Aquatic autotrophs require inorganic carbon. In what forms is inorgvqos5 g)51oc4zvrwnyqqkv4 69 1j3s6t -yuxqanic carbon present in aquatic ecosysu gxqqk36sc61sov r1 qtyvj-q5y5 94 4wzovn)tems?

  Which of the following correctly describes how energy is losinv q-ox(wx(k ii.1 n4t from ecosystems?

  What is the name of thn ln-u 4nu*n.pe process that converts carbon dioxide in the air to carbo* 4.n-pulnnun hydrates?

  Which of the following statements a0 mgsyd0. zrp8re correct descriptions of food chains?

The diagram below shows a simplified scheme of the m5 3rn1 myk,.ceyoto5a ovement of carbon in the ocean5n yao53et1c.r,kmy o.

Identify the processes marked I and II.

  The illustration shows a rice cultivation system that eliminates the nep:z6q 7ns2 uxyed for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fern, is grown in these fields becau q px26unsy:z7se 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 lww7igy 4.ui - qmk0.gof carbon from the atmosphere to other carbon sinks. Which is the main source g-y. kgi.um i4l70wwqof energy for the carbon cycle?

The food web below shows the feeding relation*a6 a if7f anvq4/jpzsn4x8/nships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typicoocep3;-og , ually used for pyramids of energy?

  The image below shows an Are+y epgf az0 ;1gyase+0 56 wzbdh+;klctic food web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle requires the longest hb *+sf/a:c ks-fgafi x9 svp8b 64c0rtime?

  Which of the following s3hjxufqs.tyn+ nk* 30tatements 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 k/5zbu5inrr7 an ecosystem having four trophic levels? The size of each level represrkubr57 5i/znents 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 e*ipx e5jo/p 8a i.nk;q5amo m7v/3ctmcosystem.

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

  Which of the organisms in the food web blz:a5azctr9n b lwz2 a.f )v87elow is both a secondary and a tertiary consumer?zc87) 2wt5l alnzf9r a .bavz:

  Which of the following statements about greenhouse ga 8snaa/*yy *ob ,r0slk*an xi5ses is NOT true?

  Nutrients are constantly cycled in ecosystems, including in the atmosphere achsr-j* l,ae -s a gaseous form. Which of the following elements is nlej,hs- a-rc*ot found in the atmosphere?

  A student set up an aquatic mesocosm using a commercially available seawater5nzb-0j o :ksx4h* iyu-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it near xhb5:0uyz4- jkis*no 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 fr0lroc2a:2j an incorrect description of energy flow in terrestriac0jal 2rf: o2rl ecosystems?

The following diagram shows a trophic level pyramid -ri:t*( dc0td:p qu7j /mqku sw4 qq,yof 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 terrestrial ecosys6st/;3:z1):oda 8 ye lwij atyq: cfohtem with the numbers showing the flow of energy(t63wodq:l za81h;/toc ia:ys: y)ejf 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 qu:atw908d0sqxa7i a qu7 gp5sea urchins use calcium carbonate to build their shells. Which of the following is NOT a source of carbon for these ocean-dp8awx75aqatgidqsu0 7qu 0 :9welling organisms?

  The figure below shows the flow of energy per unit area per year in arbitraryv3 e5 jxklmr)9 units. Gross production is the total kJ obtained through photosynthesis, and net production is the kJ remaining after respiration. 39)kjemrv5 lx


What percentage of net production (kJ after respiration) is lost to decomposers by primary consumers?

  Which of the following statemen n kr*c,j;aoo; (hh/.vtcpd.ets describe 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 concenirvh8glf0;m+wt(ye( 6h ybc*z d: e8c tration of atmospheric carbon dioxide measured at Mauna Loa Observatoy t;c8b(wl6:y*c vhf8+e zmi hr0deg(ry 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 yb pp lzg(l:06mesocosm using seawater to simulate conditions in the food l 0p6gz(p y:blweb (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 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 concentratlw5) gycksvma+0. . opion of atmospheric carbon dioxide over time at Mauys 5+0 ag)o pkm.l.cwvna 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 expla67s 2hgauh( dcins the annual fluctuations of carbon dioxide in tug(shd h ca672he atmosphere?

The image below shows global se64c d:,bmyrwzwbw/r 8a 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 shj.:y*y yi aw:9 oup;euows the food web in a salt marsh, one of the most productivejieyy uy.u* pa :9:o;w habitats 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 a1 vz9z qip+05xtf 8gvti+,dgc nd 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 eh 6pc1p0+jutnk(it(;d e v4hs 6qgq l1,tef0 litter can be affected by the mass of initial leaf litter added. The student placed an incretve p(q1+6k0itegt p,shcd64;uhjf(l 0 n q1easing 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 a hydrothermaua1a6oe + lc)hl vent deep in the oceans, where a diverse ecosystem is supported. A number of organisms thrive in these areas of high presh)euc1olaa +6sure 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 foref r-ey4/g4 tuh ixxl48sts and marine phytoplankton in their role in the carbon cyif44x hyr-e/x gl8 ut4cle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a salty wmt8u8d4/u :nesr: ;:nowcb 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 2kqzowwa n3le4 8c0 l*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 it plays .vaak, sl7h w9in the carbon cycle. 9svha,ak7 l.w
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 lpe -5pw3nqz)e7s+f lg,*syd a graph obtained by plotting values for net primary productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome+ez-ll)p 5ywne3 *7fdspqs , g 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. What is repre0 bffylw,wmr40ruytp7k n h+16h;: eqsented by the 0h7+bqmf y0r:uwly,t1 r enpf4h;6kw letters?

  The diagram shows the carbon stored in some of Earthu+mj9ueq qf*)’s carbon reservoirs, and the estimated annual carbon flux, in GT/yr,mj) + 9fqeuqu* between reservoirs.

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