Aquatic autotrophs require inorganic carbon. In what forms is inorganiclrlwi 8h/a97t fki0)o carbon present in aquatf)/a0hk8otrwii ll 97ic ecosystems?

  Which of the following correctly decbz9s4kq (af x6c/ec /scribes how energy is lost from ecosystems?

  What is the name of the process that converts rifv x1,kuyw,l qg20o/w 3 noi)6-tfccarbon dioxide in the air to carbohydratf 0 oiwunyro), x2i,/gq- f6ktw3lc 1ves?

  Which of the following statements are correct descriptions ofuge9 tuii,36 sjgd5+o food chains?

The diagram below shows a simpl yj-a)jl6g 3sbified scheme of the movement of carbon in the oce3)jgabj6s l-yan.

Identify the processes marked I and II.

  The illustration shows a rice cultivation system that eliminates the need for feg *di0sfb( aed. z) 6 ozaq2wim-bv3;ortilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields because they harbour blue-sia;fwbdmbi6adqo3* )0 e.o 2zz-g( vgreen 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 cycling of carbon from the atmosphere to other ca/ ihxgn44k m3-*c; fw .izo-mf,uykovrbon sinks. Which is the main source of energy for theyio , whio4uzcnk-*4kxffv;m ./ g3m- carbon cycle?

The food web below shows the feedi4ts pdwd7(lgqv +7ba-ng relationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyramids xgw /3rr;llc/of energy?

  The image below shows an Arctic food web. wo-p.p7; ;hnj2h 8vgo.2ilxl yjv* j q

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle requires thr kem(pzv1 ).- dz229gtuhenye longest time?

  Which of the following statements are true? 9oua -;p:it m-x5 +tqhtvsxt0h;)ag l
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 ff/fymgm:go5 t1-/ 2ztx(prdz low of energy in an ecosystem having four trophic levels? p/:z/f5t -t1og2 yxm mdgz(rf The size of each level represents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the flow of energblf ,f0x vb7b2y 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 belowqi c3x 8wwt9rf5r4)cy is both a secondary and a tertiary consumer?c 3 i8wr9qrt5fw)c4xy

  Which of the following statements about greenhouse gases is NOT tr:v,f9-th jarmf/.ckc ue?

  Nutrients are constantly cycled in ecosystems, including in the atmosphe*8h5w qv.tgymp2b3ak n) u jr y+:vyg(re as a gaseous form. Which of the followmq. a(gyw)yvyt 32unjrpg85 v+ kh*b:ing elements is not found in the atmosphere?

  A student set up an aquatic mesocosh 6pqz/69olfvrauihhih 7/i99 6x4r pm using a commercially available seawater-filled glass orb, which included algae, shrimp, some corals and gra6/9 76ihhr9pq9 huhai vxo/f 6rlz4 pivel. 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 descriptiow0 xus.+m xwv7.iy; pgn of energy flow in terrestrial ecosystem7 sixvg.+;m0puwx yw.s?

The following diagram shows a trophic level pyramid6fm;we f ze,jh0d)1s cwj:m c/ of 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 ,10xyqn/nn0tn* x zfb a small terrestrial ecosystem with the numbers showing the flo0nt/bqy xfnn*xz10 , nw 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 carbonate to e9y5sfxe7w7-1:lo m ,g jqej xkceg;2 build their shells. Which of the following is NOT ef7x jsgx e q-k:gmw 1y79o ej,;elc52a source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy per unit areesem,7 fea 5u9q b6i6ta per year in arbitrary units. Gross productio utm7a, 6es5eqi9fbe6n is the total kJ obtained through photosynthesis, 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 statemeub i opzvj3 0ovd /,w+pvdz0z )/9 t,gjz24zcbnts describe 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 atmospheric carbon dioxide p .k ybllr3(y4l gy:t0measurelyyypl.tr:3(4lgk0 bd at Mauna 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 aquatic mesoc-ck b o n+dnk;u p(9(u(qh8qqbosm 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 orgabqnd;k(q+k 9 nbu( (hoq ucp-8nisms to 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 concentration of atmospheric carbon tovl0+qfpxrpz j ih9bo-(* cse29)6urc2s*gdioxide over time at Mauna Loa Observatory in Hawaii, Unitedfx -*q9 p(zvrjl6)t+ue2h9s*0sc2o ribo gp c 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 expl,ihqsve4)ce1 kj0s;y*mq/ roains the annual fluctuations of carbon dioxide esc e0rqm4k;y h,io/q)*j 1svin the atmosphere?

The image below showsr 4tod:*z 4ebn: d i4md2(jypndf(qrx , x2zq0 global sea levels from the 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 productiveh0edzd *1mh c5uzw, 5od2*qgp ha**d12 dh55z,ucd gpzm0wo h eqbitats on Earth.


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 by which d,fsx gtur65c 1etritivores 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 stud)i1qrt- sa kpw 7lyaawes 0n6:e-l.)wy how food chains in leaf litter can be affected by the mass of initial leaf litter added. The student placed an increasing mass of leaf litter in three differll-s y)t -ap1nk)iwwq:6w7 ea0sear .ent 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 number 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 oceans, where a diverse ec-rv)4 jj ej70*zcxhjbms5(z fosystem is supported. A number of organisms thrive in these areas of hirjb jcz-4f0hzse(v*j7 )xjm 5gh 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* fd2kl zhkm8 y-+shxe h)6wy0 phytoplankton in their role in the carbon cyclw-xsz* y6 kd 8hmk0lehy+2)fh e.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a salt marsh ecosyst q9a*madkzh2 7qudh;+em.


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 shq k8wgclu,g/k;-ug: eowing four levels.
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 playstbz(llt 56q.l in the carbon cycle. z5q ltl(bl. 6t
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 p-cnn5f m 1isk -t.3hn qg)p8ch1vldw0 lotting values for net primary productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome and the grey dots represel)w1 fg5n-qc.k0 dpms8-n ih ct1v3nhnt 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 cd i73wrpvv4xw*i ts9*ycle in a swamp. What is represented by the le*rii9 sd v*pw34w tx7vtters?

  The diagram shows the carbon stored in so(sv f,tsnj46p me of Earth’s carbon reservoirs, and the estimated annual carbon flux, in GT/yr, between r4sv(,6s tjfpn eservoirs.

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