Aquatic autotrophs requp+6h/v +ygacj5 y/bfzv5gr60 a,sx x nire inorganic carbon. In what forms is inorganic carbon pr,vhayn0yx/zb+a 6x+5 /grf g6csjvp5 esent in aquatic ecosystems?

  Which of the following correctly describes how energy 5d *o vmsx;9stis lost from ecosystems?

  What is the name of the process that converts carbon diox:g-s8ql,1k fq3p2d- wnhpnwv ide in the air to carbohydrateq3w12-fkn sp,g-lpw :8hq vd ns?

  Which of the following statements are correct descriptions of food chains q cql-h8/ltr7?

The diagram below shows a simplified scheme of the movem(ai dc+x2b v,uent of carbon in the ocean. 2 x(cvu+ abid,

Identify the processes marked I and II.

  The illustration shows a rice cultivam1ga1yga )+a*+wl;q 2il;dmgz t ujd9tion 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 fieldsa*tj2 ad;u1gl1m)lmdg yqa+ 9giw;+z 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 carbo8/o-dirwvh i 1sgzu86 n from the atmosphere to other carbon sinks. Which is the main source of energy for the ca6zi8hv/g dw8 1rio-us rbon cycle?

The food web below shows the feeding rela *w61*.2 +bq-sp6a tbn+ lbzemyf 4u nxr:awuftionships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyrami sy7a k1ou, 0rvc;iw*un;x6 if ur,z4kds of energy?

  The image below shows an Arctic food web. *j2bvyna4e)c z27rqzt+yym*

Which of the following organisms is not a heterotroph?

  Which of the following proqd 9 2epp/kbdd;/eq c:cesses in the Carbon cycle requires the longest time?

  Which of the followinx:-sd4x2tzub 3 m 2e yiq10rtxg 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 fl7 h:lm lklkjh,j108ej ow of energy in an ecosystem having four troph:llk7klj0m 8,je1 h jhic levels? 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 energy per area per year in an ectyu+v b+/bmc t0; n:nqosystem.

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 a qu(il( g(d6 mhpxhi4:qh;gy3nd a tertiary c gu((h qp 4dyql:h3;xgm6i(i honsumer?

  Which of the following statements about greenb(a4 q(edwu3aq eg57 +drxyg)2iv7c ehouse gases is NOT true?

  Nutrients are constantly cycled in ecosystems, including in fvue2)7u wzq 7the atmosphere as a gaseous form. Which of the following elements is not)2wef77q vuz u found in the atmosphere?

  A student set up an aqu1: gxl.op.yy fatic mesocosm using a commercially available seawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student plac1yopxf . lg:.yed 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 followingi6 jmihn9sr2+l5tl p0 statements is an incorrect description of energy flow in terrestrial ecosysnrpt+j0l6 i9shl 5m2items?

The following diagram shows a trophic level py5ytk jph+b/ qpxk0oki .6;wg4 ramid 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 show5pu w-eyv*0uls the productivity of a small terrestrial ecosystem with the numb-wu vly5e*pu0ers 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 carbonate to build their she +q+-ircf4knct+c l9wy 4kd b jtz72r3lls. Which of t72c4y kt+fq+krw9r-+c lzbd inj43c t he following is NOT a source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy per u/s8 ooujlb)*,te l9 cknit area per year in arbitrary units. Gross po *o)cksj/8le, tb lu9roduction 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 statements descf mp9cjy yn*fravnl,;0*u g,mf6sm+ ;ribe 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+)f z zitm2b7;:os3rk9ruxw c dioxide measured at Mauna Loa Observatory in Hawaii, USizrs:u3 rw7cmb9 z2x kt ;)fo+A.

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 mesocox4i(tdo 1 qp4csm using seawater to simulate conditions in the food web (shown in the image below) and test its stability. He usq144i( txcpdo ed 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 concentration of atmospheric carbon dioxide 8xo5pxht2jqjpo z6 ,/ over time at Mauna Loa Observatory in p6/zqtp xj oo52,xhj8Hawaii, 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 explf9a 1td c7lm a)5*d/bzgltqu7 ains the annual fluctuations of carbon dioxide in the atmosphere? 7zdfgq 5bul )7 tam/1at*l9cd

The image below shows global sea levels from the years 1880 to 2020xna (u9 lyrf;**;ssg q.

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, onwa pfv;*paf 43e of the most productive habitats on Earp ; vap3f4awf*th.


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 obtain nutrition. l t8g.xoyq xard, w+18
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 iy:+8la5h3 bd bh d.:kyyyc qi4n 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 qb ky8h3l :4hyy:dybcd .+i a5a 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 oce3akbh:9vr;2nde0b ;qbup:kw r/g4 efz9 /j vcans, where a diverse ecosystem is supported. A number of o;b e03 9:;abwehrn24qvg:kdp/fku zbcvj9 /rrganisms 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 foxaaoy; e- ,pm;rests and marine phytoplankton in their role in the carbon yoeax;a- ,m;pcycle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a saji:swzw 0mb2/ yex(gqv )9bgh0u5n 9y lt 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 ensoodsre9/*q0 ; ol qm3ergy 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 a6w,rv.v47 8flcljf si nd describe the role it plays in the carbon cycle.6l, 4rlj wsficvf7. v8
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 kq3slu kz f573g,w2plnet primary productivity (x-axis) and the q5wk7g3pklfulz,2 s3 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. Wgc rqlmg:44 m8hat is represented by the letterscg4q 8mrg lm4:?

  The diagram shows the carbon stored in some.pywys7 ts5ey29nl*h of Earth’s carbon reservoirs, and the estsye5ln97 ws *y.phy t2imated annual carbon flux, in GT/yr, between reservoirs.

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