Crabs, earthworms, mites and snails feed on the remains of dead plantl j-axq tc2nm5na3-+ zs and animals. Wha-2ac3t xq m al+jzn-n5t type of organisms are these?

  Which of the following is not a srl o;c22 twv2ikqw2ekc*r+4j d68 w csaprotroph?

  Some fungi obtain nutr,z2aqwp6y, ve ients by releasing digestive enzymes into their surroundings. The enzymes break down things such as dead and dawv ,ezp2y6q ,ecaying leaves and the fungi then absorb the products. Which of these terms best describes these fungi?

  The illustration shows a rice cultivation system that eliminates th9 eamx gpp/bte d99o)q1 pa8;ze need for fertilizers, herbicides and pesticides by using ducks in the organic cultivation of rice. In addition, Azolla, an aquatic floating fern, is grown on these fields because it harbours blue-green algae which can fix aom /qp9pap8)et dz 9xg 9;ba1etmospheric nitrogen. Using this system, rice, ducks, and fish can all be produced for human consumption in one location.

  Identify the row in the table which gives the correct information about the di.;5.qz t7q+f jxgsfpdfferent types of organisms.. fdzxsf p.+5q t7gqj;

  A student set up an aquatic mesocosm usih3fpu;slhc8+ a u3dg.+ t3gzrng a commercially available seawater-filled glass orb, which included algae, shrimp, some corals and grah hcu3 r3+;3lzsgdgp f8. t+uavel. The student placed it near 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 is/are true for hogu2ude;t;u4fo ,zc4(ko 9 ll6lcx t;olozoic nutrition?
I. Demonstrated by saprotrophs
II. Involves complete or partial ingestion
III. Food is digested internally

  Which term refers to organisms that are both autotrophic and heteroq xofq j h-xl xw(yz9e;,f 6y.wu-j;s1trophic?

  What are incisors usedlp69ms qoxw7 +x9+uu y for?

The image below represents the skull of a ma*g7 zrzqtaak hy(9ft ++0(nv4ew5mnq 2 2vdgorilla, chimpanzee, and human.

1.1.Outline the roles of different types of teeth.

1.2.Gorillas are primarily herbivorous but have large canines. Suggest a reason why.

1.3.Compare and contrast the teeth of a carnivore with a herbivore.

2.In terms of diet, distinguish between a folivore and a frugivore.

  Chytrids are unicellular organisms that feed on pollen through extrace*1xoo za2gg+5)+ nxnpr tx;srllular secretion of digestive enzymes and absorption of the breakdown products. Which statement describes the nutritional mode of this orgtngx*grxn)o+ ox 1r+5zs2a p; anism?

  Zooxanthellae are algae that live inside coral. Corals fnhnve:op4k5 z*s3nwswd 9,zyy; 6xo: eed on the carbon compounds produced by zoox 5n;4oynpew svz6*3hkswonz:: 9yd,xanthellae from carbon dioxide, water, and sunlight. Which describes the nutrition of these organisms?

  A student wants to set up an aquatic mesocosm uk p.e5:( gdxrksing seawater to simulate conditions in the food web (shown in the image below) and test its stability. He used seawater:.gk expr 5(kd 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 ,which is   .

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.

1. A student had a small pond in the backyard and wanted to add somviqd ioq7qj2v8.4o j;5sgm d ,e fish. The fish would be predators of the pond and feed on the zooplankton (prey) growing in the pond. Zooplankton are small floating or weakly swimming organisms that are dependent on the phytoplankton or algae for their supply of nutritioqmgjd.oio2 j5i4 vqd8, s7v ;qn.

She wanted to first determine whether Fish A or Fish B would be more suitable, or if both fish could be added to the pond. As a trial, she set up four mesocosms using water from the pond. She monitored the mesocosms and then added the fish to three of the mesocosms as shown. She took samples of water from the different mesocosms and tested it for chlorophyll content at a research lab nearby.


1.Outline why the mesocosms used would be considered a ‘closed system’.

2.Describe why adding mud or soil to the mesocosms would be advantageous.

3.Outline the reason for including ‘Mesocosm A’ with the experiment.

4.Explain the reason for monitoring chlorophyll content to analyze the effects of the fish as a predator.

5.State another variable that could be monitored to see the effect of adding fish to the mesocosms.

The following table shows the results obtained for chlorophyll (μg dm$^{-3}$) with the different additions of fish.

6.From the results obtained, suggest why the student decided to add both fish A and fish B to the pond.

1.Describe the process by whichl8uy6tq38u rb uw 3-uu 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.

1.Outline the differences between mixoi lb3r/pxx 3-strophic and holozoic nutrition.

2.Describe how herbivores are adapted to eating plants.

3.Explain the differences between obligate anaerobes, facultative anaerobes and obligate aerobes.