Aquatic autotrophs require inorganic p:sn*x*d*cr a nd;1xu carbon. In what forms is inorganic carbon prr:sx pd*cx* d1*an ;nuesent in aquatic ecosystems?

  Which of the followingovg wxid/2wfy*kyi:)o/d4 4o correctly describes how energy is lost from ecosystems?

  What is the name of the process that converts carbon dioxide in the air to/0lk x (kurl:h carbolx:( lrh0uk/khydrates?

  Which of the following statements are corre 5 gzey2i5w an+ebzm j.t1o+w4ct descriptions of food chains?

The diagram below shows a simplified scheme of the movement of carbon in the 3ihbdk +ef30rocean.0f3r he3+d kbi

Identify the processes marked I and II.

  The illustration shows a rice cultivatbbu/h8 q7zti9 ion system that eliminates the need for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields because tuzbb7 8h9t qi/hey harbour blue-green algae that fixes $N_2$​. This system produces duck, fish and rice for human consumption.


What would be a possible food chain for the rice cultivation system shown in the image?

  There is continuous cyclincy3.xn(pr1mt frxf)/c iq0y 9vdy/ p-g of carbon from the atmosphere to other carbon sinks. Which is the main source of energy for the carbon cycypf xqfc0t-ydvpcrxy/mi r)3 9/ 1 (n.le?

The food web below shows the fed7utg i6v7l4 )7a hmgaeding relationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyrao.sig+*awjz e, fv0 6lmids of energy?

  The image below shows an Arctic food webjzz,g0 h) /cs14ub rol.

Which of the following organisms is not a heterotroph?

  Which of the following processes in ec1i6,c5tg llg( ;tdwthe Carbon cycle requires the longest time?

  Which of the following statemel.iuta6y.e y. nts are true?
I. Living organisms release energy from organic compounds and convert it to heat during the process of respiration.
II. Since heat cannot be transformed into other forms of energy it is lost from ecosystems.
III. Light energy from the Sun is converted to chemical energy by producers and then converted to heat during respiration.

  Which of the following diagrams shows the flow of energy in an e2fk nl,8 g+r v-zhc3o5ksn +ticosystem having four trophic levels? The size of eagv 2 t+k,nhrcofzis3-8n5l+ kch level represents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the flo u+gb.jal :t.m0lg7okw of energy per area per year in an ecosystem.

Aproximately what percentage of energy from the producers reaches the tertiary consumers?

  Which of the organisms in the food web below is es+ssx6 g6 4wqboth a secondary and a tertiary cons4+6q6ssxs wegumer?

  Which of the following statements about grv( achw65/47c cn uoln8 s2eqweenhouse gases is NOT true?

  Nutrients are constantly cycled in ecosystems, including in the atmo+2q+ muv6fcs usphere as a gaseous form. Which of the following elements is not uqmvc6 + +usf2found in the atmosphere?

  A student set up an aquatic mesocosm using a commercially available seawat -i adsfd91.sper-filled glass orb, which included algae, shrimp, some corals and gravelis1.9p -ad dfs. The student placed it near a window to provide a light source. Which of the following statements are true?
I. The algae are autotrophs, produce carbon compounds and provide oxygen for organisms in the mesocosm
II. Saprotrophs present in the water and gravel help to recycle nutrients found in dead organisms
III. Herbivores usually present in a natural ecosystem can be excluded in the mesocosm

  Which of the following statements is an incorrect description of energy 24r6xlnj t6n sflow in t6nns64rljx2 t errestrial ecosystems?

The following diagram shows a trophic level pyramid ofh8xh 0w,,qs sjj.u z:jw)/jg y energy.

1.Label the bottom (step A) and topmost steps (step D) of the pyramid to describe what types of organisms are present in the two levels.
2.State which trophic level can support the largest population of people, step A or step B?
3.Explain why animals at level D are most vulnerable to becoming extinct.

  

The diagram above shows a simplified diagram of the movement of carbon in the ocean. Which of the following rows correctly identifies processes involved in the carbon cycle?

The following image shows the productivity of a small terrestrial ecpjxb ))d w::dbosystem with the numbers showing tb jdpwb:)):x dhe flow of energy(kJm$^{-2}$yr$^{-1}$)

Net production = Gross production – energy lost to respiration
1.Outline how light energy is sequentially transformed into other forms of energy in the terrestrial ecosystem shown in the image.
2.Calculate the percentage of energy captured by the producers that is available to the secondary consumers in the ecosystem shown above.

  
What kind of fuels can be formed in conditions such as those shown in the picture above? The soil is anaerobic, acidic and waterlogged.

  Corals, oysters and sea urchins use calcium carb-x.t 7m ht;ha 3dl9aayonate to build their shells. Which of the following 3hm- axyh 9;ltad7 t.ais NOT a source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy ll7f w3k3fe 3hcf5j:)ymvm/l per unit area per year in arbitrary units. Gross production is the total kJ obtained through pyfw h35v k l m33l7fe:j/l)cmfhotosynthesis, and net production is the kJ remaining after respiration.


What percentage of net production (kJ after respiration) is lost to decomposers by primary consumers?

  Which of the following statements dew6i iw;.8 30 i9h;umsfo6a ,x1vdyhuxy 3r ievscribe a chemoautotroph?
I. Bacteria and extremophiles living in hostile environments like hydrothermal vents
II. Organisms which obtain their energy from oxidation reactions and form organic molecules primarily from carbon dioxide
III. Chemoautotrophs are dependent on the Sun for survival

  The following graph shows the concentration of atmos fd5j2 9sd1twrfv+mv8pheric carbon dioxide measured at Maudf+ jv2958r fd stwvm1na Loa Observatory in Hawaii, USA.

Which of the following statements do not explain the rise and fall of the carbon dioxide levels shown in the graph above?

A student wants to set up an aquatvv(t c )ve 9*8t-sh3j ghat6wf9f,(j/wrp qnyic mesocosm using seawater to simulate conditions in the food web (shown in the image below) and test its stability. He used seawater and sand from the area to set up the system and added some small organisms y6rv)fhqpn93v j* ta te stv(9c(/fhj ,wwg-8to the mesocosm.

1.In the food web shown, identify an autotroph.
2.State a reason why phytoplankton shown in the food web would be a good addition to the mesocosm.
3.Discuss how saprotrophs perform a necessary function for the mesocosm.
4.Describe the disadvantages of using mesocosms in scientific investigations.

The following graphs show the concentratiojeaq-1y +a;-pe*nrgbk 8v- wa n of atmospheric carbon dioxide over time atv ea1e-ap *j;kr -a8+nwb-g yq Mauna Loa Observatory in Hawaii, United States.



1.Describe the overall trend in atmospheric carbon dioxide levels over time.
2.State one factor that has significantly contributed to increases in atmospheric carbon dioxide concentration as seen in the graphs.
3.Explain why the concentration of atmospheric carbon dioxide fluctuates annually.

  Which of the following statements e2le0-tos2h rw xplains the annual fluctuations of carbon dioxide i20 lr2o-h wsetn the atmosphere?

The image below shows global sea levels from z,mlkx fe.; -othe years 1880 to 2020.

1.There is a trend line showing changes in sea level from 1920 to 1960 and another trend line showing changes in sea level between 1980 and 2020. Describe the differences in sea level change between these two periods of time.
2.Outline the reasons for linking atmospheric carbon dioxide levels to the rise in sea levels.
Ecosystems growing in salt marshes are able to help reduce the effects of climate change by the sequestration (capture) of carbon. Sea level rise (SLR) has affected these ecosystems by flooding and eroding coastal areas.
The results from a recent study modelling the effects of a one-metre sea level rise on carbon sequestration by salt marshes in New York, United States, are shown in the graph below. The data shows the predicted effects by the year 2100.



3.Suggest an explanation for the difference in carbon sequestration between no SLR and one meter SLR, shown in the prediction graph.
4.Draw a diagram of the carbon cycle for a terrestrial ecosystem, and include carbon sinks, and processes associated with the cycle.

The diagram below shows the food web in a salt marsh, one of the most produc)rgl-yie 0s, ncaz/-r tive habitats on Eart gi c)0,/y-sranzerl- h.


1.The numbers on the arrows show the percentage of gross primary production that flows into different trophic levels or is used in plant respiration.
2.Define gross and net primary production.
Identify the herbivores shown in the system.
3.If the energy available to consumers from producers in organic compounds is 300 g m$^{-2}$yr$^{-1}$(dry), calculate the amount of energy that is lost by export to the tide.1
4.(1)The table below shows the NPP for three trophic levels in a food web. Draw a pyramid of energy from the information in this table, labelling it appropriately with the trophic levels and corresponding NPP values (rounded to 3 significant figures as in the table).


(2)Outline a limitation of the ecological pyramid of energy.
5.Explain how a food web provides a more accurate representation of an ecosystem’s feeding relationships than a food chain.

1.Describe the process bxzy vizv+ )f(xbua+ :0y which detritivores and saprotrophs obtain nutrition.
2.Describe how a quadrat can be used to estimate the population of poppies in a field.
3.Energy and nutrients move through ecosystems differently. Describe how energy and nutrients move through terrestrial ecosystems.

A student wanted to study how food chains in leaf litter can be xozo, old6uj:t7/4 nl affected by the mass of initial leaf litter added. The student placed an increasing mass of leaf litter in three different tree holes and waited a few weeks. To collect data, the student collected all the leaf litter and placed it in an apparatus, as shown below. The heat from the light bulb dried out the litter from above and the heat and light drove the invertebrates through the wire mesh to the beaker below. The invertebrates were collected, the n7loo /ujzotd,46n x: lumber of species counted, the species were identified and then they were put into their respective trophic groups.



1.(1)State the independent variable in the experiment.
(2)State the dependent variable in the experiment.
2.Suggest how the dry biomass of the leaf litter can be obtained.
3.Explain why using the dry biomass of leaf litter is advantageous to using the fresh biomass.


4.From the two graphs provided, describe the results of the experiment.

The image below shows a hydrothermal vent deep in the ocea rv7vm9;(xxhsns, where a diverse ecosystem is supported. A number ofhm;rx79 xvvs( organisms thrive in these areas of high pressure and darkness.


1.State an example of a chemoautotroph that is likely to be found in the hydrothermal vent shown above.
2.Compare and contrast photoautotrophs and chemoautotrophs.

1.Compare and contrast forests and marine phytoplan(,c zuk,qe vd)wx:jl* kton in their role in the carbon d,k(,xj*vzqw u: l)c ecycle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a foof b.,2-uwbas6.*q kq3k. lwpbumbc;t d web in a salt marsh ecosystem.


1.Identify all the detritivores in the food web shown above.
2.Define secondary productivity.
3.Explain why energy is lost during the transfer from producers to herbivores.
4.Describe a method a farmer could use to estimate the gross primary productivity per month of his wheat crop.

1.Draw and label a trophic pyramid of energy showing four levels.pghzyc2c5 g 81u1moz d5l;:ap
2.Explain how the presence of a food web in an ecosystem makes it more stable than the presence of a single food chain.
3.The production and transfer efficiency of energy varies between ecosystems.
Describe how energy flows in and out of terrestrial ecosystems.

Dissolved $CO_2$
is increasing in standing waters of lakes and ponds. Research has shown this will impact the nutritional quality of phytoplankton (primary producers) and may further affect zooplankton (consumers) that feed on the phytoplankton.
Mesocosms were used to monitor three species of zooplankton, the water flea (Daphnia magna), the seed shrimp (Heterocypris incongruens) and the rotifer (Brachionus calyciflorus) under three different conditions of $CO_2$
in ponds and shallow lakes:
Treatment C - present day levels of $CO_2$, (control)
Treatment 1 - moderate increase of $CO_2$(possible future levels)
Treatment 2 - high increase of $CO_2$(more extreme future levels)
Glass jars filled with filtered pond water were injected with both carbon dioxide and air under pressure, and the representative species of zooplankton, water flea, seed shrimp or rotifer were added to the jars. They were monitored for survival, growth rate and body size over the next several days.
The image below shows the three species of zooplankton that were studied in the mesocosms.

The survival probability of the three species of zooplankton were monitored over several days in the mesocosms and the results are shown in the graphs below.


1.Giving a reason, predict which zooplankton is the least resilient to the effects of increased carbon dioxide.
2.Describe how using mesocosms for research is both an advantage and a disadvantage in predicting the effects of increasing carbon dioxide in the atmosphere.

1.Explain how limestone is made and describe the role it playqe8j (9hv yud m/gk1v9s in the carbon cycyvhd8qju/ 1g k(e9v9 mle.
2.Oil and natural gas are extracted to be used as fuels. Describe the formation of oil and natural gas.
3.Nutrients are cycled in all ecosystems. Draw and label the carbon cycle showing at least four stores or sinks and at least four flows or processes.

  The following image is a graph obtained by plotting values for n/b8im* l(i 7:jivxdm uet primary productivity (x-axis) and lxui8i b*djvm i:m7/(the biomass of herbivores (y-axis). The black dots represent one biome and the grey dots represent another biome.

The x-axis shows the increasing net primary productivity of biomes, and the y-axis shows the increasing biomass of herbivores. Which of the following choices correctly identifies the biomes represented in the graph above?

  The diagram illustrates the carbon cycle in a swamp. What is represented by thzmj02 ei1g5gg e eiz25mg1 0gjgletters?

  The diagram shows the carbon stored in some of Earth’s carbon reservoirs, ehh; :-ph,eyq 4.aaxaand the estimatha;:a qayhp-4,eh.ex ed annual carbon flux, in GT/yr, between reservoirs.

Which is a net flux between two reservoirs in the carbon cycle?