Aquatic autotrophs require inorganic carbon. In what forms is i/3lylhb+/; 3m sn-sa3a cf vannorganic carbon present in aquatic ecos/- lm3vfcsn/ 3abhn a;saly3 +ystems?

  Which of the following correctly describes how energyti rv9*oivh.4-l+2 (ul c lzwn is lost from ecosystems?

  What is the name of the process that converts carbon j :m*yos54a ghaz)9)7o elwax dioxide in the air to carbo97 y) xzjg e*mo4hls a5aa)wo:hydrates?

  Which of the following statements are correct descript6 p/ xjit;s yspgj;7d2lt9xd9ions of food chains?

The diagram below shows a simplified scheme of the movement*qpzqe yjfllq ,ht l sl28+9.6 of carbon in the oceapl98t +l2fz q 6qyl*sj l,he.qn.

Identify the processes marked I and II.

  The illustration shows a rice cultivation system thaqsg u3s)l+ g*jn. clgr(t8j z(t eliminates the need for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquatic floating fsur*j(t8ng q +3 szjlcgl)g(.ern, 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 thp0dscv +ka yc8xp2*1 ze atmosphere to other carbon sinks. Which is the main source of energy for the carbon 2sya1v0kdc+c8p *xzp cycle?

The food web below shows the feeding 0zx n5eyw9kod. lp qr4);gw.mll);eprelationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typical (x1ehz:kz4a 3 3j vzs2im k(gzgdeb9 -ro3p8xly used for pyramids of energy?

  The image below shows an2zux4lawhb3:9h(w :6 edu )vaeotc0r Arctic food web.

Which of the following organisms is not a heterotroph?

  Which of the followi p898s axn7zlpng processes in the Carbon cycle requires the longest time?

  Which of the following statements a50y2c,m/-p jab vdwjkre 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 d 1)cs,xogc7-dru0e+ v8 6yiwm ,ehc ,a3bba pviagrams shows the flow of energy in an ecosystem having four trophic levels? The size of each level reprvw 6vyapi )o8ucx10s+ rem,ab,b 7d3 -,cg hecesents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below shows the flow of afp4 m*8xr6wpu-) zma k- l cara,f87yenergy 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 3 wq4lunyac0,e-vj4m1wc4xz below is both a secondary and a tertiary ywqj-c34an4xcz 40v, muew 1lconsumer?

  Which of the following statements about greenhouse gas/x v7b u+ ,m-l:a4(dqpzfc kzyes is NOT true?

  Nutrients are constantly wznx 8(rcjb7 e.-cse gcx*mm o25 2s9vcycled in ecosystems, including in the atmosphere as a gaseous form. Which of the fes 7 2*8ogxew2bcsmrzcx9m5 c jnv(.-ollowing elements is not found in the atmosphere?

  A student set up an aquatic mesocosm using a commercr3 glqs83 ywk8r:zgx.ially available seawater-filled glass orb, 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 l8kxrgy r qw8:gz.3s3are 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 descript wrzty1nu27 r0ion of energy flow in ten y t0zrwr172urrestrial ecosystems?

The following diagram showsg9 7.hxcuavh6f 6vm6(n-drg n6f cv; h 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 t: ug51j d/eundhe productivity of a small terrestrial ecosystem with the numbers showing the flow of :eg j1dun/5udenergy(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 carbonah1uyj c i*fvh 2,ged2/te to build their shells. Which of thev*fc 2he /1yijh g2,du following is NOT a source of carbon for these ocean-dwelling organisms?

  The figure below shows the flow of energy per unit area per year in arf+3n/mpscs0 k 5t2sg a1:li cwbitrary units. Gross production is the tota:031cg 5np/ +swcil2 tssmakfl 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 chemoautotrop s/z/v3q+xa e+ejqcbxxkz8 b3r 82s (gh?
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 dioxideo,eos . mnox3. measured at Mauna Loa Observatory in .ms3o,oexo.n 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 mesocosm usinltl51o-ggzw, g seawater to simulate conditions in the food web (shown in the image below) and tes gtl1-,ozlg5wt 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 atmospher ;51 h umwgvwdr;aaf dp24p4w1ic carbon dioxide over time at Mauna Loa Observatory in Hawaii, United States. rha 5w41 ;4pddgw2wu ; 1vpafm



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 a2h s h-zu3k8rannual fluctuations of carbon dioxi ha r3uhz8-2skde in the atmosphere?

The image below shows global sea levels from the years 1880 to 2020. h5a44+ s0 mcydq5roc x

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 productiezc4-y l0i, uh xj5za+ve hab0ijlh ,5+zyu -caezx4itats 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 detritivorev v13 /gpd4dx3o a-v ktudep7,s 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 c4z - wrh gzce ve5h,d+.d;b ,87sqmxqthains 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 be q,tb8zer,w5;vs7x4 zm h.ed-gdch+qlow. 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 hydrothermal vent deep in the o)psh ,nmr1v 7 md 3e.t3,hnoh9-jnxwlceans, where a diverse ecosystem is supported. A number of organisms thrive in these areas of high pressure n7 1p)d3v3, l,oh.s-wnt9rxhmhnejm 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 rolenv 6nd dmj/0f8 ;3nyqe in the carbon cm en;vqy0ndnfd 3/ 86jycle.
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a salt marsh eco/ ;/ (oeqxj bnzv7ku wqwpr)1obs-92e system.


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 eyivvd y0;3 - /ye:x2a h4twffpyramid 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 limestone is made and describe the role it plays in the carbon cy p,*/jlgvwn ,sclelg/j*v swn,p ,.
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 ppam,gov94z7k5b ny8b lotting values for net primary productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome g495,pky8bbmvn 7 oazand 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 5a5/w(rr cdh aoz8. mvis represented by the let/ m(8hd5o .rvara5czwters?

  The diagram shows the carbon stored in some of Earth’s catc./ gut itpxzsf50h1y2- 3u vrbon reservoirs, and the estimated annual carbon flux, in GT/yr, between reservoirs. 1uthxtv./ sy -5g3uc0ptf2 iz

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