Aquatic autotrophs require inorganic carb7n vkzaxo7)e q./e06 nm yc2glon. In what forms is inorganic carbon present in aqkcv0a)7.lq egyn e/m 26xzn7o uatic ecosystems?

  Which of the following correctly describes hoa;sx dpod7w0 1w energy is lost from ecosystems?

  What is the name of the+ y v*f2dix6 5/wvmsiq process that converts carbon dioxide in the air to carbohydrat*+wvydf is/m5vxi2q 6es?

  Which of the following statements are corr sew;r41ge:fbtgvi) * ect descriptions of food chains?

The diagram below shows a simp p4kw-be misbf6 d .,w+o9fqw-lified scheme of the movement of carbon in the oce.wp+ k efsq9o mi6w-bbw4f,d-an.

Identify the processes marked I and II.

  The illustration shows a rice cultivation sysnadv soq 21o/o4l7zl-tem that eliminates the need for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla7z ov lo-dl/2on4aqs1, 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 the atmosphere to06e /c5o wnvm ck7t2ey other carbon sinks. Which is the main source of energy c0mt 5nk 26y7eocv/wefor the carbon cycle?

The food web below shows the feeding relatybp( ep/5lc6hionships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typic 3 ;rynhyln-h(ally used for pyramids of energy?

  The image below shows an Arctic food webe:rn/l m-yypn5wg2)m. wy8s*zn ,lj f .

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle rec y5v9 x9oegodu/-r0qquires the longest time?

  Which of the following st1 h1qmz (toxe 56bedf1,wk-xe atements 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 jn fgx 91nogf8k5 zw.1in an ecosystem having four trophic levels? The size of each level repreojxk1w8fz. gfn5 9 ng1sents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the flow of enre g:z)6 3wgp;p6w yksergy 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 both a secondary and a t 9 )fpb 1 f*i,ntl5bgfsyeg.,uertiary csf *iegfy 9 nu)1.,lp,tfg5b bonsumer?

  Which of the following statements about greenhouse 6zso7, ,mdn2u /dmvp sgases is NOT true?

  Nutrients are constantly cycled in;bf+ce,fb0c /qmc 0vd ecosystems, including in the atmosphere as a gaseous form. Which of the following elements is not found in the atmospherc+ bc/;0,0fdbevmqcf e?

  A student set up an aquatic mesocosm using a commercially available (ac8*clpv* :q0es fmiseawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it near ali0 8:(eq**accvs fmp 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 incorretttybm9ov) (o2s 9 .iqct description of energy flow in tervb92 .(mqo)s yti ot9trestrial ecosystems?

The following diagram shows a trophic level py q fr2 .4cs,j*ijq m,yq5oi/zgramid 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 ter,n4w* anpp5jsfo 6c5j restrial ecosystem with t pc*j5pjo5, afn n6s4whe numbers 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 urch+tqk3aoj8uv6*.d rb mins use calcium carbonate to build their shells. Which of the following is NOT ajo a 6bm8rvt*.3u +qdk source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy per unit area per year in arb(iw k vapr r5 m8v+zbq5.trwv9+ux w06itrary units. Gross production is thw w 6 +k(rztu5xiq 58vrrvm wvbp+0a9.e 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 statements descrm : *tkz;rmxmpjy)(t. ibe 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 diox1kw3oz3 tvmo3 k ,8wnqide measured at Mauna Loa Obsertw8o31 m nkzoq,vkw33 vatory 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 s 13 ;*yjdewp3o cgxx:fet up an aquatic mesocosm using seawater to simulate conditions in the food web (shown in the image below) and test its stability. He used seawater x o3dy31;jgc e:w x*pfand 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 concentration of atmospheric carbon dioxi( qwr(i,)qs dig9 0d8b kbod7yde over ti)90qs7o d(qrwiibgyb(d8 ,kd me at 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 explains the annual fluctuations ofo,e.,5ck k-yruuhqqn (*qh4 z carbon dioxide in t5r( .,kh4e- uo,qcz hkuqqyn*he atmosphere?

The image below shows global sea levelsz. p/ld0lf)(2tnyd zqaae: to(m01ey 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 marshwzb5.y dj 8vs 7j0bh(b, one of the most productive habitats on zh(sjbybv w8.d5jb 70 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 detritivorelccrfk *dx6 5.-78vyh7ypysyb v-m q6s 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 food7jkd0j-1*k:j towf:c fg gk5 q 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 different tree holes and waited a few weeks. To collect data, the studkt:gj 5 w-k:*fqo kjjc017fg dent 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 ve+xouzm, (bwu /nt deep in the oceans, where a diverse ecosystem is support/, zubuo(wx +med. 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 forestsxb:k1gwo8vs30 l :wlb and marine phytoplankton in their role in the carbon3v kowl :wb:1 xlg08bs cycle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a foo*jp ckmfb3e8* (:sh vhd 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 lxfa9m p)g p l.(omk mvp.j5t:8evels.
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;jo jx.;:nxi6h0s bon is made and describe the role it plays in the carbon cycn io;s:bjo0 j.n6 hx;xle.
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 plout jy1pkv;)a1 r vf/:vtting values for net primary productivity (x-; ptvjy:)kv1 /uvaf1 raxis) and 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 swavuvv2h-xa-:a 1do mc: mp. What is represented by the letters?h--v1: av:xcav umo d2

  The diagram shows the carbon stored in some of E vw+c+sfdu r61arth’s carbon reservoirs, and the estimated annual carbon flux, in GT/yr, 6rf wvs+1udc +between reservoirs.

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