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BSc Environmental Science > LEC.144 Global Change Biology > Flashcards

LEC.144 Global Change Biology Flashcards

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Biology 101 flashcards
1
Q

What are 3 threats to food production?

A
  1. Soil salinity/erosion/desertification
  2. Lack of incentive for rural careers
  3. Climate change (increased CO2 + global temps., changing rainfall patterns)
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2
Q

How does plant breeding work (4 steps)?

A
  1. Select plants showing traits of interest
  2. Cross 2 parental lines to produce offspring
  3. Select offspring that show both traits
  4. Multiple generations of backcrossing to recover most of genetic material of original elite line over time
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3
Q

What are 3 advantages to plant breeding?

A
  1. Free
  2. Limited technology required
  3. Socially acceptable
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4
Q

What are 4 disadvantages to plant breeding?

A
  1. Time-consuming + labour-intensive
  2. Difficult to modify multi-genic traits
  3. High genetic uniformity = vulnerability
  4. Can plant breeding keep up with climate change?
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5
Q

What are 3 examples of plant breeding approaches used to protect food production under specific, climate-related stresses?

A
  1. Drought tolerance of rice
  2. High temp. tolerance of wheat
  3. Disease (blight) tolerance of potatoes (blight more problematic under climate change)

(All are globally important food security crops)

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6
Q

How are changing monsoon patterns affecting rice yields?

A

Rice adapted to flooding but changing monsoon patterns mean fields are often exposed to drying soils

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7
Q

How can plant breeders increase drought tolerance of rice and who has this been trialled by?

A

By introducing genes from wild rice relatives that show greater root growth for water capture, IRRI

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8
Q

How can plant breeders increase tolerance of wheat to increased temps.?

A

By crossing wheat with Aegilops

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9
Q

Blight-resistant potato varieties already exist, so what is the current issue with blight tolerance of potatoes?

A

Blight-resistant potato varieties aren’t highly favoured by consumers

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10
Q

What are 3 differences between genome editing and genetic engineering 2.0?

A
  1. Non-targeted vs. targeted DNA insertion
  2. Foreign DNA vs. own DNA/single nucleotides
  3. Selectable marker gene vs. marker-free DNA insertion
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11
Q

What are 4 advantages of GM crops?

A
  1. Introduce new traits by overcoming species barriers to hybridisation
  2. Selectively modify single genes regulating a trait/stack traits
  3. Precise location of new genes (especially with genome editing)
  4. Faster than plant breeding once genes isolated/cloned
  5. Increased yield, profitability, + farmer convenience
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12
Q

What are 2 human health issues associated with GM crops?

A
  1. Potential allergenic effects
  2. Herbicide residues from herbicides that GM crops are tolerant to
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13
Q

What are 2 environmental disadvantages of GM crops?

A
  1. Toxic GM pollen falls on milkweed which is eaten by monarch caterpillars
  2. Seed dispersal can lead to hybridisation with weed species
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14
Q

What is agronomy?

A

Soil and crop management (e.g. tillage, planting date, crop choice/rotation, fertiliser additions, soil pH management, water management - irrigation)

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15
Q

Why are crop yields stagnating in Europe?

A
  1. Climate change?
    2.. Reached genetic yield potential?
  2. Plant breeding sufficiently funded?
  3. Soil compaction limiting wheat yields?
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16
Q

Which strategy in Bangladesh has increased rice yield and decreased water use?

A

Alternate Wetting + Drying (AWD) - can be easily implemented by measuring height of water table

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17
Q

By what % does AWD decrease CH4 emissions by during periods of soil drying?

A

26%

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18
Q

What chemical prevents heat-induced loss of grain set in some wheat cultivars and is used to delay fruit ripening?

A

1-MCP (blocks action of plant hormone ethylene which is produced when plants are under stress)

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19
Q

What is a potential compound that will provide a solution to potato blight without being toxic to humans?

A

Potassium phosphite

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20
Q

Define primary air pollutant

A

Chemicals emitted directly into atmosphere e.g. NO, SO2

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21
Q

Define secondary air pollutant

A

Chemicals formed by reactions in atmosphere between primary pollutants and other agents (e.g. light) e.g. NO2, O3

22
Q

How does dry deposition of SO2 and NOx inhibit photosynthesis (2 ways)?

A
  1. Disrupts H+ gradient across thylakoid membranes
  2. Decreases pH so decreases Rubisco enzyme activity
23
Q

How does wet deposition (acid rain) of SO2 and NOx affect soil and plants?

A

Soil: Increases acidity and decreases fertility
Plants: Weathers cuticle, reduces growth, leaches cations from leaves, and germinates seeds (early seed growth)

24
Q

What in a plant does ozone damage (oxidative stress)?

A

Membrane lipids, proteins, and DNA

25
Q

Which type of UV radiation damages DNA in humans?

A

UV-B

26
Q

What are effects of UV-B on plants/fungi?

A

Decreases growth of decomposer fungi and plants, reduces plant disease, reduces herbivory

27
Q

What is phenology the study of?

A

The timing of development in plants and animals e.g. flowering, emergence from hibernation

28
Q

How will warm- and cold-blooded animals be affected by increased temp. due to climate change?

A

Warm-blooded: Well-buffered to DIRECT temp. effects so responses to climate change are more likely to be indirect
Cold-blooded: Growth tightly coupled to temp. (positive correlation)

29
Q

What are 3 predicted effects of increased temp. due to climate change?

A
  1. Development will start earlier in spring and/or won’t stop in winter
  2. More generations per year so greater population buildup
  3. Species may move north or beyond favoured habitats
30
Q

What have recent trends in the UK shown in terms of plant development?

A

Spring is getting earlier (earlier flowering/leafing) and Autumn is getting later (leaf fall)

31
Q

What are 3 biotic interactions?

A
  1. Disease (viruses, bacteria, fungi -major problem in crops e.g. potato blight)
  2. Herbivory (vertebrates, invertebrates - mites = aerial parts + nematodes = roots, insects have diff. modes of eating e.g. sap suckers/chewers so diff. host tissues attacked)
  3. Competition
32
Q

What does herbivory have a negative and positive correlation with?

A

Negative: Tannin concentration, fibre content (closely linked to lignin content), + toughness of rainforest leaves
Positive: Water content + N2 concentration of rainforest leaves

33
Q

What does CO2 decrease the rate of?

A

Decomposition so increased CO2 will reduce recycling of nutrients + carbon (effect of warming has opposite effect short term)

34
Q

What type of animals are corals and what 2 features do they have?

A

Colonial animals, 1. Symbiotic algae (zooxanthellae) 2. Polyps

35
Q

Where is there the highest species richness of corals and their reef-associated species?

A

Indo-Pacific Ocean

36
Q

What are 6 threats to coral reefs that are causing them to decline globally?

A
  1. Nutrient enrichment from polluted run-off
  2. Over-fishing (disrupts balance - certain amount of herbivores needed to keep algae under control)
  3. Aquarium trade
  4. Crown-of-thorns starfish (COTS) outbreaks
  5. Dredging (releases sediment so corals need to produce mucus to get sediment off polyps)
  6. Increasing cyclone/hurricane intensity
37
Q

What are the 2 sources that corals gain energy from?

A
  1. Photosynthesis of their symbiotic algae (mutualistic relationship as corals provide nutrients for algae)
  2. Catching plankton in water column with their tentacles
38
Q

Define coral bleaching

A

When relationship between host and symbiotic algae is disrupted —–> loss of tissue biomass + coral skeleton visible

39
Q

What do corals do to protect themselves from UV?

A

Secrete photoprotective fluorescent proteins that can reflect + dissipate UV light

40
Q

What is used to measure heat stress in coral reefs?

A

Degree heating weeks (4-8°C weeks = widespread bleaching is likely)

41
Q

What are 6 definite triggers of coral bleaching?

A
  1. Heat stress
  2. Light stress
  3. Cold stress
  4. High dissolved inorganic nitrogen (DIN)
  5. Hypoxia
42
Q

What are 5 endpoints of coral bleaching?

A
  1. Cell death of host
  2. Digestion of symbiont by host
  3. Expulsion of symbiont (exocytosis)
  4. Host cell detachment
  5. Bacterial/viral lysis
43
Q

What are 3 cascades (triggers –> endpoints) of coral bleaching?

A
  1. Unfolded protein response
  2. Photoinhibition of symbiont
  3. Disrupted balance of nitrogen/phosphate between coral and symbiont
44
Q

How can corals recover from bleaching?

A

Symbiotic algae can increase in population size or are reabsorbed from water column, if coral mortality already occurred then recovery will require new larvae to settle + establish colonies on reef

45
Q

What caused the Global Coral Bleaching Event between 2014-2017 (worst in recorded history)?

A

By strongest El Nino on record (2°C warming of Pacific equatorial waters)

46
Q

Why does ocean acidification occur?

A

Excess CO2 from atmosphere absorbed into oceans –> mixes with sea water to form H2CO3 –> dissociates into MORE H+ (acidity) and less CO32- (shell-building)

47
Q

What are corallites?

A

“Cups” built by polyps

48
Q

What happens to corallites with increased CO2 concentrations?

A

Shorter (coral skeletons don’t form properly under more acidic conditions)

49
Q

What are 2 ways fish behaviour is affected by ocean acidification?

A
  1. Reduced auditory response when exposed to more acidic conditions
  2. Reduced olfactory ability to detect predators in more acidic conditions
50
Q

What can be used to predict how ocean acidification will affect marine life?

A

Volcanic CO2 seeps (pH similar to expected change by end of century, lower coral diversity/recruitment/abundance and altered species interactions BUT little difference in coral cover)

51
Q

What are 3 reasons why ocean acidification experiments have been criticised?

A
  1. Will have an effect but magnitude of effect has been disputed
  2. Publication bias
  3. Variability in natural environment
52
Q

Where are corals shifting their distribution to track optimum temperature?

A

The poles

BSc Environmental Science (13 decks)

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