Aquatic autotrophs require inorganic carbon. In what forms is inorgj,e *j98 0xmlgz ncakhfq:7n1 anic carbon present in fxj97je:q1 n mn0akg c8 l,*hzaquatic ecosystems?

  Which of the following:e1lxeg/xx ce)xbw 16 correctly describes how energy is lost from ecosystems?

  What is the name of the process t:qjbe 2suh,eej-3zy1o a,d p/hat converts carbon dioxide in the air to carbohydrates?qa:3hjj, zey pod e1ub,se/- 2

  Which of the followinxb( mpg*a)q0r g statements are correct descriptions of food chains?

The diagram below shows a simplified scheme of the movement-c c6oumoff )/8gyn0 x of carbon in the ocea mog86)n-0of /fuccyx n.

Identify the processes marked I and II.

  The illustration shows a rice cultivation system that eliminates the n*wq9ez+ )w;e*fqsgek eed for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields because they harbou+)egw 9zfq*ek ;sw*eqr 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 cycling of carbon9-znja7giu;i 2ul 4a n from the atmosphere to other carbon sinks. Which is the main source of enn ia7u4l a -nj2u;zig9ergy for the carbon cycle?

The food web below shows the feo/baxqwg se l7rplf a /9f pm,6y angyt1(8/*0eding relationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyramids of enraaub1tnn0 rh9n aw -7+(m 7ftergy?

  The image below shows an cx m;*dvh+lv-v i h,m-Arctic food web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle requires the longes6x5 s)nk7p8pwxf oyl b0kf:c2 t time?

  Which of the following zdsl*zr7b,1 ;d a;rdl statements 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 ecosyste50oeu 7(5yrd nc ,gyzwh7qaa3m having four trophic levels? The size of each level repr 5gcy0 qnuaew(d a5yo37hz,7resents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the flow of energy per area per year in an :-ch f*xrh9;ge v )njpcx/ve-ecosystem.

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

  Which of the organismstu ,uvplb ;h.g.:n 1ig in the food web below is both a secondary and a tertiary co.;hngtib, .1v:gpul unsumer?

  Which of the following statements about greenhouse gx8z/u3u y9r y u k9id6sio20jzases is NOT true?

  Nutrients are constantly cycled in ecos(3 zvj,:v vizmystems, including in the atmosphere as a gaseous form. Whiv:3zviz mj( ,vch of the following elements is not found in the atmosphere?

  A student set up an aquatic p swh 4z-9 oqvo9qq:9umesocosm using a commercially available seawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it4 q9wp9qo: v9zhquso- 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 descrpk2+e mg6g.+w q.26et aoxcdv iption of energy flow in terrestrial ecosystems6eg.egd+kqaw6c o.+ x2m 2vpt?

The following diagram shows a trophil)tr a+c:.e jwh.-kbic level pyramid 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 a small terrest jyl:z9zjjc) 8cw5e-m rial ecosystem with the numbe m9-e)z jwc8yzj:j5c lrs showing the 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 i)c,-s9 ,cv-kh g kpiicarbonate to build their shells. Which of the following is NOT a source of carbon for these ocea 9k pi)v-i,gh ik,c-csn-dwelling organisms?

  The figure below shows the flow of energy per unit -os pyud87p )farea per year in arbitrary units. Gross production is the total kJ obtained through photosynthesis, and net pyps8fpd -u)o7 roduction 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 describe a chemo2vo5e o+ vyh--ucsdg 9autotroph?
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 dioxip44kgsr9 0t br6-8ms wink r)cde measured at Mauna Los9k 4c )r0smi 4wp 6t8-rngkbra 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 mesocosm using (5( mf(yetywn,bive6 z:zz41* w d,l:zpvtbaseawater to simulate conditions in the food web (shown in the image below) and test its stability. He used seawater and sandp z(dwev1*yt z(tlw bn:4izzavyf(5,,e b:6 m from the area to set up the system and added some small organisms 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 thdlja(p-au+ut 4 e u1q j.3n+zpe concentration of atmospheric carbon dioxide over time at Mauna Loa Observatory in3uu+4 njp j.p+1 laze-datq(u 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 zds . k9lg)7ivquttsj 1hd807 explains the annual fluctuations of carbon dioxide i 9.izs ) jdhq78t7dlksgu 01tvn the atmosphere?

The image below shows global sea levels from the years wch0.eu/c6 a p1880 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 f.3n, td xg6qisalt marsh, one of the most productive habitats on Earth.d.tx, q63fign


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 detritivores and sapr80 u.-hr wzzujs-u0:g neuq12 kpna(motrophs 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 affected b1,ni :-bg eewvy 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 number of species counted, the specie-e,vwn eb1gi: s 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 ;a *2orxui dhr7 2wxz.deep in the oceans, where a diverse ecosystem is suppodoz;27x * . 2xurhawrirted. A number of 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 f-+ hah+9c1a8nxfqh z(dvzw n7 orests and marine phytoplankton in their role in the carbon cycle.zv+z9 wfnh(da-a1xch8h+q n7
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a8 pl0jikl7 d k1h,qcc7 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 e8r.txb s ph i8 jw;b(3xv+dk3ynergy showing 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 a8w u uc/tkiu d*datvj+pe i b7p+,4xhe1-gt94nd describe the role it plays in the carbon cycleeex-7juu +4 itt1pw a/d* cv9h upt4d+ib8g, k.
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 iswep* . xl2v3db a graph obtained by plotting values for net primary productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome and the grey dots represent2vl*x b.wpd 3e 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 i3i d tmaz76d-n( nvp8hs represented by the letterai73dn( ph t6- zndmv8s?

  The diagram shows the carbon stik5qmsqstb-(n-d6j* p *a(x uored in some of Earth’s carbon reservoirs, and the estimated annual carbo-aus *(qt qji pmks b5(6*-nxdn flux, in GT/yr, between reservoirs.

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