of carbon12 to carbon 14
ratio of oxygen18 to oxygen16
ice cores
ratio of magnesium to calcium (more mag = higher temp)