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1. The figure below represents the transfer of energy through a woodland ecosystem.

s u n

8 0 0 0 0 0

d e c o m p o s e r s

A B

C

D

p r o d u c e r s1 0 0 0 0

p r i m a r yc o n s u m e r s

s e c o n d a r yc o n s u m e r s

K e y :e n e r g y f l o w

f i g u r e s r e p r e s e n t e n e r g y v a l u e s i n k J

(a) f the 800 000 kJ of energy which reaches the producers! only 10 000 kJ ofenergy is converted to growth in the producers.

(i) "alculate the percentage of the energy reaching the producers that isconverted to growth in the producers. #how your working.

$nswer % .................................. &

'

(ii) *+plain what happens to the energy reaching the producers that is not converted to growth.

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'

Macmillan Academy 1

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(iii) ,ame one decomposer.

................................................................................................................

'1

(iv) #tate two ways in which energy is transferred from primary consumers todecomposers at C.

1 .............................................................................................................

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'

(b) #uggest why the percentage energy transfer between producers and primaryconsumers at A is less than that between the primary consumers and secondaryconsumers at B.

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'-

'Total 10 marks

2. (a) *+plain the meaning of the term primary succession.

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Macmillan Academy 2

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The figure below shows a primary succession in a temperate climate.

X represents an e+ample of deflected succession.

d r y i n i t i a lc o n d i t i o n s

( b a r e r o c k o r s a n d d u n e )

l i c h e n s !m o s s e s

g r a s s e s !h e r b a c e o u s

p l a n t s

s m a l ls h r u b s

m i + e dw o o d l a n d

g r a s s l a n d

X

(b) *+plain the role of pioneer plants in succession on a bare rock or sand dune.

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'-

(c) #uggest two ways in which deflected succession at X could be caused.

1 ......................................................................................................................

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Macmillan Academy 3

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(d) *+plain how biomass changes during a primary succession.

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'Total marks

3. "omplete the following passage by inserting the most suitable terms in the blankspaces.

/iving organisms are interacting constantly with each other and with the environment.

*ach individual organism is a member of a group! the ........................................ !

which consists of all the individuals of a species in an area. This area is known as the

........................................ . $ll the organisms of the different species in an area form a group

called the ........................................ . $ll the species and the nonliving components

interacting within an environment are collectively known as the ........................................ .

hotosynthetic organisms such as green plants form the first feeding or

........................................ level in the food chain and are known as ........................................

because they can manufacture their own food. $nimals are dependent upon the

photosynthetic organisms to obtain energy and are known as ........................................ .

'Total 2 marks

Macmillan Academy 4

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4. ver the last few years there has been much public concern over the diet of people inthe 34 and its effects upon their weight and health.

5ody 6ass 7nde+ is a calculation used by doctors to indicate whether a person is

underweight or overweight.

(a) #tate the medical term used to describe a person whose 5ody 6ass 7nde+ isgreater than -0.

.........................................................................................................................

'1

The table below shows the daily intake of certain components in three diets!A! B and C for men in the 34.

iet A 9 a normal balanced diet for a typical man

iet B 9 a weightreducing low fat diet9 restricted to avoid fats9 includes any fruit! vegetables and proteins9 energy intake is monitored carefully

iet C 9 a weightreducing low carbohydrate diet9 restricted to avoid carbohydrates9 e+cludes fruit as these contain sugars

9 includes any nonstarchy vegetables! proteins and fats9 energy intake is not counted and may e+ceed 10 000 kJon some days

iet Anormal balanced

diet

iet Bweightreducing

low fat diet

iet Cweightreducing

low carbohydratediet

energy : kJ 20 ;000 8000

fats : g 82 -< 1<

carbohydrates : g 2= 00 0

proteins : g 88 2; 1;=

combinedminerals : g

1 1 18

Macmillan Academy 5

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(b) 7n any unbalanced diet it is possible that there may be a deficiency of certainnutrients.

#uggest one nutrient that may be deficient in diet B and one in diet C.

iet B ..............................................................................................................

iet C ..............................................................................................................

'

(c) (i) *+plain which diet! B or C! is likely to cause more rapid weight loss.

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(ii) #tate the relationship between energy intake and energy use that wouldallow a person to lose weight.

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'1

Macmillan Academy 6

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(d) octors suggested that diet C may not be very healthy in the long term! as itcontains unlimited amounts of fats and no fruit.

#uggest what potential health problems! other than continued weight loss!

might result in a person who kept to a low carbohydrate diet! similar to diet C.

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'Total marks

5. *+plain how the fungal decomposition of deadwood is of benefit to the living treeswithin a woodland.

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'Total < marks

Macmillan Academy 7

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. #ome drinking water is e+tracted from the ground. >roundwater is tested for a range of substances including nitrate ions.

*+plain why the presence of nitrate ions in ground water is a cause for concern.

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'Total < marks

!. 7n this ?uestion! one mark is available for the ?uality of the use and organisation ofscientific terms.

The caterpillar of the /arge *lephant @awk 6oth feeds on willowherb. escribe indetail how you could investigate the distribution and abundance of willowherb in anature reserve.

'2

Auality of Britten "ommunication '1

'Total 8 marks

Macmillan Academy 8

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". $ll organisms can be classified according to where they get their energy and theelement carbon. The table below shows the four forms of nutrition (photoautotrophic!photoheterotrophic! chemoautotrophic! chemoheterotrophic) that are possible. $

number of different bacteria (kingdom rokaryotes) are shown in the table to identifytheir forms of nutrition.

CA#B$% &$'#C(

carbon dio+ide(autotrophic)

organic carbon(heterotrophic)

(%(#)*

light(phototrophic)

photoautotrophic

................................

cyanobacteria

photoheterotrophic

purple nonsulphur

bacteria

&$'#C(chemicalreactions

(chemotrophic)

chemoautotrophic

nitrifying bacteria

chemoheterotrophic

................................

saprophytic bacteria

(a) "omplete the table with the names of two other kingdoms. +rite your answerson the dotted lines in the shaded ,o-es.

'

(b) *+plain why organisms need to obtain energy and carbon.

energy .............................................................................................................

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carbon .............................................................................................................

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(c) ,itrifying bacteria are chemoautotrophs. #ome nitrifying bacteria gain energy

from converting nitrite ions (, C

) to nitrate ions (,- C

).

*+plain how the activity of these bacteria affects the growth of plants in anecosystem.

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'

Macmillan Academy 10

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5acteria are metabolically very diverse and show all four forms of nutrition identified inthe table above. This diversity can be shown in a simple piece of apparatus called aBinogradsky column.

$ glass tube! -0 cm tall and = cm in diameter! is set up with the lower third containingriver mud! some shredded newspaper as a source of cellulose! and the mineralssodium sulphate and calcium carbonate. The top twothirds of the column is filled withriver water and the tube is sealed and placed under a bright light source. $fter threemonths different types of bacteria establish themselves in Dones.

Eig. 1 shows some chemical changes occurring in a Binogradsky column containingsi+ types of bacteria.


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$ r r o w s s h o w f l o w o f F o r g a n i c a c i d s

h y d r o g e n s u l p h i d e

s u l p h u r

5 a c t e r i a m a r k e d G d e p e n d o n l i g h t f o r t h e i r m e t a b o l i s m .

$ * H 5 7 "

B $ T * H

$ , $ * H 5 7 "

B $ T * H

$ , $ * H 5 7 "

# * 7 6 * , T

c y a n o b a c t e r i a

; " I ; @ " @ I ;

c o l o u r l e s s s u l p h u r b a c t e r i a

G ; 1 ;

g a i n e n e r g y f r o m o + i d a t io n o f @ #t o c o n v e r t " " @

p u r p l e n o n s u l p h u r b a c t e r i a

g r e e n s u l p h u r b a c t e r i a

; " I ; @ # " @ I ; #

; 1 ;

; 1 ;

G

G

D e s u l f o v i b r i o

l o s ! r i d i u m d i f f i c i l e

Jim eacon

ig. 1


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Eig. gives more details of the metabolic activities of the si+ types of bacteria.

c e l l u l o s e

g l u c o s e

C $ o r g a n i c a c i d s2

c o l o u r l e s s s u l p h u r b a c t e r i a

g r e e n s u l p h u r b a c t e r i ac y a n o b a c t e r i a

G

G

D e s u l f o v i b r i o

p u r p l e n o n s u l p h u r b a c t e r i a G



ig. 2

(d) 3se the information given in Eigs. 1 and ! and in the table to identify the forms of nutrition of

(i) los!ridium and Desulfovibrio ................................................................

'1

(ii) green sulphur bacteria ...........................................................................

'1


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(e) (i) ,ame the element that is being recycled in Eig. .

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'1

(ii) 3se Eig. 1 to describe how two named types of bacteria recycle sulphur inthe Binogradsky column.

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(f) 3nusual communities of animals are found deep in the ocean in warm! sulphurrich water.

3se the information given in Eigs. 1 and to suggest which type of bacteria is theproducer at the base of food chains in these communities.

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'1

(g) >as gangrene is a condition caused by the bacterium los!ridium perfrin"ens.

#uggest why gas gangrene only occurs in severely damaged tissue where bloodsupply is restricted.

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'TotalF 1; marks


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/. (a) lants rely on the cycling of nitrogen to supply them with nitrogen in a form thatthey can absorb.

#elect! from the list! the most suitable word or term that matches the statements

(i) to (iv) below.

acti0e transport nitrogen i-ation

denitriication Nitrobacter

denitriying ,acterium Nitrosomonas

diusion osmosis

endocytosis Rhizobium

nitriication

(i) The conversion of nitrate ions into nitrogen gas.

................................................................................................................

'1

(ii) $ bacterium that fi+es nitrogen.

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'1

(iii) $ method by which nitrate ions pass into root hair cells.

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'1

(iv) The conversion of ammonium ions into nitrite ions.

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(b) 5efore the widespread use of artificial fertilisers! farmers used a variety ofmethods to improve the fertility of the soil and so improve the yield of their crops.Two of the methods in common use wereF

9 loughingin7n which legumes! such as beans! alfalfa or clover! were grown in a fieldand then harvested. The roots were then ploughed back into the soil ratherthan being dug up or burnt.

9 Crop rotation7n which different crops were grown in a field in each year for three years.7n the fourth year! the KfallowL year! the field was not used for crops. 7n thefollowing year the crop cycle was started again.

*+plain how ploughingin and crop rotation are able to improve the fertility of thesoil.

loughingin ....................................................................................................

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"rop rotation ...................................................................................................

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1. rimary succession is the simplest type of succession! beginning with a bare surfacesuch as rock or sand. The first organisms to colonise the area form the pioneercommunity.

escribe two effects of the pioneer community on the habitat.

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'Total marks

11. "halk grassland communities are found in areas of southern *ngland such as the#outh owns. Boodland rather than grassland is the clima+ community for this habitat.>raDing by sheep and rabbits maintains the grassland.

(i) efine the term clima# communi!y .

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'1

(ii) #uggest how graDing by sheep and rabbits could prevent a woodland clima+community from developing.

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'1

'Total marks


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12. $ common plant found in chalk grassland communities is birdLs foot trefoil. $ group ofstudents used a point ?uadrat to determine the percentage cover of birdLs foot trefoil inan area of chalk grassland. They placed the point ?uadrat at one position on thegrassland and lowered the metal pins! as shown in the figure below. They recorded the

first hit on each species made with each pin. This was repeated at nine other randomlyselected locations within the area of grassland. Their results are shown in the followingtable.

m e t a l p i nh o l e s t o t a k e p i n s

m e t a l s p i k ep u s h e d i n t o

g r o u n d

?uadrat number 1 - < = ; 2 8 10

number of hits on birdLs foot trefoil - 8 2 8 - 1 1

number of hits on other species 1; 1 0 1- 1; 1 < 1; 0 8

$n estimate of percentage cover for a species can be made by calculating the numberof hits as a percentage of the total hits.

(a) 3sing the results in the table above! calculate the percentage cover for birdLs foottrefoil. #how your working and e+press your answer to the nearest 0.1&.

$nswer % ........................................&

'


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(b) $ footpath runs through the area of grassland and one student observed that veryfew birdLs foot trefoil plants were found on the trampled areas.

*+plain how the students could use a transect to determine whether there is a

link between trampling and the abundance of birdLs foot trefoil on this footpath.

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'Total 2 marks


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13. $ study was carried out in southeast #cotland on the release of nitrous o+ide (,)

from agricultural land. ,itrous o+ide is produced by the action of bacteria in the soil.

7n the study! si+ plots of grassland! A to ! were treated in different ways. lots B to were treated with substances containing nitrogen. The ?uantities applied to each plotcontained the same mass of nitrogen! although in different compounds. The tablebelow shows the results obtained for the various treatments.

plot treatment, produced :

kg ha C1

A nothing added =2

B inorganic fertiliser =-1

C urea 10

D sewage sludge 1- =-2

( cattle manure -1

poultry manure ; ;1

escribe three variables in this e+periment that the researchers would have taken intoaccount to ensure that the results were valid.

1 ...............................................................................................................................

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- ...............................................................................................................................

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'Total - marks


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14. "oral reefs occupy 0.& of the worldLs oceans but provide habitat and breedinggrounds for =& of the worldLs fish species. The figure below shows a food web for acoral reef community.

f i s h

c o r a l

D o o p l a n k t o n

f i + e d

a l g a e

( s e a w e e d s )

s e a s l u g

s p o n g e

f r e e l i v i n g

a l g a e

( p h y t o p l a n k t o n )

s y m b i o t i c

a l g a e

( e . g . i n c o r a l s )

Heefs are under threat from a variety of sources. ne of these is the water that drainsfrom agricultural land that is rich in fertilisers. $nother is the discharge of untreatedsewage into the sea.

*+plain how these forms of pollution could alter the ecological balance of a coral reef.

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'Total < marks


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15. The diagram below shows part of the nitrogen cycle.

+

+

X

*

$ 6 6 , 7 3 67 , #

, 7 T H 7 T *7 , #

" / M * H( $ / * > 3 6 * )

E N

> H $ # #

H $ 5 5 7 T

d e a t h a n d d e c a y

, 7 T H > * , 7 , $ 7 H( 7 , 7 T H > * , ! , )

, 7 T H $ T *7 , #

(a) 3sing only the information in the diagram! state one e+ample of each of thefollowingF

(i) secondary consumerO

................................................................................................................

'1

(ii) producer.

................................................................................................................

'1


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(b) (i) ,ame the process +.

................................................................................................................

'1

(ii) #tate a way in which nitrogen in air can be converted directly into nitrateions! as indicated by arrow X.

................................................................................................................

'1

(iii) #tate the type of bacteria that carry out process *.

................................................................................................................

'1

(iv) The bacterium $%i&obium also has a role in the cycle shown in thediagram.

*+plain the importance of $%i&obium in the nitrogen cycle.

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'Total 2 marks


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1. >rasslands which have been left undisturbed for several years often have ant mounds. $nts make burrows in the soil and bring fine crumbs of soil to the surface! where itaccumulates as a mound. *ach mound is about =0 cm across and about 0 cm high.

lants grow on the mounds. $nts of the type that make mounds in grassland do notfeed on plants.

$ student noticed that a plant called wild thyme! '%ymus drucei ! seemed to be morecommon on ant mounds than it was on other parts of the same grassland! not occupiedby ants.

7n order to test the hypothesis that wild thyme was indeed more common on antmounds! the student e+amined all the mounds in an area of grassland about 100 m by100 m! noting whether or not wild thyme was present.

$fter surveying all

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(ii) escribe two ways in which the survey methods could have been improved. >ivea reason for each of the changes you have suggested.

1 ......................................................................................................................

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(b) Two more terms commonly used by ecologists are popula!ion and communi!y .

#tate the difference between a popula!ion and a communi!y .

.........................................................................................................................

.........................................................................................................................

'1

'Total < marks

1". Eig. 1 shows the transfer of energy through a food chain in a wood.

The figures represent the energy in the levels of the ecosystem in 6J m C

y C1

.

s u n

2 = 0 0 0 0

- 0 0 0 0

< 0 0

o a k t r e e

< 8 0 =

h a w k s p a r r o w

c a t e r p i l l a r

e n e r g y t r a n s f e r % 0 &

e n e r g y t r a n s f e r % 1 . 8 &

e n e r g y t r a n s f e r % 8 &

ig. 1


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Eig. shows what happens to the food available to caterpillars in the food chain shownin Eig. 1.

E > 3 T 7 > * # T 7 , Q

$ # # 7 6 7 / $ T 7 ,

* > * # T 7 ,

* N " H * T 7 ,

> H B T @ Q H * $ 7 H

# T H $ > *

H * H 3 " T 7 ,

H * # 7 H $ T 7 ,

* " 6 # * H #

e a t e n

n o t e a t e n

n o t d i g e s t e d

m e t a b o l i c

w a s t e

ig. 2

(i) Eig. 1 shows that each trophic level has less energy flowing through it than theprevious trophic level.

3se the information in Eig. to e+plain why this is the case.

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(ii) *+plain the differences in the percentage of energy transferred between thetrophic levels shown in Eig. 1.

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'Total = marks

1/. The figure below shows some of the stages that have occurred during succession at>lacier 5ay in $laska.


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3sing the information in the figure!

(i) e+plain what is meant by the term succession O

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2. #tatements about the nitrogen cycle are written below.

1 a g e n u s o f b a c t e r i u m a s s o c i a t e d w i t h l e g u m i n o u s p l a n t s

2 c o n v e r s i o n o f n i t r a t e i o n s t o n i t r o g e n

3 s w e l l i n g o n t h e r o o t o f a l e g u m i n o u s p l a n t

4 c o n v e r s i o n o f a m m o n i u m i o n s t o n i t r a t e i o n s

5 a n a n i m a l t h a t e a t s p l a n t s

T

#elect from the following terms the appropriate letter to match each statement. Britethe letter in the bo+.

The first one has been done for you.

s e c o n d a r y c o n s u m e r

& p r i m a r y c o n s u m e r

' d e n i t r i f i c a t i o n

+ n i c h e

* d e c a y

# n i t r o g e n f i + a t i o n

6 R h i z o b i u m

7 n o d u l e

X l i g h t n i n g

8 n i t r i f i c a t i o n

'Total < marks


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21. The figure below illustrates the profile of a sand dune system! together with kitediagrams of some plant species. This summarises the results of a belt transect carriedout over the dunes.

s e a c o u c h g r a s s

m a r r a m g r a s s

d a n d e l i o n

r e s t h a r r o w

w i l d t h y m e

b i r d s f o o t t r e f o i l

w i l l o w

s e as h o r e

e m b r y od u n e

y e l l o wd u n e

s e m i f i + e dd u n e

f i + e dd u n e

d u n es l a c k


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The results of the transect were initially recorded using the $"EH scaleF

A C abundant

C C common

C fre?uent

$ C occasional

# C rare

(a) utline the advantages and disadvantages of using a scale! such as the $"EHscale.

advantages .....................................................................................................

.........................................................................................................................

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disadvantages .................................................................................................

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'-

(b) *+plain

(i) how such a transect would have been carried outO

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(ii) how the $"EH readings would have been converted to kite diagrams. Roumay use the space below for any diagrams to help your answer.

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(c) The distribution of plant species in sand dunes will be influenced by a number ofabiotic factors! such as temperature.

*+plain how to measure! in different parts of the sand dune system! variations intemperature of the sand or soil.

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(d) #and dune systems are a result of the process of succession. The semifi+eddunes represent an intermediate sere between yellow and fi+ed dunes.

*+plain

(i) what is meant by a sereO

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'1

(ii) the process of succession in a system of sand dunes! or in an area youhave studied.

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22. 7n this ?uestion! one mark is available for the ?uality of spelling! punctuation andgrammar.

The diagram below represents the energy flow through an ecosystem.

;

1

; ; 1 1 < 1 8

r e s p i r a t i o n

< ;

;

1 0 =

= < ; =

; 2

1 < 2 8

- 8 -

- - ; 8

8 8 - -

0 8 1 0

t e r t i a r y c o n s u m e r s

s e c o n d a r y c o n s u m e r s

p r i m a r y c o n s u m e r s

p r o d u c e r s

d e c a y

a n d

o t h e r

l o s s e s

1 =

- 1 ;

1 8 0

1 1 2 2

1 2 0 0 0 0 0

s u n l i g h t

9 e y :

g r o s s p r o d u c t i v i t y

n e t p r o d u c t i v i t y

a l l f i g u r e s g i v e n a r e i n k J m y r C C 1

*+plain how energy is transferred through food chains and food webs in an ecosystem.Rou should refer to the efficiency of this transfer in your answer.Rou will gain credit if you make use of the information in the diagram.

'

Auality of Britten "ommunication '1

'Total 10 marks


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23. avid 5ellamy! the president of lantlife! describes peat bogs as Kthe Sewel of 5ritainLshabitatsL.

KRou walk with a spring in your step C the peat underfoot is ninetenths water C to the

tireless song of a hovering skylark! on an undulating carpet of green! shot through withred! pink! burnished gold and orange! yellow and white flowers that thrive here. Thereare hundreds of insect species in the pools and on the plants and an abundance ofroundleaved sundew! one of several carnivorous plants that get their nutrients(especially nitrogen compounds) from the insects they trap in their sticky leaves.L

*+plainF

(i) why very wet soils are usually nitrogendeficient and how the sundew is at acompetitive advantage in such soilsO

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24. $ group of students carried out an investigation into the growth of the #cotch Thistle!(nopordum acan!%ium) in two different sites! A and B.

$t each site! 1= plants were selected and their heights measured and recorded. These

are summarised in the table below.

height of plants : mm

site A site B

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(b) *+plain what is meant in the table above byF

(i) meanO

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(ii) s!andard devia!ion.

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(c) The figure for s.d. at site B is greater than the figure for site A. *+plain what thismeans.

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'1

(d) 7n order to draw a statistically valid conclusion from their results! the studentscarried out a ! test.

5efore calculating a ! value! they had to state a ,ull @ypothesis.

(i) #tate what the ,ull @ypothesis would be in this investigation.

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The calculation gave a value for ! of .;

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25. The table below compares the mean protein yields of two cereal crops! with that of twolegume crops.

crop mean protein yield: kg ha

C1

cereal maiDe 1

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#ome of the data from the investigation are shown in the table below.

numbers per 100 g of soil

stage of treegrowth

mean number of indi0iduals of all

types of mite

mean number of indi0iduals of alltypes of springtail

mean number of species of springtail

tree seedlings 1-2= 1=

young trees =;< -00 1-

mature trees 181 -1 11

clima+ forest!not cut or

burned sincerecords began

80 21= 1;

#tate three conclusions that you can draw from the data in the table.

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'Total - marks


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2!. ,itrifying and denitrifying bacteria are involved in the nitrogen cycle.*+plain the role in the nitrogen cycle of

(i) nitrifying bacteriaO

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(ii) denitrifying bacteria.

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'Total < marks

2". Head the following passage carefully! then answer the ?uestions below.

$%i&obium is a bacterium that is closely associated with the roots of certainplants known as legumes. These plants produce chemicals to attract thebacteria and e+tra root hairs are produced. The bacteria attach to the surfaceof the root hairs. "hemical links are formed between a comple+

5 polysaccharide on the bacterial surface and lectin! a protein! formed by theplants. The bacteria penetrate the cell walls of the root hairs and enter thecells. The presence of the bacteria stimulates the cells of the root to divide!forming swellings known as nodules.

The bacteria produce an enDyme! nitrogenase! that is the catalyst for the10 conversion of nitrogen gas to ammonia. The bacteria use carbon compounds

manufactured by the plant to respire! making energy available for thisconversion. The ammonia is then used to form amino acids. ,itrogenase onlyfunctions in low o+ygen concentrations. The root cells produce a pigment!leghaemoglobin! that is very similar to haemoglobin. /eghaemoglobin absorbs

15 o+ygen! leaving low concentrations in the nodules.


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(i) $%i&obium is a prokaryotic organism.

#tate one characteristic that is typical of prokaryotes! but not of eukaryotes.

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(ii) /ectin (line =) and polysaccharides are compounds that are formed from smallmolecules Soined together by chemical bonds.

*+plain how the small molecules are Soined together to form these compounds.

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(iii) /eghaemoglobin contains the same metal element as haemoglobin.

,ame this metal element.

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(iv) #tate the names of two proteins! other than lectin! mentioned in the passage.

1 ......................................................................................................................

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(v) ,ame the process that occurs in $%i&obium to convert nitrogen gas intoammonia.

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'1


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(vi) 7t has been suggested that o+ygen is an inhibitor of nitrogenase.

*+plain one way in which o+ygen could act as an inhibitor.

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'Total 10 marks

2/. #tate the word or phrase that best describes an organism that obtains its food byeating only producers.

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'Total 1 mark

5-3-1-ecosystems (1).doc

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