WJEC. BY5 Energy Flow Questions

Transcription

1 NAME: OPTION GROUP WJEC BY5 Energy Flow Questions Question Book 1 (Legacy Qs from Jan 2000 to June 2009) Question Number(s) Due Date & Pass Mark Homework Mark Resist Question number(s) Resist Due Date & Pass Mark Mark Resit 1

2 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

10 10 Examiner only Arholwr yn unig 6. The diagram below represents the flow of energy through a deciduous forest ecosystem. The values quoted are in kilojoules per square metre per year (kj m 2 yr 1.) SOLAR RADIATION FOREST TREES TOTAL PRIMARY PRODUCTION 2080 LOSSES RESPIRATION OF TREES 1180 NET PRIMARY PRODUCTION 900 FEEDING BY HERBIVORES 10 Z W X Y UNAVAILABLE TO ANIMAL FEEDING 290 DETRITIVORES (0006/16) 10

11 11 Examiner only Arholwr yn unig (a) Most of the net primary production passes to the detritivores by the routes labelled W and X. (i) Give two processes represented by X. [2] (ii) Which of the two routes, W or X, provides most energy for the detritivores? Explain how you arrived at your answer. [2] (b) (i) The trees fail to convert kj m 2 yr 1 into primary production. Give one example of how these losses occur. [1] (ii) Explain why 290 kj m 2 yr 1 is unavailable to animal grazers. [1] (c) What is represented by (i) organism Y; [1]... (ii) process Z. [1]... (iii) In the diagram, would box Y or box Z contain the highest energy value? [1]... (d) Calculate the percentage of the net primary production that is consumed by herbivores. [1] (e) What is the final form of energy after it has completed its passage through this system? [1]... (Total 11 marks) (0006/16) Turn over. 11

12 12

13 13

14 14

15 15

16 16

17 17

18 5 Examiner only Arholwr yn unig 4. A group of students produced a pyramid of biomass for a field of grassland. A number of areas of 1m 2 were sampled. All the plant material in each 1m 2 area was cut down to soil level and weighed. All animals in each 1m 2 area were identified, sorted into carnivores and herbivores and weighed. The results are shown in the table below. Organisms Mean Biomass/g/m 2 Green Plants 1400 Herbivores 200 Carnivores 20 (a) (i) Using this data construct a labelled pyramid of biomass on the graph paper below. [3] (312-01) Turn over. 18

19 6 Examiner only Arholwr yn unig (ii) Give two reasons for the loss in biomass between trophic levels in the food chain. [2] (b) State two sources of error in collecting data for pyramids of biomass. [2] (c) Only a small percentage of the light energy which falls on green plants is incorporated into biomass. Give two reasons for this. [2] (Total 9 marks) (312-01) 19

20 10 Examiner only 6. (a) Explain why not all of the energy present in primary consumers is passed onto secondary consumers. [3] (b) Three types of primary consumer were studied. Each type can be used for human food consumption. Different numbers of animals were used so that identical masses could be used. Each group was supplied with 1000kg of food and at the end the conversion efficiency was calculated. The conversion efficiency is the daily mass increase expressed as a percentage of the daily food consumption. The results of the study are shown in the table. 5 sheep 300 rabbits 1 cow Initial mass/kg Time taken to consume food/days Total mass gain/kg Daily food consumption/kg day 1 Daily mass increase/ kg day 1 Conversion efficiency/% (i) Complete the table by inserting the correct missing figures. [3] (ii) Suggest, giving a reason, which primary consumer you consider to be the best for use as a meat producer. [1] primary consumer... reason (Total 7 marks) (312-01) 20

21 4 Examiner only 4. The diagram below shows a pyramid of energy for a tropical forest. The amount of energy entering at each stage is shown in kjm 2 y Tertiary consumers Decomposers Secondary consumers Primary consumers Primary producers (a) Use the information in the diagram to explain why food chains rarely contain more than four or five trophic levels. [1] (b) The tertiary consumers include hawks which feed on other birds. Draw a food chain in the space below to show how energy from the leaves of the primary producer reaches the hawk. [1] (c) The primary consumers lose 50 kjm 2 y of their energy through respiration. (i) What percentage of the remaining energy of the primary consumers is taken up by secondary consumers? (Show your working.) [3] (ii) Explain what has happened to the rest of the primary consumers energy. [2] (312-01) 21

22 5 Examiner only (d) List the two trophic levels that are likely to have the greatest effects on atmospheric CO 2 levels and hence on global warming. Explain your choices. [4] Level.... Explanation... Level.... Explanation... (e) Apart from disruption of the food chains, give two other effects that deforestation might have on the primary and secondary consumer populations. [2] (Total 13 marks) (312-01) Turn over. 22

23 Detailed Feedback 23

24 24