Crabs, earthworms, mites and snails feed on the remains of dead plaotv ;b)yj 0fi3nts and animals. What type of organisms are 0fi)3 vjo yb;tthese?

  Which of the following is not a saprz a*,)c kye:o .(uhghcotroph?

  Some fungi obtain nutrients by releasing digestive enzymes i9o cx2af-1 iupnto their surroundings. The enzymes break down things such as dead and decaying leaves and the fungfau29 c1-x opii then absorb the products. Which of these terms best describes these fungi?

  The illustration shows a rice cultivation system that eliminates the need for fe8vtl, *xahsy0rtilizers, herbicides and pesticides by using ducks in the organic cultivation ofs vlyx 8th,a0* 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 correct in dsaepy;.6m)qx x5 e1kformation about the different types ofde q.x;yp 1a xm)s5k6e organisms.

  A student set up an aquatic mesocosm using a commercially avai(-1l 4at d/n5 pmln.8ckgdiz blable seawater-filled glass orb, which included algae, shrimp, some corals and gravel. The student placed it near a window to provide a light source(l.5dtag/8dm-znnp 1ib4l ck. 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 holoz,av y* 0t3g gqxc7x:hib7, bpvoic 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 heterotrog*1drt/nap v )phic?

  What are incisors used for?kdf 9xtl;5e+aufe 4y 6

The image below represents the skull of a gorill 13ry,zcs7wxk h1yo )9wi)k4fc hhoj /a, 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 extracellulg*x3iq n4os(u ar secretion of digestive enzymes and absorption of the breakdown products. Which statement desx 4n g3uqos(i*cribes the nutritional mode of this organism?

  Zooxanthellae are algae that live inside coral.mhdz 5 zxav7l-v(v+- e.cqgw. Corals feed on the carbon compounds produced by zooxanthellae from carbon dioxide, water, and sunlight. Which describes v(x. .v5v -q+l- gez m7hczwadthe nutrition of these organisms?

  A student wants to set up an aquatic mesocosm using seawater to simulate chg1rr01xy qw7onditions in the food web (shown in the image below) and test its stability. He usw 1rxq1gr h7y0ed 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 want-lkvn(m1 w,z l s1a7laed to add some fish. The fish would be predators of ml s,v1(l7nkzl-w aa1the 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 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 saprotro;,*fx0a b p xiuo pe+xt.l,by9phs 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 mixotrophic and holozoic tzl ,fk,oa( duq)0kz4 nutrition.

2.Describe how herbivores are adapted to eating plants.

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