Learner Resource

LIFE SCIENCES

LEARNER RESOURCE

Adapted and compiled by J. Gerber and J. Goliath 2

LIFE PROCESSES

QUESTION 1

1.1 The following diagram shows an investigation that was carried out to determine the site of auxin production and its effect on growth and and development in plants.

tip cut off auxin paste

Plant shoots used in an investigation on auxins

1.1.1 Explain why the lateral buds in B, and not C, were able to develop into lateral branches. (2)

1.1.2 State ONE possible deduction that can be made from the diagrams with regard to the site where auxins are produced. (1)

1.1.3 (a) What would happen if shoot B was illuminated from one side for a few days? (1)

(b) Explain your answer to QUESTION 1.1.3(a). (2)

1.2 In Diagram I below, the growing point of a shoot is separated from the rest of the plant by a piece of plastic. It is then exposed to light from one side only.

plastic

Diagram I Experiment

Diagram II below shows possible results.

A B C D Diagram II

Possible results

1.2.1 Which growth hormone is being investigated? (1)

1.2.2 (i) Which letter (A, B, C or D) from Diagram II, shows the correct result expected after three or four days? (1)

(ii) Explain your answer in QUESTION 1.2.1(i). (3)

1.2.3 (i) Filter paper is permeable to the hormone being investigated. If the same experiment was repeated with a thin piece of filter paper instead of a piece of plastic, which letter (A, B, C or D) from Diagram II would then show the correct result? (1)

1.3 The graph below shows the growth response of roots and shoots to auxins applied at different concentrations.

Auxin concentration (parts per million)

1.3.1 At what concentration of auxins do shoots show the most growth? (2)

1.3.2 At what concentration of auxins does growth begin to be inhibited in roots? (2)

1.3.3 Name TWO places in plants where auxins are produced. (2)

1.3.4 Explain the role of auxins in apical dominance (2)

1.4 Explain the role of

(a) chemicals (2)

(b) thorns as plant defense mechanisms (2)

QUESTION 2

2.1 Study the following diagrams and answer the questions that follow.

2.1.1 Identify parts A, B, C, D, E and F. (6)

2.1.2 Write the name and diagram number (1 or 2), of the neurons which are represented by each of the following arrows in Diagram 3:

(a) G (2) (b) H (2)

2.1.3 State ONE function of the neuron represented by:

(a) Diagram 1 (2) (b) Diagram 2 (2)

2.1.4 What is a synapse? (2)

2.1.5 What is the functional unit of the nervous system? (1)

2.1.6 What is the purpose of neurotransmitters in a synapse? (2)

2.2 In the diagram below letters A, B, and C represent regions of the human nervous system that can be blocked by chemicals for medical reasons. Study the diagram and answer the questions that follow.

2.2.1 Write the letter (A, B, C or D) for each of the following statements, using the key given above:

(i) When the skin of the toe is stimulated, the toe moves and the patient knows it is moving. (2)

(ii) The patient can feel the toe being touched or pinched, but cannot A move the toe. (2)

(iii) When the skin of the toe is stimulated, the toe and foot move involuntarily, but the patient cannot move the toe voluntarily or feel it is moving. (2)

(iv) The patient can move the toe, but cannot feel the stimulus. (2)

2.2.2 List THREE ways in which the brain is protected. (3)

2.3 Study the diagram below and answer the questions that follow.

Adapted and compiled by J. Gerber and J. Goliath Portion of the central nervous system of a human 7

2.3.1 Identify the parts labeled A, B, C and D. (4)

2.3.2 State TWO functions of D. (2)

2.3.3 If someone accidentally steps on a sharp pin with a bare foot, the foot is immediately lifted without thinking of the action. Name the structure which brings about the rapid unconscious action. (1)

2.3.4 Describe the path followed by the impulse to bring about the action named in QUESTION 2.3.3. (5)

2.3.5 Describe ONE advantage of the action named in QUESTION 2.3.3 (2)

2.4 The following diagram shows the pathway through which impulses are transmitted in bringing about the knee-jerk in humans. Study the diagram and answer the questions that follow.

2.4.1 Identify the neurons marked A and B. (2)

2.4.2 Write the letter and name of the structure that is stimulated by the hammer. (2)

2.4.3 Explain what would happen if part C is severed. (2)

2.4.4 Give TWO examples of reflex actions other than the knee-jerk in humans. (2) 2.4.5 Why are reflex actions important to the human body? (1)

2.4.6 Differentiate between a reflex arc and a reflex action. (2)

2.5 Study the diagram below which shows the human brain (longitudinal section), spinal chord (transverse section) and the right leg.

2.5.1 Identify the parts labeled A, B, C, D and F (5)

2.5.2 What will be the effect on the body if part B is damaged? (2)

2.5.3 Give the LETTER of the part that secretes the hormone TSH (1)

2.5.4 Give the letter of the part that coordinates the movement of the legs under normal circumstances. (1) 2.5.5 Draw and label the type of neuron as indicated by E. (7)

2.5.6 Explain the reflex action shown in the diagram. (5)

2.6 Describe the effects of the following drugs on the central nervous system

(a) dagga (2)

(b) Heroin (2)

(c) Ecstacy (2)

(d) Tik (2)

2.7 Answer the following questions based on the autonomic nervous system:

2.7.1 Name the TWO subdivisions of the autonomic nervous system. (2)

2.7.2 Tabulate the responses of the autonomic system in terms of

(a) heart rate

(b) blood vessels in the skin

(c) peristalsis

(d) pupil size (9)

2.8 Study the diagram below showing a reflex arc.

B Reflex arc

2.8.1 Identify the neuron labelled A. (1)

2.8.2 Name the type of neuron that is connected to structure B. (1)

2.8.3 Explain the effect on the body if the neuron mentioned in QUESTION 2.8.2, is damaged. (3)

2.8.4 Explain the significance of reflex actions in humans. (2) (7)

QUESTION 3

3.1 Study the following diagram and answer the questions that follow.

B I C J D K E L F

Section through the human eye

3.1.1 Write the letters of the parts which are responsible for the following:

(a) Protection of the eye from physical damage (3) (b) Accommodation (3) (c) Refraction of light rays (3)

3.1.2 Write the name of the labelled part which is responsible for the following:

(a) Movement of the eye ball (1) (b) Conversion of light stimuli into impulses (1)

3.1.3 Explain the role of part E in bright light conditions. (4)

3.2 Study the following diagram and answer the questions that follow. Adapted and compiled by J. Gerber and J. Goliath 12

Longitudinal section through the human eye

The structures which enable the eye to focus on objects are missing in the above diagram.

3.2.1 Draw a longitudinal section through the missing parts to indicate the appearance of these structures when a person is (a)reading a book and (b) looking at a distant hill. (7)

3.3 A person sitting in a darkened room covers one eye. A dim electric bulb, positioned at varying distances from the person is switched on at one-minute intervals for a period of 10 seconds. During this period the diameter of the pupil of the eye is measured. Adapted and compiled by J. Gerber and J. Goliath 13

The results obtained are shown in the graph below. Study the graph and answer the questions below. ) m m (

l i p u p

r e t e m a i D

Change in pupil size

3.3.1 Which structure in the eye controls the size of the pupil? (1)

3.3.2 Between which5 TWO consecutive time intervals did the following changes in the diameter of the pupil occur?

(i) Smallest increase (2) (ii) Biggest4 decrease (2)

3.3.3 Why did the diameter of the pupil remain the same during the third and fourth time interval?3 (1) 0 1 2 3 4 5 6 7 8 9 3.3.4 At which time interval was the electric bulb the greatest distance away from the person? Explain your answer. Time (minutes) (4) 2 3.3.5 Explain the papillary mechanism for the period between the 8th and 9th minutes. (4)

3.3.6 Describe the general relationship that exists between the diameter of the pupil and the distance of the electric bulb from the eye. (2)

3.3.7 In which way does the pupil carry out a protective function in the eye? (1)

3.4 Study Diagrams I and II that illustrate the lens and parts of one layer of the human eye, as well as the graph below and answer the questions that follow.

3.4.1 Identify parts A and B. (2)

3.4.2 Which Diagram (1 or 11) shows part of the eye

(i) where the ciliary muscles are contracted. (1) (ii) under dim light conditions. (1)

3.4.3 Explain your answer in QUESTION 3.4.2 (i). (2)

3.4.4 Which letter on the graph indicates each of the following:

(i) The eye looking at a nearby stationary object (1) (ii) The eye looking at an object moving towards the viewer (1)

3.4.5 Explain the significance of the elastic nature of the lens. (2)

3.5 Study the following diagrams showing visual defects and answer the questions that follow.

3.5.1 Which diagram (A or B) illustrates (a) short-sightedness (1) (b) long –sightedness (1)

3.5.2 Compare short-sightedness and long-sightedness by completing the table below.

Short-sightedness Long –sightedness Shape of eyeball (a) (b) Focal point on retina for nearby (c) (d) objects Corrective type of lens (e) (f) Corrective corneal laser surgery (g) (h) (8) 3.6 Explain the nature and treatment of the following:

(a) astigmatism and (4)

(b) cataracts (2

3.7 A person took part in an experiment on the eye’s response to light. A lamp was placed at seven different positions from the person’s face. The diameter of the person’s pupil was measured at each position.

The table below shows the diameter of the person’s pupil when the light was placed at various distances from the person’s face.

Position of the lamp Diameter of the pupil (mm) 1 1,2 2 1,8 3 2,4 4 3,0 5 3,6 6 4,2 7 4,8

3.7.1 (i) At which position was the lamp furthest from the eye? (1) (ii) Explain your answer in QUESTION 3.7.1 (i). (2)

3.7.2 The lamp was moved from position 1 to position 2. What happened to the muscles in the iris of the eye that caused the change in the diameter of the pupil? (4)

3.8 Jabu took part in an experiment on the eye's response to light. A lamp was placed at seven positions from Jabu's face. The diameter of Jabu's pupil was measured at each position.

The results are shown in the table below.

POSITION OF THE LAMP DIAMETER OF THE PUPIL (mm) 1 1,2 2 1,8 3 2,4 4 3,0 5 3,6 6 4,2 7 4,8

3.8.1 (a) At which position was the lamp furthest from the eye? (1)

(b) Explain your answer to QUESTION 3.8.1(a). (2)

3.8.2 When the lamp was moved from position 1 to position 2, describe the mechanism that caused the change in the diameter of the pupil. (4)

3.9 Study the diagram below showing a longitudinal section through an eye.

A longitudinal section through a human eye

3.9.1 Label parts 2, 3, 4 and 5 respectively. (4)

3.9.2 Name and describe the process that causes part 1 to dilate. (6)

3.9.3 State how the following defects can be treated to improve vision:

(a) Long-sightedness (b) Astigmatism (c) Cataract (d) Short-sightedness (4) (14)

QUESTION 4

4.1 Study the diagram and answer the questions that follow.

C E BB D

The human ear

4.1.1 Identify the parts labelled B, C, D and F. (4) 4.1.2 Explain how the pinna of the ear is suited for its function. (2)

4.1.3 Write the letter of the part which:

(i) Has receptors for balance (1)

(ii) Secretes a waxy substance called cerumen (1)

(iii) Equalizes pressure on either side of part B (1)

(iv) Transmits impulses to the brain (1)

(v) Part in which the organ of Corti is found (1)

4.2 Explain the (a) cause and (2) (b) treatment of middle ear infections. (2)

4.3 Draw a labelled diagram of part of the human ear to show the air-filled cavities and the structures they contain. (9)

4.4 A person walking barefoot stepped on a thorn with his left foot. He immediately withdrew his left foot, balancing himself on his right foot. Explain how the person managed to maintain balance and body position. (15)

4.5 Study the following diagram of the human ear and answer the questions that follow.

A B C D E

Human ear

4.5.1 Part A secretes a wax known as cerumen. Sometimes the wax forms a solid plug against part B.

(i) State TWO functions of cerumen. (2)

(i) Explain the effect on hearing if a waxy plug is formed against part B. (3)

4.5.2 (i) Will sound waves reach part D if part C was removed? (1)

(ii) Give a reason for your answer. (2)

4.5.3 Name the part of the brain to which nerve E will conduct nerve impulses and give a reason for your answer. (3)

4.6 Study the diagram below showing a portion of the human ear and answer the questions that follow.

4.6.1 Provide labels for parts A, C and D, respectively. (3)

4.6.2 State ONE function for parts B and D, respectively. (2)

4.6.3 How are parts A and C together suited for the amplification of sound? (2)

4.6.4 Explain what would happen if part E is blocked with mucus. (2)

QUESTION 5

5.1 Study the following passage and answer the questions that follow.

Messenger substances are produced in endocrine glands of the human body and then transported to other parts of the body where they are involved in regulating the activity of particular parts. Slow, sustained or ongoing responses to these substances complement or support the other more rapid and short-lived responses of the body. 5.1.1 Write a scientific name for each of the following phrases taken from the passage:

(a) Messenger substances (1) (b) Particular parts whose activities are regulated (1)

5.2 Complete the following table by writing the numbers 5.2.1 to 5.2.9 in your answer book and next to each number the correct missing information.

Gland Position in Hormone Function of hormone the body 5.2.1 5.2.2 Growth hormone 5.2.3 5.2.4 Below the larynx 5.2.5 5.2.6 5.2.7 5.2.8 5.2.9 Prepares the body for an emergency (9)

5.3.1 Give labels for the glands numbered 1 and 2. (2)

5.3.2 Name hormone A. (1)

5.3.3 Describe the negative feedback mechanism that operates when the thyroxin level in the blood is too high, as indicated by process C. (4) Adapted and compiled by J. Gerber and J. Goliath 22

5.4 Make a flow chart showing a feedback mechanism involving two glands that control thyroxin production in humans. (7)

5.5 Study the diagrams below and answer the questions that follow.

5.5.1 Identify glands B and C. (2)

5.5.2 A study of all three glands in Diagram 1 showed that they each have a large number of

blood capillaries close to the cells. Give an explanation for this feature. (2)

5.5.3 All three glands in Diagram 1 were stimulated in the person shown in Diagram 2. Which ONE of the glands, A or B, was stimulated first? (1)

5.5.4 Explain your answer to QUESTION 5.5.3. (5)

5.5.5 What happens to each of the following in the person in Diagram II?

(a) Blood supply to the gut (1)

(b) Breathing rate (1)

(c) Hair-erector muscles of the skin (1)

5.6.1 Label the parts numbered 1 and 4. (2)

5.6.2 Write down only the NUMBER of the gland that:

(a) Produces the hormone glucagon (b) Produces a hormone that controls the growth of long bones (c ) Produces an iodine-containing hormone (d) Produces a hormone that is involved in the re-absorption of some salts by the kidneys (4)

5.6.3 State TWO similarities between hormones and nerves with regard to their functions. (2)

5.6.4 State ONE functional difference between hormones and motor nerves. (2) (10)

5.7 Describe the role of the hypothalamus and the adrenal glands in bringing about changes to the blood vessels of the human skin and explain why these changes take place. Content (17) Synthesis (3) (20)

NOTE: NO marks will be awarded for answers in the form of flow charts or diagrams.

QUESTION 6

6.1 Study the diagram and answer the questions that follow.

Section through the skin

6.1.1 Identify parts A and C. (2)

6.1.2 What change will part B undergo if the environmental temperature suddenly rises?(1)

6.1.3 Explain the advantage of the change named in QUESTION 6.1.2. (4)

6.1.4 (i) Give the name of the hormone that will have the opposite effect on part B to that which a rise in the environmental temperature has. (1) (ii) Under what conditions will the hormone named in QUESTION 6.1.4 (i) be secreted? (1) (iii) Explain the significance of the effect on part B of the hormone named in QUESTION 6.1.4 (i). (5) (iv) What effect will the hormone named in QUESTION 6.1.4 (i) have on the activity of the thyroid gland? (1) (v) Explain your answer in QUESTION 6.1.4 (iv). (2)

6.2 The graph below shows the effect of strenuous exercise, followed by a cold shower, on the body temperature of an athlete.

Diagram I Diagram II

6.2.1 Which part of the brain responds to the temperature changes that occur at A (1) and B on the graph? (1) 6.2.2 What was the maximum temperature reached?

6.2.3 For what period of time did the person engage in strenuous exercise? (1) 6.2.4 Why should body temperature not be allowed to fluctuate too much? (1) 6.2.5 Which diagram (I or II) would represent the condition of the skin after

15 minutes (1) 6.2.6 Explain your answer to QUESTION 6.2.5. (2)

6.3 Study the following diagrams and answer the questions that follow.

Diagram 1 Diagram 2

Diagram 3 Diagrams showing processes involved in thermoregulation in mammals

6.3.1 Identify part A and state its function. (2)

6.3.2 In which diagram (1 or 2) will:

(a) The skin be pale if the person is lighted-skinned (1) (b) The sweat glands produce more sweat (1)

6.3.3 Explain your answer in QUESTION 6.3.2 (a). (2)

6.3.4 Diagram 3 shows a response to a particular environmental temperature. Which diagram (1 or 2) shows a response of a human to the same environmental temperature? Explain your answer. (3)

6.3.5 Describe how the process illustrated in diagram 3 helps in the regulation of the body temperature of the dog. (3)

6.4 Answer the following questions on thermoregulation in some mammals.

6.4.1 A mouse will lose more of its body heat than an elephant under the same low environmental temperature conditions. Which ONE of the following can account for this observation:

The mouse …

(a) is smaller than the elephant. (b) is more active than the elephant. (c) has a larger surface area to volume ratio than the elephant. (d) has smaller ears than the elephant. (2)

6.4.2 Explain how the mouse can still maintain a constant body temperature although it loses excessive body heat to the cold environment. (2)

6.5 Study the graph below and answer the questions that follow.

e r Fluctuations in the body temperature u t a

r of a human when taking a cold bath e p m e

y ) d o C 0 B (

37 0 10 20 30 40 50 60 Time (minutes)

6.5.1 What is the normal body temperature of this person? (2)

6.5.2 How long did36 it take for the body temperature to return to normal? (2)

6.5.3 Why did the body temperature of this person decrease? (2)

6.5.4 Explain how shivering helps to maintain body temperature. (3) 35 6.5.5 (i) Will you lose more heat through your thumbs or through your ears? (1)

6.6 Describe how the principle of negative feedback operates in controlling the glucose concentration of the blood in a normal healthy person. Also describe the causes, symptoms and management of the disease diabetes mellitus which results from an inability of the body to normalise the glucose concentration of the blood. Content 17 Synthesis 3 NOTE: NO marks will be awarded for answers in the form of flow charts or diagrams.

QUESTION 7

7.1 Define each of the following terms:

7.1.1 Asexual reproduction

7.1.2 Sexual reproduction

7.1.3 Alternation of generations

7.1.4 Diploid

7.1.5 Haploid

7.2 Tabulate the advantages and disadvantages of

7.2.1 Asexual reproduction

7.2.2 Sexual reproduction

7.3 Study the diagram below of the life cycle of a plant in which the gametophyte generation is dominant.

gametophyte

spores (n) malesex organ Female sex organ (n) (n)

cell division C cell division A

male gamete (n) female gamete (n) sporophyte

process B zygote

7.3.1 Is the life cycle represented that of a moss or a flowering plant? (1)

7.3.2 Name the following

(a) Cell division A (1)

(b) Process B (1)

(c) Cell division C (1)

7.3.3 Is the gametophyte haploid or diploid? (1)

7.3.4 Are seeds produced during the life cycle of this plant? (1)

7.4 Define the following concepts

7.4.1 Metamorphosis (2)

7.4.2 complete metamorphosis (2)

7.4.3 incomplete metamorphosis (2

7.5 Study the diagram below and answer the questions that follow:

7.5.1 What type of metamorphosis is illustrated in the diagram above? (1)

7.5.2 Name the phases labelled A, B and C (3)

7.5.3 Explain the difference between phases A and B (2)

7.5.4 Explain ONE disadvantage of this type of metamorphosis (2)

7.5.5 Explain ONE advantage of this type of metamorphosis. (2)

7.6 Study the diagrams below showing the structures of two flowers.

Flower A Flower B

7.6.1 Define pollination. (2)

7.6.2 Which flower (A or B) is wind-pollinated? (2)

7.6.3 Give TWO visible reasons for your answer to QUESTION 1.18.2. (2)

7.6.4 After pollination the pollen grain germinates and fertilisation takes place.

The fertilised ovule develops into a seed and the ovary of the flower develops into a fruit.

Seeds of rare and endangered plants are stored in seed banks to maintain biodiversity.

(a) Give FOUR reasons why seeds are important (4)

(b) State FOUR uses of seed stored in seed banks. (4)

7.7 Name SIX different strategies that animals use to ensure reproductive success in different environments. (6)

7.8 Define the following concepts

(a) Ovipary (2)

(b) Ovovivipary (2)

(c) Vivipary (2)

(d) precocial development (2)

(e) altricial development (2)

QUESTION 8

8.1 Study the diagrams below and answer the questions that follow.

8.1.1 Provide labels for A, B, E and G (4) 8.1.2 State ONE function each of C and F, respectively (2)

8.1.3 State the LETTER and NAME of the part where sperm are produced. (2)

8.1.4 Explain why it is necessary for part D to 'hang outside' the body of the male. (2)

8.1.5 Name the following:

(a) The cells that secrete a male sex hormone (1)

(b) The hormone that stimulates the development of secondary sexual characteristics

in males (1)

8.1.6 During a vasectomy, part B is surgically cut. Explain how this procedure will act as a method of contraception. (2)

8.2 The diagram below represents a cross-sectional view of a human seminiferous tubule in which spermatogenesis is occurring. Study the diagram and answer the questions that follow.

8.2.1 Name the hormone produced by the cells of Leydig. (1) 8.2.2 Name TWO functions of the hormone named in QUESTION 8.2.1 (2) 8.2.3 Identify part labelled A. (1)

8.2.4 Make a neat, labeled diagram of part A. (4)

8.3 Study the diagram below showing the sequence of events of the development of an ovum in a 28-day cycle.

8.3.1 Identify the following:

(a) Follicle labelled A (1)

(b) Structure labelled C (1)

(c) Process shown at B (1)

(d) Hormone responsible for the formation of part A (1)

(e) Hormone responsible for the formation of part C (1)

8.3.2 What type of cell division resulted in the formation of part D? (1)

8.3.3 If the events shown above took place in a 28-day cycle, state whether fertilisation took place during this period. (1)

8.3.5 Explain HOW and WHY the production of FSH is inhibited when fertilisation

takes place. (4)

The human foetus

8.4.1 Provide labels for A and B (2)

8.4.2 Explain ONE way in which the part labelled B is structurally adapted for its

function. (2)

8.4.3 Name TWO functions of the fluid found at C. (2)

8.5 Study the graph below which shows the menstrual cycle and the influence of the different hormones on it.

8.5.1 On which day does ovulation take place? (1)

8.5.2 Between which days does menstruation take place? (1)

8.5.3 State any ONE function of luteinising hormone (LH). (1)

8.5.4 Describe the changes in the level of LH shown in the graph. (3)

8.5.5 Describe the relationship between the level of oestrogen and the

endometrium from day 7 to day 14. (2)

8.5.6 Explain why it is necessary for the level of progesterone in the

blood to increase after ovulation. (2)

8.5.7 Did fertilisation take place in the 28-day cycle illustrated in the graph? (1)

8.6 Study the graph below which shows the number of pregnancies recorded of girls under sixteen in a province in South Africa from 2001 to 2006.

8.6.1 Between which two years did the greatest increase in the number

of pregnancies occur? (2)

8.6.2 What was the percentage increase in this period? (1)

8.6.3 Draw a table to show the data from which this graph was drawn. (6)

8.6.4 In a relationship, is it the man's or woman's responsibility to use contraception to prevent pregnancy? (1)

8.6.5 Give a reason for your answer to QUESTION 8.6.4. (2)

8.7 Read the paragraph below and answer the questions that follow.

MALE CONTRACEPTIVE CHEMICAL

Gossypol is a chemical which is extracted from the seeds of cotton plants. When gossypol was given to rats, mice, dogs and monkeys, it caused a reduction in the fertility of the male animals by reducing their sperm count. Scientists wanted to investigate the idea that gossypol could be used as a human male contraceptive.

[Adapted from: Liffen and Liffen, 1987]

8.7.1 State a hypothesis for the investigation that scientists wanted to do. (3)

8.7.2 State FOUR planning steps that must be followed by researchers before the investigation above is undertaken on humans. (4)

8.7.3 In the investigation above, name the following:

(a) Dependent variable (1)

(b) Independent variable (1)

8.7.4 Explain ONE reason why some people might:

(a) Support research on male contraception (2)

(b) Object to research on male contraception (2)

ENVIRONMENTAL STUDIES

POPULATION AND COMMUNITY ECOLOGY

1.1 Read the following passage and then answer the questions that follow.

In 1990 the estimated impala population in a certain environment was approximately 8 000. Large populations of lions and cheetahs were also present. Between 1990 and 2000 about half the sizes of the populations of lions and cheetahs were eliminated. By 2002 the number of impala increased to about 80 000 and nearly all the grass, shrubs and young trees had been eaten.

During the winter, 80% of the impala population was wiped out and this decline continued until only 4 000 impala were left. The vegetation, however, continued

to degenerate for a long time. In the beginning it was estimated that the carrying capacity of the area was only 20 000 impalas.

1.1.1 Differentiate between (a) intraspecific competition and interspecific competition. (2) (2)

(b) prey and predator. (2)

1.1.2 By referring to the passage, give the names of organisms that are

involved in

(a) intraspecific competition. (2) (b) interspecific competition. (2)

1.1.3 Why did the impala population continue to decline after 80% had

died during the winter? (2)

1.1.4 Explain what is meant by

(a) carrying capacity (2)

(b) population (2)

1.2 Study the following graph and answer the questions that follow.

1.2.1 What is the carrying capacity of this habitat? (1)

1.2.2 How many rabbits were present in 1995? (2)

1.2.3 Name growth phase W. (1)

1.2.4 Suggest a reason for the shape of the curve at each of the following:

(a) W (2)

(b) X (2)

(c) Y (2)

1.6 Study the table below and answer the questions that follow.

Year Human population in millions 1650 500

1750 750

1850 1 000

1950 2 010

2050 8 000

1.6.1 Use the information in the table to draw a line graph. (11)

1.6.2 Name the type of growth form shown in the graph. (1)

1.6.3 State TWO reasons why the growth form has this specific pattern. (2)

1.6.4 From your graph determine the following:

(i) The population size in the year 2000 (2)

(ii) The time taken for the human population to double for the first time (2)

1.6.5 It is important for any country to understand how the population will grow in the future.

(i) How was the human population for 2050 determined? (1)

(ii) List TWO reasons why determining such figures is important. (2)

(iii) Name TWO current world issues that could change the above figure. (2)

(iv) State TWO strategies that this population will need to apply to ensure its survival. Adapted and compiled by J. Gerber and J. Goliath 44

1.7 An insect pest was accidentally introduced onto a farm. Within months it had become a serious problem as it had no enemies (predators) in its new habitat.

To solve this problem, the farmer decided to introduce the natural enemy of this pest.

Data was kept on the growth patterns of the insect population and the population of its natural enemy (predators).

The result is indicated in the graph below.

Population size of a pest and its natural predator over a period of time

20 18 16 ) 14s d n a s e 12 z u i s o

10h n t ( o i t 8 a l

p 6 o P 4 2 0 0 3 6 9 12 15 18 21 24 27 30 33 36

Time (months) 1.7.1 According to the graph, how many predators were introduced onto

the farm? (2)

1.7.2 What is phase A on the graph called? (1)

1.7.3 Explain the shape of the graph at A. (2)

1.7.4 Was the introduction of the natural enemy successful in controlling the pest population or not? (1)

1.7.5 Give a reason for the answer in QUESTION 1.7.4. (2)

1.7.6 Suggest ONE reason why the farmer decided to use the natural enemy

instead of chemicals in controlling the pest population. (2) Adapted and compiled by J. Gerber and J. Goliath 45

1.7.7 Briefly describe the interaction between the insect pest population and its natural enemy. (4)

1.8 An experiment was carried out with two different species (A and B) of flour-beetles

Two jars were each filled with 500 g of flour. 25 males and 25 females of species A and 25 males and 25 females of species B were placed in each jar.

Temperature: 25 oC Temperature: 25 oC

Relative humidity: 30% Relative humidity: 70%

flour beetles

Jar X Jar Y

Apparatus to investigate competition among flour beetles

NOTE: The optimum relative humidity under normal conditions for species A is 25 % and for species B is 60 %.

The beetles were counted every week over a period of three months.

The results are shown in the table below.

Jars Species A Species B

Number of beetles increased Number of beetles decreased until X all died

Y Number of beetles decreased Number of beetles increased until

all died

1.8.1 What type of competition occurs in the jars? Give a reason for your answer. (2)

1.8.2 Name the factor that has been investigated and also state whether

this factor is density-dependent or density independent. (2)

1.8.3 Which species, A or B, is more tolerant to high humidity (1)

1.8.4 Regardless of which species was successful in the jars, its numbers usually increased, then started levelling off and eventually it decreased.

(i) What type of growth form is this? (1)

(ii) State TWO reasons why the increase in numbers was initially slow. (2) (iii) Name this initial growth phase. (1)

(iv) Why do the numbers level-off at a certain stage? (2)

1.8.5 What would you expect to happen to the populations if a third jar

with the same quantity of flour and the same number of beetles

was kept at 25oC and at 10% humidity? Give a reason for your

answer. (4)

1.9 A group of students wanted to determine the population size of two species of butterflies. Their results are indicated in the table below.

October 2004 November 2004

Number marked and Number in Number marked in released in recaptured / second recaptured / second sample sample first sample

20 300 10 Species A Species B 25 75 05

1.9.1 Define the term population. (3)

1.9.2 Estimate the number of butterflies of species A in the area by using

the following formula:

P = F x S

F = Number caught in the first sample

S = Number caught in the second sample

M = Number marked in the second sample

Show all workings. (3) 1.9.3 Suggest TWO reasons why there were differences in the numbers

between species A and species B in the recaptured / second (4)

sample?

Part of an ecosystem with earthworms, plants and a bird

1.10.1 With reference to the diagram give ONE example of each of the

following interactions:

(i) Intraspecific competition (2)

(ii) Predation (2)

1.10.2 Define the term population. (3)

1.11 A certain area has a population of 5 pairs of birds that consists of 5 males and 5 females. During spring every pair of birds produces 4 offspring, 2 males and 2 females. Presume that no immigration or emigration takes place, predators are absent and all the offspring live to become breeding pairs the following year. The area can support a population of 1 000 birds.

The table below shows the size of the population at the end of each year.

Year Number of birds 0 10 1 30 2 90 3 270 4 810

1.11.1 List THREE requirements that the group of birds must satisfy

before it can be called a population. (3)

1.11.2 Use the data from the table and plot a line graph that shows the growth of the

population. (11)

1.11.3 During year 5 a fire destroyed 70% of the habitat of the area but miraculously no birds were burnt to death. What effect could this have on the size of the population?

Give a reason for your answer. (3)

1.11.4 Give ONE term for each of the following statements from the paragraph above:

(a) 'no immigration or emigration'

(b) 'The area can support a population of 1 000 birds.' (2)

1.12 Read the article below on elephant culling.

TOO HUNGRY, TOO DESTRUCTIVE, TOO MANY: SOUTH AFRICA TO BEGIN ELEPHANT CULL

An elephant herd at the Kruger National Park has 20 000 elephants, 5 000 more than is sustainable. Ecologists say the animals' huge appetites and fondness for 'habitat re-engineering' – reducing forests to flatland by uprooting trees and trampling plants – is the main problem.

Culling of the excess elephants is seen as an advantage in that it generates revenue for the communities from the sale of ivory and other elephant products. It will also provide meat to the local communities. Alternatives to culling include contraception and relocation of entire elephant families. The removal of fences between the Kruger National Park and parks in neighbouring Mozambique will eventually help with migration into less congested areas.

The 1998 figure of 8 000 elephant increased to 20 000 in 2008 and it is expected to reach 34 000 by 2020. [Adapted from The Guardian, 26 February 2008]

1.12.1 Give the main reason mentioned above in support of the culling of elephants. (1)

1.12.2 Name TWO alternatives to culling proposed above. (2)

1.12.3 Draw a bar graph to show the change in the elephant population from 1998 to 2020. (6)

1.13 The graph below shows the ecological footprint and biocapacity of different countries in 2005. Biocapacity is the environment’s capacity to supply resources and absorb waste

Comparison of the ecological footprint and biocapacity of different

a countries in 2005 b

o d l n g 400

n i s r 300 ) n p s t o 250 i e o l r l i o

a 200 f t

m l c ( 150

a e y c h i t 100 i g c

o 50 a l p o 0 a c c E o i b

Country

Ecological footprint Biocapacity

1.13.1 Define the term ecological footprint (2)

1.13.2 Which countries have a larger biocapacity than ecological footprint? (4)

1.13.3 Which of these countries are developing countries? (1)

1.13.4 Which country has the biggest ecological footprint? (1)

1.13.5 Which country has the smallest ecological footprint? (1)

ADDITIONAL QUESTIONS LIFE PROCESSES

1.1 The apparatus below was set up to investigate the effect of two different environmental factors on the behaviour of woodlice (small invertebrate animals). The usual habitat of the woodlice is decaying vegetation.

The apparatus consisted of four flattened, inter-connecting covered dishes. Two of these dishes were placed in dark and two in light conditions. Moist paper was placed in one of the two dishes in the dark and one of the two dishes in the light.

Ten woodlice were placed in each of the four dishes and allowed to move freely between the dishes.

The number of woodlice present in each dish after 15 minutes is shown in the diagram below.

Inter-connected dishes

Moist paper

The apparatus used to investigate the effect of two different environmental factors on the behaviour of woodlice

1.1.1 According to the investigation, which conditions did the woodlice prefer? (2)

1.1.2 Explain ONE way in which the validity of this investigation could have been improved. (2)

1.2 Sipho did an investigation in his laboratory to look at the effect of different concentrations of auxin on cell elongation in coleoptiles (young stems). He used the following procedure:  Fifteen (15) coleoptiles from one species of oat plants were used.  All the coleoptiles used were of the same length.  The tips of twelve (12) coleoptiles were cut.  These coleoptiles were put into four groups (A, B, C and D). Each group of three coleoptiles was injected with a different concentration of auxin as shown in the table below.  The last group (E) was used as a control in which the coleoptiles were not injected with auxin and tips were not cut. After four days the length of coleoptiles in each group were measured and an average was calculated. TREATMENT GROUP TIP CONCENTRATION AVERAGE (PRESENT/ OF AUXIN INJECTED LENGTH OF ABSENT) (ARBITRARY UNITS) COLEOPTILE (mm) A Absent 1 36 B Absent 2 60 C Absent 3 32 D Absent 4 24 E Present 0 30

1.2.1 Formulate a hypothesis for the investigation above. (3)

1.2.2 Suggest why Sipho cut off the tips of each coleoptile before he injected them with auxin. (2)

1.2.3 Apart from the factors that were kept constant, state ONE other factor that Sipho should have kept constant in all the groups. (1)

1.2.4 What conclusion can be drawn from the results, about the effect of auxin concentration on cell elongation in the coleoptiles? (2)

ADDITIONAL QUESTIONS ENVIRONMENTAL STUDIES

1.1 A group of Grade 12 learners wanted to use the mark-recapture technique to determine the population size of a type of fish (Tilapia sparrmanii) in a large dam

Their results are shown in the table below.

OCTOBER 2010 NOVEMBER 2010 Number marked Number in Number and released in first recaptured/ marked in sample second sample recaptured/ second sample Tilapia 15 150 10 sparrmanii

1.1.1 List FOUR steps that should be considered when planning to determine the population size using this investigation. (4)

1.1.2 Use the formula below to estimate the population size of Tilapia sparrmanii in the dam.

P = F x S M

F = Number caught in the first sample S = Number caught in the second sample M = Number marked in the second sample

Show ALL working. (3)

1.2 Study the case study below and answer the questions that follow.

TENSIONS AND ISSUES AROUND MINING AT MTUNZINI

Plans are in place for 2 800 ha of forestry and farming land, just outside the North Coast town of Mtunzini in KwaZulu-Natal, to be mined for minerals such as zircon, ilmenite and rutile. These valuable minerals are used in everyday products from paint, pigment and toothpaste to titanium golf clubs.

Tension is rising between some Mtunzini residents and the mining firm, Exxaro KZN Sands, over whether mining should take place there.

One group of residents accused Exxaro of being environmentally unfriendly. Another group of residents, such as amakhosi and leaders from the tribal areas, supported the project saying that mining would have positive spin-offs for the community.

1.2.1 Name the THREE different role players/stakeholders involved in the issue above. (3)

1.2.2 State TWO advantages and TWO disadvantages of mining activities at Mtunzini. (4)

1.3 Study the pictures and a graph below showing community interactions and answer the questions that follow.

C Changes in the population density of two Paramecium species in the same habitat over time

P. aurelia

P. caudatum

0 2 4 6 8 10 12 14 16 Days

1.3.1 Name the following (a) Community interaction represented in A (b) Type of competition represented in B (c ) Community interaction represented in C (3)

1.3.2 Describe the community interaction represented in A. (3)

1.4 Study the table below showing changes in the human population size of the world from 1650 to 1950 and projected to 2050.

Year Human population size (millions) 1650 500 1750 750 1850 1 000 1950 2 010 Adapted and compiled by J. Gerber and J. Goliath 57

2050 8 000

1.4.1 Use the information in the table to plot a line graph. (6)

1.4.2 From your graph determine the following: (a) The population size in the year 2000 (2) (b) The time taken for the human population to double for the first time (2)

1.4.3 Give TWO reasons why it is important for any country to understand how the population will grow in the future. (2)

1.5 Study the graph below showing the growth of a population over a period of time.

1.5.1 Identify the growth form indicated by the graph above. (1)

1.5.2 Identify the phases labelled A, B and C. (3)

1.5.3 Write down the letter (A, B or C) of the phase in the above graph which illustrates rapid growth. (1)

1.5.4 Explain why the population size at C stayed constant. (3)

1.5.5 Give TWO reasons why the population growth at A was slow. (2)

1.6 The birth rate is the number of births per 1 000 people in the population whilst the death rate is the number of deaths per 1 000 people in the population.

The table below shows the birth and death rates in three countries, A, B and C, between 1960 and 2000.

Country Year

1960 1988 2000

A Birth rate 15,8 16,2 14,3

Death 12,3 11,5 10,9 rate

B Birth rate 34,0 35,4 39,6

Death 22,7 21,5 19,4 rate

C Birth rate 32,9 17,5 15,2

Death 17,7 7,4 6,6 rate

1.6.1 Which country (A, B or C) had a decreasing birth rate from 1960 to 2000? (1) 1.6.2 Which country (A, B or C) is most likely a developing one?

1.6.3 Give a reason for your answer to QUESTION 1.6.2. (1)

1.6.4 Explain TWO reasons why the death rate in all three countries had decreased from 1960 to 2000. (1)

******************************

Adapted and compiled by J. Gerber and J. Goliath