Life Sciences Grade 12 P2 Eastern Cape Mock 2012 Memo (Eng)

Downloaded from hlayiso.com Province of the EASTERN CAPE EDUCATION NATIONAL SENIOR CERTIFICATE GRADE 12 SEPTEMBER 2012 LIFE SCIENCES P2 MEMORANDUM MARKS: 150 This memorandum consists of 9 pages.

Downloaded from hlayiso.com 2 LIFE SCIENCES P2 (SEPTEMBER 2012) SECTION A QUESTION 1 1.1 1.1.1 A √√ 1.1.2 A √√ 1.1.3 B √√ 1.1.4 C √√ 1.1.5 A √√ 1.1.6 A √√ 1.1.7 C √√ 1.1.8 D √√ 1.1.9 D √√ (9 x 2) (18) 1.2 1.2.1 Endometrium √ 1.2.2 Herbivore √ 1.2.3 Predator √ 1.2.4 Fertilisation √ 1.2.5 Symbiosis √ 1.2.6 Population √ 1.2.7 Census/Counting √ 1.2.8 Decomposers √ 1.2.9 Interspecific competition √ (9 x 1) (9)

Downloaded from hlayiso.com (SEPTEMBER 2012) LIFE SCIENCES P2 3 1.3 1.3.1 Both A and B √√ 1.3.2 Both A and B √√ 1.3.3 A only √√ 1.3.4 None √√ 1.3.5 Both A and B √√ 1.3.6 A only √√ 1.3.7 B only √√ 1.3.8 B only √√ (8 x 2) (16) 1.4 1.4.1 B√ C√ A√ D√ (in this sequence) (4) 1.4.2 D√ (1) 1.4.3 B√ (1) 1.4.4 Primary succession √ (1) TOTAL SECTION A: 50

Downloaded from hlayiso.com 4 LIFE SCIENCES P2 (SEPTEMBER 2012) SECTION B QUESTION 2 2.1 2.1.1 (a) 3√ (1) (b) 2√ (1) 2.1.2 - Amniotic fluid √ (1) 2.1.3 - Act as a shock absorber √/ protect foetus against injury - Maintain constant body temperature/ - Medium for free movement of foetus. √ - Prevents dehydration of the foetus. √ (Mark first TWO answers only) (2) 2.1.4 Placenta. √ / chorion villi (1) 2.1.5 - Provides nourishment for the embryo √ - Supplies oxygen/ removes carbon dioxide √ - For attaching the embryo to the mother √ - Allow for diffusion of nitrogenous excretory wastes from the foetus to the mother. √ - secretes its own progesterone after ±12 weeks to maintain pregnancy √ (Mark first TWO answers only.) (2) 2.1.6 - umbilical cord √ (1) 2.2 2.2.1 A – Hypophysis / Pituitary gland √ B – Thyroid gland √ C – Pancreas √ (3) 2.2.2 (a) B √ (b) A √ (2) 2.2.3 - The pituitary gland (A) secretes the hormone TSH √ which - stimulates the thyroid gland (B) to secrete thyroxin. √ - an increase in thyroxin in the blood inhibits the pituitary (A) - which secretes less TSH. √ - this cause the thyroid gland to secrete less thyroxin. √ - which in turn reduce the inhibitory effect on the pituitary gland √ - which will then increase the amount of TSH that it secretes. √ (Any 4 x 1) (4)

Downloaded from hlayiso.com (SEPTEMBER 2012) LIFE SCIENCES P2 5 2.3 2.3.1 A – Semi-Circular Canals. √ (1) B – Ampulla √ (1) C – Utriculus √ (1) D – Sacculus √ (1) E – Cochlea √ (1) F – Auditory nerve √ (1) 2.3.2 (a) head movement √/ nodding / speed and direction of head movement (1) (b) changes in the body position √/ gravity (1) (c) sound waves √ (1) 2.3.3 - by the bony labyrinth. √ (1) 2.3.4 (a) cerebellum √ (1) (b) cerebrum √ (1) [30]

Downloaded from hlayiso.com 6 LIFE SCIENCES P2 (SEPTEMBER 2012) QUESTION 3 3.1 3.1.1 This visual courtship display in peacocks is a way that the males attract a mate √ of the same species as a prelude to mating √ (Any 2 x 1) (2) 3.1.2 The embryo within the egg is protected √ from drying out by a shell, √ is nourished by the yolk √ and albumin and is able to develop successfully √ on land. (Any 2 x 1) (2) 3.1.3 Many eggs are eaten by predators √ or washed away √ by the currents and never are fertilised. So thousands off eggs are laid to ensure that some will be fertilised √ and developed into codfish. (Any 2 x 1) (2) 3.1.4 Release of sperm and eggs is synchronised √ which increase the probability that external √ fertilisation of the eggs will occur since the gametes are released in the same places √ at the same time. (Any 2 x 1) (2) 3.1.5 Providing parental care increases the probability √ that the offspring will survive until they are independent √ and fully mature to produce their own offspring. √ (Any 2 x 1) (2) 3.2 3.2.1 The estimated population size of Species A and B over eight weeks 2000 1800 1600 Estimated population size 1400 1200 1000 Species B 800 Species A 600 400 200 0 1 2 3 4 5 6 7 8 Time (weeks)

Downloaded from hlayiso.com (SEPTEMBER 2012) LIFE SCIENCES P2 7 Guideline for the assessing of the graph Correct type of graph and the 1 joining of points Title of graph 1 Correct label and scale x-axes 1 Correct label and scale y-axes 1 Key/ labelling of species A and B 1 Plotting of points 1: 1 to 6 points plotted correctly 2: 7 to 12 points plotted correctly 3: 13 to 15 points plotted correctly 4: all 16 points plotted correctly (9) NOTE: If the wrong type of graph is drawn, 5 marks will be lost for:  ‘Correct type of graph and joining of points’  ‘Plotting of points’ If labels of the axes are transpose then 2 marks will be lost for:  * ‘Correct label and scale for X and Y axes 3.2.2 As the numbers of Species B increases the number of Species A decrease because they (Species A) are the food for Species B √ / In week 1 the numbers of Species A increase more than Species B because they had enough food √/ If Species B would have been the prey, their numbers in week two would have been less because than there would have been more predators (species A) in week 1. √ (Any 1 x 1) (1) 3.2.3 Both would die, √ because the food for Species A would be finished and species A will die leaving Species B without food and they will also die. √ (2) 3.2.4 Species A numbers will increase √ because there will be no predators to kill them. √ (2) 3.3 3.3.1 - The natural resources vary/ - Changing ecosystems - Building of new houses, etc. - Population growth - Increase in waste √ (Any 1 x 1) (1) 3.3.2 - Since 1961 – 1975 the ecological footprint is higher than the biocapacity. √ - After that (1976) the ecological footprint drop below the biocapacity /biocapacity increase above the ecological footprint. √ - During the 1980’s and 1990’s the ecological footprint remained more or less constant. √ - and even dropped slightly in the late 90’s early 2000’s √ (Any 3 x 1) (3)

Downloaded from hlayiso.com 8 LIFE SCIENCES P2 (SEPTEMBER 2012) 3.3.3 - Those countries having higher ecological footprints than their biocapacity will acquire resources from neighbouring countries, √ - thus increasing competition for the resources √/ lead to unrest/war (1) 3.3.4 - 12/13 years √ (1) [30] TOTAL SECTION B: 60 SECTION C QUESTION 4 4.1 4.1.1 Extinct – species that no longer exists √ / last individual of the species have died. Endemic – Organisms which are only found in a restricted area / country / part of a country. √ (2) 4.1.2 - Alien trees were removed from the area. √ (1) 4.1.3 - If endemic species go extinct, they are lost forever √/ as they do not occur anywhere else √ in the world. (Any 1 x 1) (1) 4.2 4.2.1 - James’s hearing is better/not /same/different  than Sandra’s √ - James’s hearing of lower frequencies is higher/lower/the same/different √ than that of Sandra’s √ - Sandra’s hearing of higher frequencies is higher/lower/the same/different √ than that of James. √ (Any 2 x 1) (2) 4.2.2 - James can hear things, √ that Sandra cannot hear. √ (2) 4.2.3 - 19 √ Hz (1) 4.2.4 James. √ He has a range of 19 to 20 300 = 20 281 Hz √ whereas Sandra, has a range of 18 to 20 100 = 20 082 Hz √ (3) 4.2.5 Independent – James and Sandra/person √ Dependent – Lowest and highest frequency √ of sound (2) 4.2.6 No, √ the sound that they(bats) produce have a much higher frequency √ than the range that James can hear. √ (3) 4.2.7 - hammer/maleus, √ anvil/incus √ and stirrup/stapes √ (3)

Downloaded from hlayiso.com (SEPTEMBER 2012) LIFE SCIENCES P2 9 4.3 - When it is hot √ - Heat receptors √ - in the skin √ - and receptors in the hypothalamus √ - are stimulated by the high temperature √ - The stimulus in the skin is converted into an impulse √ - and transmitted to the hypothalamus √ - which acts as the heat regulating centre of the body √ - Impulses are sent from √ the hypothalamus - to the sweat glands √ - and erector muscles √ - More sweat is produced √ - and more heat is lost √ - by evaporation of sweat √ - The erector muscles relax √ - causing the hair √ - to lie flat on the skin √ - trapping very little air between the hair √ - Insulation is thus reduced √ - Dilated blood vessels allow more blood to the skin √ - and more heat is thus lost from the body √ - by radiation/ conduction / convection √ - thus lowering the body temperature to normal √ (Any) (17) ASSESSING THE PRESENTATION OF THE ESSAY Marks Descriptions 3 Well structured – demonstrates insight and understanding of question 2 Minor gaps in the answer 1 Attempted but with significant gaps in the answer 0 Not attempted/nothing written other than question number Synthesis (3) TOTAL SECTION C: 40 GRAND TOTAL: 150