Aquatic autotrophs require inorganic carb4:nkozo(a1 l1 vchx 091skbdips* ve5on. In what forms is inorganic carbon present i1dlxk15c:nvk1 oi*o40 sep s9(vbazhn aquatic ecosystems?

  Which of the following correctly describes how energgrzrp6f 4a7qz5gk/t5u y3,xgy is lost from ecosystems?

  What is the name of the process that cu7c oysg2 j-f3n-o 2 j3ph4h(uosoj o+onverts carbon dioxide in the air to carbohydra 72o(cp3jg s-2hoo+uhujfoj-s o 34nytes?

  Which of the following stateme* a ukoe b/ xu-3v1*fxn3)c fbw;9pzzonts are correct descriptions of food chains?

The diagram below shows a simplified scheme of the movemeql/k t2-57u/v oiggov nt of carbon in the oceanuto g7klq/i v-/2 5gvo.

Identify the processes marked I and II.

  The illustration shows a rice cultivatiozs.mzwt 7jy3f fjl101kgo* oe: 0b0kvn system that eliminates the need for fertilizers, herbicides and pesticides by raisinggz zfwkm b0f.0k*je1:v71olt0s 3y jo 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 the atmospher 403n,m(3pgbugab v gae to other carbon sinks. Which is the main suabpg0,4 (m3n g3avgbource of energy for the carbon cycle?

The food web below shows the feeding relationsh(z66 j r wosqwl3kx7q-ips in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyram j9rzci:n)dr k:t p):zids of energy?

  The image below shows an Arctic food w+e ke7)fz ):brib-pvr eb.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycloi-35+ sdb x6wrmkz z1e requires the longest time?

  Which of the following statement:h:cs5 qw(hsrk su4iwu/s9 8ww9c7uds 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 ecosystem nx -7lmx99g hphaving four trophic levels? The size of each level represent-x9g hn9 plmx7s energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the a kqt;xtlpw+ vo4;f;0flow of energy 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 secoqct i2+ v5k,cd dg+k h0.mu-prndary and a tertiary consumepd dcg+ t+ir2-.5hvkq ,uc0k mr?

  Which of the following statements about greenhouse gasent/d e,i+t p1ys is NOT true?

  Nutrients are constantly cycle0j4p /;zb f,, 8dvixsc kgte5 v4gfgj*hod92wd in ecosystems, including in the atmosphere as a gaseous fggx 4;ez80jfdg4hsbi 2,kvw/,v9otcdf j5p*orm. Which of the following elements is not found in the atmosphere?

  A student set up an aquatic mesoo:cb ot 34ok9qcosm using a commercially available seawater-filled glass orb, which included algae, shrimp, sbo43 coq kt9:oome corals and gravel. 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 stan s9mul8 l)+b+5e4ws n n8)+cwnxjdastements is an incorrect description of energy flow in terrestrialnubdw wcx+ +n84lns )j98as5m sn+ el) ecosystems?

The following diagram shows a trophigciv0 4+q8ali c 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 shg0q1ndc* ojjg d.8k +ujl: ;riows the productivity of a small terrestrial ecosystem with the numbers showing the flow of enerl:8nojk;1 d r dqj.*ju cg+0iggy(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 shells. Wh11 (nd o0y-h,dqv wartich of the following is NOT a source of carbon for theshva1q(1 d,rd-yo nw0t e ocean-dwelling organisms?

  The figure below shows the flow of energy per u;0hcrbxvobyoqiu6f) .0 a*lm8 en7. nnit area per year in arbitrary units. Gross production is tv8n0.yoqce* f);0.axm bu nribo 67lhhe 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 describe a chemoautotg *1a,lm0m l1i,swk3c y.u orbroph?
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 d64 xw -jdcc;ra thzy9q-g sb+9ioxide measured at Mauna Loa Obccxtb;+9d- j r9ah4swq- 6zgyservatory 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 aquatv3o2 rm, 16v)no xiczyic mesocosm 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 organisms)3xz2 6, ciymr1 vovno 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 covx* 9tkybh0 k-9zkd4uncentration of atmospheric carbon dioxide over time at Mauna Loa Observatory in Hawaii, Unit d40buk xk9 -ty9*kvhzed 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 of cxx2qb : 68dt 1tws2ipfarbon dioxide in the :dx8q 21xtp6tbswf2iatmosphere?

The image below shows global sea levels from the yeak 4t( z*i k;xvz*j7zorrs 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 oy d) 3-guwytf9a.yb; crb2b9 most productive habitats on Earthoygd c w9-92)3 byt.fbuyb ra;.


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 obtain2 n xna.kkufo6pp-m 53 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 awpj2; z1ip 1;wz8yue 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 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 ej1iw2pw ;81za ;uyzptrophic 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, w)uhf f.awxb)wmj1bdu:q 340there a diverse ecosystem is supported. A number of organisms thrive in these areas of q)1:3 u 4h0dfb. fam)jbtuwxw 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 marine phytoplankton in their role in the cz l5neps;5 0hcarbon cy l5p5s;hc0enzcle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in au;rb mpv ob8b2 ,;y5od 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 of28l(k6 (l:2vdpiu vvtbsgloi3y h 7. q 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 limesto/af ;zd;g7n-v6o ct iye7d wa*ne is made and describe the role it plays in the carbon cycle.n;y/7g d f7a tdcae6* wz-ivo;
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 fozx wr7w470 8.ukfe9yh ;i 0y/k2e xdxc-sri fqr net primary productivity (x-axis) and the biomass ofz .hw dxyqik -7krc4e s9exy80 r7uf/0i2x;w f 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 illustrateskh mu+; owx5qunk d.31 the carbon cycle in a swamp. What is represented by the letters? uq.d+ kwum3k h;onx15

  The diagram shows the carbon stored in some of Earth3: l5ekhgjdc vf3,iu(*smr 9w ’s carbon reservoirs, and the estimated annual carbon flux, in GT/yr, betwwh,c dm5 sjge( r3k9*:ilv3ufeen reservoirs.

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