Aquatic autotrophs require inorganic carbon. In what forms is ix1i:w23qvo rknorganic carbon presvqxr3 i12:owk ent in aquatic ecosystems?

  Which of the following correctly describes how el(oq2uu: a 5a3 snnjl5s01ka3mv:qg gnergy is lost from ecosystems?

  What is the name of the (zp 1chev-;c ks7ma,sprocess that converts carbon dioxide in the air to carbohyma e-psvc 1k(7 ;szch,drates?

  Which of the following statements are correct descriptions of f3wvi6njo ).wf ood chains?

The diagram below shows a simplified scheme of the movement of carbon ipto6.h0wpez - n the ocean.6.w -zth epo0p

Identify the processes marked I and II.

  The illustration shows a rice cultivation system that eli8zwze4;flv ag 4 tq5)6niq3ldminates the need for fertilizers, herbicides and pesticides by raising ducks in rice paddies. Additionally, Azolla, an aquaticqv qdanl4;g)i fz6z4l3ew85t 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 carbon from the atmospt 8oan ;3g2v 7jm b0dvz2q5mdjhere to other carbon sinks. Which is the main;08mvoga 2q jz5m d32ntbd 7vj source of energy for the carbon cycle?

The food web below shows thlj d0 is-. b-m4k-pvfpe feeding relationships in a soil ecosystem.

Draw a food chain with five trophic levels.

  What units are typically used for pyramids 0ld8c8d6 orip3zr f;rof energy?

  The image below shows an Arctic food+i / r 4qofpj1f)scz+b web.

Which of the following organisms is not a heterotroph?

  Which of the following processes in the Carbon cycle requires.+o1bnad p3e3vbd9m+fa x /ict1(hsq the longest time?

  Which of the following st /yc +*yb+wocrr 5d yt1*grp/patements 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 an ecosi:lll):yyc 7ph( c)k pystem having four trophic levels? The size of l(y:p)i hlp7 :)cy klceach level represents energy values (in $kJm^{−2}yr^{−1}$) in the energy pyramids below.

  The figure below sho szjx ba+a5,elqux .02ws the flow of energy per area per year in an ecosystem.

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

  Which of the organisms in af0j4f+ .ann+e-: v:s yxufxc the food web below is both a secondary and a tertiary consumer? nf0xyfsa:u c.na:f+ -x 4v+ej

  Which of the following statements about greenhouse gases is NOT (* lakjwnqod)ygh + 73gq1,jb true?

  Nutrients are constantly cycled in ecosyste2:fyoxyx 1t68nr 9thjms, including in the atmosphere as a gaseous form. Which of the followif yxy1:8th t6j n9o2xrng elements is not found in the atmosphere?

  A student set up an aquatic(qcxp; f// j8)self cg 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 sourg/;jx)c/f l p(sq8fcece. 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 iqp ni10 8h4/d.m,fggy n njee+n terrq e1me/+ 0ggyi,hn4.d npjfn 8estrial ecosystems?

The following diagram shows a trophic level pyramid of energy/1:efty aj- pz.

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 terrestepkpdl d5d44 73cqwzbsw cs 43wy,m63c 0bmg;rial ecosystem with the numbers showing the flo;m703sbcwwp35q e g d l446pc4dzws m kb,3cydw 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 urcou-lg uf f1dps(1i n n6-;mft.hins use calcium carbonate to build their shells. Which of the following is NOT a source of carbon for these on-l dn o- 1. ftgf1m6;usfi(pucean-dwelling organisms?

  The figure below shows the flow of energy per unit vn( i+j5za (ub7io7 elarea per year in arbitrary units. Gross production is the total kJ obtained through photosynthesis, and net production is the kJ remaining aftv+je(znla(bo57 i7 iu er respiration.


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

  Which of the following statements describe a chemoautxbixcsd7h5g2q/ mn l8 jo (u 0q4f3pq7otroph?
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 con:e1u gi u2lln;(*algb centration of atmospheric carbon dioxide measured at Mauna Loa Observator: uu(le 1 in2gl*gba;ly 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 mesocosm using seawater to s) 4g+;aiedg p yz+-yjz u:6b;nv* iu26pib sjdimulate conditions in the food web (shown in the image below) and test its stability. He used seawater and sand fro zyi+ ds2nd :iaju-p;ibbggep6)v + u;j6 4*zym 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 atmospheric carbon dioxidewl e.e tbd m4;a0p hpgdd*q;63 over time at Mauna Loa Observatory in Hawaii, United.wq0 edmh4gabptp*d;63 ed; l 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 f7oef-w2mm:f g*llj3(m cg8ealuctuations of carbon dioxide in the atmosphej-g l fglwm7c*3m8 am(f:2 oeere?

The image below shows global sea levels from the years 18u*ysi.o*q17 uc*p zxr80 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 manudes. o)vu 38rsh, one of the most productivev ueos 8dn.3)u 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 and sapr mlk2fm0we))4htnul kx9p6c e8 sy*c3otrophs 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 studc hr.7fmn,g:ly how food chains 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 apparalgc,f.7rm: n htus, 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 hydrotherm(wga4to)h:. dhen/wq hx yem t8z1-a)al vent deep in the oceans, where a diverse ecosystem is supported. A number of orgzhg )d:e(w 4)8x t/o .yhh qn-wata1emanisms thrive 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 forb-drc leydv 6u7*7)mc ests and marine phytoplankton in their role in the carbon cycle. 6)e7 d- vdccr7*yublm
2.Describe how aquatic autotrophs absorb carbon dioxide from the surroundings.

The image shows a food web in a salt mar2 i(uu g2oz/ e2n wcpbz6s))tgq;0tgo sh 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 four levels1jc.yiit +tc b ec13;j.
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 andmn 02gwcs.y 2r w7zrh: describe the role it plays in the carbon cycles gz:wr hw2.0nc2y 7rm.
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 obtaolt7 nsq18z at0ev7d 2ined by plotting values for net primary productivity (x-axis) and the biomass of herbivores (y-axis). The black dots represent one biome and the grey dots represent another bi7qsetat0n 8d1 v72olzome.

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 swaoopun/hxrw+nzn 9 7 :1l*cx/nmp. What is represented by the lettehxnrlw +z / nnc /pn*79x:1ouors?

  The diagram shows the carbon stored in somcju;jn )+*g nmuudw f 0/i-1qxe of Earth’s carbon reservoirs, and the estimated annual carbon flux, in GT/yr, between x)+dfqjum wg*ui0;c -j/1nun reservoirs.

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