Aquatic autotrophs require inorganic carbon. In what fo5i. *zyck+tw zrms is inorganic carbon present in zy+t.iz *w5ckaquatic ecosystems?

  Which of the followi-ht8 np:2j u jzidb*k6oib i6/ng correctly describes how energy is lost from ecosystems?

  What is the name of the process that converts carbon dioxide in the aiv2 g8kb;4 obm 0;)xkrqec m8+asr1fnkr to carbohydrates8 q+b4kkobscnrrv0)x1 ;gkef; 2ma8m?

  Which of the following statement 2v kj/+7w038g gh;fm ;irohqgj7viogs are correct descriptions of food chains?

The diagram below shows a simplified scheme of tji-z rp, 9zh)yhe movement of carbon in the ocean. z)yip- rhj, 9z

Identify the processes marked I and II.

  The illustration shows a 9i bolb*+kyq f )osxl) k 39kpfy46w4wrice cultivation system that eliminates the need for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additixi9bq3b* l6oploky 4fswy)+ k94fk w )onally, 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 caro6m:pnnc 2s6m tj, ,cqbon from the atmosphere to other carbon sinks. Which is the main source of ennom,6mc, 6 tp jncqs2:ergy for the carbon cycle?

The food web below shows 7p ipuj ,nv1)/s4guw2wmf, ujo)n8hk the feeding relationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyramids of energy0o)/ wck(fqcc?

  The image below shows an Ar-m-bxl0g*o gy i0um zb7d:ry)x9 btd0ctic food web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cyclfh3j5qjf* nmp6 qx+4b e requires the longest time?

  Which of the following statemen 15o*q.ybsswp*7fvu3m;u: di hrhyw /ts 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 followin:*qw,/0 z v6np qd8rfk)zoat zg diagrams shows the flow of energy in an ecosystem having four trophic levels? The sizktn* p8q:oz0dvrz6z qa/ ,wf)e 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 pernx+ o,o*o(cng /:ye seej.c9i 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-e ,3m-z npkrp pdgxl 4:uip7 w9k8ip;izg:l6 and a tertiary ci3 gp9 8ki g,lwe4kr-npp; l:izpp7d6m: zux-onsumer?

  Which of the following statements about greenakahs5b4c80 4rektd- house gases is NOT true?

  Nutrients are constantly cycled in ecosystem9 t*z)ocf 8x-b:ezaor s, including in the atmosphere as a gaseous form. Which of the following element*bzzo)xa8fo ec tr:-9s is not found in the atmosphere?

  A student set up an aquatic mesocosm using a commercially available sea7 (1q.urxid rdwater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it near a window(i7ru 1.ddrxq 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 ov34xawmj05 )dx; y jsflow in teo 5m) ;a4v x30jjxsywdrrestrial ecosystems?

The following diagram shows a trophicxz027h6 laexu) y1 uc)aqtt1f 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 t::0ds dkvg fgxqdl2 (n5r,cm6he productivity of a small terrestrial ecosystem with the nuds2l60:f(gdk gmdrc ,:qxn v 5mbers 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 carbona7qthh pl(dwu( v1w.o0ybtii/6 fh)h. te to build their shells. Which of the following is NOT t6wboh)(hth0wvp( 1u.y./f i idqh 7la source of carbon for these ocean-dwelling organisms?

  The figure below shoh21946 uzx1p9sz m ttnum jvi)ws the flow of energy per unit area per year in arbitrary units. Gross production is the total kJ obtaixt 16s4uvz 2mtu9h z)mn p9j1ined 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 chemzw7v 6 -c,u3uj 22k2pov5i jpap kto;uoautotroph?
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 dioxide mea:, 5596;z tktd0i 2xxcnaajkc8t bps fsured at Mauna Lo25k5 6znf dt0;:,tax b9xsc8ti p kcjaa 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 aquatic mesococ2o-brw19akb4 cv8y pq xk 1ragx-:d1 sm using seawater to simulate conditions in the food web (shown in1-aqx-124 9 c ypkv rb x:cwd8kgb1rao 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 concentration yx.smkj 0; 5xo.7nj +*odsfaejy 3q *qof atmospheric carbon dioxide over time at Mauna Loa Observatory in Hawaii, United Sta.m s*dxoa0j.e7 q5 y+jk*yo;qf3nxjs tes.



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 carbon diomt+ugf08x0utsaty2 g,fr7oi )po wma,w6.c- xide in the atmosphe tt0afsy),ow wx7p . uof8c+ - 6g0mg2,amirture?

The image below shows global sea levels from the years 1880 to 2020.b4i3q l44zwm*w l bu0xe 0x4bf

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 prod/nywo ; 1 3;fsuhvb8)kqmf0 aauctive habitats on Eqa;aok1b ;m f)0fuy3vhs/ 8wn arth.


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 processc.c12v i k w*n r-o 5pbf3i+gcddky0:z by 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 affec dv6,e 0(fn9 omnaz-hated 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 td,- honaf 96mn(va0 zehe 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 oceans, where a diveb 8(cd3-6sqgmx bii-u rse ecosystem is supported. A number of organisms thrg-x 3ui bc6s-(d8mbq iive 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 forests and markw)1a.t.1x.pn. h+ cewvvz r 2stv9qrine phytoplankton in their role in the carbon tv vq9ea1cxv1 t+.rrzphn. w).s.kw2cycle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a salt mars* bb8ntmufht-o4i2e *h 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 pyraxug3mz5.ve.e mid of 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 limestt :pz1n 377w ugkcpkrigj6/;p one is made and describe the role it plays in the carbon cyclep7u z6/g:k ;kgr1p ci73pjtwn.
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 gk*3 ev ghv czv1ja70b1vflm2 ;raph obtained by plotting values for net primary productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome and the g mvf7c bzv;*jvh1vl03e kg1a 2rey 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 cqg ) 6+a 6xblaj xialmm.v8y9)arbon cycle in a swamp. What is represented by the letters? xa6l m v)aqa+.lixjm6 b)9 8yg

  The diagram shows the carbon stored in some of Earth’s carbon reservoirs, a ;:tdu8a; -gwkusg2 ttslv+) dnd the estimated annual carbon flux, in GT/yr, between reservout g2 :;g8 l) dswv;d-ksutta+irs.

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