life sciences paper 2 learner guide july 2011

8/6/2019 Life Sciences Paper 2 Learner Guide July 2011

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Life SciencesPaper 2Winter School 20114 July 15 JulyLearners Guide


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Life Sciences Paper 2 Exam Revision Learners GuideWinter School July 2011

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Introduction:

Have you heard about Mindset? Mindset Network, a South African non-profitorganisation, was founded in 2002. We develop and distribute quality andcontextually relevant educational resources for use in the schooling, health andvocational sectors. We distribute our materials through various technology platforms

like TV broadcasts, the Internet (www.mindset.co.za/learn) and on DVDs. Thematerials are made available in video, print and in computer-based multimediaformats.

At Mindset we are committed to innovation. In the last two years, we successfully rana series of broadcast events leading up to and in support of the NSC examinations

Now we are proud to announce our 2011 edition of Matric Exam Revision, which willbegin with our Winter School in July. Weve expanded the broadcast to support youin seven subjects - Mathematics, Physical Sciences, Life Sciences, MathematicalLiteracy, English 1st Additional Language, Accounting and Geography.

During our Winter School, you will get Exam overviews, study tips on each of thetopics we cover, detailed solutions to selected questions from previous examinationpapers, short question and answer sessions so you can check you are on track andlive phone in programmes so you can work through more exam questions with anexperienced teacher.

Getting the most from Winter SchoolBefore you watch the broadcast of a topic, read through the questions for the topicand try to answer them without looking up the solutions. If you get stuck and cant

complete the answer dont panic. Make a note of any questions you have. Whenwatching the Topic session, compare the approach you took to what the teacherdoes. Dont just copy the answers down but take note of the method used.

Make sure you keep this booklet for after Winter School. You can re-do the examquestions you did not get totally correct and mark your own work by looking up thesolutions at the back of the booklet.

Remember that exam preparation also requires motivation and discipline, so try tostay positive, even when the work appears to be difficult. Every little bit of studying,revision and exam practice will pay off. You may benefit from working with a friend or

a small study group, as long as everyone is as committed as you are. Mindsetbelieves that the 2011 Winter School programme will help you achieve the resultsyou want.

If you find Winter School a useful way to revise and prepare for your exams,remember that we will be running Spring School from the 3rd to 7th October andExam School from 19th October to 22nd November as well.
http://www.mindset.co.za/learnhttp://www.mindset.co.za/learnhttp://www.mindset.co.za/learnhttp://www.mindset.co.za/learn


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Programme Outline

The Mindset Winter School is designed to focus on two subjects each day. For eachsubject you will find the following sessions:

Examination Overview

This is a 15 minute session that gives details of what you can expect in eachexamination paper. Practical guidelines are also given on how to prepare for theday of the exam.

Topics Tips

In this session you will be given a 15 minutes summary of the key ideas you needto know, common errors and study hints to help you prepare for your exams.

Topic Session

An expert teacher will work through specially selected questions from previousexam papers.

Interactive Q & A

After every topic you will get the chance to test yourself.

Live Phone-in

This is your chance to ask your own questions. So submit your question to theHelp Desk and we might call you back to help you live on TV. All questions yousubmit will be answered within 48 hours as normal.

Winter Broadcast School Schedule


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Topic 1: Life Processes

Question 1Adapted from June, 2009, P2 HG, 1.1.

1.1 Provide the number on the stem where the concentration of Auxin will be

highest (1)

1.2 How will this influence the growth of the stem? (2)1.3 What conclusion can be made because of this? (2)

Question 2Adapted from June, 2008, P2 hg, 1.1.2 1.1.3

The tip of an actively growing seedling was removed and then placed on one side ofthe stem as shown in the diagram below. The seedling was kept in a dark room.

2.1 Provide a hypothesis for this experiment.2.2 Explain the result and conclusion of this experiment.

Question 3Adapted from Exemplar, 2011, P2, 2.3

A group of Grade 12 learners wanted to investigate the effect of light coming fromone direction on the growth of shoots. They planted some wheat seeds in two seedtrays and allowed it to germinate. When young shoots appeared above the soil level,

the shoots were exposed to light from all directions for three days. After three days,the trays received different treatments as follows:


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Tray A: The shoots were exposed to light from all directions.Tray B: The shoots were exposed to light from one direction only.

The diagrams below show the effects of these treatments. Study it and answer thequestions that follow.

3.1 Formulate a hypothesis for the investigation above. (3)3.2 Explain why it was important to include tray A as part of this investigation. (2)3.3 State ONE conclusion that may be drawn from this investigation. (2)3.4 A third tray (C) was set up in a similar way as tray A and tray B. The tips of

the shoots were covered with aluminium foil. The diagram below shows the

appearance of the shoots at the start and after being exposed to light fromone direction only.

What conclusion can you draw from the results obtained in tray C? (2)3.5 Name ONE use in agriculture of the following:

Auxins (1)Gibberellins (1)


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Question 4Explain how roots how auxins cause roots to grow downwards (towards gravity). (5)

Question 5The diagram below illustrates the structure of the central nervous system and part of

the spinal cord of a person who has had an accident. Study the diagram and answerthe questions that follow:

5.1.1 Label numbers 1, 2, 3 and 9. (4)5.1.2 Give the number(s) of the part(s) responsible for the following responses in

this person:(i) Deep breathing(ii) Controlling high body temperature(iii) Increased pulse rate(iv) Loss of memory (8)

5.1.3 In order to determine the condition of the person, a doctor examined fluidtaken from between the parts marked 11 and 12.(i) Identify parts 11 and 12. (2)(ii) Name the fluid present between 12 and 13. (2)(iii) Give TWO functions of the above-mentioned fluid. (2)

5.2. Explain how the following affect the nervous system:i) Daggaii) Tik (4)


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Question 6Adapted from exemplar, 2011, P2, 1.4

The diagram below shows the human brain (longitudinal section), spinal cord(transverse section) and the right leg.

6.1 Name part 1, 4 and 5. (3)6.2 Identify the type of response indicated by the leg lifting up as indicated in the

diagram. (1)6.3 Explain fully how this response occurs in the body. (5)6.4 Tabulate the structural and functional differences between parts indicated by

3 and 4. (5)

Question 7

Adapted from Nov, 2003, Physiology, 1.3

Copy the table below in your answer book. Complete the following table on thehuman eye by, under A, adding the numbers of the diagram below the table next tothe appropriate label and, under B, making a tick () if the statement under B isTRUE or a cross (X) if the statement is FALSE in respect of each part.

Part of Eye A B = Refractslight rays

1.Vitreous humor

2. Retina3. Cornea

4. Iris

5. Blind spot

6. Pupil

7. Sclera

8. Lens

9. Conjunctiva

10. Choroid


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Question 8Adapted from June, 2010, Biology, 2.1

Study the diagrams and answer the questions.

8.1 Name the process that accounts for the change from Diagram I to Diagram II.(1)

8.2 Using letters and names of the parts labelled A to E, describe THREEchanges that occur during the process named in QUESTION 8.1. (9)

8.3 Which diagram (I or II) represents the state of the eye when a person isreading a book? (1)

8.4 Explain why some people, over the age of 40, tend to wear glasses withconvex lenses. (5)

8.5 How would a blind person be able to read the questions on this questionpaper? (1)


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Question 9Adapted from June, 2008, Biology p2 HG, 2.2

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

9.1 Identify parts B and G. (2)9.2 State the function of each of parts C and E. (2)9.3 Explain:

(a) Why you can often clear a buzzing/humming in the ear by swallowing. (3)b) Why the membrane labelled F is much larger than membrane C. (2)

9.4 A dog has lost part A in an accident. Part A is replaced with a stiff, non-elastic,solid plastic structure.(a) Is the plastic structure as effective as the original ear of the dog? (1)(b) Explain your answer to QUESTION 2.2.4 (a). (2)

9.5 Explain how part D and the retina of the eye function in similar ways. (4)

9.6 Give ONE reason for part D being spirally shaped. (2)


Study the diagram below and answer the questions that follow.

10.1 Identify the parts labelled B, C and F. (3)10.2 Explain how the pinna of the ear is suited for its function. (4)


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Question 12Adapted from exemplar, 2011, P2, 3.1

Study the diagram below and answer the questions that follow.

12.1 Give labels for the glands numbered 1 and 2. (2)12.2 Name hormone A. (1)12.3 Describe the negative feedback mechanism that operates when the thyroxin

level in the blood is too high, as indicated by process C. (4)

Question 13Adapted from June, 2010, Paper2 hg, 1.6


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13.1 Label layer B and part C. (2)13.2 Write down the letters of TWO parts in the diagram which are involved inthe insulation of the body. (2)13.3 What will happen to part F on a cold day? (2)


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

14.1 Which part of the brain responds to the temperature changes that occur at Aand B on the graph? (1)

14.2 What was the maximum temperature reached? (1)14.3 For what period of time did the person engage in strenuous exercise? (1)14.4 Why should body temperature not be allowed to fluctuate too much? (1)

14.5 Which diagram (I or II) would represent the condition of the skin after 15minutes? (1)

14.6 Explain your answer to QUESTION 14.5. (2)


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Topic 2: Environmental Studies

Question 1 (Population Ecology)

1.1 Various possible answers are provided for each question. Indicate the

correct answer by writing only the letter of your choice next to the relevantquestion number.

1.1.1 A population consists ofA different ecosystems.B communities of different organisms.C individuals of the same kind.D different species.

1.1.2 Which of the following represents a population?A Different types of animals in a nature reserve.B Cats and dogs in the backyard of your home.C All the fish in the sea.D All the trout in the Vaal river.

1.2 Give the correct biological term for each of the following descriptions. Writeonly the term next to the relevant question number.

1.2.1 The phase during population growth where animals adapt to their newenvironment.

1.2.2 The maximum number of organisms of a particular kind that can be supported

by resources in the environment.

1.2.3 The natural ability of a population to increase in size.

1.2.4 One-directional movement of organisms into a population.

1.2.5 A population without emigration and immigration.

1.2.6 Determining the population size by counting all organisms.


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1.3 For each of the phrases in COLUMN I, state whether it applies to A only, Bonly, both A and B or none in COLUMN II. Write down A only, B only, both Aand B or none in the answer book.

COLUMN I COLUMN II

1. Maximum number of individuals anenvironment can sustain

A. Natality B. Carrying capacity

2. Direct technique A. Petersen method B.Quadrat method

3. Displays exponential growth A. Geometric growth form B.Logistic growth form

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

1.4.1 Identify the growth from illustrated above.

1.4.2 Identify the phases labelled A to D.

1.4.3 Briefly explain phase A.

1.4.4 Which phase is NOT illustrated above?

A

B

C

D


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1.5 The graph below shows the number of bacteria growing in a nutrient mediumwhich was kept at a constant optimum temperature for a period of 30 hours.

1.5.1 How many bacteria were present at 10 hours?

1.5.2 From the fifth hour, how long did it take the bacteria population to double insize?

1.5.3 At which of the following time periods was the growth rate the greatest? Writeonly the letter of your choice.A 0 - 5 hoursB 5 - 10 hoursC 10 - 15 hoursD 15 - 20 hours

1.5.4 Give a possible reason for the increase in growth rate for the periodmentioned in Question 1.5.3.

1.5.5 For how many hours was the population of bacteria found to be above 4000?

(Show calculations)

1.5.6 Give ONE possible reason why the population of bacteria suddenly began todecrease after 25 hours.

1.6 A biologist wants to determine the number of trout in an aquatic population.He caught 25 trout and tagged them. The trout was released. Few monthslater, he catches 15 trout of which 5 were tagged.


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Question 2 (Human Populations)

2.1 Various possible answers are provided for each question. Indicate the correctanswer by writing only the letter of your choice next to the relevant questionnumber.

2.1.1 What was the population size when the industrial revolution started?A 100 000.B 1000 000.C 1000 000 000.D 2000 000 000.

2.1.2 According to the graph, what event lead to a significant decrease in thehuman population?A Industrial revolutionB Bubonic plaqueC Agricultural revolution

D Bronze age


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2.2 Study the population pyramid of the South African population.

2.2.1 What does a population represent?

2.2.2 What is represented by the horizontal axes?

2.2.3 What is represented by the vertical axes?

2.3 Study the population pyramids of different populations.

2.3.1 What is the percentage of females between 0 - 4 in pyramid A?

2.3.2 What is the percentage of males between 35 - 39 in pyramid B?

2.3.3 What is the percentage difference between age groups 15-19 and 25-29?

2.4.1 What is the age group between 15 - 44 called?


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2.5 Study the map of the world that indicates the ecological footprints of thedifferent countries. The darker the colour, the greater the ecological footprint.

2.5.1 What is meant by the term ecological footprint?

2.5.2 State the units that are used to measure ecological footprints.

2.5.3 Which country has the greatest ecological footprint?

2.5.4 Provide TWO possible reasons why the country mentioned in QUESTION2.5.3 has the greatest ecological footprint?

2.5.5 Which southern hemisphere country has the greatest ecological footprint?

2.5.6 What will happen in South Africa if the ecological footprint is not kept less thanthe biocapacity?

2.6 Write an essay discussing THREE strategies the learners ofSouth Africa could use to combat (lessen) our ecological footprinton the South African environment.


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2.7 Study the population pyramids of different populations.

2.7.1 What colour in the pie graphs indicates numbers of developed countries?

2.7.2 Provide reasons for your answer.


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3.3 Study the diagrams below and name the type of social organization and itsbenefit to the population.

3.4 Study the graph below of the interaction between two populations of mitesnamely genuss Typhlodromus and Eotetranychus, and answer the questionsthat follow.

3.4.1 Name the type of interaction illustrated in the graph.

3.4.2 Provide the complete scientific name of the prey.

3.4.3 Provide the complete scientific name of the predator.

3.4.4 What is the number of prey at week 5?

3.4.5 What is the number of predators at week 55?

3.4.6 Describe and explain the pattern shown by the interaction in the graph.

3.4.7 Create a table to indicate the population size of the two species from day 20to day 40.


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3.5 Study the diagrams below and name the type of competition with reasons.

3.6 Study the diagrams below and name the type of social interaction isillustrated. Briefly describe the relationship.

3.7 Study the diagrams below and name the type of social interaction isillustrated.Briefly describe the relationship.


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3.8 Source: 2011, Life Sciences paper 2 Exemplar, Question 4.2

Read the paragraph below on the culling of elephant

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 morethan is sustainable. Ecologists say the animals' huge appetites and fondness for'habitat re-engineering' - reducing forests to flatland by uprooting trees and tramplingplants - is the main problem.

Culling of the excess elephants is seen as an advantage in that it generates revenuefor the communities from the sale of ivory and other elephant products. It will alsoprovide meat to the local communities. Alternatives to culling include contraceptionand relocation of entire elephant families. The removal of fences between the KrugerNational Park and parks in neighbouring Mozambique will eventually help withmigration into less congested areas.

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

3.8.1 Give the main reason mentioned above in support of the culling of elephants.

3.8.2 Name TWO alternatives to culling proposed above.

3.8.3 Draw a bar graph to show the change in the elephant population from 1998 to2020.

3.9 Source: 2011, Life Sciences paper 2 Exemplar, Question 4.3

Using examples, describe predation, competition and symbiosis, explaining howeach interaction influences the population size of the organisms involved.


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Question 4: Ecology Succession

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

4.1 What biological process is illustrated above?

4.2 Differentiate between primary and secondary versions of the above-mentioned process.

4.3 What do we call the first species that occupy barren or bare soil?


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Topic 3: Reproduction

Question 1Adapted from Exemplar , 2011, Paper 2,Question 1.5.

Study the diagram below of the life cycle of a plant in which the gametophytegeneration is dominant

1.1. Is the life cycle represented, that of a moss or a flowering plant? (1)1.2. Name the following:

a) Cell division Ab) Process Bc) Cell division C (3)

1.3. Is the gametophyte haploid or diploid? (1)1.4. Are seeds produced during the life cycle of this plant? (1)

male gamete (n)

gametophyte

malesex organ (n)

femalesex organ (n)

cell division A

female gamete

process Bzygote

sporophyt

cell division

spores (n)


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Question 2Adapted from February, 2011, Paper 1, Question 3.3.

Study the diagram of a flower below and answer the questions that follow

2.1. Label parts A, B and D (3)2.2. Describe TWO ways how the structures in a flower are adapted for each of

the following:a) Wind pollination (2)b) Insect pollination (2)

2.3. What do the following structures develop into after fertilisation?a) Structure Cb) Structure E (2)

2.4. Give the letter/s of the parts that forms part of the:a) male whorlb) female whorl (4)

Question 3Adapted from Feb/Mar 2011, Paper 1, Question 3.1.

The diagram below represents the female reproductive system.


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3.1. Label structures A, B and C (3)3.2. State THREE functions of D (3)3.3. Fertilisation usually takes place at Y. Why will a blockage at X:

a) Prevent fertilisation at Y (1)b) Not necessarily lead to infertility (2)

Question 4Adapted from Exemplar, 2011, Paper 2, Question 2.1.

Study the diagram below showing the sequence of events of the development of anovum in a 28-day cycle

4.1. Identify the following:a) Follicle labelled A

b) Structure labelled Cc) Process shown at Bd) Hormone responsible for the formation of part Ae) Hormone responsible for the formation of part C (5)

4.2. What type of cell division resulted in the formation of part D? (1)4.3. If the events shown above took place in a 28 day cycle, state whether

fertilisation took place during this period. (1)4.4. Explain your answer to question 4.3. (3)

4.5. Explain HOW and WHY the production of FSH is inhibited whenfertilisation takes place. (4)

C

B

D


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Question 5Adapted from November, 2010, Paper 1, Question 3.1.

The diagram below shows part of the female reproductive system. Structures B to Gand processes 1, 2 and 3, occurring in the Fallopian tube and uterus are magnified.

5.1. Label C and D. (2)5.2. State which processes are taking place at 1, 2 and 3 respectively. (3)5.3. State how many chromosomes are present in the following structures:

a) Eb) Each cell of structure G (2)

5.4. Draw an enlarged labelled diagram of structure F to show its details. (5)5.5. State TWO functions of fluid A. (2)5.6. Structure B transports substances to and from the foetus.

a) Name ONE useful substance transported to the foetus.b) Name ONE waste product transported from the foetus. (2)


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Question 6Adapted from September, 2009 (Free State) , Paper 1, Question 1.4.

Study the diagram below which shows the male reproductive system and answer thequestions that follow.

6.1. Provide a label for part E. (1)

6.2. State ONE function of part:a) Ab) Dc) Ed) Ge) H (5)

6.3. Explain the function that parts B and C have in common. (2)6.4. Write down the LETTER of the part in which meiosis occurs and name the

type of cells that forms at the end of the process. (2)6.5. Name the cells found in structure G that are responsible for the production of

Testosterone. (1)6.6. Describe a permanent contraceptive method in males. (2)


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Question 7Adapted from June, 2009 (Gauteng) , Paper 1, Question 4.2.

The following questions refer to the figures below, which illustrates the changing ofhormones; the ovarian cycle and the changes of the endometrium during the

menstrual cycle. Study the figures and answer the questions that follow.

7.1. Identify the hormones A, B, C and D. (4)7.2. Explain why the structure of H changes so much from day 4 to day 28. (1)

7.3. Give TWO reasons why menstruation takes place. (2)7.4. What causes hormone B to peak at day 14. (1)7.5. Name the hormone that is secreted by G. (1)7.6. Why do the levels of hormone C begin to rise steeply after day 14 on the

graph. (1)


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Solutions to Topic 1: Life Processes

Question 1 Plant Hormones

1.1 1 (1)

1.2 It will cause the stem to bend towards the light (2)1.3 Stems are positively phototropic (2)


2.1 Stems are positively/negatively phototropic (3)2.2 Result - stem will bend to the left

Conclusion - substances which promote growth are formed at the tip of thestem. (3)


3.1 Shoots will grow towards the lightOR

Shoots will grow awayfrom the lightOR

Light has no influence on the shoot

3.2 It is the control - To verify the results of the experiment./To allow forone variable only.

3.3 Shoots grow towards the source of light

.

3.4 The auxins that make the shoot to grow towards the light is in the tipsof the shoots .

3.5 (a) Apical dominance(b) Tall growth of a plant/stimulate seed germination

(3)

(2)

(2)

(2)

(1)(1)(10)


Under the influence of gravity, Auxins settle at the bottom of the root. A highconcentration of Auxins here (in the root) inhibits cell division and elongation. Thecells on the upper end grow faster and the root bends downwards. Roots aretherefore positively geotrophic.

Question 5 Nervous System

5.1.1 1 - cerebrum 2 - cerebellum 3 - spinal cord9 - medulla oblongata (4)

5.1.2 i) 9 ii) 6 iii) 9 iv) 1 (8)

5.1.3 i) 11 - pia mater 12 - arachnoid (2)ii) cerebro-spinal fluid (1)


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iii) protection distribution of nutrients (2)

5.2

Question 6 CNS Reflex Arc

6.1 1 - cerebrum 4 - motor neuron 5 - cerebellum (3)6.2 Reflex Action (1)6.3 When hammer knocks knee receptor converts stimulus into impulse

Impulse then taken via sensory neuronAnd enters the spinal cord via dorsal horn of grey matterMakes a synapse with an interneuron which in turn makes a synapseWith a motor neuron which leaves via the ventral horn of grey matterTaking the impulse to the muscle (effector) causing it to contractPulling the leg up - knee jerk reflex (max 5) (5)

6.4Can't get table hereSensory neuron Motor neuronUnipolar MultipolarTransfers impulses from receptors Transfers impulses from CNSto CNS to effectors

4+ 1 for table (5)

Question 7 Eye

Part of Eye A B = Refracts light rays

1.Vitreous humor 10

2. Retina 9 X

3. Cornea 1

4. Iris 5 X

5. Blind spot 8 X

6. Pupil 3 X


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(20)

Question 8 Eye

8.1 (eye) accommodation (1)8.2 the ciliary muscles , part A contracts

the suspensory ligaments , part B slackensthe lens E becomes more convexORthe ciliary muscles , part A relaxesthe suspensory ligaments , part B become tautthe lens E becomes less convex (9)

8.3 Diagram II (1)

8.4 With old age the lensloses its elasticity / the ability to become more convex /ability to change shapeimage focusing behind the retina/image not focussing onretinaThe convex lenses of the glasses allows the light rays toconverge on the retinathus forming a clear image. (5)

8.5 It would be in Braille (1)(17)

Question 9 Ear

9.1 B: Semi-circular canals G: Auditory meatus/canal (2)9.2 C: Transmits pressure waves to the perilymph of the inner ear

E: Prevents pressure build-up of sound waves / distortion /easesvibrations out of the inner ear/ absorbs vibrations (2)

9.3 (a) - A buzzing sound is caused by a difference in the pressurebetween the outer and the middle ear- Swallowing opens / closes the Eustachian tube- to equalise the pressure (3)

(b) - To amplify sound (2)

9.4 (a) No (1)

7. Sclera 11 X

8. Lens 2

9. Yellow spot 9 X

10. Choroid 12 X


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(b) It is not moveable or flexiblefor more accurate collection of sound / for finding the directionthat the sound is coming from (2)

9.5 - Both receive stimuli- and convert to impulses

- which they send through the sensory neuron Any (2 x 2) (4)2.2.6 - Larger surface area

- to accommodate more receptors- fits into smaller area / takes up less space Any 2 (2)

(18)

Question 10 Ear

10.1 B - tympanic membraneC - malleus/hammer F - cochlea

10.2 Has many ridges to direct the sound waves along the auditory canalExtends outside the head/large flaps/funnel shapedto trap sound waves(Mark first TWO only) (any 2)

10.3 (a) D (b) G(c) E

(3)

(2)

(3)

(8)Question 11 Endocrine System

11.1 1 - Growth hormone/FSH/LH/TSH/ ADH any 12 - thyroxin6 - adrenalin/aldosterone any 1 (3)

11.2 Insulin - lowers blood sugar levelGlucagon - increases blood sugar level (4)

11.3 High thyroxin concentration in the blood will stimulate the pituitaryglandto secrete less TSH.

The lower level of TSH will make the thyroid glandto secrete less thyroxinwhich will decrease the level of thyroxin in the blood (6)

Question 12 Endocrine System

12.1 1 pitituary gland2 thyroid gland

12.2 Thyroid stimulating hormone/TSH

High thyroxin concentration in the blood will stimulate the pituitarygland

(2)

(1)


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to secrete less TSH. The lower level of TSH will make the thyroid glandto secrete less thyroxinwhich will decrease the level of thyroxin in the blood (any 4) (4)

(7)

Question 13

13.1 B EpidermisC Erector muscle (2)

13.2 A D (2)13.3 Constrict (1)

(5)

Question 14

14.1 Hypothalamus

14.2 37,5 oC

14.3 10 minutes

14.4 Most human activities is controlled by enzymes and enzymes requireoptimum temperatures to function

14.5 Diagram I

14.6 Blood vessels dilated to bring more blood to the surface and moreheat will be lost.

ORIncreased sweat productionwhich will cool down the body

(1)

(1)

(1)

(1)

(1)

(2)(7)


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Solutions to Topic 2: Environmental Studies

Question 1 (Population Ecology)

1.1.1 C

1.1.2 D1.2.1 Lag phase1.2.2 Carry capacity1.2.3 Natality1.2.4 Immigration1.2.5 Closed1.2.6 Census / Direct method1.3.1 B only1.3.2 Neither A or B1.3.3 Both1.4.1 Logistic growth form1.4.2 A - lag phase

B - exponential growth phaseC - decelerating growth phaseD - equilibrium / stationary phase

1.4.3 - Organisms are new to the environment- it needs time to adapt to environmental conditions- also new food sources

1.4.4 Extinction phase1.5.1 1000 per mm1.5.2 2,5 hours

1.5.3 C 10 - 15 hours1.5.4 Bacteria have adapted to environment1.5.5 30 -14 = 161.5.6 Exceeded carrying capacity / High environmental resistance1.6

M x CN = R

N = Population sizeM = Number captured during first catchC = Number captured during second catchR = Number of tagged organisms

25 x 15N = 5

= 3255

= 125 trout


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Question 2 (Human Populations)

2.1.1 C2.1.2 B2.2.1 Percentage of a specific gender of a population according to different age

groups2.2.2 Percentage of the population2.2.3 Different age groups2.3.1 82.3.2 4.22.3.3 = 4 - 2

= 2%2.4.1 Reproductive2.4.2 (a) C

(b) B(c) A(d) B

2.4.3 (a) A(b) C(c) B

2.4

Province Population size Percentage

Eastern Cape 13,5

Free State 5,7

Gauteng 22,4

KwaZulu-Natal 21,3

Limpopo 10,9

Mpumalanga 7,2

Northern Cape 2,2

North West 6,4

Western Cape 10,4

Total 49 991 300


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2.5.1 The ecological footprint compares human demands with the planetsecological capacity to meet those demands.

2.5.2 Global hectares2.5.3 USA2.5.4 It has a great amount of industries

Great number of carNot signed Kyoto protocol

2.5.5 Australia2.5.6 Any TWO of the following:

Collapsing fish stocks

Diminishing forest cover

Depletion of freshwater systems

A build-up of pollution and waste, which creates problems such asglobal climate change

2.6 Write an essay discussing THREE strategies the learners of

South Africa could use to combat (lessen) our ecological footprint on theSouth African environment.

2.7.1 Green2.7.2 Has smallest population BUT largest consumption AND hazardous waste

production

Question 3 (Community Ecology)

3.1.1 C

3.1.2 B3.2.1 Herbivore3.2.2 Saprophytes / heterotrophs3.2.3 Intraspecific / intraspecies3.2.4 Competitive exclusion3.2.5 Resource partitioning3.3 Fish = confusing predators

Zebras = confuse predatorsAfrican wild dogs = ensure successful huntingBees = division and specialization of labour

3.4.1 Predation or predator-prey interaction3.4.2 Eotetranchys sexmaculetus

CriteriaMarks allocated1 2 3

Strategies One valid strategy Two valid strategiesThree or morevalid strategies

DiscussionValid discussion ofone strategy

Valid discussion oftwo strategies

Valid discussion ofthree strategies

Synthesis

Significant gaps in

logic and flow ofanswer.

Minor gaps in logicand flow of answer.

Well structureddemonstrates

insight andunderstanding ofquestion.


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3.4.3 Typhlodromus occidentalis3.4.4 +- 1003.4.5 +- 123.4.6 When the number prey increases there is more food available

That means that all the cubs of a lynx litter will receive food and all will reachmaturityThat increases the predator populationAs the predator population increases the predation pressure wouldincreasewhich means that the predators will be killing more prey causing adecrease in prey populationAs the prey population decreases the predators will have less food and theirnumbers will be decreasingThe decrease in predators allows the number of prey to increase

3.5 Lions = intraspecific competition (same species)Lions and hyenas = interspecific competition (different species)

3.6 Mosquito on skin = parasitism (parasite benefits while host is harmed) Nest intree = commensalism (bird benefits while tree is NOT harmed or benefitted)

3.7 Bee on flower = mutualism (Both bee and flower benefits) Clown fish in seaanemone = mutualism(Both fish and anemone benefits)

3.8.1 Damage to the environment3.8.2 Contraception

Relocation of elephant familiesRemoving fences to allow migration(Mark first TWO only)

3.8.3

Mark allocation of the graph

0

5000

10000

15000

20000

25000

30000

35000

40000

1998 2008 2020Num

berofelephants

Year

Elephant population from 2008 to 2020

Caption for graph 1Correct label for X-axis 1Correct label for Y-axis 1Appropriate scale for Y-axis 1

Drawing of bars (D) 1 mark if 1 to 2 bars are drawn correctly2marks if all 3 bars are drawn correctly


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3.9

Predationo A predator captures and kills other animals (prey) for its foodo Example: Lions that capture and feed on antelopeso Prey population will decrease and the predator population will increase

Competitiono Interspecific competition

Happens when large numbers of organisms of different speciesdepend on same resources.

Example: Flour beetles One species will decrease in population size while the other will

increaseo Intraspecific competition

Happens when large numbers of organisms of different speciesdepend on same resources.

Example: Flour beetles One species will decrease in population size while the other will

increaseo Intraspecific competition

Happens between organisms of same species that share thesame available resource.

Example: Owls competing for same resources. Stronger owlswill survive

The owl population will decrease Symbiosis is the close association between two organisms so

that one or both benefit

o Parasitism One organism benefit (parasite) while the other is harmed (host) Example: Tapeworm and humans The host organisms population size will decrease and the

parasite population increaseo Mutualism

Symbiotic relationship between two organisms in which bothbenefit

Example: Bacteria and roots of leguminous plants Both populations will increase

o Commensalism

Symbiotic relationship between two organisms in which onebenefits without harming the other

Example: Sharks and sucker fish/Remora (benefit) The population size of the organism that benefits will increase in

size


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Marks Description

3 All three interactions discussed with no irrelevant information2 Two interactions discussed with no irrelevant information OR three

interactions discussed with little irrelevant information

1 One interaction discussed with little or no irrelevant information OR twointeractions discussed with little irrelevant information0 Not attempted/nothing written other than question number/no correct

information

Question 4 (Ecology Succession)

4.1 Ecological succession4.2 Primary is when the soil has never supported life but secondary referred to

succession where the environment has been damaged4.3 Pioneer species


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- which provides for the nutrition/gaseous exchange /excretion of theembryo- Allows for implantation /attachment of the embryo- Contracts during labour for childbirth

Mark first THREE only (3)

3.3.a) The sperm will be prevented from reaching the ovum /prevents the ovumfrom travelling along the Fallopian tube (1)b) The ovum produced in the other ovary can still be fertilised in the otherFallopian tube. (2)

Question 4

4.1. (a) Graafian follicle(b) Corpus luteum(c) Ovulation(d) FSH(e) LH (5)

4.2. Meiosis (1)

4.3. No (1)

4.4. If fertilisation occurred the corpus luteum would stay intact and not bedestroyed (3)

4.5 If fertilisation occurs high levels of progesterone enters the bloodThe high levels of progesterone inhibits the production of FSH

Low levels of FSH stop the development of a ovum inside a Graafian follicle

No ovulation occurs when the individual is pregnant (4)

Question 5

5.1. C- Endometrium /Uterine wall D- Ovary (2)

5.2. 1- Ovulation 2- Fertilisation 3- Mitosis (3)

5.3. a) 23

b) 46 / 23 pairs (2)


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5.4.

(5)5.5. - Acts as a shock absorber /prevents physical or mechanical damage

- Protects the foetus from drying out - Insulates the foetus against temperature fluctuations - Allows foetal movement for growth and development

Mark first TWO only (2)5.6. a) Oxygen

(Dissolved) food (examples ; glucose ,amino acids , water)Antibodies Nutrients Mark first ONE only (1)b) Metabolic waste Carbon dioxide Nitrogenous waste/ (examples urea, ammonia, uric acid)

Water Mark first ONE only (1)

Question 6

6.1. E - Vas deferens /Sperm duct (1)6.2. (a) A Stores urine, temporarily

(b) D carries sperm and urine out of the body(c) E carries sperm from epididymis to urethra(d) G produces sperm and male sex hormones(e) H Holds the testis away from the body to lower the temperature for

optimum sperm production/acts as temperature regulator (5)6.3. Both these glands provide secretions that help with the production of

semen/aids the efficiency of sperm (2)6.4. G , haploid spermatids/sperm cells (2)6.5. Cells of Leydig /Interstitial cells (2)6.6. Vasectomy The Vas deferens/sperm duct is cut/severed thereby preventing

sperm from entering into the ejaculatory duct/urethra (1)


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Question 7

7.1. A- FSHB- LHC- Progesterone

D- Oestrogen (4)7.2. H represents the thickness of the endometrium / uterine lining.

Around day 5/6, which is just after menstruation, the lining starts to build upagain, as the levels of oestrogen start to increase / This is to prepare theuterus for implantation of a zygote. (1)

7.3. A decrease in progesterone levelsdue to the disintegration of the corpusluteum causes a shedding of the endometrium as fertlisation did not takeplace Mark first TWO (2)

7.4. A decrease in oestrogen, (after ovulation) (1)7.5. Progesterone (1)7.6. Ovulation has occurred and the ovum is now in the Fallopian tubes. If

fertilisation should occur, the endometrium must be ready forimplantationProgesterone is responsible for the thickening of theendometrium Mark any 3 (3)

life sciences paper 2 learner guide july 2011

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