climate change

Question 1

what are greenhouse gases and some eg

Answer 1

a gas that both absorbs and emits radiation in the infrared range. CO2 and methane.

Question 2

list all anthropogenic activities that contribute to global GHG emissions

Answer 2

1. burning of fossil fuels to provide energy –> coal is the most carbon intensive fossil fuel, it results in more CO2 emission
2. transportation –> combustion of gasoline and diesel
3. industrial purposes –> increased demand for energy comes from worldwide economic growth and development. non-combustion processes include semiconductor manfacture and petrochemical production
4. clearing of forests –> clearing of forests and mangroves and draining of waterlogged peatlands decrease amt of CO2 sinks available. the subsequent decomposition and burning of biomass releases more GHGs. –> conversion of forests and grasslands to cropland and pasture.
5. Food choices –> the growth in per capita meat consumption is strongly linked to increasing levels of income in many countries in the world. Coupled with global human population growth, global meat consumption also increased accordingly. –> industrial style agriculture had made meat more affordable to the masses.

Question 3

State 4 effects of GHG emissions on climate change –> related to environment

Answer 3

1. melting of ice sheets, polar ice caps and glaciers resulting in rise of sea levels.
   2.heatwaves and heavy rainfall
2. stress on freshwater supplies.
3. release of GHG in frozen organic matter.

Question 4

how does melting of ice sheets, polar ice caps and glaciers result in sea level rise

Answer 4

thermal expansion of seawater –> ocean temp rises, particles move more vigorously, causes expansion of water, increasing overall vol of ocean, rise in average sea levels.
melting of polar ice caps –> addition of water to the oceans.

Question 5

comparison of melting of land ice vs sea ice

Answer 5

melting of sea ice does not result in any increase in sea level, as sea ice already displaces water. Melting of sea ice affects marine animals as they lose access to feeding grounds. There is loss of albedo. –> as melting occurs, more of the less-reflective water surface is exposed and absorb more sunlight –> air becomes warmer and more ice melts

Question 6

impact of heatwaves and heavy rainfall on ecosystem

Answer 6

rainfall increases in tropics –> produces more pollution such as erosion and sedimentation due to run-off and water-borne diseases and lower water quality likely to increase, and increased risk of flooding, and eutrophification. Number of frost days is expected to decrease, increasing growing season and increase food production.
rainfall decrease in already dry subtropics –> increase drought, cause more heat-related deaths

Question 7

why is scarcity of freshwater is expected to increase

Answer 7

1. groundwater depletion that is affected by change in precipitation pattern –> affects replenishment of groundwater negatively.
2. decline in water quality
   -areas with increased precipitation: corresponding increase in runoff, larger levels of sediment and contaminants into waterways and drinking reservoirs
   -areas with drought: groundwater reserves may be depleted and residual water is often of inferior quality.
   -increase in temp –> bloom in microbial population, reduce amt of dissolved O2 in water
   -salination in water supplies by coast side.

Question 8

what is permafrost

Answer 8

a layer of soil or rock that is frozen all year round. Stores an immense amount of carbon and methane

Question 9

Impact of thawing of permafrost

Answer 9

allow organic matter within the permafrost to decompose, releasing carbon into atmosphere at a faster rate.
Release of methane and increased microbial synthesis of methane.

Question 10

carbon fixation

Describe physiological characteristics of plants in dry environments

Answer 10

Varying their methods of carbon fixation:
in C4 plants, carbon fixation and Calvin cycle take place in different cells. CO2 is converted to a 4C compound by an enzyme that does not bind to O2. 4C compound is sequestered to a deeper tissue layer where less O2 is present. CO2 is then released and enter the Calvin cycle without competition from O2.
in CAM plants, carbon fixation occurs at night. CO2 is converted to 4C compound which release CO2 for Calvin cycle in the day. This allows stomata to remain close in the day and open at night.

Question 11

observable features

Describe morphological characteristics of leaves that help to reduce loss of water

Answer 11

1. leaf has small surface area to volume ratio.
2. thick waxy cuticle and epidermis
3. stomata only present on bottom surface of leaf.
4. sunken stomata where stomata are found in grooves and often surrounded by hair. Creates a region of high humidity at stomata opening and reduce likelihood of evaporation and water loss through transpiration

Question 12

state effect on physiological and morphological changes on plants by droughts and high temperatures (water availability is limited)

Answer 12

-reduction of water content and turgor, and cell expansion slow down or ceases.
-alteration in level of photosynthetic pigment
-rapid decrease in amount of RuBisCO and lower amt of carbon fixation
-increased ratio of roots to shoots.
-stomatal closure
-decrease in no. of stomata to reduce transpiration.
–> plant growth is retarded and many plants dehydrate and die under prolonged conditions.

Question 13

think about pollen

how does global warming affect reproduction of plants

Answer 13

reduce pollen viability.
disrupts flowering process and affects seed production in plants

Question 14

talk about ratio

how does global warming affect body size of animals

Answer 14

larger surface area to volume ratio of smaller body sizes serve as efficient heat dissipaters in warm climates.

smaller surface area to volume ratio of larger body sizes may help in heat conservation in cold climates

Question 15

how does change in temperature affect insect metabolism

Answer 15

in ectotherms, rates of both somatic growth and ontogenetic development increase with increasing temperature, time to maturity is shorter at higher temperatures.
majority of ectotherms grow slower but mature at a larger body size in colder environments. Cold environments allow ectotherms to reach a relatively large body size by prolonging growth and delaying production.

Question 16

what is thermal safety margin

Answer 16

the difference between an organism’s thermal optimum and its current climate temperature

Question 17

how are insects with different thermal safety margins (tropic vs temperate) affected by climate change

Answer 17

insects in tropic environments: they have small thermal safety margins, even small amounts of warming will likely decrease performance and approach near-lethal temperatures much faster. Many species have small dispersal ranges that increase their risk of extinction through small changes in habitat or environment
insects in temperate environments:
have large thermal safety margins –> broader thermal tolerance. warming may enhance fitness as it causes initial increases in population growth rates and performance. In warmer winters, insects will not all die out. When spring starts earlier, these insects emerge even earlier and can persist in the environment even longer.

Question 18

how does timings of seasonal life cycle events change with climate change. state one example as well

Answer 18

global warming confuses these signals to alter life cycle and seasonal events, leading to mismatches of timing of migration, breeding and food availability leading to species being out of sync with other species or other important natural events in their ecosystem.
possible examples : - marmots ending their hibernations about three weeks earlier than they did 30 years ago.
-birds are migrating and arriving at their nesting grounds earlier.

Question 19

effect of climate change on plant distribution and animal migration

Answer 19

as global temp rises, both animal and plant populations are projected to gradually shift upwards to higher elevations and towards northern latitudes where temp are cooler in order to stay within their ideal range of environmental conditions. Compared to animals, plants are more sedentary and may be in greater risk of being affected by changes in climatic condition. The rate of climate change is likely to exceed the migration rates of most plant species.
Being trapped at the top, alpine wildlife is vulnerable to several damaging effects –> vegetation changes, invasion of new predators and pests, reduced winter snowpack and increases in extreme weather events.

Question 20

Describe impact of temperature changes on distribution of insects

Answer 20

with the warmer climate, many species including insects would migrate northwards or expand their range to remain within their temperature tolerance ranges.

Question 21

Using the examples of dengue and malaria carriers, Aedes Aegypti and Anopheles mosquitoes, how has global warming affected their spread

Answer 21

they have expanded their ranges towards the northern latitudes and those diseases may become increasingly common in more northerly regions. increased temp and precipitation can increase abundance of mosquitoes and result in faster disease transmission.
Aedes Aegypti and Anopheles mosquito –> lives and breeds in moist tropical regions, thrives in regions with warm temp, humid conditions and high rainfall. –> global warming leads to duration for development from first install to emergence is shorter and rate of enzyme-catalysed reactions increases and there is decreased length of reproductive cycles. global warming could result in more rainfall in certain areas and create more pools of stagnant water for mosquito breeding. Hotter months leads to increased incidence of dengue fever in summer. Results in temperate regions becoming warmer and conditions are more suited for survival of Aedes mozzies and move to higher latitude and expand distribution and higher altitudes become warmer and allow for colonisation of mozzies higher up mountains.

Question 22

define biodiversity

Answer 22

the variety of plant and animal life in a particular habitat

Question 23

what are some problems that migrating organism may face

Answer 23

-they may need to compete with other native species for food and other sources
-may be new predators to deal with and may not be able to deal with if not properly adapted.
- possible exposure to new forms of disease may inhibit effectiveness of their migration
- may put into competition with other species over food and other resources and and cause changes to the food web that result in ecological disruptions as predators are separated from prey.

Question 24

Describe the whole process of how global warming result in death of coral reefs.

Answer 24

Corals have a calcium carbonate exoskeleton that helps to build up the reef. Zooxanthallae are symbiotic with corals as they photosynthesise and produce food for corals. Algae absorb light energy and protect the corals from harmful effects of sunlight . Nitrogenous waste from corals serve as nutrients for algae. Mutualistic relationships it is beneficial to both parties. Extended periods of elevated temperatures cause zooxanthallae to leave the corals –> coral bleaching. Acidification of the ocean due to increased CO2 emission decreases calcification rates of corals and growth is reduced. Over-fishing of herbivorous fish meant that corals are under increased threat from the macro algae. The loss of coral reefs reduces habitats for many other marine organisms and disrupt the ecosystem.

Question 25

describe the impact from the loss of biodiversity

Answer 25

1. loss of biomedicines
2. loss of genetic diversity of foods

over a quarter of all pharmaceutical products come from rainforest produce.
genetic diversity in crop production is vital to the sustainability of a food source. Without consistent mutation, and genetic variation within the population, a species cannot continue to thrive in the face of disease or pestilence.

Question 26

impact of climate change on crops

Answer 26

1. global warming can reduce crop yield. –> too much or too little water at any particular growth stage reduces growth potential. For some temperate cereal crops, low flower bud initiation starts earlier and reduces yield.
2. can alter patterns of weeds, plant pasts and pathogens. –> there could be increase pressure from insects and disease vectors. May reproduce more often if cold winters do not keep them in check. Lower-latitude pests may move to higher latitudes.
3. can lead to loss of arable land. –> lead to more vigorous hydrological cycle and more extreme rainfall events. High precipitation and flooding can result in submergence and soil erosion that destroys vegetable plots.

Question 27

impact of climate change on fisheries

Answer 27

world’s oceans are gradually becoming more acidic due to increases in atmospheric carbon dioxide levels. Extreme ocean temperatures and ocean acidification place coral reefs at risks. Acidity could harm sehllfish by weakening their shells.

Question 28

impact of climate change on livestock

Answer 28

1. higher temperatures can cause heat stress in animals –> increase vulnerability to disease, reduce fertility, and reduce milk production.
2. can affect food availability of livestock –> causation of drought results in loss of pasture grazing land for livestock and there is also decrease in crop production yields.

Question 29

where and how long

Egg stage of Aedes Aegypti Mosquito

Answer 29

eggs are laid on damp surfaces in areas likely to temporarily floods.
Laid eggs can survive for very long periods in dessicated state but can hatch within one to two days in water.

Question 30

Adult stage of Aedes mozzie

Answer 30

emerges from pupal stage after two days by ingesting air to expland the abdomen and splitting open the pupal case and emerging head first. Three days after the female mozzie has taken a blood meal, it will lay eggs and the cycle begins again.

Question 30

Larval stage of Aedes mozzie

Answer 30

after hatching, the larvae, the larvae feed on organic particulate matter in water such as algae and other microscopic organisms. The larvae breathe oxygen through a posteriorly located siphon, which is held above the water surface. Larval stage is temperate dependent –> passes through four instars and takes generally takes about four days to develop into a pupa

Question 31

Pupal stage of Aedes mozzie

Answer 31

after the 4th instar,it enters pupal stage that is also aquatic, and they do not feed and take approx two days to develop into full grown adult

Question 32

how does dengue develop in humans

Answer 32

injection of the dengue virus into the bloodstream and injects keratinocytes and injects and replicates inside the Langerhans cell. Infected Langerhans cells secrete cytokines to help limit the spread of infection. The cells travel from infection site in the skin to lymph nodes and display viral antigens in cell surface and activate the innate immune response by activating monocytes and macrophages. Now, monocytes and macrophages are targeted by the virus . As infected monocytes and macrophages travel thru the lymphatic system, virus spreads throughout the body and infects more cells and results in viremia –> high level of dengue virus in bloodstream.

Question 33

How does the immune system defeat the dengue virus

Answer 33

infected cells produce and secrete small proteins: interferons which are part of cytokines and activate both innate and adaptive immune system defences and help the immune system recognise dengue-infected cells and help protect uninfected cells from infection.
Adaptive immune response: B cells produce antibodies IgM and IgG that are released in the blood and lymph fluid where they specifically recognise and neutralise dengue viral particles. Cytotoxic T cells recognise and kill the cells infected with the virus.

Question 34

name the 4 dengue serotypes

Answer 34

DEN-1, DEN-2, DEN-3 and DEN-4

Question 35

why can severe dengue be contracted

Answer 35

after recovery from first dengue infection, a person is still susceptible to future dengue infections as the memory cells can only provide immunity from re-infection with the initial serotype.
infection with dengue can result in Dengue Hemorrhagic Fever(DHF) and Dengue Shock Syndrome which is more serious.
Severe dengue is more frequently observed with secondary infection with a different serotype as antibodies from the first infection help the virus infect host cells more efficiently and increasing viremia.
Antibody-dependent enhancement of infection occurs when pre-existing antibodies present in the body from the primary infection bind to an infecting DENV particle during a subsequent infection with a different serotype. Antibodies from the primary infection cannot neutralise the virus and the outcome is an increase in the overall replication of the virus and higher risk of severe dengue.
During a secondary infection, cytotoxic T cells produced provide partial immunity and if high qty of cytokines are released, serious inflammation and tissue damage can contribute to the severity of dengue.

Question 36

how does severe dengue lead to serious inflammation

Answer 36

with increased vascular permeability, the leakage of plasma from the circulatory system can cause fluids to collect in body cavities. Another symptom is severe bleeding where stomach and intestinal bleeding can cause death and have the tendency to bruise easily. The loss of plasma and protein can cause shock with signs of circulatory failure.