Habitat destruction — Paper 3 · IGCSE Science - Combined 0653

7 Fig. 7.1 shows some processes occurring in a forest growing on a hill. clouds water vapour X tree leaves fall onto the soil surface of soil roots Fig. 7.1 (a) Name the process labelled X. … [1] (b) (i) The leaves of the trees contain carbohydrates, for example sugar. Describe how leaves use a carbon compound in the air to make sugar. … … … [2] (ii) When leaves die they fall onto the soil. Decomposers (bacteria and fungi) feed on the dead leaves and use the sugar present in the leaves. Suggest and explain how the carbon in the sugar is returned to the atmosphere by the decomposers. … … … [2] (c) The trees in the forest shown in Fig. 7.1 are cut down. Predict and explain the effect of clearing the trees on the amount of rain falling on the area. … … … [1] (d) A storm occurs higher up the hill and water comes flowing down the hill. Suggest how the soil in the cleared area will be affected by water from heavy rainfall flowing down the hill. Explain your answer. … … … [2]

8 marks

Mark scheme: 7(a) transpiration ; 1 7(b)(i) carbon dioxide from the air ; is used in photosynthesis / reacts with water ; 2 7(b)(ii) by respiration ; carbon dioxide released ; 2 7(c) rainfall reduced (no mark) less water being transpired / evaporated from trees ; 1 7(d) soil easily eroded ; due to lack of tree roots ; 2

This question in 0653/33 Oct/Nov 2017

4 Fig. 4.1 shows a giant panda which lives in bamboo forests in China. Fig. 4.1 (a) The panda has the diet of a herbivore. It feeds almost entirely on bamboo shoots. Define the term herbivore. … … [1] (b) Table 4.1 shows the mass of protein contained in 100 g of bamboo shoots and 100 g of beef. Table 4.1 nutrient bamboo shoots / g beef / g protein 2.6 20.0 (i) State the roles of protein in the body. … … [2] (ii) Calculate the mass of bamboo shoots needed to provide the same amount of protein as 100 g of beef. mass = … g [2] (iii) Use your answer from (ii) to suggest why the panda has to eat large amounts of shoots every day. … … … [2] (c) Deforestation is causing the population of pandas in the area to decrease. Suggest two reasons why deforestation decreases the population of pandas in bamboo forests. 1. … … 2. … … [2]

9 marks

Mark scheme: 4(a) an animal that gets its energy / feeds only on plants ; 1 4(b)(i) growth (of tissues) ; repair (of tissues) ; 2 4(b)(ii) 20.0 / 2.6 ; ×100 = 770 ; 2 4(b)(iii) the bamboo does not contain much protein / nutrition ; a lot needed to satisfy need / panda needs a lot because it is big ; 2 4(c) only food supply disappearing ; danger of loss of habitat ; more difficult to find a mate ; max 2

This question in 0653/32 Feb/March 2018

7 (a) The rate of photosynthesis in trees in a European forest changes during the year. Fig. 7.1 shows how the rate of photosynthesis changes between the months of January and August. rate of photosynthesis January February March April May June July August month of the year Fig. 7.1 Use the information in Fig. 7.1 to state the month during which the trees have the greatest rate of photosynthesis. … [1] (b) Fig. 7.2 shows how the appearance of one of the trees in the forest changes from January to June. tree in January same tree in June Fig. 7.2 In the forest there are many tall trees which are very close together. The forest also has smaller plants which grow on the ground between the trees. Suggest and explain why the greatest rate of photosynthesis in these smaller plants occurs between March and April. … … … … … [3] (c) Some trees are removed from the forest. (i) Suggest two reasons why this causes a reduction in the population of birds. 1. … 2. … [2] (ii) Describe one effect this removal of trees has on the soil. … … [1]

7 marks

Mark scheme: 7 7 7 7( 7(a) July ; 7(b) (more) less sh idea th (c)(i) loss of loss of birds m (c)(ii) soil mo ) light is availabl hading by trees hat light is neede f habitat ; f food that may l migrate from / lea ore likely to beco e (on forest floo ; ed for photosynt ive in the trees ave the area ; ome eroded ; or) ; thesis ; ; m 1 3 max2 1

This question in 0653/32 May/June 2018

7 (a) The rate of photosynthesis in trees in a European forest changes during the year. Fig. 7.1 shows how the rate of photosynthesis changes between the months of January and August. rate of photosynthesis January February March April May June July August month of the year Fig. 7.1 Use the information in Fig. 7.1 to state the month during which the trees have the greatest rate of photosynthesis. … [1] (b) Fig. 7.2 shows how the appearance of one of the trees in the forest changes from January to June. tree in January same tree in June Fig. 7.2 In the forest there are many tall trees which are very close together. The forest also has smaller plants which grow on the ground between the trees. Suggest and explain why the greatest rate of photosynthesis in these smaller plants occurs between March and April. … … … … … [3] (c) Some trees are removed from the forest. (i) Suggest two reasons why this causes a reduction in the population of birds. 1. … 2. … [2] (ii) Describe one effect this removal of trees has on the soil. … … [1]

7 marks

Mark scheme: 7 7 7 7( 7(a) July ; 7(b) (more) less sh idea th (c)(i) loss of loss of birds m (c)(ii) soil mo ) light is availabl hading by trees hat light is neede f habitat ; f food that may l migrate from / lea ore likely to beco e (on forest floo ; ed for photosynt ive in the trees ave the area ; ome eroded ; or) ; thesis ; ; m 1 3 max2 1

This question in 0653/33 May/June 2018

7 Rainforest is often cleared for agriculture. Trees are cut down and burned to prepare the land for planting crops. This practice is called ‘slash and burn’. The burning of the trees produces carbon dioxide gas and a smoky haze made from very small carbon particles suspended in the air. Fig. 7.1 is a picture of clearing land by slash and burn. smoky haze Fig. 7.1 (a) The wind carries the smoky haze to neighbouring countries. Suggest and explain how the smoky haze affects the rate of photosynthesis in plants in these countries. … … [1] (b) After slash and burn there is an increased risk of loss of soil from the area. Suggest a reason for this loss of soil from the area. Explain your answer. reason … … explanation … … [2] (c) State two effects of slash and burn on the animals living in the trees. 1. … 2. … [2] (d) The practice of slash and burn causes the concentration of carbon dioxide in the atmosphere to increase. Explain why this is undesirable for the environment. … … … [2]

7 marks

Mark scheme: 7(a) rate is reduced (no mark) haze / smoke particles reduce light / block stomata ; 1 7(b) (reason) lack of tree roots in soil ; (explanation) roots stabilise the soil ; or (reason) trees and plants not present to protect soil / bare soil is exposed ; (explanation) wind and rain can easily reach soil to erode it ; 2 7(c) any two of lose their habitats / move to new areas ; lose food supplies ; may be suffocated / burned by the burning process ; Max 2 2 7(d) carbon dioxide is a greenhouse gas ; contributes to global warming ; any valid consequence of global warming ; Max 2 2

This question in 0653/33 Oct/Nov 2018

7 (a) Fig. 7.1 shows a picture of a sloth and some information about sloths. Sloths live in the Amazon rainforest. They feed on the leaves of trees. Sloths are eaten by an animal called a jaguar. Fig. 7.1 (i) Use the information in Fig. 7.1 to construct the food chain for the sloth. … [2] (ii) Complete this sentence about the sloth. The sloth is a … consumer because it eats the producer. [1] (b) Rainforests are being destroyed by deforestation. Fig. 7.2 shows the area of deforestation each year in the Amazon rainforest. 30 000 25 000 20 000 area of deforestation / km2 15 000 10 000 5 000 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 year Fig. 7.2 (i) State the year that had the greatest amount of deforestation. … [1] (ii) Explain why the trend seen in deforestation between 2004 and 2010 benefits sloths. … … … … [2] (c) Plants in the rainforest take up water and mineral ions from the soil. Fig. 7.3 is a diagram showing some of the cells in the root of a plant. soil particles root … cell xylem vessel root hair Fig. 7.3 (i) Complete the label on Fig. 7.3 to identify the cells between the root hair and the xylem vessels. [1] (ii) Draw one arrow to show the pathway taken by water from the soil into the root. [1] (iii) Describe how water moves in and out of cells. … … … [2] [Total: 10]

10 marks

Mark scheme: 7(a)(i) leaves → sloth → jaguar correct order ; arrows in right direction ; 7(a)(ii) primary ; 1 7(b)(i) 1995 ; 1 Question Answer Marks 7(b)(ii) any two from: amount of deforestation is decreasing ; less habitat being destroyed ; decrease in (the rate of) loss of leaves / food source ; 2 7(c)(i) cortex ; 1 7(c)(ii) arrow drawn going into the root hair ; 1 7(c)(iii) by, diffusion / osmosis ; through a partially permeable membrane ; 2

This question in 0653/33 Oct/Nov 2020

1 (a) A blue dye is dissolved in water to make a blue liquid. Fig. 1.1 shows a cut plant stem in a beaker of the blue liquid. leaves plant stem blue liquid Fig. 1.1 The plant stem is left in the blue liquid for 24 hours. (i) Complete the sentences to explain why the leaves turn blue. Choose words from the list. Each word may be used once, more than once or not at all. cortex mesophyll phloem root hair stomata xylem The blue liquid moves up the plant stem in vessels called … . In the leaves, the blue liquid moves out of the vessels into … cells. Water in the blue liquid then diffuses out of the … into the air. [3] (ii) Fig. 1.2 shows the cross-section of the plant stem from Fig. 1.1. A B C D Fig. 1.2 The blue liquid only stains the transport vessels in the stem blue. Identify the letter in Fig. 1.2 that shows these transport vessels. … [1] (b) Plants make their own food. They make large molecules from smaller molecules. (i) The boxes on the left show some large molecules. The boxes on the right show the smaller molecules the large molecules are made from. Draw one straight line from each large molecule to the smaller molecules it is made from. large molecules smaller molecules oil amino acids protein fatty acids and glycerol starch glucose [2] (ii) Oils are stored in the seeds of a plant. A test is used to find the presence of oil in seeds. State the name of this test. … [1] (c) Oil from palm trees has many uses. Fig. 1.3 shows the mass of palm oil used worldwide between 2006 and 2016. 60 55 mass of 50 palm oil used worldwide / × 109 kg 45 40 35 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 year Fig. 1.3 (i) Use Fig. 1.3 to determine the mass of palm oil used worldwide in 2011. … ×109 kg [1] (ii) Areas of rainforest are removed to plant palm trees for oil. Describe how deforestation affects the animals living in the rainforest. … … … [2] [Total: 10]

10 marks

Mark scheme: 1(a)(i) xylem ; mesophyll ; stomata ; 3 1(a)(ii) D ; 1 1(b)(i) oil amino acids protein fatty acids and glycerol starch glucose one correct ; three correct ; 2 1(b)(ii) ethanol (emulsion) ; 1 1(c)(i) 48 (× 109 kg ) ; 1 1(c)(ii) any two from: loss of habitat ; less food OR disruption to food, webs / chains ; less shelter ; migration (of species) ; extinction (of species) ; 2

This question in 0653/32 Oct/Nov 2021

1 (a) A blue dye is dissolved in water to make a blue liquid. Fig. 1.1 shows a cut plant stem in a beaker of the blue liquid. leaves plant stem blue liquid Fig. 1.1 The plant stem is left in the blue liquid for 24 hours. (i) Complete the sentences to explain why the leaves turn blue. Choose words from the list. Each word may be used once, more than once or not at all. cortex mesophyll phloem root hair stomata xylem The blue liquid moves up the plant stem in vessels called … . In the leaves, the blue liquid moves out of the vessels into … cells. Water in the blue liquid then diffuses out of the … into the air. [3] (ii) Fig. 1.2 shows the cross-section of the plant stem from Fig. 1.1. A B C D Fig. 1.2 The blue liquid only stains the transport vessels in the stem blue. Identify the letter in Fig. 1.2 that shows these transport vessels. … [1] (b) Plants make their own food. They make large molecules from smaller molecules. (i) The boxes on the left show some large molecules. The boxes on the right show the smaller molecules the large molecules are made from. Draw one straight line from each large molecule to the smaller molecules it is made from. large molecules smaller molecules oil amino acids protein fatty acids and glycerol starch glucose [2] (ii) Oils are stored in the seeds of a plant. A test is used to find the presence of oil in seeds. State the name of this test. … [1] (c) Oil from palm trees has many uses. Fig. 1.3 shows the mass of palm oil used worldwide between 2006 and 2016. 60 55 mass of 50 palm oil used worldwide / × 109 kg 45 40 35 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 year Fig. 1.3 (i) Use Fig. 1.3 to determine the mass of palm oil used worldwide in 2011. … ×109 kg [1] (ii) Areas of rainforest are removed to plant palm trees for oil. Describe how deforestation affects the animals living in the rainforest. … … … [2] [Total: 10]

10 marks

Mark scheme: 1(a)(i) xylem ; mesophyll ; stomata ; 3 1(a)(ii) D ; 1 1(b)(i) oil amino acids protein fatty acids and glycerol starch glucose one correct ; three correct ; 2 1(b)(ii) ethanol (emulsion) ; 1 1(c)(i) 48 (× 109 kg ) ; 1 1(c)(ii) any two from: loss of habitat ; less food OR disruption to food, webs / chains ; less shelter ; migration (of species) ; extinction (of species) ; 2

This question in 0653/33 Oct/Nov 2021

7 (a) Fig. 7.1 is a diagram of two guard cells surrounding an open stoma from a plant leaf. stoma guard cell Fig. 7.1 (i) Draw a label line and the letter C to identify one chloroplast in Fig. 7.1. [1] (ii) Complete these sentences about guard cells and photosynthesis. Choose words from the list. Each word or phrase may be used once, more than once or not at all. carbon dioxide epidermis evaporation mesophyll nitrogen osmosis oxygen palisade transpiration Guard cells are found in the lower … of the leaf. The stomata are pores that allow the gas needed for photosynthesis to enter. This gas is called … . Water vapour diffuses out of the stomata during the process of … . [3] (b) Fig. 7.2 shows a food chain from a forest. green plants deer tiger Fig. 7.2 (i) Place ticks (✓) in all the boxes that describe the tiger. carnivore herbivore primary consumer secondary consumer tertiary consumer [2] (ii) State the name of the type of organism that gets its energy from waste organic matter. … [1] (c) Deforestation has undesirable effects on the animals in a food chain. Suggest two undesirable effects on the animals. 1 … 2 … [2] [Total: 9]

9 marks

Mark scheme: 7(a)(i) any chloroplast labelled ; 1 7(a)(ii) epidermis ; 3 carbon dioxide ; transpiration ; 7(b)(i) carnivore ; 2 secondary consumer ; 7(b)(ii) decomposer ; 1 7(c) any two from: 2 loss of habitat ; loss of food ; (possible) extinction / species may become endangered ;

This question in 0653/32 Feb/March 2023

7 (a) Fig. 7.1 shows part of a food web. hawk bear grouse chipmunk marmot insects seeds grasses Fig. 7.1 (i) Identify the two herbivores in Fig. 7.1. … and … [1] (ii) Identify one tertiary consumer in Fig. 7.1. … [1] (b) Complete the sentences about producers. Use words from the list. Each word may be used once, more than once or not at all. carbon dioxide magnesium nitrate oxygen photosynthesis respiration iodine transpiration Producers make their own organic nutrients using the process of … . The raw materials needed for this process are water and … . The products of this process are glucose and … . Plants also need … ions for making amino acids. [4] (c) Food webs are affected by deforestation. Fig. 7.2 is a bar chart showing the area of deforestation each year for one country. 30,000 25,000 20,000 area of deforestation 15,000 each year / km2 10,000 5,000 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 year Fig. 7.2 Describe the trends shown in Fig. 7.2. … … … [2] [Total: 8]

8 marks

Mark scheme: 7(a)(i) insects and marmot ; 1 7(a)(ii) hawk / bear ; 1 7(b) photosynthesis ; carbon dioxide ; oxygen ; nitrate ; 4 7(c) the area of deforestation decreases then increases ; identifies lowest point is in 2012 / overall the decrease is greater than the increase / decreases to 4500 km2 (pa) ; 2

This question in 0653/33 May/June 2023

4 (a) Fig. 4.1 shows some of the parts of an insect-pollinated flower. F A E B D C Fig. 4.1 (i) State the letter on Fig. 4.1 that identifies: an ovule … where pollination occurs. … [2] (ii) Fig. 4.1 does not show the sepals and petals of the flower. State the function of: sepals … petals. … [2] (b) An animal gets its energy by eating only plants. State the term that describes this type of animal. … [1] (c) Plants use carbon dioxide for photosynthesis. (i) Complete the word equation for photosynthesis. carbon dioxide +  + oxygen [2] (ii) Fig. 4.2 is a graph showing the effect of carbon dioxide concentration on the rate of photosynthesis. 25 20 rate of 15 photosynthesis in arbitrary 10 units 5 0 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 percentage concentration of carbon dioxide in the air Fig. 4.2 Describe the effect of increasing carbon dioxide concentration on the rate of photosynthesis shown in Fig. 4.2. Include data in your answer. … … … … [2] (d) Deforestation causes an increase in carbon dioxide concentration in the atmosphere. State two other undesirable effects of deforestation. 1 … 2 … [2] [Total: 11]

11 marks

Mark scheme: 4(a)(i) C ; F ; 2 4(a)(ii) protect, bud / flower ; attract, insects / pollinators ; 2 4(b) herbivore ; 1 4(c)(i) water ; glucose ; 2 4(c)(ii) (rate of photosynthesis) increases then levels off ; use of data, e.g. maximum rate = 18 (arbitrary units) / stops increasing at 0.07 (%) ; 2 Question Answer Marks 4(d) any two from: habitat destruction ; disrupts food chain ; extinction ; loss of soil ; flooding ; 2

This question in 0653/33 May/June 2024

3 Fig. 3.1 shows part of a food web from a coral reef habitat. shark parrotfish unicornfish coral zooplankton phytoplankton Fig. 3.1 (a) (i) Circle the word that describes the phytoplankton in the food web in Fig. 3.1. animal decomposer herbivore producer [1] (ii) Identify one primary consumer shown in Fig. 3.1. … [1] (iii) Explain why the shark shown in Fig. 3.1 is described as a carnivore. … … [1] (b) Coral is being damaged by marine pollution. (i) Use Fig. 3.1 to explain the effect this has on the number of parrotfish in the habitat. … … … [2] (ii) Pollution of freshwater and marine environments is one cause of habitat destruction. Describe one other cause of habitat destruction. … … [1] (c) Coral reef habitats release carbon dioxide into the atmosphere. State a process in the carbon cycle that removes carbon dioxide from the atmosphere. … [1] [Total: 7]

7 marks

Mark scheme: 3(a)(i) producer ; 1 3(a)(ii) zooplankton / unicornfish ; 1 3(a)(iii) feeds on / eats, animals / fish (only) ; 1 3(b)(i) (parrotfish) numbers would decrease ; 2 as less food available (for parrotfish) ; 3(b)(ii) any one from: 1 increased area for housing / crop production / livestock production ; extraction of natural material ; construction, e.g. building roads / building railways ; 3(c) photosynthesis ; 1

This question in 0653/33 May/June 2025

3 Tigers are endangered animals that live wild only in parts of Asia. Tigers catch and eat many different animals. (a) (i) Table 3.1 shows some information about the number of tigers that live wild. Table 3.1 estimated number of tigers year that live wild 1900 100 000 2000 3500 2020 4500 Suggest two reasons for the difference in the number of tigers between 1900 and 2000. 1 … 2 … [2] (ii) Circle all the words that describe the tiger. carnivore consumer decomposer herbivore producer [2] (b) Tigers are part of an ecosystem. (i) Circle two words in bold to give a correct description of an ecosystem. An ecosystem is a community of habitats / organisms and their climate / environment, interacting together. [1] (ii) State the word that describes the number of different species that live in an area. … [1] (c) Tigers have a similar alimentary canal to humans. The flow chart in Fig. 3.1 shows the direction that food moves as it passes through the alimentary canal. Complete Fig. 3.1. mouth … stomach … large intestine Fig. 3.1 [2] [Total: 8]

8 marks

Mark scheme: 3(a)(i) any two from: 2 • climate change ; • habitat destruction / deforestation ; • hunting ; • pollution ; 3(a)(ii) consumer ; 2 carnivore ; 3(b)(i) organisms AND environment circled ; 1 3(b)(ii) biodiversity ; 1 3(c) oesophagus ; 2 small intestine ;

This question in 0653/32 Oct/Nov 2025

3 Tigers are endangered animals that live wild only in parts of Asia. Tigers catch and eat many different animals. (a) (i) Table 3.1 shows some information about the number of tigers that live wild. Table 3.1 estimated number of tigers year that live wild 1900 100 000 2000 3500 2020 4500 Suggest two reasons for the difference in the number of tigers between 1900 and 2000. 1 … 2 … [2] (ii) Circle all the words that describe the tiger. carnivore consumer decomposer herbivore producer [2] (b) Tigers are part of an ecosystem. (i) Circle two words in bold to give a correct description of an ecosystem. An ecosystem is a community of habitats / organisms and their climate / environment, interacting together. [1] (ii) State the word that describes the number of different species that live in an area. … [1] (c) Tigers have a similar alimentary canal to humans. The flow chart in Fig. 3.1 shows the direction that food moves as it passes through the alimentary canal. Complete Fig. 3.1. mouth … stomach … large intestine Fig. 3.1 [2] [Total: 8]

8 marks

Mark scheme: 3(a)(i) any two from: 2 • climate change ; • habitat destruction / deforestation ; • hunting ; • pollution ; 3(a)(ii) consumer ; 2 carnivore ; 3(b)(i) organisms AND environment circled ; 1 3(b)(ii) biodiversity ; 1 3(c) oesophagus ; 2 small intestine ;

This question in 0653/33 Oct/Nov 2025