Aquatic autotrophs require inorganic carbon. In what forms is inorukksze:m ;y n7fpa44 +ganic carbon present in aquatic ecosystemsm ;npa4u:4 kf+yzk7es?

  Which of the following correctlyjr je(hnxj7ka-;zv-w /+9dvn describes how energy is lost from ecosystems?

  What is the name of the process that converts carbon dioxide in1 kqoe pq3hw6* the air to carbohydrates1ke*3o6 qqhpw?

  Which of the following stnd+f8n s4.tu8kwz kk58lj/daatements are correct descriptions of food chains?

The diagram below shows a simplifieo2y9h4 exsyig,w.* 8 9eedj xgd scheme of the movement of carbon in the oce,*gy oj4ixywgee e98 9h2s .xdan.

Identify the processes marked I and II.

  The illustration shows a rice cultivation system that eliminates the need for xe8b2e5(j3e cbb tcu6fertilizers, herbicides and pesticides by raisingcbb eet(j x b26358ceu 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 cycdu l 1l +6r7ilb-1twh* o,whjogwpce2j *h1 4sling of carbon from the atmosphere to other carbon sinks. Which is the main source of energy for the ca*jgd i*u wwj lo,t- h b6 hlw1oh141plscer72+rbon cycle?

The food web below shows the feeding relationomz s6 iy 2m,:c-jwg(jships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typicalentxee )7;u:r 9wxvk7ly used for pyramids of energy?

  The image below shows )tqolrw )dv+pi4. 6nuan Arctic food web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle requires the d(irthrmj, tw5 p f:)-longest time?

  Which of the following statements arex,wr4l8o ltj7it:yf+ v gb.4w 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 enevv1*71h ohbhko l+*j ergy in an ecosystem having four trophic levels? The size of each levokhv+1jb*7h olh1v* eel 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.ad71tqgj4xv )n u4ad in an ecosystem.

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

  Which of the organisms in the food web below swxlaxd7y m+b9-4 cdvw:c7,cis both a secondary and a tertiary consumer? 7x+ :bdcwa7sc -y mwl9 4vd,cx

  Which of the following state,;6u ,unwjx hdments about greenhouse gases is NOT true?

  Nutrients are constantly cycled in ecosystems, including iv:z :dj pwiuezg1gs-a81 c g0hxvj/8/n the atmosphere as a gaseous form. Which of the following elements is not found in 0:a-p1ed/u 8/1:hcvgzixj vw gzg s8jthe atmosphere?

  A student set up an aqc(nnio* t7 l1ruatic mesocosm using a commercially available seawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it near a window to provide a light *roic7(1 nltnsource. 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 followig q;pq50i m2j ga(2lf:whhf/eng statements is an incorrect description of energy flow in terrestrial ecosystemj;mh(5gf/ e0gw2 h2qa:lfpi qs?

The following diagram shows a trophic level pyramid of eneg* n) g,cxy7lu6 ( eo2)*uomgvk-n vbyrgy.

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 terrestrialx5l ww30whb .p ecosystem with the numbers showing the flow of energw0wl35 h.xwp by(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 urchz7aofk48i iy7gzf 27nins use calcium carbonate to build their shells. Which of the following is NOT a s27afzf78ny7 o kzi4g iource of carbon for these ocean-dwelling organisms?

  The figure below shows the fhsy-z 4 v lsjji13h(hkk*z 46dlow of energy per unit area per year in arbitrary units. Gross production is the total kJ obtained through photosynthesis shh6j*i4z(yk4v ld3skhz-1 j, 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 chemoautn2x2uay4:,b)fu 94n8-cs qi ysy eopaotroph?
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 atmospheri34trgf8h r y,gbz4s4p c carbon dioxide measured at Mauna Loa Obt3y4p b,4 f4r g8szrhgservatory 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 aquati:vc)d4wl6z x*,mj)ghmy+q7ua,t r(euk n2o mc mesocosm using seawater to simulate conditions lk um7x) 6*ewcdymjq2 4m,o)+zta, rn(:gh vuin 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 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 atmospheriv*elf)wo 6:wdsu )eoamp:9l 5c carbon dioxide over ti:wv ufa l o)65e):slpe9mo* wdme at Mauna 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 explainoiaw 6vhv 44g;lo;m,g s the annual fluctuations of carbon dioxide in the atmv;m, w l;6hvao4gg4ioosphere?

The image below shows global sea levels from the9; lloioh.otdz0h1 i 5 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 fo ovkxg3h2y:l1p cicb/ qik, .+od web in a salt marsh, one of the most productive habitats on Eartc1hx3/oqk,v y +.k:iiglb p 2ch.


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 obtabv1mf0m -(nxvv2l rv4in 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 ckv4/1m pkrf 4uhains 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 f u/ prvk41m4kthe 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 inz pxsc., y0 tk:arl7+q the oceans, where a diverse ecosystem is supported. A number of organisms thrive in these areas of high pressure and darkyl:. zxkc art7 ,pqs+0ness.


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 the914ow m;mn opyir role in the carbon cycle. ;y1pm4 wno9mo
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a salt marsh ecosysjhc+ ebf/qsc:4i w .y2tem.


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 ener+dm y/e6peu j7gy 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 in the carbon. q g(h4a-)/rxiz klnw cycl/ )z4.(-lxrkh gwqnai e.
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 grapncf+u 4b+6,clj eta/kh obtained by plotting values for net primary productivity (x-axis) and ekcf,janb+/c+l 6 t4uthe 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 arv pyeky 2.nh,.lr7*u swamp. What is represented by the lettersy r.ln7rhe,*2 v. kypu?

  The diagram shows the carbon sto vs5d.z/;n9 yyvzso9u(uuhyrv+ 8c+ a red in some of Earth’s carbon reservoirs, and the estimated annu zy8cya zv+;y9 uv.vh9s(us/rno +ud5 al carbon flux, in GT/yr, between reservoirs.

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