MEMORANDUM GRADE 11. LIFE SCIENCES: End-of-year exam Paper 2

Transcription

1 MEMORANDUM GRADE 11 LIFE SCIENCES: End-of-year exam Paper 2 MARKS: 150 TIME: 2½ hours

2 Section A Question A C B D C (2 5) [10] biome gymnosperms pistil pollutants Cnidaria [5] D F B J I A E C G H [10] Platyhelminthes (1) humans (1) Page 2 of 8

3 1.4.3 It absorbs nutrients from the intestine of the host. (2) Humans eat pork that is undercooked and contains tapeworm cysts. The tapeworm grows in human intestines. Segments of the tapeworm containing ripe eggs leave the humans via the faeces. Pigs eat the eggs. Eggs hatch in the pigs stomachs and the embryos burrow through the stomach walls into the bloodstream. The embryos develop into cysts in the muscles. (4) Tapeworm cysts develop in children s brains. The children have fits and possibly die. (2) Build proper toilets and enclose pigs so they do not eat human waste. (2) [12] reduce, reuse, recycle (3) vermicomposting (1) Earthworms aerate the soil, loosen the soil and eliminate the foul smell of decaying organic waste. (any 2) Earthworm farms provide increased job opportunities and encourage the rapid development of rural areas. (2) [8] Biocontrol is the use of natural predators to reduce an alien pest population. (1) The alien plant population numbers decreased rapidly soon after the biocontrol was introduced. The alien plant population and biocontrol population numbers show a similar trend in terms of increase and decrease in numbers. (2) It is the key to safe and successful biocontrol. (2) [5] Total Question 1: 50 marks Total Section A: 50 marks Page 3 of 8

4 Section B Question Chordata It has a vertebral column and a dorsal nerve cord. (2) a) cladogram (1) b) ancestor or ancestral stock (1) c) point of divergence (1) d) Yes. They evolved from a common ancestor that lived about 10 million years ago. (2) e) between 5 and 6 million years ago (2) A high percentage of cheetahs live outside protected National Parks and in farmlands. Some farmers shoot and poison cheetah in an attempt to protect their livestock. There has been a loss of habitat for cheetahs. There is a lack of sufficient prey to support the cheetahs population. (any 3) The climate where the Anatolian shepherd dogs come from is very similar to parts of southern Africa with little rain, and extreme heat in summer and cold in winter. Anatolian shepherd dogs have coarse, light-coloured fur that effectively cools their bodies. They are large, move fast and can go for days with very little food or water. (any 4) They form a strong bond with the livestock they will protect. (1) Anatolian shepherd dogs stay with the herd and are very sensitive to changes in herd behaviour. They aggressively protect herds of goats, sheep or cattle from predators such as cheetah, leopards, baboons, jackals, caracals and poachers. The dogs are trained to bark and maintain aggressive posture to scare away predators. The predators are not harmed but are encouraged to seek other food sources. The programme has been highly successful. Farmers who have Anatolian shepherd dogs guarding their livestock report no stock losses. Farmers will therefore not kill or poison predators because their livestock are no longer threatened. This management strategy offers a long term solution for farmers and predators. (any 5) [22] carbon dioxide (1) Eskom burns fossil fuels to produce energy and Sasol uses fossil fuels to produce petroleum products. Both processes produce carbon dioxide as a waste product. (2) Page 4 of 8

5 2.2.3 Take measurements of carbon dioxide levels in the air and the amount of carbon dioxide released from the biggest producers of greenhouse gases. Uses the data collected to plot a graph that will show the trend in changing carbon dioxide levels. (3) Use alternative energy sources other than fossil fuels (coal). Improve the efficiency of the processes to decrease the amount of pollutants, such as carbon dioxide, produced. (2) [8] Question Pie chart showing percentage of different tree species occurring in industrial tree plantations Total Question 2: 30 marks a) gymnosperms/conifers (1) b) They have well-developed conducting and strengthening tissue. This allows water to travel efficiently to the tops of tall trees. The strengthening tissue or lignin that makes up the walls of the tracheids gives the trunks and branches the strength to support a tall tree. (3) c) timber, timber products such as paper, resin, turpentine (any 3) a) 8% (1) b) Black wattles are an excellent source of tannin, charcoal, wood chips and poles. They are used as a source of fuel and for building material. This provides employment for many people. However, they invade a large percentage of useful land. They use lots of water and decrease biodiversity. Millions of rands are spent each year controlling black wattle. (2) (5) Page 5 of 8

6 3.1.4 Pine leaves or needles decompose in the ground, which makes the soil very acidic and unsuitable for other plants to grow. Pine trees absorb large amounts of water. If they are planted too close to wetlands or rivers, the wetlands and rivers begin to dry out. Pines invade the natural vegetation around them. Animals that used to live in the grasslands and fynbos lose their natural habitat and some species may become locally extinct. This reduces biodiversity in these areas. (any 2) Using sugar cane fibre saves using trees. This means planting fewer alien trees as a source of wood pulp. Sugar cane fibre is a renewable source of pulp. This supports previously disadvantaged farmers. (any 2) [19] The use of off-road vehicles on the coastal dunes is having a negative effect on the size of the oystercatcher population. OR The oystercatcher population is being negatively affected by the use of off-road vehicles on the coastal dunes. (2) a) oystercatcher population size (1) b) number of off-road vehicles driving on the coastal dunes (1) In general, there is a relationship between the number of vehicles using the beach and the size of the oystercatcher population. As the number of vehicles driving on the beach increases, so the number of oystercatchers decreases. (2) The oystercatcher population may have been negatively affected by factors other than the use of off-road vehicles. Other factors could be disease, parasites, lack of food or a natural disaster. (1) The researcher could measure the amount of time spent by vehicles in the dunes rather than only noting the numbers of vehicles. Use of the dunes by people in general may also affect the oystercatcher population. (2) The use of off-road vehicles on the coastal dunes has a negative effect on the size of an oystercatcher population. (1) It has a negative impact on other animal or plant species living in the dune system. (1) [11] Total Question 3: 30 marks Total Section C: 60 marks Page 6 of 8

7 Section C Question Biogeography is the study of the distribution of species. (2) Alfred Russel Wallace and Charles Darwin (2) The cichlids occur on the continents that were once connected when they formed Gondwanaland. The common ancestor would have evolved in Gondwanaland. As different cichlid species evolved, so they probably became more widely distributed through Gondwanaland. When the continents split due to continental drift, the cichlid species occurred on each continent. (6) Africa (1) a) occurring naturally in an area or region and found nowhere else in the world (2) b) large numbers of different niches with a wide variety of food types (2) a) It reproduces rapidly, has no naturally occurring enemies and takes the place of the indigenous species. (3) b) Introduce a biocontrol. Allow overfishing of Nile Perch to take place and rapidly decrease the numbers of Nile Perch. (2) [20] 4.2 The environmental importance of the Lake St Lucia ecosystem Nutrients washed off the land in the catchment areas of the rivers are carried into the lake and absorbed by plants such as reeds and phytoplankton. A great many consumers feed on these plants so there are many food webs in the lake. Lake St Lucia is home to hippo, crocodiles, fish and birds. On the eastern shores, the sand dunes, which are the highest in the world, are covered by rare dune forest. The forest collects rainwater which replenishes the fresh water in the lake. The beach on the sea side of these dunes is the breeding ground for the endangered leatherback turtles. Local people fish in the lake. Natural materials, such as reeds, found in the wetland are used for housing and for crafts, for example basket-making. The lake has been a popular wildlife and tourist area for a long time. (any 8) Page 7 of 8

8 The impact of mining in the Lake St Lucia region Mining company s position: The mining company believes that mining the dunes will not do much damage. The dune forests will be removed and one small area at a time will be mined. There would be machinery to suck up sand, separate heavy metals and deposit the waste sand. The mining company would rehabilitate the area by building new dunes with the waste sand. These dunes will be covered with topsoil that is full of seeds of indigenous plants from the area. The mining company claims that once these plants grow, no difference will be seen between the old dune forests and the new dune forests that will be created. (4) Conservationists opinion: Conservationists do not want the dunes mined. It has taken years for those dunes to form. The layers of sand in the dunes allow fresh rainwater to filter through and seep into the lakes. It would be difficult to restore the original biodiversity and about 40% of the forest species may disappear. The Lake St Lucia area is an important area for conservation and ecotourism. The mine would be noisy and would spoil the appearance of the eastern shores of the lake. Tourists want a quiet, beautiful place in which to have a wilderness experience. (4) The local community: The local community believes it has ancestral rights to the eastern shores. They were forcibly removed by the government of the time. They do not want the dunes to be mined. They do not believe that the mining company will give the local people jobs. Even if jobs were created for the local people, mining would last for about 20 years only. Conservation and ecotourism would provide far better long-term job and economic requirements. (4) Note: Award no marks for answers in the form of flow charts or diagrams. [20] Total Question 4: 40 marks Total Section C: 40 marks Grand total: 150 marks Page 8 of 8