Cambridge IGCSE Environmental Management 0680 — 2018 Oct/Nov Paper 4 · Variant 1

1 Mexico’s economy depends on modern manufacturing industries, agriculture and tourism. There are abundant reserves of oil, natural gas and minerals. Large scale rural to urban migration is taking place. Environmental problems include a shortage of clean drinking water, deforestation and desertification. (a) Describe two problems caused by rural to urban migration. 1 ................................................................................................................................................ ................................................................................................................................................... 2 ................................................................................................................................................ ................................................................................................................................................... [2] (b) The state of Michoacan has the largest production of strawberries in Mexico. In 2016, strawberries were planted on 23 000 hectares and 539 000 tonnes were harvested. (i) Calculate the average number of tonnes per hectare of strawberries harvested in Michoacan in 2016. Show your working. ............................ tonnes per hectare [2] (ii) The demand for strawberries in Mexico and the USA is increasing. Suggest how this benefits farm workers and the government of Mexico. farm workers ..................................................................................................................... ........................................................................................................................................... the government ................................................................................................................. ........................................................................................................................................... [2] (iii) Farm workers can harvest 100 kg of strawberries in one day. They work 50 hours a week and earn between 60 to 80 USD per week. Suggest two reasons why some farm workers decide to leave their job and move to the capital city. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (c) A student visited a strawberry farm. The student collected ten ripe strawberries from one plant in a field and found their mass. The table shows the results. strawberry mass of strawberry / g 1 16 2 14 3 24 4 37 5 31 6 29 7 33 8 40 9 19 10 27 (i) Calculate the average mass of one strawberry. ........................................................ g [1] (ii) Calculate the average number of strawberries in a 5 kg tray. Show your working. ............................................................[2] The student decided that this sample of strawberries was not representative of the field of strawberries. The student proposed three further sampling methods. Method one Walk down one row of strawberry plants in the field and collect the largest ripe strawberry from ten different plants. Method two Walk down one row of strawberry plants in the field and collect the largest ripe strawberry from every fifth plant. Collect a total of ten strawberries. Method three Use a table of random numbers to select the rows and the plants in the field. Collect one ripe strawberry from each of the ten selected plants. (iii) Suggest why the student decided not to carry out method one. ........................................................................................................................................... .......................................................................................................................................[1] (iv) Explain why method three is better than method two. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[2] (v) The student used sampling method three. The random numbers used by the student are shown in the table. strawberry sample row number plant number 1 3 5 2 5 9 3 4 8 4 2 2 5 2 4 6 1 4 7 6 6 8 7 8 9 7 3 10 8 5 Complete the diagram to show the positions of the last two strawberry samples in the field. 10 9 8 7 6 plant number 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 row of strawberry plants sampled plant [2] (vi) The student recorded their results in a notebook. sample 1 mass 35, sample 2 sample 40 g, sample 6 28 g, 31 g, sample 3 24g, sample 7 34, sample 8 33 g, sample 4 29 g sample 9 16 g, sample 10 25 g Draw and complete a table to show these results. [3] (d) The table shows climate data from a weather station in the centre of the strawberry growing region. month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec average monthly 14.3 15.6 17.9 19.8 20.9 20.1 18.7 18.6 18.3 17.3 15.8 14.5 temperature / °C average monthly 14 7 6 15 46 137 172 171 141 55 14 13 rainfall / mm (i) Calculate the annual average temperature range at this weather station. ...................................................... °C [1] (ii) Explain how the average monthly temperatures in this region allow strawberries to be produced all year. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[2] (iii) Strawberry plants need a regular water supply to grow and produce ripe fruit. Using information from the table, state the six months when irrigation will be needed. .......................................................................................................................................[1] (iv) Name a method of irrigation that could be used to grow strawberry plants without wasting water. .......................................................................................................................................[1] (v) Many crops are given too much water by irrigation. Describe the damage that over-watering can do to fertile soils. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[3] (vi) Suggest two other problems for farmers of growing the same crops in large fields year after year. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (e) Many of the farm workers live, with their families, near the strawberry fields. They live in simple shelters made of poles, plastic sheeting and cardboard. They cook food over open wood fires. (i) Suggest two risks to the health of these families as a result of cooking over open wood fires. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (ii) In 2016 about 28 million people in Mexico still used wood as a fuel for cooking. Calculate the percentage of the population in Mexico that cooked in this way in 2016. Show your working. ........................................................% [2] (iii) To reduce the use of wood, a more efficient stove has been developed that uses half the fuel of an open fire and produces less smoke. Food is cooked on a hot plate above the fire. Many families did not want to use the new stove even though it uses less fuel and produces less smoke. Suggest two reasons why they did not want to change. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (iv) Some families were given the new stove to use. They found it was easier to use, keep clean and also used less fuel. Suggest two ways the government could encourage more families to use the new stove. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (v) Suggest how the use of this new stove could reduce the impact on the environment compared with burning wood on an open fire. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[3]

Mark scheme: 1(a) any two from: overpopulation in urban areas; increase in disease related to overpopulation; unemployment; low wages; no / few, schools / hospitals; AVP, e.g. housing / infrastructure, cannot keep up with population growth / depopulation of rural areas / increase in a named pollutant; 2 1(b)(i) 23.4 / 23 ;; (if answer incorrect, allow one mark for 539 000 / 23 000 [1]); 2 1(b)(ii) any one from, farm workers: make more money; more job opportunities; any one from, the government: government collect taxes; revenue spent on, infrastructure / services; goods for export; (increased) economic growth; 2 1(b)(iii) any two from: low wages / seasonal work, in rural areas; poor standard of living in rural areas; converse in city; better (named) services in city; 2 1(c)(i) 27; 1 1(c)(ii) 185 ;; (if answer incorrect, allow one mark for 5000 / 27 [1]); 2 1(c)(iii) sample, is not representative / is biased; 1 Question Answer Marks 1(c)(iv) any two from: no student bias as (selection is) random; several rows sampled; in different parts of the field; sample is representative (of whole field); AVP, e.g. largest fruits not chosen; 2 1(c)(v) (correct position indicated on diagram) row 7, plant 3; (correct position indicated on diagram) row 8, plant 5; 2 1(c)(vi) table drawn that can record all the data; correct headings including units; order of data entered; 3 1(d)(i) 6.6; 1 1(d)(ii) any two from: warm enough for growth every month; and so flowering; and ripening; no frosts to kill plants; AVP related to temperature; 2 1(d)(iii) November to April; 1 1(d)(iv) trickle drip irrigation / AVP; 1 1(d)(v) any three from: leaching; of mineral nutrients; increased evaporation; draw salts to the surface; salinisation; AVP, e.g. waterlogged soils lack oxygen for root growth; 3 Question Answer Marks 1(d)(vi) any two from: widespread crop failure; spread of insect pests and other diseases; reference to, need to use expensive treatments; nutrients used by crop need to be replaced; soil becomes, less fertile / infertile; 2 1(e)(i) any two from: asthma; lung disease; breathing problems; burns; eye problems (from smoke); fire risk / described; AVP, e.g. particulates; 2 1(e)(ii) 22.76 / 22.8 / 23 (%) ;; (if answer incorrect, allow one mark for 28 million / 123 million [1]); 2 1(e)(iii) any two from: cost; do not know how to use it; not traditional / do not want to change; 2 1(e)(iv) any two from: promotion activities to show advantages and word of mouth; make the new stoves cheaper; lots of people now know how to use it; train people to use it; provide people with materials; 2 Question Answer Marks 1(e)(v) any three from: reduces deforestation / habitat destruction; reduces air pollution; less carbon dioxide released; maintains species diversity; (reduces impact on) climate change / less global warming; AVP, e.g. less particulates; 3

2 (a) The lakes in the state of Michoacan are an important source of fish. Fishermen catch a small fish called charal from Lake Patzcuaro in Michoacan state. Each local fisherman uses a small boat and a hand–held fishing net to catch charal from the lake. (i) Suggest two reasons why local people think that this lake will always provide charal fish. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (ii) A scientist decided to take a sample of fish from Lake Patzcuaro at each of the six sites, A to F, shown on the map. N Lake Patzcuaro A B C D E F 0 8 km Suggest a method the scientist could use to collect the samples of fish so that they could be compared in a fair way. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... .......................................................................................................................................[4] (iii) The sampling method caught charal and other species of fish. The scientist recorded the following results. sample site A B C D E F number of charal 40 37 28 43 33 10fish number of different 5 6 5 7 6 2fish species Plot a bar graph of the number of charal fish at each sample site. [4] (iv) Suggest one sample site that may be polluted with raw sewage. Give a reason for your answer. sample site .............................................. reason ............................................................................................................................... ........................................................................................................................................... [1]

Mark scheme: 2(a)(i) any two from: only, small / single (hand-held) net; limit to how many fish can be caught by one person; lake has provided fish for many years; 2 2(a)(ii) valid collection method described keeping details the same at each sample point, e.g. length of fishing / number of fish; size of net; mesh size; time of day; time of year; AVP, e.g. fish at the surface / at a specified depth; 4 2(a)(iii) suitable linear scale; y axis fully labelled; x axis fully labelled; correct plots; 4 2(a)(iv) F AND as it has lowest, number of different fish species / species diversity / number of charal fish; 1 2(a)(v) any five from: eutrophication; increase in bacteria; bacterial respiration; use up oxygen; algal bloom; block light; death of plants; death of fish; disrupts, food chain / food web; 5 Question Answer Marks 2(b) any four from: do not allow development too close to the shoreline; to prevent / control, (land / water / air) pollution, e.g. litter; build sewage treatment plants; efficient rubbish collections; restrict visitors to some areas; restrict holiday activities such as, speed boats / tour boats; maintain local fishing activity; restrict vehicles near lake; advertise rules; implement fines / punishment, for abuse of rules; employ rangers to monitor, area / lake; 4