Crabs, earthworms, mites and snails feed on the remains of dead plt6tnxm5( l, wk9:ap 9xia-zjoants and animals. What type of organisms ar9znt95xp-m,x il t6:(ak wa oje these?

  Which of the following is not a saprotroph?jfd 0fklu8c).e r+s ,)dz8*alan0ts w

  Some fungi obtain nutrients by releasiy1;xg*iy qdt .ng digestive enzymes into their surroundings. The enzymes break down things such as dead and decaying leaves and the fungi then absorb the products. Which of thesgx;tdi 1.y *yqe terms best describes these fungi?

  The illustration shows a rice cultivation system that eliminates the need for tyr aq: ):uf)ofertilizers, herbicides and pesticides by using ducks in the organic :q) u:oyr f)tacultivation of rice. In addition, Azolla, an aquatic floating fern, is grown on these fields because it harbours blue-green algae which can fix atmospheric 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 corre/avxgb/3wiif b9ua uka8,1p5ct information about the different types of organismi/a8 1 u9 awfxg/u3k,p abibv5s.

  A student set up an aquatic mesocosm using a commercially available ser f6*c25x u3nxxod/v;e+um jhawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it nearu /d5rx uh xfxco*e3+m2 6;njv 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/aubp;nd/xaj- lc+k0 b/re true for holozoic nutrition?
I. Demonstrated by saprotrophs
II. Involves complete or partial ingestion
III. Food is digested internally

  Which term refers to organisms that are both autotr25un (q),rzn aq0qiqwophic and heterotrophic?

  What are incisors ush s77d8:cuvnwed for?

The image below represents the skull of a gorillafahxh:7mv,d( *ek q,sue8x 33jv+gt w, 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 extracellule 1 olk 3*0bjlw:6zsatar secretion of digestive enzymes and absorption of the breakdows3 tj kl061:ow*laezbn products. Which statement describes the nutritional mode of this organism?

  Zooxanthellae are algae that liveqm05f r4o3u/eg:n7hxoj igrw.;ge 7 r inside coral. Corals feed on the carbon compounds produced by zooxanthellae from carbon dioxide, water, and sunlight. Which describes ti:rh/g3jr7e5xo7q; 0g .u4rnwo fm g ehe nutrition of these organisms?

  A student wants to set up an aquatic mesocosm using seawater to simulatgc fj8x(1 sc;;cj+qp de conditions in the food(qf ;j;+d cccgxj18 ps 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 ,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 q ycl6,q60n dtwanted to add some fish. The fish would be predators of the pond and feed on the zooplankton (prey) growing in the pond. Zooplyd,ct660 nq qlankton are small floating or weakly swimming organisms that are dependent on the phytoplankton or algae for their supply of nutrition.

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 which detritivores and saprotrophs obty.3y.u/ m ygrzain 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 mxv k6i7up ps6+ixotrophic and holozoic nutrition.

2.Describe how herbivores are adapted to eating plants.

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