Gr.11 Life Sciences Remote learning workbook term 3 PDF

LIFE SCIENCES GRADE 11 REMOTE LEARNING WORKBOOK 1 TERM 3 2 Week Topic Page 1 Gaseous exchange: Difference between cellular 4 respiration, breathing and gas ex...

LIFE SCIENCES GRADE 11 REMOTE LEARNING WORKBOOK 1 TERM 3 2 Week Topic Page 1 Gaseous exchange: Difference between cellular 4 respiration, breathing and gas exchange. Requirements of efficient gas exchange organs 2 Gaseous exchange: Human gas exchange –structure, 16 location, functions and adaptations of the ventilation system. 3 Gaseous exchange: Ventilation of the lungs. Homeostatic 24 control of breathing 4 Excretion in humans: Excretion in various organs. 29 5 Excretion in humans: Urinary system- position of organs, 32 structure and functioning of kidney. Structure and functioning of nephron 6 Excretion in humans: Homeostatic control of water and 40 salts; role of ADH and aldosterone. 7 Population ecology: Population size: Immigration, 47 emigration, mortality, natality; fluctuations and limiting factors 8 Population ecology: Logistic and geometric growth curves 51 with phases 9 Population ecology: Interactions in the environment – 56 predation, competition, specialisation, parasitism, mutualism, commensalism 10 Population ecology: Human population 62 3  WEEK 1: TOPIC: Gaseous exchange SUB-TOPIC: Difference between cellular respiration, breathing and gas exchange. NOTES & EXAM TIPS Biological terminology Aerobic occurring in the presence of oxygen Anaerobic occurring in the absence of oxygen Aquatic (plants and animals) living in water Breathing / mechanical process of inhalation and exhalation through ventilation which air moves in and out of the respiratory organs enabling the uptake of oxygen and the removal of carbon dioxide Carbohydrate a large group of organic compounds found in cells, including glucose, sucrose, and starch Cellular the breakdown of organic compounds (glucose / sugar) in the respiration mitochondria of cells into inorganic products (CO2 and H2O) with the release of cellular energy (ATP); either aerobic or anaerobic Diffusion the movement of molecules from a region of high concentration to a region of low concentration until equilibrium is reached Gaseous the exchange of O2 and CO2 at a respiratory surface exchange occurring between the air and blood and blood and cells Glucose a simple sugar which is an important energy source in living organisms and is a component of many carbohydrates Mitochondrion an organelle found in large numbers in most cells, in which the cellular respiration and energy production occur Respiratory is a membrane through which gas exchange takes place surface Terrestrial (plants and animals) living on land Introduction It is important to distinguish between breathing, gaseous exchange and cellular respiration. Why do we need to breathe? All organisms, from simple, unicellular to more advanced multicellular organisms need oxygen (O2) to sustain cellular functions. Oxygen is used to release energy from carbohydrates found in cells. Plants and animals need energy for survival. Organisms are structurally suited to ensure that the process of the exchange of 4 gases is optimised. More complex animals have a mechanism of breathing that ensures that gases enter their bodies, and this enables gaseous exchange and cellular respiration to occur efficiently. Regulation Structure to function and control Homeostasis Important aspects of gas How the organism exchange Breathing can is designed to carry out gaseous be impaired exchange which affects general health Amounts of gases Effect of disease Balanced levels of CO2 and O2 in the blood 5 Key concepts Breathing This is a mechanical process taking oxygen into the lungs. Cellular respiration A chemical process which takes place in the cells to release energy. Gaseous exchange A physical process which involves the exchange of gases between the air and blood in the lungs. 6  SUB-TOPIC: Requirements of efficient gas exchange organs For gases to effectively diffuse across respiratory surfaces, certain requirements need to be met. This is important for both terrestrial and aquatic habitats. Well ventilated Thin and Protected permeable Large Vascular Moist Relationship between respiratory structures and efficient gaseous exchange in different organisms All organisms, from simple unicellular to complex multicellular, rely on gaseous exchange for survival. The amount of O2 taken up and CO2 released depends on the ratio of surface area to volume of the organism. What does this mean? Surface area is the combination of all the exposed surfaces of the organism. The volume is the space taken up by the same organism. 7  Therefore, the surface area to volume ratio would be the amount of surface an organism has relative to its size. In general, the smaller the organism the larger the surface area to volume ratio. Both terrestrial and aquatic plants and animals have gaseous exchange surfaces and respiratory structures that ensure effective exchange of gases (O 2 and CO2). Comparison of the respiratory surfaces of various groups of organisms 8 Requirements for effective gaseous exchange surface large thin & moist well- protection transport permeable ventilated system Dicotyledonous plant (leaf and spongy mesophyll) flat surface thin-walled water vapour air cuticle and simple increases cells allow for passes movement lower diffusion exposure to diffusion through around epidermis air stomata leaves Earthworm (skin) elongated body mucous air thin cuticle diffusion cylindrical covering is glands keep movement shape thin the skin around the moist body Insect (tracheal system) extensively lining of tracheoles rhythmic exoskeleton network of branched tracheoles is are moist body and chitin tubules tracheae and thin movements rings throughout tracheoles move air in the body and out Bony fish (gills) branched gill thin aquatic water taken gills are heart and filaments membranes animals live in through protected by blood vessels increase in water the mouth is a bony cover, surface area forced out the over the gills operculum Mammals (lungs) bronchioles alveoli have mucus cells diaphragm ribs protect circulatory divide into thin secrete a thin and ribcage the lings system many alveoli squamous layer on regulate epithelium moisture inhalation layer and exhalation 9  ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS Activities Activity 1 Complete the word search on gaseous exchange below. Identify the term from the description and then find the term in the word search. Description 1) occurring in the presence of oxygen 2) occurring in the absence of oxygen 3) (plants and animals) living in water 4) (plants and animals) living on land 5) the exchange of O2 and CO2 at a respiratory surface 6) mechanical process of inhalation and exhalation through which air moves in and out of the respiratory organs enabling the uptake of oxygen and the removal of carbon dioxide 7) an organelle found in large numbers in most cells, in which the cellular respiration and energy production occur 8) The movement of molecules from a region of high concentration to a region of low concentration until equilibrium is reached 9) many tiny air sacs of the lungs which allow for rapid gaseous exchange 10) small branches in the lungs ending in air sacs 11) fine tubes that make up part of the respiratory system of insects 10 Created with The TeachersCorner.net Word Search Maker 11 Activity 2 Surface area to volume ratio We are going to build two imaginary animals. They are called Bookus glutinous and Bookus skinny. We would like to find out how the surface area to volume ratio influences the diffusion of gasses in these two animals. Instructions You first have to build these two animals. You will need 8 textbooks of equal size. This is an individual activity but the ‘animals’ can be built together. Animal 1: Use four of the textbooks on top of one another to build Bookus glutinous as the diagram indicates. Textbook Textbook Textbook Textbook Bookus glutinous Animal 2: Bookus skinny will consist out of 4 textbooks as the diagram below indicates. Remember the textbooks must be of the same size as the other textbooks which you used to build Bookus glutinous. Textbook Textbook Textbook Textbook Bookus skinny NOTE Surface area To work out the surface area you multiply the length and width of each side. Volume To work out the volume you must multiply the length, the width and the height with one another. Ratio of surface area to volume To determine the surface area to volume ratio you must divide the volume into the surface area for the answer. 12  Question 1 1.1 Calculate the surface area of Bookus glutinous. Remember the animal has 6 sides. Therefore, work out the surface area of each side and add all the answers together to determine the total surface area. (3) 1.2 Calculate the volume of Bookus glutinous. (3) 1.3 Calculate the ratio of the surface area to the volume of Bookus glutinous. (3) Question 2 Calculate the following: 2.1 Surface area of Bookus skinny. (3) 2.2 Volume of Bookus skinny. (3) 2.3 Ratio of the surface area to the volume of Bookus skinny. (3) Question 3 3.1 Which animal has the highest surface area to volume ratio? (1) 3.2 In which animal will oxygen reach all cells through the process of diffusion? (1) 3.3 Give a reason for your answer in question 3.2. (1) 3.4 What systems are in place for an animal with a small surface area to volume ratio to ensure that all cells receive oxygen in the shortest possible time? (2) 3.5 Predict what will happen if an animal with a small surface to volume ratio does not have specialized systems in place for oxygen to reach all the cells. (2) Question 4 Gaseous exchange is the biological process by which gases move passively by diffusion across a surface. In humans this happens in the lungs. 4.1 Name the site for gaseous exchange in the lungs. (1) 4.2 Name FOUR structural requirements of an efficient gas exchange surface. (4) 13 EXAM QUESTIONS QUESTION 1 (Questions taken from various sources) Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1 to 1.2) in your ANSWER BOOK, for example 1.3 D. 1.1 Study the table and answer the question below The reason for the amount of oxygen being higher in inhaled air than in exhaled air is that… A oxygen is taken into the bloodstream and some diffuses back to the alveoli to be breathed out B some oxygen does not reach the alveoli but remains in the bronchiole until exhalation occurs C oxygen is used in the body, but oxygen is produced in the body as a waste product, which is then exhaled D some oxygen from inhaled air diffuses into the blood and is used by the cells 1.2 Several features are listed below. 1. Large surface area 2. Thin surface 3. Moist surface 4. Many capillaries Which of the above are features of an efficient gaseous exchange surface? A 1, 2, 3 and 4 B 1, 2 and 4 14  C 1, 3 and 4 D 2, 3 and 4 (2 x 2) (4) QUESTION 2 (Questions taken from various sources) Give the correct biological term for each of the following descriptions. Write only the term next to the question number (2.1 to 2.3) in your ANSWER BOOK. 2.1 The pores on the leaves of plants through which gas exchange takes place 2.2 A pigment that transports oxygen in humans 2.3 Organelle that serves as the powerhouse of the cell (3) 15  WEEK 2: TOPIC: Gaseous exchange SUB-TOPIC: Human gas exchange –structure, location, functions and adaptations of the ventilation system. NOTES & EXAM TIPS When you breathe in, air enters your body through your nose or mouth. It then travels down your throat through the larynx (or voice box) and into the trachea or windpipe) before entering your lungs. LOCATION OF THE HUMAN GASEOUS SYSTEM The human gaseous exchange /ventilation system begins from the nose in the head and moves down the windpipe/ trachea located in the neck and extends into the bronchi and lungs within the thoracic cavity(chest). The diaphragm is the gaseous exchange muscle that separates the thoracic (chest) cavity from the abdominal cavity. STRUCTURE OF THE HUMAN GASEOUS EXCHANGE SYSTEM Figures 1 and 2 below show parts of the gaseous exchange system that are directly involved in breathing and gaseous exchange. FIGURE 1 FIGURE 2 16  STRUCTURAL SUITABILITY OF GASEOUS EXCHANGE SYSTEM The human gas exchange system is well designed or structurally suited to carry out the function of gaseous exchange. STRUCTURE FUNCTION AIR PASSAGES 2 Nostrils Air from atmosphere inhaled through two openings in nose called nostrils. 2 Nasal cavities Cavities are lined with ciliated columnar epithelium with goblet cells. Mucus from the goblet cells together with the cilia trap dust/dirt and sweep it out of the nose. Mucus keeps cavity moist. Blood capillaries warm the incoming air. Has turbinate bones to increase surface for airflow. Trachea Trachea is situated in front of the oesophagus. C-shaped cartilage rings protect trachea and keep it open for easy movement of air into the lungs. Bronchus / bronchi Trachea branches into left and right bronchi that enter the upper lobes of the left and right lungs. Held open by C-shaped cartilage rings so that it does not collapse during breathing. Lined with mucus membranes to keep incoming air moist Alveoli Bronchioli end in a collection of alveoli (air sacs) that are sites for gaseous exchange. Many alveoli increase the surface area to maximise the gas exchange. Have thin walls of squamous epithelial cells allowing for easy diffusion of gases. Tissue fluid keeps the walls of the alveoli moist for easy dissolving gases. A large blood capillary network surrounds the alveoli to allow for rapid diffusion of gases between alveoli and blood. THROAT AND LUNGS Pharynx (throat region) Connects the nasal cavity with larynx. Allows entry of gases into the trachea and oesophagus Larynx Larynx contains the vocal cords. 17  Air passes over the chords and sound is produced. Epiglottis A cartilage structure on top of the larynx (voice box). It closes when food is swallowed preventing food from entering the trachea and allows only air to pass over it into trachea. Lungs Two spongy, elastic lungs are surrounded by the double pleural membrane. This organ receives oxygen from air to be send throughout the body and it receives carbon dioxide from body cells to be expelled into air. Pleural fluid acts as a lubricant and helps prevent friction during inhalation and exhalation. RIBS AND MUSCLES INVOLVED IN BREATHING Ribs Rib bones on either side of the sternum form a rib cage to protect the lungs from injury. Intercostal muscles These are muscles found between the rib bones. They contract and relax during inhalation and exhalation altering the volume of air in the chest (thoracic cavity). A sheet of muscle below the lungs. Diaphragm It contracts and relaxes altering the volume of the chest cavity which is important in the breathing mechanism. 18  FUNCTIONS OF THE GASEOUS EXCHANGE SYSTEM The main function of the gaseous exchange system in humans is to take oxygen from the air into the lungs during inhalation and that this oxygen-rich air reaches the alveoli where gaseous exchange takes place so that the oxygen diffuses into the blood to be transported to the cells of the body. It then receives carbon dioxide from the cells of the body after cellular respiration to be expelled out of body via exhalation. The exchange of gases occurs in two areas in the body: At the 1. Alveoli surface (external gaseous exchange) and 2. Between the blood and tissues (internal gaseous exchange). GASEOUS EXCHANGE IN THE LUNGS AT THE ALVEOLI SURFACE The air entering the alveoli after inhalation has a high oxygen concentration compared to the oxygen concentration in the blood of the surrounding capillaries. The inhaled air has a lower carbon dioxide concentration than that of the blood in the surrounding capillaries. This results in oxygen diffusing (moving) from the alveoli into the blood and carbon dioxide diffusing (moving) from the blood and back into the alveoli to be exhaled. Gaseous exchange between alveolus and blood 19  GASEOUS EXCHANGE BETWEEN THE BLOOD AND TISSUES The cells will have a high carbon dioxide concentration due to continuing cellular respiration. This carbon dioxide moves out of the cells and diffuses into the blood and is transported back to the heart and then to the lungs where it is exhaled. Carbon dioxide is transported from the cells to the alveoli where it is removed from the body. The air in the alveoli will be exhaled with more carbon dioxide than the air that had been inhaled. Gaseous exchange between blood and cells Oxygen is transported mainly by the red blood cells. Most of the oxygen combines with the pigment haemoglobin present in the red blood cells (erythrocytes) to form oxyhaemoglobin. It is transported via the circulatory system to all body cells for respiration to produce energy (ATP) for the cells. Most of the carbon dioxide is transported in the blood plasma in the form of bicarbonate ions from the cells and tissue to the lungs to be exhaled. ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1 to 1.4) in your ANSWER BOOK, for example 1.5 D. 1.1 Cilia are found lining which of the following structures? 20  A Larynx B Alveoli C Trachea D Pleural membranes 1.2 Air breathed out is different from air breathed in because it: A contains less carbon dioxide. B is cooler. C is drier. D contains less oxygen 1.3 The lungs of a long-term smoker will have: A constricted bronchioles. B thinner walls. C a large surface area. D an increased capacity for gaseous exchange. 1.4 Which of the following does not occur during inhalation in a human? A Pressure within the thoracic cavity increases. B The lungs expand. C The diaphragm contracts. D Pressure in the abdominal cavity increases. (8) QUESTION 2 (Questions taken from various sources) Give the correct biological term for each of the following descriptions. Write only the term next to the question number (2.1 to 2.5) in your ANSWER BOOK. 2.1 The double membrane that covers the outer surface of the lungs. 2.2 The cartilaginous structure that contains the vocal cords. 2.3 Tiny air sacs at the end of each bronchiole. 2.4 Dome-shaped muscle separating the thorax from the abdomen. 2.5 The main branches of the trachea that lead to the lungs. (5) QUESTION 3 (Questions taken from various sources) Indicate whether each of the statements in COLUMN I applies to A ONLY, B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only, B only, both A and B, or none next to the question number (3.1 to 3.3) in the ANSWER BOOK. 21  COLUMN I COLUMN II 3.1 Breathing muscles A Intercostal B Diaphragm 3.2 C – shaped cartilaginous rings A Oesophagus B Bronchioles 3.3 The structure that prevents A Epiglottis food particles from entering B Glottis lungs (6) QUESTION 4 The diagram below represents a section through an alveolus and a surrounding blood capillary in the human body. 4.1 Name the type of epithelial tissue numbered 1 and 2. (2) 4.2 Identify the blood cell labelled 3. (1) 4.3 What pigment is found in the cell mentioned in QUESTION 4.2? (1) 4.4 Which type of blood: a) enters the blood capillary at A? (1) b) leaves the blood capillary at B? (1) 4.5 In which form is most oxygen carried in the blood? (1) 4.6 Supply two structural adaptions of the alveoli which make them well suited for gaseous exchange. (2) (9) 22 QUESTION 5 Use the flow chart below which summarises the gaseous exchange process in humans to answer the questions which follow. GAS A BLOOD LUNGS AIR IN Process A GAS X CELLS ATMOSPHERE Process B GAS B GAS Y 5.1 Label process A and B. (2) 5.2 Label gas X and Y. (2) (4) 23  WEEK 3: TOPIC: Gaseous exchange SUB-TOPIC: Ventilation of the lungs. Homeostatic control of breathing NOTES & EXAM TIPS TERMINOLOGY Ventilation: The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli. Alveoli: The tiny air sacs in the lungs. Homeostasis: It is a process of maintaining a constant internal environment within the body. (Level of oxygen and carbon dioxide in the body) Inhalation: The breathing in of air Exhalation: The breathing out of air Spirometer: An instrument used to measure the volume of air that enters and leaves the human lungs during inhalation and exhalation VENTILATION Inhalation is the process of taking air into the lungs. It is the active phase of ventilation because it is the result of muscle contraction. During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. This decreases the pressure so that air flows into the lungs. 24 HOMEOSTATIC CONTROL OF BREATHING When the heart rate increases, blood flow also increases. Rapid transport of gases to and from the cells occurs. When carbon dioxide levels rise, the cells in the respiratory centre of the medulla oblongata of the brain are stimulated. Increased rate and depth of breathing causes the intercostal muscles and the diaphragm to contract and relax. More oxygen is inhaled, and more carbon dioxide is exhaled. The levels of carbon dioxide in the blood determine the rate and depth of breathing. The ability of the body to return the levels the normal is known as homeostasis The flow diagram below represents the negative feedback mechanism for homeostatic control of breathing: 25  ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS ACTIVITY 1 QUESTION 1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1 to 1.3) in your ANSWER BOOK, for example 1.4 D. 1.1 The rate of breathing is regulated by the medulla oblongata, mainly… A under voluntary control. B according to oxygen level of blood. C according to the blood pressure. D according to carbon dioxide level of blood. 1.2 The following will determine the rate of breathing in humans: A Carbon dioxide in the blood B Bronchioles in the lungs 26  C Oxygen in the exhaled air D haemoglobin in the tissues 1.3 The breathing centre in the medulla oblongata is most sensitive to change in the… A glucose level of the blood B oxygen level of the tissue fluid C carbon dioxide levels of the blood. D ATP levels of mitochondria (3x2) (6) QUESTION 2 (Questions taken from various sources) Give the correct biological term for each of the following descriptions. Write only the term next to the question number (2.1 to 2.3) in your ANSWER BOOK. 2.1 The muscles between the ribs that are involved in the mechanism of breathing. 2.2 The tendency of living organisms to maintain a constant internal environment. 2.3 Air sacs in the lungs. (3) QUESTION 3 (Questions taken from various sources) Indicate whether each of the statements in COLUMN I applies to A ONLY, B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only, B only, both A and B, or none next to the question number (3.1 to 3.3) in the ANSWER BOOK. COLUMN I COLUMN II 3.1 The exchange of air between A Ventilation the lungs and the atmosphere. B Homeostasis 3.2 Movement of gases with the A Breathing aid of muscular activity B Gaseous exchange 3.3 Controlling center for A Brain homeostatic breathing control B Medulla oblongata (3 x 2) (6) 27 ACTIVITY 2 QUESTION 1 (Question adapted from grade 12 NSC 2020 question paper: P1) Describe how the human body maintains the carbon dioxide concentration in the blood when it rises above normal limits. (5) QUESTION 2 An investigation was carried out on a person in which the volume of air taken in at each breath and number of breaths per minute were measured at rest and after running. The results are shown in the table below. Volume of air per breath Breaths per minute At rest 450 cm3 20 After running 1 000 cm3 38 2.1 Explain why the amount of oxygen taken up into the blood increases after exercise. (3) 2.2 Describe the changes that took place in the human body to bring about an increase in the breathing rate of the person. (5) 2.3 20% of the air breathed in consist of oxygen, but only 16% of the air breathed out consist of oxygen. Calculate the amount of oxygen entering the blood per breath after running. Show your calculations (3) (11) 28 QUESTION 3 (GDE 2021 Exemplar P1) The diagram below is a model that can be used to demonstrate the breathing mechanism in humans. C D Diagram A Diagram B 3.1 What do each of the following parts represent in the human breathing system? (a) A (b) B (c) C (3) 3.2 Explain ONE way in which part A in humans is adapted for its function. (2) 3.3 Which diagram (A or B) represents inhalation? (1) 3.4 Give TWO visible reasons from the diagrams to support your answer to QUESTION 3.3. (2) 3.5 Describe the mechanism of inhalation in humans. (5) (13) 29  WEEK 4: TOPIC: Excretion in humans SUB-TOPIC: Excretion in various organs. NOTES & EXAM TIPS Excretion is the process where all the metabolic wastes are removed from the body. Excretion in humans is carried out through different body parts and internal organs in a series of processes. Excretory waste products include CO2, H2O, bile pigments, urea and mineral salts. 30  ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 Identify the excretory organs labelled 1 to 5. (5) 31  WEEK 5: TOPIC: Excretion in humans SUB-TOPIC: Urinary system- position of organs, structure and functioning of kidney. Structure and functioning of nephron NOTES & EXAM TIPS The excretory system of humans consists of two kidneys, two ureters, a bladder, and the urethra. The blood circulatory system is also associated with the urinary system – the renal artery and renal vein. The function of the excretory system is to remove the toxic, poisonous substance urea, other waste salts and excess of water from the blood and excrete them in the form of a yellowish liquid called urine. Urine production and elimination are one of the most important mechanisms of homeostasis in the body. The kidneys are bean shaped organs present at the back of our bodies just above the waist, just behind the intestines and insulated and kept in position by fat. Kidneys receive blood through the renal arteries and returning it through the renal veins. The ureters which are tiny tubes transport urine to the bladder for temporary storage while the urethra will carry urine to the outside of the body. 32 Kidneys The kidney performs the following four main functions of the urinary system Osmoregulation – regulation of levels of H2O in body fluids Excretion – removal of nitrogenous waste e.g. urea Regulation of pH of body fluids Regulation of salt concentration of body fluids A. General external characteristics 1. Bean shaped: concave on one side, convex on the other side. 2. Kidney is surrounded by a dense connective tissue capsule. 3. An indentation in the concave side is called the hilum where nerves, blood vessels and lymph vessels enter and leave the kidney. 4. Renal pelvis - expanded end of the ureter that connects to the hilum. A region where urine from the kidney collects and drains into the ureter. B. The Kidney can be divided into a cortex and a medulla. 1. Renal cortex: contains upper portions of nephrons 2. Renal medulla: consists of parts of nephrons called loops of Henlé 33 The nephron - the nephron is the functional unit of the kidney. There are approximately one million nephrons in each human kidney - consists of 2 components: the Malpighian body and the renal tubule. 34 The Malpighian body (renal corpuscle) occurs in the cortex region of the kidney: it includes the cup-shaped Bowman’s capsule and a dense capillary network in the hollowed-out region of the capsule called the glomerulus. The inner lining of the Bowman’s capsule has special cells called podocytes. These cells have finger-like extensions that wrap around the capillaries of the glomerulus. There are slits between these extensions to allow substances to pass through. The renal tubule: This includes the proximal (first, or close to) convoluted tubule in the cortex, the loop of Henle which runs into the medulla and the distal (second, or distant, far from) convoluted tubule back in the cortex. The distal tubule feeds into the collecting ducts that lead to the pelvic region of the kidney. The renal tubule is surrounded by a secondary capillary network known as the peritubular capillary network. Cuboidal epithelial cells line the renal tubule and have microvilli extensions on their surface. Each of these cells has a rich supply of mitochondria. Energy supplied by cellular respiration can be used to move substances against a gradient. The formation of urine involves the following: 1. glomerular filtration or ultrafiltration 2. tubular re-absorption 3. tubular secretion 4. excretion 35  ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 36 1.1 Identify parts 1 to 9. (9) 1.2 Write the names of the organs that match the functions in the following: (i) Stores urine temporarily. (1) (ii) Produces urine (1) (iii) Carries urine to the external environment. (1) (iv) Carries urine away from the kidneys. (1) (v) Maintains composition and volume of body fluids. (1) 1.3 Name ways in which the blood in part numbered 1 differs from that in the part numbered 4. (2) 1.4 Describe THREE functions of the kidneys. (3) (19) QUESTION 2. 2.1 Name the functional unit of the kidney as represented in the diagram above. (1) 37 2.2 Identify part: (a) A (1) (b) B (1) (c) C (1) 2.3 Name the blood vessels supplying the kidney which would connect at points X and Y shown on the diagram. (2) (6) QUESTION 3 3.1 Name the network of capillaries labelled C. (1) 3.2 Describe TWO structural features of part C that allow ultrafiltration to occur. (2) 3.3 Supply labels for: (a) A (1) (b) B (1) (c) D (1) 3.4 Explain the significance of the differences in diameter between structure A and structure B. (2) (8) 38 QUESTION 4 The pie charts below show the percentage composition of solutes in human glomerular filtrate and in urine. 4.1 Explain the difference in the glucose concentration between the glomerular filtrate and the urine as shown in the pie charts. (2) 4.2 The urea concentration of urine is much higher than that of the glomerular filtrate. Describe the role of the nephron in achieving this increase in the urea concentration in the urine compared to the other filtrates. (5) (7) 39  WEEK 6: TOPIC: Excretion in humans SUB-TOPIC: Homeostatic control of water and salts; role of ADH and aldosterone. NOTES & EXAM TIPS Homeostatic regulation by the kidneys It is important that the body’s temperature is kept within a narrow range of around 37°C.The pH of the body fluids needs to be regulated and the composition of these fluids needs to be kept constant and to be kept within certain limits for effective metabolism. The kidney is involved in 3 homeostatic mechanisms: the regulation of pH of the blood the regulation of water levels (osmoregulation) the regulation of salt levels in the blood Biological terminology Osmoregulation The control of water content and salt balances in the blood and tissue fluid. Homeostasis Refers to the process of keeping the internal body environment constant/the ability of the body to maintain a stable internal environment. Aldosterone Hormone that is produced by the adrenal cortex that promotes sodium absorption. ADH Hormone that controls the amount of water absorbed by the kidneys and which is therefore responsible for osmoregulation Hormone A chemical messenger Dialysis A method of artificially removing waste products from the bloodstream if the kidneys are unable to do so on their own. Regulation of salt levels in the blood The blood and tissue fluids are affected by the presence of solutes (dissolved substances). Sodium and potassium are salts that are found in the body fluids. Sodium is important in the body for good nerve and muscle functioning. Constant levels must be maintained. 40  Homeostatic control of salt concentrations Low salt levels in blood and tissue Elevated salt levels in the blood / fluids make these fluids hypotonic tissue fluids make these fluids hypertonic. Receptor cells in the afferent and Receptor cells in the afferent and efferent arterioles of the glomeruli of the efferent arterioles will detect an kidney will detect decreased Na+ levels. increased presence of Na+. The adrenal gland in the kidney The adrenal gland will stop releasing secretes the hormone aldosterone. aldosterone. Aldosterone stimulates the reabsorption of Na+ from the filtrate and back into the Na+ will not be reabsorbed. blood. Less sodium is excreted in the urine. More sodium is excreted in the urine. Adrenal gland secretes Re -absorption of sodium more aldosterone ions increases Salt level decreases Salt level increases Normal salt levels in blood Salt level increases Salt level decreases Adrenal gland stops Re - absorption of sodium secreting aldosterone / less ions decreases aldosterone secreted Homeostatic control of salt concentrations The role of antidiuretic hormone (ADH) in osmoregulation ADH controls the amount of water re-absorbed by the blood in the capillaries within the medulla. It is produced by the hypothalamus and released into the blood stream by the pituitary gland. 41 When the water content of blood is low, osmoreceptors in the in the hypothalamus are stimulated. A message is sent to the pituitary gland, which now releases ADH in the bloodstream. ADH increases the permeability of the cells in the wall of the distal convoluted tubule and the collecting duct tube. More water now leaves the tubule by osmosis and enters the blood in capillaries in the medulla. The water content of the blood therefore increases, and the urine becomes more concentrated. When the water content of the blood is high, osmoreceptors in the hypothalamus are stimulated. A message is sent to the pituitary gland and less ADH is released in blood. Due to the low level of ADH in the blood, the permeability of the cells of the distal convoluted tubule and collecting tubules is reduced. Less water leaves the tubules. Dilute urine is passed out. Too little water in the blood Too much water in the blood Dehydration is when the blood and Overhydration occurs when the blood tissue fluid are short of water. and tissue fluids are very dilute. This can be brought about by This can be because of cooler excessive exercise, hot temperatures, temperatures, little exercise with no increased sweating or decreased water sweating and an excessive intake of intake. water. This low level of H2O is detected by the Water levels are elevated, and this is hypothalamus of the brain. detected by the hypothalamus. The pituitary gland releases antidiuretic The pituitary gland releases less ADH. hormone (ADH). The hormone is transported in the Collecting ducts and distal convoluted blood to the kidney. The permeability tubules in the kidney become less of the collecting duct and the distal permeable. convoluted tubule is increased. More H2O is absorbed and passed into Less H2O is absorbed into the blood. the blood. The blood becomes more dilute and Less water leaves the collecting duct less, concentrated urine is excreted. and more, dilute urine is excreted. 42 Alcoholic and caffeine containing drinks act as diuretics (they cause you to lose water by urinating frequently). ADH acts in an opposite way as it helps the body retain water. ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1 and 1.2) in your ANSWER BOOK, for example 1.3 D. 1.1 A hormone which is secreted by the cortex of the adrenal gland, which regulates the concentration of sodium ions and potassium ions in the blood: A Glucagon B ADH C Aldosterone D Insulin 1.2 The glucose concentration of dialysis fluid is… 43  A the same as that of blood. B higher than that of blood. C lower than that of blood. D always 0g/mol of blood. (4) QUESTION 2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (2.1 to 2.5) in your ANSWER BOOK. 2.1 The control of water content and salt balances in the blood and tissue fluid. 2.2 Refers to the process of keeping the internal body environment constant/the ability of the body to maintain a stable internal environment. 2.3 The hormone which regulates the water content in the blood 2.4 Hormone that is produced by the adrenal cortex that promotes sodium absorption. 2.5 The blood vessel which carries oxygenated blood rich in metabolic waste products to the kidney (5) QUESTION 3 A healthy man, with normal kidney function, is used in the following practical investigation. The amount of urine that he produces every 30 minutes (for an hour and a half) is measured by collecting it, measuring the amount, calculating the average and noting the average at a-minute point. He is then asked to drink one liter of water, and his urine is again collected at 30-minute intervals. The following table shows the results of the investigation. Answer the following questions. Time after drinking 0 30 60 90 120 150 180 210 240 water (minutes) Urine produced (ml) 50 320 480 180 50 60 50 35 55 3.1. Identify the following: (a) dependent variable. (1) 44  (b) independent variable (1) 3.2. A hypothesis was formulated as follows: “Drinking water increases urine production”. Would you say that this investigation proves the hypothesis is accepted or is rejected? Motivate your answer. (2) 3.3. What was the most urine that he produced in one half hour period? (1) 3.4. How long did it take for the urine production level to return to normal after he drank the water? (1) 3.5 Name the process by which the water balance in the body is maintained (1) (7) QUESTION 4 Study the following information: ADH is a chemical produced in the brain that causes the kidneys to release less water, decreasing the amount of urine produced. A high ADH level causes the body to produce less urine. Normally the amount of ADH in the body is higher during the night. It is normal to urinate 1 to 2 times per night, but more frequent trips to the bathroom should send some warning signals. Normal values for ADH ranges from between 1 to 5 µg/ml. A higher-than-normal level may occur when too much ADH is released, either from the brain where it is made, or from somewhere else in the body. This is called syndrome of inappropriate ADH (SIADH). SIADH can be caused by brain injury, brain tumours, infection in the lungs or a stroke amongst many. A lower-than- normal level may indicate damage to the hypothalamus, diabetes insipidus, excessive thirst or too much fluid in the blood vessels. A team of scientists decided that they want to research a group of people in the A ward of the hospital and see how their ADH levels differ and provide explanations to why this is possibly happening. The population information is as follows: 10 men and 10 women They received the same amount of water, meals and hours of sleep. None of them could exercise to prevent excessive sweating. All of them were monitored at a facility for 24 hours to see when they are using the bathroom and how much urine they are producing. The following results were obtained. 45  Males Females Patient ADH Urinating Patient ADH levels Urinating nr. levels frequency at nr. (µg/ml) frequency (µg/ml) night at night 1 2.4 1 11 5.6 1 2 3.3 2 12 7.9 0 3 6.2 0 13 1.6 2 4 2.5 1 14 2.3 1 5 6.9 0 15 2.45 1 6 0.5 5 16 0.69 4 7 1.2 2 17 4.8 2 8 2.2 1 18 3.5 2 9 0.43 4 19 2.12 1 10 2.8 2 20 2.3 1 4.1. Provide an aim for the investigation. (2) 4.2. What does the abbreviation ADH stand for? (1) 4.3. Why must the ADH levels at night be especially higher? (2) 4.4. Provide the numbers of two patients that may possibly have (a) SIADH (2) (b) diabetes insipidus (2) 4.5. What would be the symptom of a patient with diabetes insipidus? (1) 4.6. Calculate the percentage of this population group that are healthy. (3) 4.7. What deduction can be made in terms of ADH levels and frequency of urination, especially at night. (2) (15) 46  WEEK 7: TOPIC: Population ecology SUB-TOPIC: Population size: Immigration, emigration, mortality, natality; fluctuations and limiting factors NOTES & EXAM TIPS Population Ecology: is the part of ecology that focuses on the factors influencing the population size, growth rate, growth forms and distribution of individuals inside a population. Important terms: Species: A group of organisms with similar characteristic, that are able to interbreed to produce fertile offspring. E.g. giraffe, zebra, etc. Population: A group of organisms of the same species occupying the same habitat at the same time and can interbreed randomly. E.g. Population of lions in Manyeleti game reserve. Community: A group of populations occurring in a particular area. E.g. lion, zebra, giraffe populations in Manyeleti game reserve. Natality: Is the birth rate of a population, normally expressed as the number of births per thousand individuals per year. Mortality: Is the death rate of a population, normally expressed as the number of deaths per thousand individuals per year. Immigration: is the one-way movement of organisms into an area where they become established. Emigration: is the one-way movement of organisms out of an area to become established. Population size: Total number of individuals in a population Population density: refers to the number of individuals of a population per unit area, e.g. 10 goats per hectare (100 m X 100 m) Note: Natality and immigration cause an increase in population size Mortality and emigration cause a decrease in population size 47  The following population limiting factors prevent unlimited growth in a population: a. Shortage of food and water b. Shortage of shelter or living space c. Predation d. Diseases and parasitism e. Accumulation of toxins o Once population has reached its maximum size, the population size will not remain constant, but fluctuate within the narrow boundaries due to changes in the environmental resistance (limiting factors) o Population size may fluctuate annually or seasonally. Population size can be determined by direct and indirect techniques/methods Direct technique involves total counting of all individuals Indirect technique involves the counting of only part of the population (mark-recapture technique and quadrant technique) Formula used to determine the estimated population size: P = FxS M F = Number caught in the first sample S = Number caught in the second sample M = Number marked in the second sample ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (1.1 to 1.4) in your ANSWER BOOK. 1.1. Method of determination of population size by counting the individuals in a 48  representative sample area 1.2. The death of individuals in a population 1.3. A group of organisms of the same species, occupying a particular habitat and having the ability to interbreed randomly 1.4. The inherent ability of a population to increase by birth (4) QUESTION 2 A group of students wanted to determine the population size of two species of butterflies. Their results are indicated in the table below. October 2016 November 2016 Number marked Number in Number and released in recaptured/ marked in first sample second sample recaptured/ second sample Species A 20 300 10 Species B 25 75 5 2.1 Define the term population. (3) 2.2 Estimate the number of butterflies of species A in the area by using the following formula: P = FxS M F = Number caught in the first sample S = Number caught in the second sample M = Number marked in the second sample Show all your calculations. (3) 2.3 Suggest TWO reasons why there were differences in the numbers between species A and species B in the recaptured/second sample. (4) (10) 49 QUESTION 3 Study the graph below and answer the questions that follow. (Number of individuals) Population size 3.1 How many of the following were there in 1966? (i) Rabbits (1) (ii) Wild dogs (1) 3.2 What is the maximum number of rabbits that have survived in this environment? (1) 3.3 What effect does a small number of wild dogs have on the rabbit population? Explain your answer. (2) 3.4 Name ONE technique that can be used to estimate the size of the rabbit population. (1) (6) 50  WEEK 8: TOPIC: Population ecology SUB-TOPIC: Logistic and geometric growth curves with phases NOTES & EXAM TIPS Key terminology growth Graphs that plot population size against time curves geometric A doubling after every reproductive event, i.e. exhibit exponential growth growth; graph has a J-shape The type of population growth that starts with a few individuals and logistic many resources – growth rate and consumption then increase. As growth resources are used up, growth rate levels off, resulting in an S- shaped graph First phase in a population growth curve where growth is slow; lag phase individuals may be acclimatizing to environment; few individuals that are sexually mature and able to reproduce exponential Second phase in a growth curve; individuals have acclimatized, growth many reproducing individuals exist; in favourable conditions can phase produce many offspring Third phase in a growth curve; environmental resistance leads to a decelerating decrease in the number of individuals; initially, natality rate is higher growth than the mortality rate but later the mortality rate is equal to the phase natality rate and eventually exceeds it Forth phase in a growth curve, carrying capacity is reached and equilibrium factors limit size of population; carrying capacity is stable and able to phase maintain the population at a set value Fifth phase in population curve; without management of resource death / usage, and changes to abiotic and biotic factors in their environment, extinction the population may not be able to sustain itself and enter a phase population crash phase 51  Geometric growth curve Geometric growth is characteristic of many micro-organisms e.g., bacteria and protists. These species are able to reproduce quickly and double their numbers after every reproductive division in favourable conditions. Eventually their resources become limited and/or waste products accumulate and adversely affect the population. This causes death or an extinction event. Three distinct phases can be seen in geometric growth curves. Lag phase – population number increases slowly because: o individuals may still be acclimatising to their environment. o they need time to find mates. o most of the population is sexually immature. Geometric (or accelerated) growth phase – individuals have acclimatised, many reproducing individuals exist and in favourable conditions produce many offspring. The birth rate is higher than the death rate. There is very little environmental resistance. Extinction or death phase – resources become limited, i.e., food, space, etc., and the population is no longer able to reproduce as effectively. The mortality rate becomes greater than the natality rate. The population decreases rapidly. 52  Logistic growth form Logistic S-shaped growth is normally found in higher-order organisms (e.g., mammals) which typically reproduce slower. Populations tend not to exceed the carrying capacity and, if they do, they show higher levels of resilience to environmental resistance. An S-shaped graph forms typically consists of five phases. Lag phase: As in the geometric growth curve, the population numbers increase slowly. Exponential or accelerating growth phase: The population can reach higher natality levels because of more sexually mature individuals procreating and environmental resistance being low (because of enough food, space and shelter). Decelerating growth phase: Natality rate is still higher than the mortality rate, however, the mortality rate is gaining momentum because of higher levels of environmental resistance and old age. Equilibrium / stationary phase: Carrying capacity of the environment has been reached. One or more limiting factors are exerting a toll on the population. The carrying capacity is somewhat stable and able to maintain the population at a set value. Death / extinction phase (not shown on graph): Some populations cannot regulate their resource usage and/or changes to abiotic and biotic factors in their environment and are then unable to sustain themselves. 53  ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1 to 1.3) in your ANSWER BOOK, for example 1.4 D. 1.1 How many phases does a logistic growth curve have? A 5 B 8 C 1 D 4 1.2 Which is the initial phase in logistic growth? A Log phase B Lag phase C Declining phase D Stationary phase 1.3 Which of the following initial phase is slow? A Declaration phase B Stationary phase C Lag phase D Log phase (3x2) (6) QUESTION 2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (2.1 to 2.3) in your ANSWER BOOK. 2.1 Graphs that plot population size against time 2.2 The phase in which the carrying capacity of the environment has been reached. One or more limiting factors are exerting a toll on the population 2.3 Growth form that is normally found in higher-order organisms (e.g., mammals) which typically reproduce slower. (3) 54 QUESTION 3 Indicate whether each of the statements in COLUMN I applies to A ONLY, B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only, B only, both A and B, or none next to the question number (3.1 to 3.3) in the ANSWER BOOK. COLUMN I COLUMN II 3.1 The growth when responses A Logistic growth in a population are limiting B Stationary growth 3.2 Zero growth in phase A Lag phase B Log phase 3.3 Organisms in a population A Exponential phase multiply at a faster rate? B Log phase (3 x 2) (6) QUESTION 4 4.1 Identify the growth form in the following graph. (1) phase 1 phase 3 phase 4 phase 2 Time 4.2 Identify the phases 1 to 4 in the above graph. (4) QUESTION 5 Tabulate two major differences between logistic and geometric growth forms. Include (7) an example of a species representing each growth form. 55  WEEK 9: TOPIC: Population ecology SUB-TOPIC: Interactions in the environment – predation, competition, specialisation, parasitism, mutualism, commensalism NOTES & EXAM TIPS KEY TERMINOLOGY Term Definition/explanation Predation The act of preying on another animal Predator Heterotrophic organisms (usually animals) that hunt, kill and eat other organisms Predator – prey curve A curve that describes the dynamics of biological systems in which two species interact Competition Social interaction between organisms fighting for dominance over the same limited resources (food, living space) Interspecific competition Competition between two or more different species Intraspecific competition Competition within members of the same species 56 Competitive exclusion Process whereby species can exist independently and survive; when placed in the same environment, one species will out compete the other and cause its extinction / death Resource partitioning A specialisation that limits interspecific competition; through resource partitioning, different carnivores, herbivores and even plant species can co-exist and survive in the same environment since each occupies a different ecological niche Mutualism Species that partake in this relationship benefit equally Commensalism Symbiotic relationship where one organism benefits without harming or affecting the other organism Parasitism Symbiotic relationship in which one organism benefits from the relationship (parasite) while causing harm to their host Social organization Interactions that increase the chances of survival through shared efforts of individuals benefiting the members of the population Herding behavior Individuals in a group which act collectively without centralized direction Pack hunting Typically associated with cooperative coordinated, purposeful movements in the catching and killing of prey ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 1.1 Indicate whether each of the statements in Column I applies to A ONLY, B ONLY, BOTH A AND B or NONE of the items in Column II. Write A only, B only, both A and B, or none next to the question number (1.1.1 to 1.1.4). 57  Column I Column II 1.1.1 Kittens competing for their A: interspecific competition mother’s milk B: intraspecific competition 1.1.2 One of the species benefits and A: commensalism the other is unaffected B: mutualism 1.1.3 Organisms have overlapping A: resource partitioning. niches and compete for the same resources but they coexist B: temporal partitioning because they use the resources slightly differently 1.1.4 Example of social organization A: division of labour in bees that increases the chances of survival B: a herd of zebras (4 × 2) = (8) QUESTION 2 Study the diagrams below. Identify the interactions between the organisms. Classify them as: parasitism, mutualism or commensalism. A. As the hermit-crab moves about in search of food the anemone is brought into contact with a greater supply of food and the crab is protected by the anemone’s stinging cells (2) 58  B. In return for shelter, the clownfish cleans the anemones, chasing away their predators and dropping scraps of food for the anemone to eat. (2) C. Ticks on horses if not treated can lead to tick fever. (2) (2) D 59  E Ants protect the Acacia from herbivores and kill any plants that start to grow near the tree. The Acacia makes nectar for the ants to eat. (2) (10) QUESTION 3 The following investigation was carried out by gr.11 learners to demonstrate competition between plants: Four pots of the same size were filled with equal amounts of soil. Seeds of bean and pea plants from the same species were planted in each pot as follows: Pot A – 25 bean seeds Pot B – 3 pea seeds and 3 bean seeds Pot C – 5 pea seeds and 7 bean seeds Pot D – 9 pea seeds and 9 bean seeds The seeds were watered well and left in a place with enough sunlight. After two weeks the number of plants in each pot was counted. The average height of the plants above the ground was also measured. The results are shown in the table below. Number of plants Average height of plants (cm) Pot A 8 2 Pot B 6 6 Pot C 8 5 Pot D 8 3 60 3.1 In which pot (A, B, C or D): (i) Will intraspecific competition occur? (1) (ii) Will the least competition occur? (1) (iii) Was a single population found? (1) (iv) Will the most interspecific competition occur? (1) 3.2 What is the carrying capacity of the pots? (1) 3.3 Why was the average height of the plants used instead of a single reading only? (1) (6) 61  WEEK 10: TOPIC: Population ecology SUB-TOPIC: Human population NOTES & EXAM TIPS Modern humans have evolved 200 000 years ago. The population size then, was probably less than several hundred. Today, the human population stands at 7,66 billion. The graph above shows an exponential growth in that: Population size is increasing continuously The rate at which the population is growing is becoming greater and greater The doubling period for the population is becoming shorter and shorter Reasons for exponential growth Agricultural improvements Through agricultural improvements, man has been able to increase and secure food availability 62  Medicinal improvements Medical technology has improved drastically in the space of few hundred years. Effects of pathogenic diseases and their subsequent spread can be countered. Technological improvements Technology has made our daily lives easier and more convenient. Carrying capacity was further increased. Age-gender population pyramid Data regarding a population can be gathered through conducting a census and ordered according to the number of individuals of a certain age category and of a certain gender. The results are then presented as a population pyramid. Three types of population pyramids can be observed, namely: Expanding or growing population pyramid Stable population pyramid Declining population pyramid 63 64  ACTIVITIES/WORKSHEETS/EXAM TYPE QUESTIONS QUESTION 1 Study the following population pyramid before answering the questions below: 1.1 Which age-gender population pyramid is displayed in the diagram above? (1) 1.2 Give THREE reasons for your answer in QUESTION 1.1. (3) 1.3 The life expectancy of an average South African was 49 years in 1960 but reached 60 years in 2016. What can this increase in life expectancy be attributed to? Give TWO factors. (4) (8) 65 QUESTION 2 Study the age-gender pyramid below representing a developing country and a Developed country. 2.1. Which pyramid represents the distribution of a developed country? (1) 2.2. Give TWO reasons for your choice in QUESTION 2.1. (2) 2.3. Which group (male or female) has the larger percentage reaching old age in pyramid B? (1) 2.4. Which TWO age groups has exactly the same percentage of male and female in pyramid A? (2) (6) 66 QUESTION 3 The diagrams below represent the age distribution of the human population of a developed country and a developing country in one year at a certain time. 3.1 What percentage of the female population is aged between 5 and 9 years in Pyramid A? (1) 3.2 Which age group makes up exactly 5% percent of the male population in Pyramid A? (1) 3.3 What percentage of the female population are aged 65 to 69 years in Pyramid B? (1) 3.4 Which group (male or female) has the larger percentage reaching old age in Pyramid B? (1) 3.5 Which pyramid represents the population distribution of a developed country? (1) 3.6 Give TWO reasons for your answer to QUESTION 3.5. (2) (7) 67