Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ECO3B: Managing Conservation > W6: L23 = Systems Ecology [Elevated CO2 Impacts] (Prof. Sally) > Flashcards

W6: L23 = Systems Ecology [Elevated CO2 Impacts] (Prof. Sally) Flashcards

1
Q

Graph on Atmospheric CO2 attributes? (6)

A
  • Atmospheric CO2 has varied 10-fold through Earth’s history.
  • Geochemical & biological processes influence carbon cycling.
  • As plants evolved overtime, CO2 decreased & O2 increased.
  • At the time plants first evolved, CO2 was much higher.
  • During the Pleistocen, it oscillated between 180-200ppm.
  • Current CO2 levels were last seen on Earth 3mya.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Carbon cycle revision attributes? (2)

A
  • Stocks.
  • Fluxes/Flows.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Egs of Stocks? (4)

A
  • Plant biomass.
  • Soil carbon (SOM).
  • Fossil carbon.
  • Atmosphere.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Egs of Fluxes/Flows? (5)

A
  • Photosynthesis (GPP) [sink].
  • Plant respiration (R) [source].
  • Microbial respiration & decomposition [source].
  • Animal respiration [source].
  • Combustion (natural/man-made) [source].
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Drivers of the terrestrial carbon cycle? (2)

A
  • Photosynthesis.
  • Respiration.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Photosynthesis (A) attributes? (7)

A
  • Affected by temperature, CO2 concentrations, water availability & plant competition.
  • Leaves are the fundamental anchor of the terrestrial carbon cycle.
  • Exchange of H2O for CO2 is a tradeoff governing photosynthesis & plant growth.
  • Uses light energy to drive the electrons from water, converting solar energy into chemical energy.
  • Stomata & chloroplasts are key ingredients of leaf functioning.
  • Either produces energy (ATP) or glucose.
  • Pathways are C3, C4 & CAM.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Photosynthesis?

A

= the conversion of CO2 into organic compounds using light energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Controls of Photosynthesis? (2)

A
  • Land uptake of CO2.
  • The loss of water.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What factors are photosynthesis affected by? (4)

A
  • Temperature.
  • CO2 concentrations.
  • Water availability.
  • Plant competition.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain Light response curve? (6)

A
  • x-axis = Absorbed light.
  • y-axis = Photosynthesis rate (A).
  • Positive linear = light limited.
  • Constant = CO2 limited.
  • Negative photosynthesis = respiration.
  • Carbon capture.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does Carbon capture depend? (2)

A
  • Light availability.
  • Metabolic processes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Light availability?

A

= how quickly ATP/NADP can be produced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Metabolic processes?

A

= how quickly CO2 can diffuse into the chloroplast.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Photosynthetic pathways in terrestrial plants? (3)

A
  • C3 photosynthesis.
  • C4 photosynthesis.
  • CAM photosynthesis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

C3 photosynthesis attributes? (6)

A
  • Used by most plants (99.6%).
  • Uses RuBisCO to convert CO2 to O2 and sugars (energy).
  • Converts CO2 & RuBP into 3-phosphoglycerate.
  • Plants have a fundamental problem that makes them inefficient.
  • Enzyme RuBisCO can bind to both O2 & CO2, so it will sometimes respire instead of photosynthesise (photorespiration).
  • Inefficient & wasteful.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the fundamental problem that makes plants with C3 photosynthesis inefficient?

A

They are sensitive to O2 concentration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Egs of plants that have C3 photosynthesis? (3)

A
  • Potatoes.
  • Oranges.
  • Rice.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is it named C3?

A

It’s because the first products in the process of carbohydrate production (Calvin cycle) contain 3 carbons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Photorespiration?

A

= when the enzyme RuBisCO can bind to both O2 & CO2, and will sometimes respire instead of photosynthesise.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is C3 photosynthesis inefficient & wasteful?

A

It’s because it uses an enzyme that both captures CO2 & releases it, depending on O2 concentrations & air temperatures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How was the photorespiration problem solved?

A

C4 carbon fixation.

22
Q

C4 photosynthesis attributes? (7)

A
  • “Improvement” on C3.
  • C4 evolved about 30-40mya, multiple times.
  • Most C4 plants are grasses.
  • Responsible for 20% of GPP.
  • C4 grassy systems spread to current dominance in tropical & subtropical regions when CO2 levels were low (180ppm).
  • Physically separates RuBisCO from the O2.
  • How was the problem fixed?
23
Q

How the problem of RuBisCO fixed by C4 photosynthesis?

A

C4 photosynthesis evolved a new enzyme called PEP carboxylase.

24
Q

Result of the fixed problem of C4 photosynthesis? (2)

A
  • More efficient at low CO2 & high temperature.
  • Larger energetic cost, but avoids wasteful photorespiration process.
25
Q

How does C4 photosynthesis affect water loss? (5)

A
  • C4 reduces stomatal aperture & still get more CO2 into the leaf.
  • Reduces water loss.
  • Confers an advantage in drought conditions.
  • Increases Water use efficiency (WUE).
  • Therefore, C4 plants thrive in environments with high temperature, low CO2, high O2 & low water (drought).
26
Q

Which environments do C3 plants thrive in? (4)

A

Environments with:

  • Low temperatures.
  • High CO2.
  • Low O2.
  • High water.
27
Q

Which environments do C4 plants thrive in? (4)

A

Environments with:

  • High temperatures.
  • Low CO2.
  • High O2.
  • Low water (drought).
28
Q

Egs of C4 plants? (2)

A
  • Maize.
  • Sugarcane.
29
Q

CAM photosynthesis attributes? (6)

A
  • Evolved about 30-40mya.
  • Occurs in many plant families.
  • Temporal separation of fixation of CO2 & Calvin cycle.
  • Nighttime accumulation of CO2.
  • Minimises loss of water in hot arid climates& minimises photorespiration.
  • Advantage in dry areas.
30
Q

Summary of C3 photosynthesis? (2)

A
  • Uses RuBisCO to convert CO2 to O2 & sugars (energy).
  • Because ruisco also binds to O2 to produce CO2 (photorespiration), it’s inefficient at low CO2 or high temperatures.
31
Q

Summary of C4 photosynthesis? (4)

A
  • Separates RuBisCO from the O2 (prevents photorespiration).
  • CO2 is converted to a C4 acid & transported to bundle sheath cells where RuBisCO reaction occurs in the absence of O2.
  • Extra pathway requires more energy (more light).
  • More efficient at low CO2 & high temperatures.
32
Q

Summary of CAM photosynthesis? (3)

A
  • Separates CO2 uptake (night time), from photosynthesis (day time).
  • Extra pathway requires more energy (more light).
  • Reduces water loss in hot arid climates & photorespiration.
33
Q

Explain the response curve: Photosynthesis vs Light in relation to C3 & C4 plants? (6)

A
  • x-axis = Light.
  • y-axis = Photosynthesis rate.
  • C3 plant curve = linear increase then a stabilising.
  • C4 plant curve = linear increase then a stabilising.
  • C3 plant curve is below C4 plant curve.
  • Both curves start below zero.
34
Q

Why did the Photosynthesis & Light curve stabilise?

A

Due to co-limitation.

35
Q

Explain the response curve: Photosynthesis vs Temperature in relation to C3 & C4 plants? (5)

A
  • x-axis = Temperature.
  • y-axis = Photosynthesis rate.
  • Both C3 & C4 plant curves are unimodal.
  • C3 plant curve comes before C4 plant curve.
  • Unimodal = hill-shaped (increase then decrease).
36
Q

Why are the C3 & C4 plant curves unimodal in the Photosynthesis & Temperature response curve?

A

It’s because of their limitations/co-limitation, where both plants are unable to thrive at very high temperatures.

37
Q

Explain the response curve: Photosynthesis vs CO2 in relation to C3 & C4 plants? (5)

A
  • x-axis = CO2 concentration.
  • y-axis = Photosynthesis rate.
  • C3 plant curve = curved linear increase.
  • C4 plant curve = linear increase at low CO2 & then stabilising.
  • C3 plant curve is under C4 plant curve but continues to surpass C4 plant when it stabilises.
38
Q

Why does the C4 plant curve of the Photosynthesis vs CO2 response curve stabilise?

A

Due to co-limitation & photosynthesis being better adapted in C4 plants at low CO2 concentrations.

39
Q

Things to note about the Map showing the abundance of C4 grasses globally? (4)

A
  • Be able to explain why C4 plants are found in those parts of the world.
  • Think about water & temperature.
  • NB: CO2 is the same all over the world.
  • When thinking about change over time, consider changes of CO2 levels as well.
40
Q

Scales of measurement to consider when talking about CO2 effects? (3)

A
  • Leaf scale.
  • Whole plant scale.
  • Ecosystem scale.
41
Q

CO2 effects at Leaf scale?

A

Increasing CO2 from 350-700ppm increases photosynthesis (~40%).

42
Q

CO2 effects at Whole plant scale?

A

Increasing CO2 from 350-700ppm will lead to the plant growing about 20% more.

43
Q

CO2 effects at Ecosystem scale?

A

Net carbon assimilation will increase about 14% more.

44
Q

Effects of CO2 on plant growth & functioning? (5)

A
  • Increased rate of photosynthesis.
  • More CO2 & less photorespiration.
  • Decreased rate of transpiration at the leaf level.
  • Decreased water loss is due to a partial closure of the stomata.
  • The effects on the plant’s physiology and growth in the longer term are less clear because plants will adjust their physiology in many ways.
45
Q

Why do C3 plants thrive in low light environments?

A

It’s because RuBisCO requires less energy.

46
Q

Explaining plant distribution attributes? (5)

A
  • Mapping the factors limiting plant growth globally.
  • Equator = warm, wet & little light (C3 plants).
  • Poles = cold & no light (C3 plants).
  • Orange & red regions = hot & dry (C4 plants).
  • Links map showing abundance of C4 grasses globally.
47
Q

Experimental evidence that C3 plants respond more to high CO2? (3)

A
  • BER.
  • Graph of BER vs C3, C4 & CAM plants (box-and-whisker).
  • Photosynthetic pathways have different functional responses.
48
Q

BER stands for?

A

Biomass Enhancement Ratio.

49
Q

BER?

A

= indicates the difference in biomass for plants grown at ambient & elevated CO2 levels.

50
Q

What should you focus on when interpreting box-and-whisker plots?

A

Focus on reading the median.

51
Q
A

ECO3B: Managing Conservation (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions