Aquatic autotrophs require inorganic carbon. In what forms ivsb0qasl* mx np/2 ne,;h7un0s inorganic carbon present in aquatic ecosysteb0n xmvnp*q7uah;l n 0, 2/ssems?

  Which of the following correctlrc 2(iykz0(wp g 5qt3oy describes how energy is lost from ecosystems?

  What is the name of the proz/ ddap (w5a-qcess that converts carbon dioxide in the air to carbohy -dzqap/( daw5drates?

  Which of the following statements are correct descript.pb6.k6xtme-t v,ejpions of food chains?

The diagram below shows avvy .5lq d4v,hu g)pgvc)p ,q1 simplified scheme of the movement of carbon in the ocean. gq14 ,)v lv5hvgd)y,uq. pvcp

Identify the processes marked I and II.

  The illustration shows a rice cultivation system that eliminates the need f 9t t;g/ bnvu ,.rd*reqn(hfs3or fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields because they harbour bn r,;tt/r.u3d *fsbgnhv9 q(elue-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 * 9hi-bj4r:4zxonph) r -uf gito other carbon sinks. Which is the main source of energy for the carbon oi49rgzh i-f* p:4n)rb-hujx cycle?

The food web below shows the feeding relationshipsed ,i- h r(fta3/adk)a in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyramit +lnj..i,hoy g;+bta ds of energy?

  The image below shows an .(joq6u d7:lcm bcm)fArctic food web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon 6vea pf01egxw.wek8 *.nrh((h-aj mmcycle requires the longest time?

  Which of the following statements are tn v(sn 7azmo6px: l9v/rue?
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 energys mqnuhz. ;d g*iox +ad3+d(5w in an ecosystem having four trophic levels? The size ofn ;zaixgd 3o.m+su(5 ddh q+w* each level represents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the flow of energy m:zj9izee(1 tper 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 secl4xzm7v f6 5jpondary and a tertiary co4flv76zmp5 xjnsumer?

  Which of the following statemn c8qj0pcx m28ents about greenhouse gases is NOT true?

  Nutrients are constantly cycled in ecosystems, including in the atmosphere as j1mz9 v jowcj+h v;,g8 iz6qp*a gaseous form. Which of the ,hovq18g6zi+;j jzv9*cwjpm following elements is not found in the atmosphere?

  A student set up an aq+f/e 3;9 upx.eomlt5i0m q1 iclbhi.quatic mesocosm using a commercially available seawater-filled glass orb,3qi tc.xoei flmei50 ql/19;um ph+.b which included algae, shrimp, some 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 statements is an incorrect description of energy flow in k; oav (rg2fx-terrestr-gfxr;v(ak o 2ial ecosystems?

The following diagram sho +yo3lizb5q7c kek/u;-xc6ik ws 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 a small terryithg8xi sp bs+411yd8h xf2/estrial ecosystem with th f 82xbyisg81s/ 4dtyihpx 1h+e 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 urchins use calcium carbonate to builtpr/9mgjt1aj wxcu 5( o* cj;xcr 6,x0d their shells. Whicx0g9tc rp ,/6xxoa cu*;c r1w(mjj5jth of the following is NOT a source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy per unit area pe93 qs pukp,od7r year in arbitrary units. Gross production is thq3,u9sk d7pop 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 describe a chez8.rbe p3o +jvmoautotroph?
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 atmodf3 rs0,w9dk mspheric carbon dioxide measured at Mad9k3 srdwf,0 muna 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 aqua lyib9lu/3q5vaf1 2 )rav1fovtic 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 arf/fl2 lyv5voaq1ia)9v br13u ea 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 di9em ,vg 0rehw/oxide over time at Mauna Loa Observatory /gr0 mee9h,w vin 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 fluctuatione g1qot)5. gdks of carbon dioxide in the atmosphdqt5og1 g.) keere?

The image below showya.h yt6m xhb,q8dl4ub ;9c ,dny6+z ws global sea levels 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 productier6 iwlt/d/ik bg:-( cve habita l r:-kebi /6wt(/igdcts 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 gmri m ;61ge1bc6a2brby which detritivores 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 food chains in leaf litter can be affec9p4 jzx:ogs u8ted 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 puz49jxg :8os 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 o 7hmmg7rgex cy1:9epap s /-bz;3wzf2ceans, where a diverse ecosystem is supported. A number of organisms thrive in these areas of high pres;/f:my m7ra3zxs 1hz epb2cpgg9 7ew-sure 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 phytopla 6h2njtcfy ht-kkka -t/g/(0xnkton in their role in the carbon cyclhy/x( 2h6 tk-/kct j-0fgatkn e.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a sa7fgj 4uz/xpy9 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 energy showing f*qk-hl kxa3y4qccm ucw*-z .7our 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 it plays in the carbon ::/ w6wa,f-cbpa - uzsqb nqe-cyclecu: ,aza- b-bpn :wqq-6/fwse.
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 net primarybu19jdc8 m2 ft productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome and the grey dots represent another biome. j92tmb1udc8f

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 sen 51wegkd0+q.vx b9 carbon cycle in a swamp. What is represented by the lette5 v1xk. es9b+eqd0nwg rs?

  The diagram shows the carbon stored in some of Earth’s carbon rav ,c*xx7a, pb7hk628lq adnsh.el0reservoirs, and the estimated annual carbon flux, in GT/yr, between reserv 2h eba,8l 7 np.a6rxqd7h,0xvkl*ascoirs.

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