Aquatic autotrophs require inorganic carbon. In what forms is inorgufnd;ae dg 73 f0m99fa6+ egrn;a3ntganic carbon pres9f rtnadn693na7u f aed em3;gg;g+0fent in aquatic ecosystems?

  Which of the following correctly describes how energy is los)qlhv e)3m:ovt from ecosystems?

  What is the name of the process th f4,qt3jgu4xtw ey5sj;-+ xlrat converts carbon dioxide in the air to carbohydra xr53l4se;tut+gwxjf j y4,q-tes?

  Which of the following statements are correct descripti,6eb*g. ovjsi p,j 8acons of food chains?

The diagram below shows a sim77vtqc/kuk9wz)v z h4 plified scheme of the movement of carbon in the oceah4)zc k9vqu/wk7 ztv7 n.

Identify the processes marked I and II.

  The illustration shows a rice cuw8w4muby/ m way2lx9zk402n iltivation system that eliminates the need for fey n48zx4w wbwal/2 muky29m0irtilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields because they 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 cycling of carbon from the7v5 gk2( te f 7alykk;6ywfxw8 atmosphere to other carbon sinks. Which is the main source of energy forywt6f8l(a xkeg;2 f wk7k5 v7y the carbon cycle?

The food web below showxwt goq6+ts(g f5 nj*)qy68 ics the feeding relationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyramids of ep-:kz/s d it9knergy?

  The image below shows an Aru+s f h/jp..yq );y92ccd1nxds5y j gfctic food web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle requires the lonbfafmoz rkxo.3/j+f f56 + xa3gest time?

  Which of the following stz j8jc2*5xq42 d1 fryvtrcg46b:2tdqeyo b+zatements 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 ecosysteaq ktwc42nd,wc fsv 6f)/fu.. m having four trophic levels? The size of each level representnt ucfc4.dq2 f,/awfv)6.wsk s 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 ecosyst(cqjwyhs nb :m2(if+, em.

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

  Which of the organisms in -)gh5*,yjb g y+,ee na0jbt mithe food web below is both a secondary and a tertiary consy) y-j bebht*j,e5m ia+ ng,0gumer?

  Which of the following statements about greenhouse gases is NOT tru-c;3ti zuam, ae?

  Nutrients are constantly cycled in ecosystems, including in the .tz7:wgax* ; mi56d.xvxs. f d2iz tg/5qxya katmosphere as a gzxt giqdd:* . y5t5a;ix7v /mk6z.x2 sgxf wa.aseous form. Which of the following elements is not found in the atmosphere?

  A student set up an aquatic mesocosm using 3v ,+sifn5*bfob-cd xeg s:w1a commercially available seawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed fdsn-, be+v fc:x*g5b 1i3swoit 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 incorre,w+bh0c2w0e-1sgy + pj*ompl82 ghwrch d+ xsct description of energy flow in terrestrial ecosystehh8e0g*h b+mpp-ys+ccj,20w lr gww2 +sx d1o ms?

The following diagram shm f be+ssd-dpc3b6/ a( d9csi7ows a trophic 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.vqf*0zoirxz , 9vt 1u a small terrestrial ecosystem with the numbers showing the flow of energy(kJiz*zf10o uv .x9q,rv tm$^{-2}$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 c6-(8 rb. ps*qvodyprj lzxa(-alcium carbonate to build their shells. Which of the following is NOT o6 b.(p-p*8rqxrdsvz alyj- (a source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy per un( m;5v;dwt pxkit area per year in arbitrary units. Gross production is the total kJ obtained through w;mk( ;dvp tx5photosynthesis, 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 describe a chemoautojrc0 ,rzn8pq1qokfb)o6b i j rc-j33 ,troph?
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 thiem* jm:,2iug a):r xre concentration of atmospheric carbon dioxide measured at Maur u* ix:gej)ma2:m,r ina 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 mesocosm using seawater to simuc.6dv. hzlq w0 pdf9y9late conditions in the food web (shown in the image below) and test its stability.d6..wzy90l q d hvc9pf He used seawater and sand 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 the concej phl9w:-rx ct9f) z2)p*wiw ycj2df51y l1uc ntration of atmospheric carbon dioxide over time at Mauna Loa Observatory in Hawaii, Unite - f1icu9*9pl)d)j2x52jy hw1wpfwr tlc: zycd 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 statyfo vkc9u(9 /y 2mdr7/gixxt.21 nlm-*gobrfements explains the annual fluctuations of carbon dioxide in tg/i9 .v /y 2dxo gokmlm2*nbryu-1 9( ffcx7trhe atmosphere?

The image below shows global sea le4.n 8u)f.69k6hjd:thazcm 9kl p pqhjvels 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 productiv /rbrs-5k/tf zd6a- rv guow+w+.t7bze habitats -k wd6obzzr a f-vgu+7w+ts./ rbt5r/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 detritivores and saprotrophs obg e-7ido2ltwoee 8+ 6itain 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 ho.vn,zzi) fx r 2mb7 g4;qsr*diw food chains in leaf litter can be affected by the mass of initial leaf litter added. The st ,7d.;m rr2xn sz)izfvq*b4giudent 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 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 arzmbw 9a0koy3k v33l ad .-lh4 hydrothermal vent deep in the oceans, where a diverse ecosystem is supported. A number of organisms thrivek3m dw09b-al .3h4 yovrlk 3az 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 marw9;bz rh ,vp7line phytoplankton in their role in the carbon cyclep9br;v l7 ,zhw.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food webo(wog wasc4 x/te1 81r 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 trophzwgt j6 95f(dlic pyramid of energy 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 and describe the role itu 86rv.a w+n aigh9rv0 plays in the carbon cyclv g.n6r8 raih0vu9w+ae.
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 forf+,9qm hkww. g net primary productivity (x-axis) and the biomas m.+9wq gkwhf,s 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 swama *wsc2f,n8sb0syvi) p. What is represented by the lci sb0f*,)a 2v8wssn yetters?

  The diagram shows the carbon stored in s*czi5z nm6yk/ome of Earth’s carbon reservoirs, and the estimated 5 kzczym6 i*/nannual carbon flux, in GT/yr, between reservoirs.

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