Life Sciences Grade 12 IEB Paper 1 2018 Memo

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE EXAMINATION NOVEMBER 2018 LIFE SCIENCES: PAPER I MARKING GUIDELINES Time: 3 hours 200 marks These marking guidelines are prepared for use by examiners and sub-examiners, all of whom are required to attend a standardisation meeting to ensure that the guidelines are consistently interpreted and applied in the marking of candidates' scripts. The IEB will not enter into any discussions or correspondence about any marking guidelines. It is acknowledged that there may be different views about some matters of emphasis or detail in the guidelines. It is also recognised that, without the benefit of attendance at a standardisation meeting, there may be different interpretations of the application of the marking guidelines. IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 2 of 10 QUESTION 1 1.1 COLUMN A COLUMN B [G] A new population is established by a very small A Outbreeding number of individuals from a larger population. B Jean-Baptiste Lamarck [A] Promotes heterozygosity. C Alfred Wallace [K] One of the first scientific thinkers who proposed an idea of evolution. D Gene flow [B] Theory of inheritance of acquired characteristics. E Punctuated equilibrium [J] A form of macroevolution with a constant rate of F Homologous variations over long periods of time. G Founder effect [D] Movement of genes from one population to another. H Charles Darwin [H] Formulated the theory of evolution by natural selection. I Extinction [L] Structure which once performed a function in an J Gradualism ancestor of an organism. K Erasmus Darwin [F] Similar structures in organisms acquired from a common ancestor. L Vestigial organ [C] Proposed a similar mechanism of evolution to that of Charles Darwin. 1.2 Question 1.2.1 1.2.2 1.2.3 1.2.4 1.2.5 1.2.6 Answer C C B B A B 1.3 1.3.1 1 mm = 22-24 mm A to B = 10-15 mm 10 mm × 1 mm / 23 mm = 0,42 – 0,68 mm (Accept range) (Check final question paper for measurements) 1.3.2 (a) Time/mya different time periods. (b) 0,4 mm (Check final question paper for measurements) (c) Drill hole gets bigger over time / the younger the fossil Increase till 250 mya; slight decrease till 200 mya; increase till 50 mya. (Accept other reasonable answers.) IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 3 of 10 (d) Thicker shells/ better camouflaged/ harder shell (Accept other reasonable answers) (e) Used 7000 / large sample shells can calculate average /more data removes influence of outliers published in journal therefore peer reviewed / results repeatable . (f) Graph line lower lags behind prey. 1.4 Statement A, B or C 1.4.1 South Africa has more cases of FAS than the rest of A/C the world. 1.4.2 Abnormalities caused by foetal alcohol syndrome are B reversible. 1.4.3 FAS can be prevented by avoiding alcohol during A pregnancy. 1.4.4 Children with FAS have physical abnormalities and A intellectual disabilities. 1.4.5 FAS largely affects poverty stricken areas. C 1.5 Item Term Answer 1. Permanent contraception for female IUD B 2. Inserted into the uterus 1. Prevents STIs Male condom A 2. Chemical barrier 1. Tracking fertile days in the menstrual Rhythm method A cycle 2. Prevents embryo implantation 1. Foreskin is removed Vasectomy D 2. The fallopian tubes are tied off 1. Prevents ovulation Contraceptive pill C 2. Contains reproductive hormones IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 4 of 10 1.6 1.6.1 Label on diagram. 1.6.2 Correct Term/Description letter (a) Mature Graafian follicle C (b) Ovulation D (c) Corpus luteum E (d) Releases oestrogen at the start of the menstrual B cycle. (e) Starts developing as a result of FSH release. A (f) Produces a hormone to inhibit FSH production E after ovulation. (g) Remains in place if fertilisation does occur. E (h) Occurs due to a surge in LH. D 1.7 1.7.1 Description Label number(s) Diagram A Diagram B Place where fertilisation takes place. 3 11 Place where the male reproductive 6 9 cells are deposited. Organ which protects a developing 4 foetus. Structure where meiosis takes place. 2 8 / 11 Structure which develops into the fruit. 12 1.7.2 Heading: Differences between sexual and asexual reproduction. Sexual Asexual (column headings) Production of gametes No production of gametes Results in variation Clones of parent Slower process Faster process Requires larger input of energy More energy efficient Pollination/Pollinators required No pollination Requires sexual reproductive Any vegetative part structures e.g. flower Usually 2 parents One parent Construction of table format (Accept other relevant differences) IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 5 of 10 1.8 1.8.1 Heading Y – axis: growth hormone concentration X – axis: age Units included in axis headings (ng/ml) Scale (check y-axis carefully) Plotted correctly (all 6 correct, 3–5 points correct) Line graph 1.8.2 Pituitary / hypophysis. 1.8.3 Hormones transported in blood to target organs. 1.8.4 Puberty/adolescence occurring growth spurt. 1.8.5 (a) 50–60 years. (b) Old age all processes slow down / growth plates closed / growth in height ceased / renewal of tissues slows. 1.8.6 (a) Acromegaly (b) Enlarged (flat) bones of hands/feet/face; coarsening of skin enlarged or protruding tongue/ thickening of soft tissues/ enlarged heart. IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 6 of 10 QUESTION 2 2.1 2.1.1 Australopithecus africanus. 2.1.2 Foramen magnum (or described) towards centre of skull (descriptions meaning the same). 2.1.3 Freed hands able to carry tools / weapons whilst moving / carry offspring to safety; cover large distances / with little energy expenditure); see predators / source of food easily; live in a greater variety of biomes, e.g. forest and savannah increased cooling. 2.1.4 Ape's teeth would be larger; pronounced canines; U shape of dental arch gap in upper jaw for canines (diastema). 2.1.5 Measuring the volume of the brain-cast; which was a model of actual brain size / using cranium of skull; determining volume (Accept any suitable measurement of volume) description of how volume measured use a endocranial cast. 2.1.6 Belief that early humans originated in Europe/ England had a larger brain; and more apelike jaw/teeth. 2.1.7 Open minded about new evidence; rather than sticking to preconceived ideas; allowing many scientists to examine evidence to reduce chance of hoax / mistakes made by scientists; prevent societal views to slant their ideas on science; collaboration more important than competition as human evolution largely an unknown field. 2.2 2.2.1  mtDNA / genetic evidence modern Africans have largest number of variations  Fossil evidence oldest Homo sapiens fossils found in Africa  archaeological evidence oldest evidence of symbolic thought found in Africa / e.g. Art (Blombos Cave);  burial of dead (Klasies Cave, Border Cave);  tools/artefacts (Pinnacle Cave, Blombos) (line of evidence explained) × 2 2.2.2 200 000 – 45 000 = 155 000 years. 2.2.3 Larger brain enabled to plan ahead / communication; use of fire source of warmth in inhospitable areas / defence against prey / social organisation bipedalism cover large distances pronounced chin to allow for more space for tongue for communication. (List two characteristics and explain how each enabled them to survive. Accept any reasonable answers) 2.2.4 Multiregional Homo sapiens evolved independently in separate regions from Homo erectus / Homo neanderthalensis. IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 7 of 10 2.3 2.3.1 Cradle of Humankind/ Malapa. 2.3.2 Allows time for scientists to study fossils; to identify species time needed to remove fossil from rock; to collect many specimens; peer review requires time; dating to confirm ages. 2.3.3 Transitional fossil explanation of specific feature, e.g. long arms, / arched feet / showing characteristics of both Homo and Australopithecus / new species fills gap in evolutionary record /explanation of human evolution. 2.3.4 Increased tourism / South Africa on map to find good fossils / enhances scientific understanding of human evolution in the public. (Any reasonable explanation) 2.4 A – divergent common ancestor shows species evolve differences homologous structure explained. B – convergent parent species not closely related show similarities in form / analogous structure explained. IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 8 of 10 QUESTION 3 3.1 3.1.1 Not enough food available. 3.1.2 Interspecific. 3.1.3 Variation in head size lizards with larger heads able to access more food greater chance of surviving and reproducing genes/traits for larger heads passed to offspring over time population had a greater number of larger head individuals. 3.1.4 YES: as geographically isolated / allopatric speciation therefore reproductively isolated / cannot interbreed / produce viable offspring OR NO: not enough time to accumulate changes /only head size has changed can still interbreed when reintroduced. 3.1.5 Microevolution small changes / only change in head size in short period of time / small scale in small population. 3.2 3.2.1 96–99(%) 3.2.2 11/12/13 months 3.2.3 4 °C 3.2.4 Storage facility for seeds / place to preserve seeds. 3.2.5 Verge of extinction; used by locals for medicinal purposes; overuse. 3.2.6 The longer the seeds are stored less likely they are to germinate. 3.2.7 Cuttings / vegetative propagation remove a piece of plant, place in water add growth hormones / and allow growth of roots, plant it out / tissue culture/ cloning/micropropogation remove small number of cells from plant place in growth medium add growth hormones allow callus to develop and growth of plantlet plant it out. (name one explanation) 3.3 3.3.1 Patient has more glycogen granules / healthy subject has less glycogen granules has more dark patches – only or healthy has less dark patches. 3.3.2 Used as a comparison /control to show state of healthy liver. 3.3.3 (a) Insulin (b) Heading arrows high blood glucose levels  insulin released from beta cells (pancreas/ islets of Langerhans)  insulin travels in blood to liver  membrane of liver cells more permeable to glucose  glucose absorbed  converted to glycogen. (any 5 sequential steps) IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 9 of 10 3.3.4 Enlarged liver – excess glycogen stored and no glucagon secreted to convert glycogen to glucose low blood glucose – no / low secretion of glucagon to convert glycogen to glucose enzyme needed to release glucose from glycogen missing. Accept any reasonable answer for each symptom. QUESTION 4 4.1 A – prostate gland B – vas deferens / sperm duct C – urethra D – scrotum 4.2 4.2.1 Tip of penis 4.2.2 (a) True (b) True (c) False 4.3 4.3.1 Testes 4.3.2 Rapid physical growth in puberty; development of secondary sexual characteristics; regulate secretion of LH and FSH; sex drive; sperm production. 4.3.3 High levels of testosterone in blood inhibits secretion of LH and FSH from pituitary gland acts on testes stop secreting testosterone resulting in less sperm production. (5 good facts sequentially) 4.3.4 Unfair advantage reduce pressure from coaches and parents to take steroids reduce peer pressure to take steroids steroids have serious side-effects, e.g. lowers fertility, disrupts secretion of reproductive hormones steroid side-effects more pronounced in adolescents high levels of aggression testing acts as a deterrent highlight the dangers of taking steroids. 4.4 Larger footprint / image on right in developed countries use more natural resources / ecological debtor to sustain lifestyle represented by larger figure in cartoon indicates greed using more land more negative impact. Smaller footprint / image on left in developing countries no shoes/ thinner figure suggests lack of use of resources / ecological creditor. (Accept any reasonable suggestions.) 4.5 4.5.1 (a) Secondary. (b) Started with soil / not bare rock / soil present / plants grew here before / no lichens and moss / annual plants first colonisers. 4.5.2 Hardwood trees. 4.5.3 Living space; sunlight; water; soil nutrients; increase in competition; increase in diseases; pests. IEB Copyright © 2018 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I – MARKING GUIDELINES Page 10 of 10 4.5.4 YES – long term with changing plant communities increase in nutrients in soil would come animals increase in food increase in shelter. OR NO – long period of time before climax community / stable community pioneer community has low biodiversity seeds from crops present lead to different communities. 4.5.5 (a) Pioneer coloniser. (b) Community – group of populations/species in an area. Ecosystem includes interaction with environment / groups of communities interacting with each other. (c) (i) Early – short one growing season / 2 – 12 months. (ii) Late – longer more than a year. (d) Reduces competition with parent plants lifespan of early stage plants short if dispersed widely better coverage of new areas. Total: 200 marks IEB Copyright © 2018