Crabs, earthworms, migopl0 8 (fwni 83azi1l/0tpbmtes and snails feed on the remains of dead plants and animals. What(mlgib0/onwz f3lp i80 tap81 type of organisms are these?

  Which of the following is nots)yb -/ n8o+q;cftc cj a saprotroph?

  Some fungi obtain nutrients by releasing digestive enzymes into ub:d r( ch;(c kw k1(s(wpay-rtheir surroundings. The enzymes break down things such as dead 1;wk ((u(rsk:c-r(cpdyha wb and decaying leaves and the fungi then absorb the products. Which of these terms best describes these fungi?

  The illustration shows a rice cultivation sy:o w45j7q3 2welv+rngfpl;tfr8kke;stem that eliminates the need for fertilizers, herbicidee;wjfre8 wg7lqkf; lkv 43+5rnp 2:ots 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 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 dk9 q5c6 lnj7b bod+(mwhich gives the correct information about the different types of orqljb bnk 7(5 6+doc9dmganisms.

  A student set up an aquatic mesocosm using a commercially availu gi0v -3o9jvlable seawater-filled glass orb, which included algae, shrimp, some corals and gravel. T 9vv ig0j3ul-ohe 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 holozoic numoo)f w tx3rs9vfv.;3 trition?
I. Demonstrated by saprotrophs
II. Involves complete or partial ingestion
III. Food is digested internally

  Which term refers to organisms that48wvvpwmg4.9hxzc + q are both autotrophic and heterotrophic?

  What are incisors used mqpue97y r64*; ecpuofor?

The image below represents the s4 mxrsa3og4y9kull of a gorilla, 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 extracelluu/hv:x. 15hnso mfc*wy -xsa/ lar secretion of digestive enzymes and absorption of the breakdown products. Which h5xs:f 1nmcxy*uaw. ho/s -v/statement describes the nutritional mode of this organism?

  Zooxanthellae are algae thatm+: kkvpr65s7)nta qa live inside coral. Corals feed on the carbon compounds produced by zoox s6pna k:57rtm q+)avkanthellae from carbon dioxide, water, and sunlight. Which describes the nutrition of these organisms?

  A student wants to set,mx32 ufu6 m *+psud /bvxnqb( up an aquatic mesocosm using seawater to simulate conditions in the food web (shown in the image below) and test its stability. He used seawater and sand from the area mbs v xq,uu6/*mndbf3p(+2u x 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 wkr4-w* z(dnvn)v p)k wanted to add some fish. The fish would be predators of the pond and feed on the zooplankton (prey) growing in the pond. Zooplank(4zk) wwrv* npk-d nv)ton 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 obtain nutrition*jepyc / xx::s.

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 mixotrophic and holozoic nutryg (e0i,zwa8z ition.

2.Describe how herbivores are adapted to eating plants.

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