bio january 2006 edexcel as unit3

This publication may be reproduced only in accordance with Edexcel Limited copyright policy. ©2006 Edexcel Limited.

Printer’s Log. No.

N23409AW850/R6103/57570 7/7/7/7/3/7500

Paper Reference(s)

6103/03Edexcel GCEBiologyBiology (Human)Advanced SubsidiaryUnit 3 Paper 03Tuesday 10 January 2006 – MorningTime: 1 hour

Materials required for examination Items included with question papersRuler Nil

Instructions to CandidatesIn the boxes above, write your centre number, candidate number, your surname, initial(s) andsignature.The paper reference is shown above. Check that you have the correct question paper.Answer ALL THREE questions in the spaces provided in this booklet.Show all the steps in any calculations and state the units. Calculators may be used.Include diagrams in your answers where these are helpful.

Information for CandidatesThe marks for individual questions and parts of questions are shown in round brackets: e.g. (2).The total mark for this question paper is 38.

Advice to CandidatesYou will be assessed on your ability to organise and present information, ideas, descriptions andarguments clearly and logically, taking account of your use of grammar, punctuation and spelling.

Turn over

Examiner’s use only

Team Leader’s use only

Question LeaveNumber Blank

1

2

3

Total

CentreNo.

Candidate No.

Surname Initial(s)

Signature

Paper Reference

6 1 0 3 0 3

*N23409A0116*

www.XtremePapers.net

http://www.xtremepapers.net

Leaveblank

2

Answer ALL questions in the spaces provided.

1. The diagram below shows the skull of a mammal.

(a) State the term that is used to describe the form of feeding shown by this mammal, inwhich organic material is obtained from the bodies of other organisms.

.......................................................................................................................................(1)

(b) Suggest what type of organic material probably formed the main part of the diet ofthe mammal shown in the diagram.

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

.......................................................................................................................................(1)

*N23409A0216*

Eye socket(orbit)

Canineteeth

Premolar and molar teeth



Leaveblank

3

(c) For each of the labelled features, explain how the position, shape or structuresupports your answer to part (b).

Eye socket .....................................................................................................................

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

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

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

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

Canine teeth ..................................................................................................................

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

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

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

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

Premolar and molar teeth .............................................................................................

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

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

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

.......................................................................................................................................(6)

Turn over

Q1

(Total 8 marks)

*N23409A0316*



Leaveblank

4

2. After a crop has been harvested, the remains of the plants, known as residues, may be duginto the soil to allow them to decompose. This process is called green manuring.

It has been shown that in as little as 10 weeks, in well-aerated soil, 70% of the organicnitrogen compounds in the residues are converted into nitrates. It has been estimated that0.3% of the fresh biomass in a residue will be available as nitrate for the next crop.

The table below shows the estimated potential yield of nitrate from the residues ofdifferent crops.

[Data adapted from Tremblay, N., Scharpf, H., Weier, U., Laurence, H. & Owen, J., Nitrogen Management in FieldVegetables – Agriculture & Agri-Food Canada]

(a) Explain what is meant by the term biomass.

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

.......................................................................................................................................(1)

(b) Calculate the potential yield of nitrate for the Brussels sprout crop. Show yourworking.

Answer ............................(2)

*N23409A0416*

CropFresh biomass of residueused for green manure/kg per hectare

Estimated potential yield of nitrate /kg per hectare

Brussels sprout 60 000Cauliflower 40 000 120Carrot 30 000 90Leek 20 000 60Radish 10 000 30



Leaveblank

5

(c) The initial products of decomposition of the organic compounds in the residues areammonium compounds.

Name and describe the process by which ammonium compounds are converted intonitrates in well-aerated soil.

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

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

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

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

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

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

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

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

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

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

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

.......................................................................................................................................(4)

Turn over*N23409A0516*



Leaveblank

6

(d) In a study of the rate of decomposition of cauliflower residues the effect of soiltemperatures of 10, 15 and 25°C on the rate of nitrate release was estimated.

The graph below shows the results of this study.

[Data adapted from Tremblay, N., Scharpf, H., Weier, U., Laurence, H. & Owen, J., Nitrogen Management inField Vegetables – Agriculture & Agri-Food Canada]

(i) Compare the rate of nitrate release from cauliflower residues at 10°C with thatat 15°C.

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

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

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

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

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

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

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

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

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

................................................................................................................................(3)

*N23409A0616*

��

��

��

��

��

��

��

��

� � ��

� � � � � ��

��

��

��

��



Leaveblank

7

(ii) Using the information in the graph, suggest why 15°C is the best soiltemperature for sowing a crop after green manuring.

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

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

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

................................................................................................................................(2)

Turn over

Q2

(Total 12 marks)

*N23409A0716*



Leaveblank

8

3. A group of students carried out an investigation to determine the energy flow in arainforest food chain. They collected invertebrate animals from trees, identified them andplaced them in the appropriate trophic level.

For each trophic level the animals were counted, weighed and the energy contentdetermined. Using their data and other sources of information the students produced adiagram to show the energy flow along the food chain. The diagram is shown in Figure 1.

Figure 1

*N23409A0816*

Sunlight

200 × 103 kJ m–2 y–1

140 × 103 kJ m–2 y–1

24 × 103 kJ m–2 y–1

7000 kJ m–2 y–1

700 kJ m–2 y–1

70 kJ m–2 y–1

Producers Respiration

Primary Consumers

Secondary Consumers Decomposers

Tertiary Consumers



Leaveblank

9

Some farmers clear plots of rainforest to use for crops. The trees are felled and then burnt.This practice is called slash and burn. The soil is left covered in ash, which is rich in nutrients.However, the nutrients are soon used up by the growing crops. Within two or three years theplot is abandoned and the farmer moves on to a new plot.

The abandoned plot is colonised by tree species and eventually the land is covered bysecondary rainforest. The sequence of events is shown in Figure 2. This figure also showsthat the total biomass of the rainforest trees is made up of leaves, stems and branches, rootsand leaf litter. These components of the biomass change as the rainforest is cleared, farmedand then abandoned.

Figure 2

The biomass components are shown in million tonnes per hectare.


Biomasscomponent

Leaves

Leaf litter

Branches

Roots

Primaryrainforest

50

400

50

200

Farming

10

50

10

50

Secondary rainforest

50

200

50

50

50

300

50

75

Slash and burn

Plotabandoned

25 years10 years



Leaveblank

10

BLANK PAGE

*N23409A01016*



Leaveblank

11

(a) Define the term net primary production (NPP).

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

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

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

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

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

.......................................................................................................................................(2)

(b) (i) Explain why only a small percentage of the light energy falling onto a leaf isconverted into chemical energy.

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

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

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

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

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

................................................................................................................................(2)

(ii) Explain why only 10% of the energy locked up in the secondary consumers istransferred to the tertiary consumers.

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

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

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

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

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

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

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

................................................................................................................................(3)




Leaveblank

12

BLANK PAGE

*N23409A01216*



Leaveblank

13

(c) The energy shown entering the decomposers in Figure 1, is much greater than thatentering all of the consumers. Suggest an explanation for this difference.

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

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

.......................................................................................................................................(1)

(d) (i) Using Figure 2, compare the components of the biomass of the primary rainforestwith those of the secondary rainforest after 25 years.

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

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

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

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

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

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

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

................................................................................................................................(3)

(ii) Using all of the information provided, suggest why slash and burn farming isconsidered to be unsustainable.

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

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

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

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

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

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

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

................................................................................................................................(3)




Leaveblank

14

BLANK PAGE

*N23409A01416*



Leaveblank

15

(e) Suggest how the biodiversity of the surrounding rainforest could be changed by thepractice of slash and burn. Give reasons for your answer.

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

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

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

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

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

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

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

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

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

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

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

.......................................................................................................................................(4)

TOTAL FOR PAPER: 38 MARKS

END

Q3

(Total 18 marks)

*N23409A01516*



16

BLANK PAGE

*N23409A01616*



bio january 2006 edexcel as unit3

Documents