PROVINCE OF KWAZULU-NATAL
DEPARTMENT OF EDUCATION
LEARNER ASSISTANCE REVISION BOOKLET
GRADE – 12
LIFE SCIENCES
MARCH 2020
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2020 Learner Assistance Revision Booklets LFSC Grade 12reduce
Grade 12 Life Sciences study guide from the 2020, 82 pages. Read online or get the free PDF download.
Publisher: KZN Support Documents
Life Sciences · Grade 12 · 2020. Study guide, 82 pages. Read online or download the PDF.
- Subject
- Life Sciences
- Grade
- Grade 12
- Document type
- Study guide
- Year
- 2020
- Publisher
- KZN Support Documents
- Curriculum
- CAPS
- Pages
- 82
- File size
- 2.5 MB
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How to use this Revision Booklet
o You must use this Revision booklet together with the Life Sciences Mind the Gap Study
Guide, which is a complementary booklet.
o Ensure you understand all the relevant concepts and content.
o THIS Revision Booklet focuses mainly on the core concepts of the topic and questions at
recall and understanding cognitive levels.
o Over and above this, learners are advised to practise answering the following from past
examination papers.
o multiple choice questions
o relevant terminology
o matching questions
o Drawing and interpreting of graphs
o Interpreting tables
o Interpreting and drawing of diagrams
o Doing calculations
o Writing essays in Life Sciences
NB: The document comprises of paper 1 and paper 2 topics
2
TOPIC: REPRODUCTIVE STRATEGIES IN VERTEBRATES
Activity 1
Complete the following table by writing the correct biological term for the provided
description.
1.1 DESCRIPTION BIOLOGICAL TERM
1.1.1 The fusion of the sperm and egg outside the body
1.1.2 The fusion of the sperm and egg inside the body
1.1.3 The development of the embryo inside an incubated
egg that is laid.
1.1.4 The development of the embryo in the uterus and the
young are born alive.
1.1.5 The complete development of the embryo inside an
egg in the female body.
1.1.6 The development of the embryo in which very little
energy is used and parental care is required.
1.1.7 The development of the embryo in which a lot of
energy is used and the young are able to move
directly after hatching.
1.1.8 Structure that provides nutrition to the embryo in the
amniotic egg
1.1.9 Structure that stores waste for the embryo in the
amniotic egg
1.1.10 Fluid filled bag around embryo
(10)
3
Activity 2
2.2 The following diagram represents a section through an amniotic
egg:
2.2.1. Identify the extra- embryonic membranes numbered 1 and 2. (2)
…………………………………..
…………………………………..
2.2.2 What fills the space between the developing embryo and the
membrane numbered 1? (1)
…………………………………………
2.2.3 State the function of the fluid in the part labelled (2)
…………………………………………………………………………..
2.2.4 State the NUMBER and NAME of the structure that:
(a) Stores waste ……………………....................................... (4)
(b) Provides nutrition ……………………………………………
(9)
4
Activity 2.3
2.3 Read the passage below.
REPRODUCTIVE STRATEGY IN KANGAROOS
The red kangaroo reproduces by sexual reproduction. After mating,
the fertilised egg undergoes gestation in the uterus. After 33 days of
gestation, the red kangaroo gives birth to an offspring that is
hairless, blind and only a few centimetres long.
The offspring moves from the vagina by following a trail of saliva
secreted by the mother to a protective pouch where it remains for a
year. During this time the offspring drinks milk from the mother who
has teats in her pouch.
After 190 days it leaves the pouch.
[Adapted from www.livescience.com]
2.3.1 State whether the red kangaroo species displays:
(a) Internal or external fertilisation
………………………………………………. (1)
(b) oviparous, ovoviviparous or viviparous
……………………………………………… (1)
(2)
5
3. HUMAN REPRODUCTION
3.1 TERMINOLOGY: MALE REPRODUCTIVE SYSTEM
No Description Biological term
3.1.1 The structure that produces sperms
3.1.2 Process that produces sperms
3.1.3 The structure where testosterone is produced
3.1.4 Sac-like structure that contains testes
3.1.5 Structure where sperms are temporarily stored
3.1.6 A tube that transfers sperms to the urethra
3.1.7 A gland that provides nutrients for the sperms
3.1.8 A gland that produces alkaline medium of semen
3.1.9 A gland that lubricates end of penis
3.1.10 Common tube for sperm and urine
(10)
3.2 Study the diagram of the male reproductive system to answer the following
questions.
Provide the LETTER and NAME of the structure that:
3.2.1 Produces sperms and testosterone (2)
…………………………………..
3.2.2 Structure where sperms are temporarily stored (2)
……………………………….
3.2.3 Common tube for semen and urine (2)
………………………………….
3.2.4 Gland that provides nutrients for the sperms (2)
………………………………….
3.2.5 Gland that secretes mucus that lubricates end of penis (2)
………………………
3.2.6 Gland that secrete alkaline fluid making semen alkaline (2)
……………………..
3.2.7 Sac-like structure that contains testes
…………………………………. (2) (14)
6
Activity 2
3.4 Study the diagram of the female reproductive system.
A
B
D
C
Provide the LETTER and NAME of:
3.4.1. The structure that produces egg cells (2)
...………………………………………….
3.4.2 The gland where oestrogen and progesterone is produced (2)
……………………………………………….
3.4.3 The Part of the female reproductive system where fertilisation
occurs ………………………………………………. (2)
3.4.4 The organ in which the foetus develop (2)
..……………………………………………
3.4.5 The inner lining of the uterus where implantation of the embryo
occurs ……..………………………………. (2)
3.4.6 The structure where penis is placed for copulation (2)
…………………………………………
3.4.7 The birth canal (2)
…………………………………………
(14)
7
Activity 3
3.5 TERMINOLOGY: SPERM CELL AND EGG CELL
NO. DESCRIPTION BIOLOGICAL TERM
3.5.1 The vesicle which contains enzymes found in the head of a
sperm cell
3.5.2 The structure in the head of the sperm that contains genetic
material
3.5.3 The organelles in the sperm that provide energy for
movement
3.5.4 Structure that assists the sperm to move
3.5.5 The organelle that contains the genetic information of the egg
3.5.6 The jelly like substance on the inside of the egg
3.5.7 The structure that protects the contents of egg
3.5.8 The outermost layer of the egg
(8)
3.6 Study the diagram of a sperm cell.
A B C D
Provide the LETTER and NAME of:
3.6.1 The vesicle which contains enzymes found in the head of a sperm cell (2)
……………………………………………………
3.6.2 The structure in the head of the sperm that contains genetic material (2)
…………………………………………………….
3.6.3 The part where organelles in the sperm that provide energy for
movement ……………………………………………………. (2)
3.6.4 The whip-like structure that assists the sperm to move (2)
…………………………………………………….
(8)
8
3.7 MENSTRUAL CYCLE
Hormone FSH Oestrogen LH Progesterone
Gland/structure
that produces
Function
3.8
3.8.1. Write an account of the role of the hormones and their functions.
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
(8)
9
3.9 The schematic diagram below shows a human ovum that is about to
be
fertilised. The diagram is not drawn to scale.
3.9.1. Identify the part: (4)
A …………………………………….
B …………………………………….
C ……………………………………...
F ……………………………………
3.9.2 Give the LETTER and NAME of the part that:
(a) Contains the mitochondria …………………………………………
(b)Contains enzymes required to penetrate the ovum .
….……………………………………..
(c) Will enter the ovum during fertilisation……………………………
(6)
(10)
10
3.10 FERTILISATION AND DEVELOPMENT OF BLASTOCYST
Complete the following table by writing the correct biological term for the provided
description.
NO DESCRIPTION BIOLOGICAL TERM
3.10.1 Fusion of sperm and egg
3.10.2 Structure formed when sperm fertilizes egg
3.10.3 A solid ball of cells
3.10.4 A hollow ball of cells
3.10.5 Embedding of blastocyst in the endometrium
(5)
11
3.11 DEVELOPMENT OF FOETUS
Complete the following table by writing the correct biological term for the provided
description.
NO DESCRIPTION BIOLOGICAL TERM
3.11.1 Fluid filled bag around foetus
3.11.2 Keeps foetus hydrated
3.11.3 Maintains a constant temperature for foetus
3.11.4 Acts as a shock absorber
3.11.5 Allows for free movement of the foetus
3.11.6 Extra embryonic membrane that attaches the foetus
to the endometrium
3.11.7 Cord that attaches foetus to placenta
3.11.8 Produces progesterone after 3 months
3.11.9 Provides nutrition and oxygen from mother to foetus
3.11.10 Removes nitrogenous waste and carbon-dioxide
from foetus
3.11.11 Acts a micro-filter for pathogenic organisms
(11)
12
3.12. Study the diagram on the foetus
3.12.1. Fill the table below.
STRUCTURE LETTER FUNCTION/S
Amnion
………. ………………………………………………………………………..
Chorion
……….. ……………………………………………………………………….
Placenta
……….. ………………………………………………………………………..
……………………………………………………………………….
……………………………………………………………………..
…………………………………………………………… ………….
Umbilical cord …………………………………………………………………………..
………. …………………………………………………………………………
(12)
13
Topic: Nervous system
HINT: You are required to know the following:
Location and functions of the following parts:
Brain
- Cerebrum
- Cerebellum
- Corpus callosum
- Medulla oblongata
Spinal cord
Activity 1
Use this table to complete the following terminology based on brain and spinal cord
Description Terminology
1.1 A collective name for the membranes that protect the
brain
1.2 A detectable change (e.g. pain, heat, light, sound) that will
be received by a receptor and converted into an impulse
1.3 The part of the peripheral nervous system that controls
involuntary
1.4 The part of the brain that controls the heart rate
1.5 The part of the nervous system made up of cranial and
spinal nerves
1.6 The structure that connects the left and right hemispheres
of the brain, allowing communication between them
(6)
14
Activity 2
2.1 Study the diagram of the human brain below
Use the diagram above to complete the table below:
Parts Function
2.1.1 A-Cerebrum
2.1.2 B-
2.1.3 C- Transmit nerve impulses between spinal
cord and brain
2.1.4 D-Spinal cord
(4)
2.2 Name the part of the brain that connects the two hemispheres of the brain
_________________________________________________________ (1)
(5)
15
HINT: You are required to know the following:
Functions of sensory and motor neurons
Structure and functions of parts of sensory and motor neurons, using diagrams: nucleus,
cell body, cytoplasm, myelin sheath, axon and dendrites
Activity 3
3.1 Description Terminology
3.1.1 Transmits impulses from the sense organs or
receptors to the spinal cord and brain.
3.1.2 Transmits impulses from the brain and spinal cord
to the effectors (muscles and glands).
3.1.3 Part that receives a stimulus and converts it into a
nerve impulse.
3.1.4 Muscles or glands that bring about a response.
3.1.5 A part of the neuron that conducts impulses
towards the cell body
3.1.6 Transmits impulses away from the cell body of the
neuron
3.1.7 A reflex action is a quick, automatic action that
involves the spinal cord and does not involve the
brain.
3.1.8 The reflex arc is the path along which an impulse
is transmitted to bring.
(8)
16
3.2 Types of neurons, namely sensory neuron, motor neuron and connector neuron
3.2.1 Identify the different type of neurons illustrated below and state their function.
TYPE FUNCTION
(a)
2
(b)
2
3.2.2 Refer to the table above and provide the LETTERS in each TYPE of neuron
for the following parts.
(a) Dendrites ______________________ 2
(b) Axon __________________________ 2
(c) cell body _______________________ 2
(d) nucleus _______________________ 2
(e) cytoplasm ______________________ 2
(14)
17
3.3 Study the diagram of the neuron below and answer the questions based on it
3.3.1 Identify the neuron above____________________ 1
3.3.2 Write down the LETTER and NAME of the part that:
(a) Transmits impulses towards the cell body of the neuron
____________________________________________ 2
(b) Transmits impulses away from the cell body of the neuron
____________________________________________ 2
(c) Insulates and speeds up the transmission of impulses
____________________________________________ 2
(7)
18
HINT: You are required to know the following:
Definition of reflex action and a reflex arc
Structure of a reflex arc and functions of each part, using a diagram: receptor, sensory
neuron, dorsal ,root of spinal nerve, spinal cord, interneuron, motor neuron, ventral root
of spinal nerve, effector
Functioning of a simple reflex action, using an example
Significance of a reflex action
Activity 4
4.1. Define the following terms in the table below.
Terms Definition
(a) Reflex action
2
(b) Reflex arc
2
4.2 Name four different types of reflex actions.
(a) __________________________ 1
(b) ___________________________ 1
(c) ___________________________ 1
(d) ___________________________ 1
(8)
19
4.3 The diagram below shows what happens during a reflex action.
4.3.1 Complete the table below based on the reflex arc:
Parts on the Label of the Function
diagram parts
Toes Receptor
Neuron A
Neuron B
Neuron C
Muscle in leg Effector
8
4.3.2 The arrows in the flow chart below represent an incomplete reflex arc. Copy
and fill in the missing parts of the reflex arc below:
The path of a reflex arc:
Receptor (A) Interneuron (B) (C)
A. _______________________
B. _______________________
C. _______________________
3
20
HINT: You are required to know the following:
Structure and functions of the parts of the human eye, using a diagram
The changes that occur in the human eye for each of the following, using diagrams:
Accommodation
Pupillary mechanism
Activity 5
5.1 Use this table to complete the following terminology based on human eye.
Description Terminology
5.1.1 The series of changes that take place in the shape of the
lens and the eyeball in response to the distance of an
object from the eye
5.1.2 The watery fluid that supports the cornea and the front
chamber of the eye
5.1.3 The outermost membrane found around the
embryo/foetus
5.1.4 The nerve that carries impulses from the retina to the brain
5.1.5 The membrane that transmits sound vibrations to the inner
ear
5.1.6 Innermost membrane in the eye that contains
photoreceptors
(6)
21
5.2 The diagram below is the structure of the eye. It has missing labels and functions.
Fill in the missing information in the blocks below.
22
5.3 Accommodation is the adjustment of the shape of the lens to see objects clearly, whether
they are far or near. The table below has an incomplete process of accommodation, with the
aid of the given diagrams below.
5.3.1 Complete the process by filling in the missing parts of the process of below.
Distant vision (object further than 6 m) Near vision (object closer than 6 m
A. Ciliary muscles _______________________ Ciliarymuscles_____________________
B. Suspensory ligaments__________________ Suspensory ligaments_______________
C.Tension on lens _______________________ Tension on lens ___________________
D.Lens is less ___________________________ Lens becomes more ________________
E. The refractive power of the lens__________ The refractive power of the lens_______
F. Light rays are focused on________________ Light rays are focused on ____________
(12)
5.4 Study the diagram below and answer the questions that follow
Write down the letter and name of the part that:
(a) Relaxes and contract during accommodation
_____________________________________
(b) Alters the shape of the lens
_____________________________________
(c) Becomes more or less convex
____________________________________ (3)
23
5.5 The pupillary mechanism regulates the amount of light entering the eye by
adjusting the size of the pupil. Label and complete the process of pupillary
mechanism shown below.
Label of the eye showing pupillary mechanism Process of pupillary mechanism
Activity 6
6.1 Use this table to complete the following terminology based on human ear
Description Terminology
6.1.1. The part of the ear that equalises the pressure on
either side of the tympanic membrane
6.1.2 The receptors in the ear that detect changes in the
direction and speed of any movement of the body
6.1.3 The part of the ear that equalises the pressure on
either side of the tympanic membrane
6.1.4 Part of the human ear that directs sound waves into the
auditory canal
24
6.2 Study the diagram below and answer the questions that follow.
6.2.1 . Fill in the table below.
Part of the ear Function
A-
B-
C-
D-
E-
F-
G-
H-
I-
(9)
25
6.2.2 The arrows in the diagram above show the path of the sound waves
follow the direction of the arrows to describe the process of hearing until
the stimulus reaches the brain.
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
__________________________________ (6)
6.3 Complete the table below on balance
Type of Part of Receptor Function Transmission Part of Action
balance the ear of of impulses brain
receptor
Ampullae
at the
base of
semi-
circular Auditory nerve
canals
transmits
Change Maculae nerve
in impulses
position
of the
head
(7)
26
TOPIC: MEIOSIS
Activity 1
The diagrams below represent two different phases of meiosis in an organism.
A
B
C
DIAGRAM I DIAGRAM II
1.1 Identify:
(a) A __________________________________________ (1)
(b) B __________________________________________
(1)
1.2 Identify the phases represented by:
(a) Diagram I ______________________________ (1)
(b) Diagram II ________________________________
(1)
1.3 State the number of chromosomes that were present in the original cell at the start of
meiosis. __________________ (1)
1.4 Give the name of the organ in a male where meiosis occurs. _______________ (1)
1.5 Describe the process responsible for the appearance of the chromosomes as
shown in region C.
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________ (4)
1.6 Identify the phase of meiosis during which the process referred to in QUESTION (1)
2.1.5 occurs. ___________________________________
27
1.7 State TWO reasons why meiosis is important. (2)
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
ENDOCRINE SYSTEM, HOMEOSTASIS AND PLANT RESPONSE
Activity 1
A. TERMINOLOGY
The following terms should be covered in this topic:
No. Description Terminology
1. A system that is responsible for chemical
coordination in the body.
2. A gland whose secretions are transported
through ducts.
3. A hormone that stimulates mammary gland to
produce milk.
4. A hormone that is responsible for osmoregulation
in the body.
5. Specialized cells in the pancreas that secretes
insulin and glucagon.
6. A hormone responsible for secondary sexual
characteristics in males
7. A hormone that is responsible for maintaining salt
balance in the blood.
8. A gland that secretes FSH and LH in females.
9. Chemical messengers produced by endocrine
glands.
10. A gland located in the neck that secretes thyroxin
hormone.
11. A hormone that controls the metabolic rate in the
body.
12. A hormone responsible for growth and
development in the body.
13. A hormone responsible for emergencies in the
body.
14. A mechanism that detects imbalances and
restores balance in the internal environment.
15. A hormone that stimulates follicles development
in the ovary.
16. Promotes the secretions of hormones produced
by thyroid glands.
17. Process of production of milk.
28
18. A hormone that lowers the blood glucose level in
the body.
19. A hormone the increases the blood glucose level
in the body.
20. A hormone that maintains pregnancy.
(20)
Activity 2
2.1 Study the diagram below and answer the questions that follow.
2.1.1 Complete the following table
Gland Hormone(s) secreted Function of the hormone secreted
Growth hormone ………………………………………………
A………………… ………………………………………… (1)
…………………(1)
……………………… Stimulates the thyroid gland to secrete
…………………….(1) thyroxin.
………………………………………………
FSH ……………………………………………(1)
……………………… Stimulates ovulation.
…………………..(1)
………………………………………………
Prolactin ……………………………………………(1)
29
B………………… ……………………… Prepares the body for emergencies.
…………………(1) …………………….(1)
C. Pancreas Insulin ………………………………………………
(Islets of ……………………………………………(1)
Langerhans)
……………………… ………………………………………………
………………(1) ……………………………………………(1)
D:………………… Testosterone ……………………………………………
…………………(1) …………………………………………..(1)
E:………………… ……………………… Regulates the metabolic rate.
…………………(1) …………………….(1)
(15)
Activity 3
3.1 Negative Feedback Mechanism
3.1.1 The diagrams below show the negative feedback mechanism
involving thyroxin and TSH.
3.1.1 Identify EACH of the following:
(a) The gland that secretes hormone A ……………………………… (1)
30
(b) Hormone B………………………. (1)
3.1.2 Name the mechanism in the diagram that regulates the level of
hormone B ………………………………………………… (1)
3.1.3 Give the NAME of gland X………………………………. (1) (4)
Activity 4
4.1 Use the following diagram below to answer :
4.1.1 Identify hormone 1……………………………….
(1)
31
4.1.2 Identify hormone 2………………………………..
(1)
4.1.3 Name the gland that releases hormone 1 and 2………………………
(1)
4.1.4 Name the disease that will occur if hormone 1 the gland mentioned in
QUESTION 4.1.3 fails to release hormone 1. (1)
……………………………………………. (4)
TOPIC: HOMEOSTASIS
Activity 1
1.1 Study the diagram below and answer the questions that follow
1.1.1 Which diagram (A or B) is exposed to warm environmental condition? (1)
…………………………………………….
1.1.2 Provide TWO observable reasons for your answer in QUESTION 5 1.1.1 (2)
……………………………………………………………………………………
……………………………………………………………………………………
32
……………………………………………………………………………………
1.1.3 Name the part of the brain that monitors the body temperature. (1)
……………………………………………………………………………………
……………………………………………………………………………………
(4)
PLANTS RESPONSE TO THE ENVIRONMENT
Activity 1
1.1 Complete the following table
Description Term
1.1.1 A plant response to an external stimulus
1.1.2 A plant response to a light stimulus
1.1.3 A plant response to a gravity stimulus
1.1.4 Plant growth substance responsible for cell
elongation
1.1.5 Plant growth substance that promote fruit
growth
1.1.6 Plant growth substance that slows down seed
germination
1.1.7 Sharp structures that protect the plant against
predators. 7
1.2 Use the below diagram to answer the following questions
33
1.2.1 Name the hormone responsible for growth responses shown in the
diagrams above.……………………………… (1)
1.2.2 Name the external stimulus at:
(a) A ………………………………….. (1)
(b) D …………………………………... (1)
1.2.3 Name the growth response caused by (1)
A………………………………….
1.2.4 Name the growth response caused by (1)
D.…………………………………. (12)
Topic: HUMAN IMPACT ON ENVIRONMENT
Each sub-section could be approached from three aspects:
1. Human activities
Human activities are centred around our requirements for survival e.g. farming for food, dams
for water supply, buildings for shelter, shops to store food and clothing, hospitals for medical
attention, burning of fossil fuels for energy to power modes of transportation and electricity for
light and heat. Human activities are often motivated by financial greed and the need for
convenience and comfort.
2. Problems in the environment caused by the human activities
The problems in the environment are listed as the sub-sections for this topic.
• Air pollution and climate change
• Water quality and quantity
• Food security
• Loss of biodiversity
• Solid waste disposal
34
3. Solutions to the problems can be discussed using the acronym S A V E ME
Stopping a human activity that has negative effects in the environment is
an obvious solution BUT people are resistant to change so asking people
STOP to slow down and reduce their negative activities could be a more
S
SLOW acceptable and realistic solution that could lead to a reduction in the
harmful impact on the environment.
People are always striving for convenience and comfort. They do not
take kindly to having those things removed so when one option is
removed it needs to be replaced with an alternative that:
• Is convenient and provides comfort
A Alternatives • More environmentally-friendly
• Cost effective
• Easily accessible
• Doesn’t replace old problems with new problems
People who want to reduce negative impact on the environment have the
power to CHOOSE a government that promotes a more environmentally-
friendly country. The governments need to put laws in place AND police
V Voting/laws those laws that force industries to take responsibility for their contribution
to negative impact in the environment. People also have the power to
CHOOSE environmentally-friendly options when in their shopping.
The importance of education cannot be over-emphasised. People will
only seek to fix a problem once they are aware it exists. A solution to a
problem can only be found once the problem has been clearly identified.
E Education
The more people know, the more contribution there will be in developing
new strategies to fix environmental disasters.
ME Management Implementation of solutions requires planning. The implementation of a
Strategies solution needs to be assessed so that no further problems are created.
35
TEACHING TOOL
Adapted from FET LFSC Training Book
36
B. Terminology.
Complete the table below by writing the correct biological term that matches the
description provided.
No. Description Biological term
1. The variety of plant and animal species on earth
The killing of pests by using their natural predators or
2.
parasites
Measurement of the total amount of carbon dioxide
3.
emissions of an individual per year
4. Removal of large numbers of trees from an area
The accumulation of nutrients in water bodies from the
5. overuse of fertilisers on land, stimulating excessive plant
growth
The access, by all people at all times, to adequate, safe
6.
and nutritious food
Growing the same species of crop on a farm year after
7.
year
8. A layer in the atmosphere that is damaged by
chlorofluorocarbons (CFCs)
9. The illegal killing or removal of organisms from their
environments
10. The type of pollution caused when water is released into
a river after being heated in power stations or industries
11. Excessive production of greenhouse gases leading to
more heat energy being trapped in the atmosphere
12. The area where an organism lives and finds the
resources it needs to survive
13. Loss of water as liquid water changes to gaseous water
vapour
14. Plants that have been taken from one area and
introduced into another area.
15. The death of every organism of a species
16. Household water that contains detergents from bathing,
showering and laundry
17. Excessive rainfall in an area for a long period of time
leading to destruction of ecosystems.
18. The access to enough safe and nutritious food at all times
to maintain a healthy and active life
19 Substances that are formed over millions of years due to
the decomposition and compression of organisms that
died a long time ago
20. Increase in the average atmospheric temperature of the
planet
(20)
37
Activity 1
1.1
1.1.1 Explain how afforestation( to cover with forests) will contribute to the decreased
levels of carbon dioxide in the atmosphere______________________________ (3)
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
1.1.2 Describe the negative impact of the rise in the carbon dioxide concentration in (3)
the atmosphere on the green house effect._____________________________
______________________________________________________________________
_____________________________________________________________________________
_____________________________________________________________________________ (6)
1.2 Study the graph below.
1.2.1 By how much did the level of sulphur dioxide pollution in Sweden decrease
between 2000 and 2005? ____________________________________ (1)
1.2.2 Compare the general pattern of air pollution levels of France to that of the other
38
countries.
1.2.3 State the following:
(a) ONE similarity ________________________________________________ (1)
(b) ONE difference ________________________________________________ (2)
1.2.4 Which country had the lowest level of sulphur dioxide pollution in 2005? (1)
_______________________________________________________________ (5)
HUMAN IMPACT: FOOD SECURITY
1.3 Read the extract below on food security.
FOOD SECURITY IN SOUTH AFRICA
One of the challenges in South Africa is access to food by the poor. In 2009 Statistics SA
conducted a survey to determine the percentage of households in each province that had
access to food.
The results are shown in the table below:
PROVINCE HOUSEHOLDS THAT
HAVE ACCESS TO
FOOD (%)
Western Cape 85
Eastern Cape 79
Mpumalanga 79
Free State 67
Northern Cape 75
North West 79
KwaZulu-Natal 77
Limpopo 88
Gauteng 82
South Africa seems to have adequate food access in urban areas, but the same cannot be
said of households in rural areas. In rural areas prices of staple foods (e.g. maize and rice)
are usually higher than in urban areas.
Increasing agriculture is the key to food security and poverty alleviation. The majority of
people living in rural areas have access to land, but more still needs to be done to make
household farming (growing crops for family use only) in these areas more efficient.
[Adapted from Food Security, Department of Agriculture, Forestry and Fisheries, March 2011]
1.3.1 What is meant by food security? ……………………………………………………………..........
…………………………………………………………………………………………………….
1.3.2 Which province showed the highest percentage of households that have access to food?
………………………………………………………………………………………………………
39
1.3.3 List FOUR farming practices that people in rural area may be faced with. …………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
………………………………………………………………………………………………………….
1.3.4 List SIX factors that negatively influence food security.
……………………………………………………………………………………………………………
…………………………………………………………………………………………………................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
1.3.5 Identify the:
(a) Independent variable ……………………………………………………………………
(b) Dependent variable ……………………………………………………………………..
1.3.6 Draw a bar graph that shows the household access to food in KZN and Western Cape.
40
ACTIVITY 2
2.1 Read the following extract and answer the questions that follow.
MANAGING INVASIVE PLANTS – METHODS OF CONTROL
Alien plant invasion is only one factor that reduces plant biodiversity. Three broad categories
cover the control of invasive plants: mechanical, chemical and biological. Several techniques
may be effective in controlling a single species, but there is usually one preferred method – the
one that is most resource efficient with the least impact on the environment.
[Extra from an article by Christopher Mattrick]
2.1.1 Give the meaning of:
(a) Biodiversity _________________________________________________ (2)
__________________________________________________________________
__________________________________________________________________
(b) Alien plants __________________________________________________ (2)
________________________________________________________________________________
_________________________________________________________________________________
2.1.2 Give TWO factors that can reduce biodiversity other than alien plant invasions. (2)
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
2.1.3 Explain how biological control is applied to control alien plants. (3)
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
2.1.4 According to the extract list TWO criteria that should be used to control alien (2)
plants.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
(11)
41
ACTIVITY 3
3.1 Read the following article and study the graph and answer the questions that follow.
STRUGGLE TO KEEP FARM POLLUTION OUT OF TAP WATER
The Raccoon River in America runs through an intensely farmed region,
covered with different crops which are regularly treated with fertilizer and
other chemicals. It is also home to millions of farm animals whose manure
is added to the topsoil. Commercial fertilizers and manures contain
nitrates, a form of nitrogen, which gets into the river when rain washes it
off fields. Polluted run-off from farms poses an acute threat to residents'
tap water. It can be fatal to babies and it has also been linked to cancer in
adults.
The legal limit for nitrates in drinking water is 10 parts per million (ppm) but
the National Cancer Institute have found that drinking water with just 5
parts per million (ppm) of nitrate increases the risk of many cancers.
The graph below shows the nitrate readings from the river as well as
treated tap water from Des Moines, a nearby city, from 2010 to 2015.
[Adapted from: www.ewg.org/research/case-study-iowa-cities-struggle-keep- farm-
pollution- out-tap-water]
42
3.1.1 Use the information in the graph to state the relationship between the seasons and (2)
nitrate levels in the river from 2010 to 2012.
__________________________________________________________________
State why the authorities of Des Moines cannot be fined for exceeding the legal
3.1.2 limit of nitrate levels in drinking water. (2)
__________________________________________________________________
__________________________________________________________________
Motivate why the drinking water of the city can still be seen as unhealthy. (2)
3.1.3
_______________________________________________________________
3.1.4 Name the type of water pollution caused by run-off water containing excessive
nitrates. __________________________________________________________ (1)
3.1.5 Describe the effect of the pollution mentioned in QUESTION 3.1.4 on aquatic life. (2)
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
(9)
3.2
Complete the missing words in the statements below:
(a) Dumpsites produce a large amount of ________________ gas.
(b) Radioactive waste can destroy ________________ acids in organisms.
(c) ________________ is necessary to reduce the amount of solid waste.
(d) Pollution at dumpsites can be prevented by using thick ________________to
line the base of the dump.
(e) Waste at a dumpsite should be flattened and buried with ______________
(f) Vegetable waste should be used to make ________________ for the garden.
(g) ________________ is South Africa’s only nuclear power station.
(h) The gas produced by landfill sites can be piped and used as
an________________ energy source.
(8)
43
3.3 Work in pairs to answer the following question.
Question adapted from DBE 2013 Grade 11 Exemplar paper II
List FOUR strategies you would use to manage solid waste if you appointed as the
head of the waste disposal division of your town.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
(4)
____
44
Paper 2 Topics:
DNA- Code of life
Activity 1
No. Terminology TERM
1.1 A tangled mass of threads found in a nucleus of cells that give
rise to chromosomes.
1.2 A string-like structure found in a nucleus of a dividing cell
1.3 Natural shape of DNA
1.4 Structural components/ building Blocks/monomers of nucleic
acids.
1.5 The weak bond between nitrogenous bases in a DNA molecule
1.6 The process by which a DNA molecule makes identical copies
of itself
1.7 A segment of DNA/a chromosome that codes for a particular
characteristic
1.8 A sudden change in the sequence/order of nitrogenous bases
of a nucleic acid
1.9
Two chromosomes that carry the same set of genes
1.10
The complete set of chromosomes in the cell of an organism
1.11 The type of sugar found in a DNA molecule
1.12 The type of sugar found in an RNA molecule
1.13
Nitrogenous base found only in RNA molecules
1.14 The stage of protein synthesis during which mRNA forms from
DNA
1.15
The place in the cell where transcription occurs
1.16
Molecule that carries the coded message from the nucleus to
the cytoplasm about the protein to be made
1.17
The organelle in the cytoplasm to which mRNA attaches
1.18 The organelle in the cytoplasm which is the site of protein
synthesis
The stage of protein synthesis that takes place in the
1.19 cytoplasm
A sequence of three consecutive bases in mRNA onto which
1.20 fit three complementary bases of tRNA during protein
synthesis
A sequence of three consecutive bases on tRNA which
1.21
complement the bases on the codon found on the mRNA
1.22
The type of nucleic acid that carries a specific amino acid
1.23 The monomers which serve as building blocks
for the synthesis of proteins
1.24 The bond between amino acids of a protein
45
Activity 2
2.1 The diagram below shows a part of a nucleic acid molecule
1 2
G
T
3
2.1.1 Identify the nucleic acid shown above ____________________ (1)
2.1.2 How many strands make up this nucleic acid molecule? ___________ (1)
2.1.3 Where is this molecule found in a cell? _________________ (1)
2.1.4 Label the following parts:
a) 1 ________________________ (1)
b) 2 _______________________ (1)
c) 3 ______________________ (1)
2.1.5 How many nucleotides are shown in the diagram ___________ (1)
2.1.6 Name the complementary base for each of the following: (1)
a) G ________________________
b) T _________________________
2.1.7 Complete the following table:
DNA RNA
2.7.1. Single stranded
Contains nitrogenous base thymine 2.7.2.
2.7.3. Ribose sugar (3)
(11)
46
Activity 3
The diagram below represents a process taking place in the nucleus of a cell.
3.1 . Identify the:
(a) The process taking place as illustrated in the diagram
__________________________________
(b) Parts:
W_______________________________________
X_______________________________________
Y _______________________________________ (4)
(c) Bond Z ________________________________ (1)
(d) Nitrogenous base V ______________________ (1)
3.2 Name the phase of the cell cycle where this process takes place. (1)
_______________________________________
(7)
47
3.3 Below is a process outlining how DNA molecule makes a copy of itself.
Fill in the missing words to complete the process.
The double helix DNA molecule_________________ to form a ladder-like
structure. ______________________bonds breaks. Double stranded DNA
_____________________Two strands are formed. Each single strand of DNA
acts as a _______________for the formation of a new DNA molecule using
free_____________________ of DNA from the nucleoplasm. Two
___________________of DNA molecules are formed. This process is
controlled by __________________.
(7)
Activity 3
The diagram below represents two stages of protein synthesis.
3.1 Provide labels for molecule/organelle:
(a) 1 ___________________ (b) 2 ____________________
(c) 3 ___________________ (d) 4 ____________________
(e) 5 ___________________ (f) 6 ____________________
(6)
3.2 Give only the NUMBER of the part which represents a:
(a) DNA template strand ________________________
48
(b) Codon _____________________________
(c) Amino acids with Anticodon _______________________
(d ) Monomer of protein ______________________________ (4)
3.3 Identify the processes taking place at organelle 6 and where mRNA is formed
___________________________
(1)
___________________________ (1)
3.4 Name the opening in the nuclear membrane that allows for the passage of
mRNA into the cytoplasm ____________________________
(1)
3.5 Name the amino acid for number 7_______________________
(1)
3.6 Provide the DNA sequence that code for glycine______________________
(2)
(16)
49
Activity 4
4.1 The diagram below represents protein synthesis
Provide labels for number 1-9.
1.
2
3
4
5
6
7
8
9
(9)
4.2 Describe what is happening in each part named in question 4.1 during
protein synthesis:
1. _______________________________________________________
2. _______________________________________________________
3. _______________________________________________________
4. _______________________________________________________
5. _______________________________________________________
6. _______________________________________________________
7. _______________________________________________________
8. _______________________________________________________ (9)
9. _______________________________________________________
(18)
50
MEIOSIS
C. Terminology.
Complete the table below by writing the correct biological term that matches the
description provided.
No. Description Biological term
Organelle found only in animal cells that forms the spindle during cell
1.
division
Structures formed when the centrosome divides into two which moves
2.
to opposite poles of the cell during cell division
3. The point where two chromatids overlap during crossing over
The division of the cytoplasm through the constriction of the cell
4.
membrane at the end of cell division
5. The failure of chromosome pairs to separate during meiosis
A representation of the number, shape and arrangement of all the
6. chromosomes in the nucleus of a somatic cell
7. Two arms of a chromosomes
8. Two set of chromosomes
9 Pair of chromosomes that have same structural features
10. Phase of cell division where DNA replication occurs
(10)
Activity 1
1.1 The diagram below represent different phases of meiosis in an organism
1.1.1 Identify :
(a) A ------------------------------------------------------------------
(b) B ------------------------------------------------------------------
(c) C ------------------------------------------------------------------- 3
1.1.2 Name two places in humans where the above process occurs.
______________________________
______________________________ 2
51
1.1.3 (a) Identify the phase represented in Diagram 3 ------------------------------------- 1
1
(b) Give a reason for your answer in 1.1.2 (a) . -------------------------------------
1.1.4 Write down the numbers of the diagrams to show the correct sequence in which the 3
phases occur. -----------,--------------,----------------------------
1.1.5 State ONE difference between metaphase 1 and metaphase II
2
----------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------
1.2 The following diagrams representing different phases of meiosis.
HINT: Use the following diagrams to :
identify the phases of meiosis
differentiate metaphase 1 from metaphase II and anaphase 1 from anaphase II
describe the process of crossing over and the significance.
1.2.1 Provide labels for structures A, B and C
A -------------------------------------------
B -------------------------------------------
C ------------------------------------------- (3)
1.2.2 Which phase is represented by :
(a) Diagram 1 ---------------------------------------------------
(1)
(b) Diagram 2 --------------------------------------------------
(1)
1.2.3 How many chromosomes were present:
(1)
(a) At the start of the process of meiosis ------------------------------
(b) At the end of the process of meiosis ------------------------------- (1)
52
1.2.3 (a) Name the error in meiosis that may occur in the phase shown in diagram 4.
------------------------------------------------------------- (1)
(b) What term is given to the error named in 1.2.3 (a) if it occurs in chromosome pair
number 21. ----------------------------------------------------------------------- (1)
(9)
1.3 Study the diagram below shows a process occurring in a human male.
(The parent cell shown below has 46 chromosomes).
46
1st meiotic division
A
2nd meiotic division
B
1.3.1 Is the number of chromosomes in a parent cell haploid or diploid?
--------------------------------------------------------- (1)
1.3.2 How many chromosomes will be found in each cell at:
(1)
(a) A ------------------------
(b) B ------------------------ (1)
1.3.3 Name TWO processes occurring during the 1st meiotic division which
contribute to the genetic variation of cells A.
------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------
(2)
(5)
53
GENETICS
TERMINOLOGY
D. ACTIVITY 1
Give the correct biological term for each of the following descriptions.
No. Description Terminology
1. Differences between individuals within a population.
2. The particular position occupied by a gene on a
chromosome.
3. a change in the nucleotide sequence of a gene, resulting in
a new allele
4. The genetic makeup of an individual.
5. The physical appearance of an individual due to the
expression of genes.
6. An allele that is always expressed in the phenotype.
7. An allele that is only expressed in the phenotype if not
accompanied by a dominant allele.
8. Both alleles influences a particular characteristic in the
same way
9. Both alleles influences a particular characteristic in the
different ways
10. The breeding of organisms over many generations in order
to achieve a desirable phenotype
11. The use of biological processes, organisms or systems to
improve the quality of human life
12. A copy of an organism that is genetically identical to the
original organism
13. The process by which genetically identical organisms are
formed using biotechnology
14. Undifferentiated cells that can develop into any cell type
15. A diagram showing the inheritance of genetic disorders
over many generations
(15)
54
Activity 2
2.1
2.1.1 For each genotype, indicate whether it is heterozygous (Hh) or homozygous (HH)
hh ____________ Hh ______________ HH_____________ Mm _________
Bb ____________ ff _______________ Jj ______________ nn __________
(8
2.1.2 For each of the genotypes below, determine the phenotype.
(a) Brown eyes are dominant to blue eyes
Key s:B-brown eyes and b-blue eyes
BB ___________________________
Bb ___________________________
bb ___________________________ (3)
(b) Round R seeds are dominant to wrinkled r
RR _________________________
Rr __________________________
rr ___________________________ (3)
(c) Bobtails t are recessive (long T tails dominant)
TT ___________________________
Tt ___________________________
tt ____________________________ (6)
(12)
55
2.2
2.2.1. For each genotype below, indicate whether it is heterozygous OR
homozygous.
Bb ______________________ DD ________________________
Ff _______________________ tt _________________________
(4)
2.2.2. Which of the genotypes would be considered purebred?
_____________________________________________________
(1)
2.2.3. Which of the genotypes would be hybrids?
_____________________________________________________
(1)
2.2.4. Determine the phenotype for each genotype using the information
provided
(a) Yellow body colour is dominant to blue.
YY ________________ Yy ______________ yy ________________
(3)
(b) Square shape is dominant to round.
SS ________________ Ss ______________ ss ________________
(3)
2.2.5. Black hair (B) is dominant to blonde(b).What would be the possible
genotype/s for a Brunette (Black hair)_________ blonde________ (2)
(14)
56
Teaching Tool 1: Steps of monohybrid cross
57
Activity 3
3.1. Fur colour in mice is controlled by a gene with two alleles. Black fur
colour (B) is dominant over brown fur colour (b).
Use a genetic cross to show the possible genotypes and phenotypes of
the offspring. if a mouse that is heterozygous for fur colour is crossed
with a mouse with brown fur.
P1 phenotype ___________________x __________________
genotype __________________ x _________________
Meiosis
Gametes ___ ,___ x __, ___
gametes
Fertilization OR
F1 genotype___, ___, ___, ____
phenotype _________________
max
P1 and F1
Meiosis and fertilization (6)
3.2. Paul and Jane both have brown eyes. Their first child has blue eyes.
Explain how this is possible by using a genetic diagram
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------- (6)
(12)
58
Activity 4
4.1 COMPLETE DOMINANCE
4.1.1 Fur colour in mice is controlled by a gene with two alleles. A homozygous
mouse with black fur was crossed with a homozygous mouse with brown fur.
All the offspring had black fur.
Using the symbols B and b to represent the two alleles for fur colour, show as
a Punnet square, a genetic cross between a mouse that is heterozygous for
fur colour with a mouse with brown fur. Show the possible genotypes and
phenotypes of the offspring.
(6)
59
4.1.2 INCOMPLETE DOMINANCE
In a certain species of rose plants, there is incomplete dominance between
the genes for red and white flower colour. This leads to the production of a
third phenotype of pink flowers as an intermediate characteristic.
Determine the genotypes and phenotypes of the F1 if a red flowering rose
plant is crossed with a white flowering rose plant.
.
(6)
60
4.1.3 CO-DOMINANCE
A farmer mated a black bull with a white cow and obtained calves with a
mixture of black and white coat colour (i.e. they were black with patches of
white on them). This is due to co-dominance between the genes for black and
white coat colour.
Use a genetic cross to explain how a calve with a mixture of black and white
coat colour came about.
(6)
BLOOD GROUPS
TEACHING TOOL 4
FILL IN THE MISSING ANSWERS
GENE COMBINATION BLOOD TYPE
(GENOTYPE) (PHENOTYPE)
IA IB a)_____________________
b)____ , c)_____ A
(6)
B B B
I I , I i d)_____________ and____________
ii e)_______________
61
SEX LINKED INHERITANCE E.g Hemophilia and Colour blindness
TEACHING TOOL 6
Sex – linked disease are caused by a recessive allele found on the X-chromosome
and not on the y chromosome. Males have only one X-chromosome while female
have two x- chromosome – therefore males mainly suffer from the disorders than
the female.
Haemophilia is a sex-linked disease caused by the presence of a recessive
allele (Xh). A normal father and heterozygous mother have children.
Represent a genetic cross to determine the possible genotypes and
phenotypes of the children of the parents mentioned in the question above
PEDIGREE DIAGRAMS
Teaching Tool 7
Steps to follow when completing a pedigree diagram.
a. Study the opening statement in a pedigree question to identity the
following when given: -
i. dominant and recessive characteristics
ii. the type of inheritance (e.g. sex linked or not)
b. study the keys as well for phenotypes
c. Write in the phenotype of all the individuals as given in the problem
d. Fill in the genotype of all the individuals with the recessive condition – it
has to have two lower case letters
e. For every individual in the diagram that has the recessive condition, it
means that each gene was obtained from each of the two parents. So,
work backwards and fill in one recessive gene for each of the parents
f. If the parents showed the dominant characteristic, then fill in the second
letter which has to be a capital letter
g. Any other individual showing the dominant characteristic will most likely
be homozygous dominant (two capital letters)
NB! Note that examples of sex linked disoders are haemophilia and
colour blindness, otherwise the question will specify in the opening
statement when you must use sex chromosomes in the genetic cross.
62
Teaching Tool 8
Tay-Sachs disease is caused by an autosomal recessive allele (n).
Children with Tay-Sachs disease lose motor skills and mental functions.
Over time, the children become blind, deaf, mentally retarded and
paralysed. Tay-Sachs children die by the age of five.
The pedigree diagram below shows the inheritance of Tay-Sachs disease
in a family
5.1 Activity 5
Freckles are small patches of coloured skin. The allele for freckles (a) is
recessive to the allele for un-freckled skin (A). The diagram below shows a
family where some of the people have freckles.
5.1.1 Write down the genotypes of:
(a) William _____________
63
(b) Ben_________________
(c) Dot ________________
(d) Claire ______________
Activity 6
6.1 The pedigree diagram below shows the inheritance of colour-blindness in a
family. Colour-blindness is sex-linked and is caused by a recessive allele (d).
The ability to see colour normally is caused by a dominant allele (D).
1 2
3 4
5
Key
:Normal male Normal female
Colour-blind male Colour-blind female
Inheritance of colour-blindness
6.1.3 How many of the male offspring of parents 1 and 2 were normal?
____________________ (1)
6.1.4 State the genotype of:
(a) Individual 2 __________________________ (1)
(b) Individual 5 __________________________ (1) (3)
64
DIHYBRID
The dihybrid cross is a cross between two individuals where we are concerned with the
inheritance of TWO characteristics at the same time
TEACHING TOOL 9
In dogs, coat appearance is controlled by two genes; one for coat colour and one for
coat pattern (presence or absence of white patches).The alleles for each
characteristic are shown in the table below.
Phenotypes
V - black without white patches
W - black with white patches
X - grey without white patches
Y - grey with white patches
Genotypes
V - BBTT OR BbTt
W - BBtt or Bbtt
X - bbTT OR bbTt
Y - bbtt
65
Activity 7
7.1 Study the information below.
WW = white wool ww = black wool
White wool is dominant trait
HH = horns hh = no horns
Horns is the dominant trait
7.1.1 Give the phenotype for the following genotypes:
(a) Wwhh ________________________________
(b) wwHH ________________________________
(c) wwhh __________________________________
(d) WwHh __________________________________
(e) wwHh _________________________________ (5)
7.1.2 List the possible gametes for each of the following parents:
(Hint: use PUNNET squares)
(a) WWHH ____________________________
(b) WwHh ____________________________
(c) WwHH ____________________________
(d) wwHH ____________________________
(e) wwhh ___________________________ (5)
7.2 In a particular type of pigeon, it was found that red eye colour (R) is dominant
over black eye colour (r), while grey tail feathers (G) is dominant over white tail
feathers (g).
Give the genotype of the following phenotypes:
(a) Black eye colour, Homozygous Grey tail feathers. _______________
(b) Heterozygous red eye colour, heterozygous grey feather. __________
(c) Homozygous red eye colour, heterozygous grey feathers ._________
(d) Black eye colour, white tail feathers. _________________
(e) Black eye colour, heterozygous grey feathers. _________________
(5)
66
7.3 The colour in mice is controlled by two alles,black (B) and grey (b).Tail length is
controlled by two alleles,long (T) and short (t).
The punnett square below shows a part of a cross between two mice. Genotype
(i) has been left out.
7.3.1 Give the:
(a) genotype of parent 1
(b) genotype of parent 2
(c) genotype of offspring (i)
(3)
7.3.2 What percentage of the offspring above is grey with short tails? (1)
(4)
67
Grade: 12
Topic: Evolution
Main concepts for Evolution
68
EVOLUTION
TERMINOLOGY: GENERAL EVOLUTION
Fill in the table with correct biological terms for the descriptions provided.
No. Descriptions Terminology
1.1.1 The distribution of species in different parts of the world
1.1.2 A tentative explanation of a phenomenon that can be
tested and may be accepted or rejected
1.1.3 Explanation of an observation that is supported by
facts, models and laws
1.1.4 The process by which organisms best suited to survival
in the environment achieve greater reproductive
success
1.1.5 The breeding of organisms over many generations in
order to achieve a desirable phenotype
1.1.6 The variety of life forms that exist on Earth
1.1.7 Process whereby new species are formed from the
original population
1.1.8 A group of organisms which can interbreed to produce
fertile offspring
1.1.9 Type of evolution involving long periods of time when
species do not change and short periods of rapid
change
69
TERMINOLOGY: HUMAN EVOLUTION
Fill in the table with correct biological terms for the descriptions provided.
No. Description Terminology
1.1.1 The mineralised remains of organism that have lived in past
1.1.2 The ability of an organism to walk on two limps
1.1.3 Using two eyes with overlapping fields of view to create the
single
1.1.4 Clear sex display
1.1.5 An organism having the pointed face
1.1.6 The ability of an organism to walk on four limps
1.1.7 The opening at the base of the skull through which the spinal
cord enters
1.1.8 The family to which humans belong
1.1.9 The genus of the fossil ‘Little Foot’
1.1.10 The hypothesis that states that modern humans/Homo
sapiens originated in Africa and migrated to other parts of the
world
1.1.11 Gap between the teeth
1.1.12 The family to which humans belong
1.1.13 The permanent disappearance of a species from earth
1.1.14 A genus for humans
70
Teaching Tool 1
Introducing natural selection
Group arrangements: Groups of three
Time: 10 minutes for discussion and notes and 5 minutes for report back.
Resources: Flipchart Paper and Markers.
Instructions:
Each group will be given a different environment and they will have to come up with
survival techniques.
• Group 1 – living in a forest •
• Group 2 – living in Iceland.
• Group 3 – living in the desert
Each group will concentrate on how to survive focussing on:
• Shelter
• Food
• Dress/clothing
Continuous and discontinuous variation
Group arrangements: Groups of six
Time: 15 minutes for discussion and notes, 5 minutes to answer the questions and 10 minutes
for report back.
Resources: Flipchart paper and whiteboard markers.
Instructions:
Firstly list FOUR sources of genetic variation
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In your groups discuss how one would approach teaching the concepts of variation to bring
about clarity. Once you have completed the discussions try to answer the 2016 Prelim question
that follows in a manner as if you were explaining the answer to your learners. Use the Flipchart
paper to write down your answer.
71
In two separate experiments, blood group frequency in humans and egg size in chickens were
investigated. The following data was collected and the results graphed.
1. Identify which graph represents:
(a) continuous variation ____________________________________ (1)
(b) discontinuous variation __________________________________ (1)
2. Describe the differences between the graphs, supporting your answer with a
description of continuous and discontinuous variation.
_______________________________________________________________
_______________________________________________________________
________________________________________________________________
________________________________________________________________ (4)
Three theories of evolution:
Jean Baptiste de Lamarck – evolution by acquired characteristics.
Charles Darwin – natural selection.
Niles Eldridge & Stephen Jay Gould - Punctuated equilibrium. Not a gradual change but a
punctuated equilibrium.
Differences between Lamarck and Darwin
Lamarck Darwin
Ducks walked on land looking for There was a great variation in the
food. appearance of the feet of duck in a
Food became scarce and they were population.
forced to look for food in the water. Those duck who had webbed feet and
The duck stretched their toes apart to entered the water to obtain food were the
swim. As a result a skin grew successful individuals.
between their toes. This was the Their offspring would survive as they could
beginning of webbed feet. obtain food.
This characteristic was then inherited Those who could not obtain food from the
by the offspring. water died.
72
Punctuated equilibrium
Evolution is not always gradual as proposed by Lamarckism and Darwinism.
Evolution involves long periods of time where species do not change or change very little
(known as equilibrium). This alternates with (is punctuated by) short periods of time where
rapid changes occur.
The following was taken from the Grade 12 Ace it! Study Guide and is based on the evidence
of evolution.
1.1 Ancestors of ducks did not have webbed feet. In terms of natural selection, explain how
the webbed feet could have evolved.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
1.2 The following questions refer to Lamarck’s explanation of evolution:
1.2.1 Describe the idea proposed by Lamarck to explain evolution.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
1.2.2 State why Lamarck’s explanation is not accepted by most scientists today.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
73
ACTIVITIES
Activity 1
1. Natural Selection
1.1 Describe your observation in Diagram A; B and C in relation to natural
selection of cacti plants.
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
(6)
74
Activity 2
2. Speciation
2.1 Use below diagram to describe speciation
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
(6)
75
Activity 3
3.1 Diagram 1 shows variation in a species of fish living in a lake. There was a
rocky island that extended across the whole length of the lake, but it was
under water due to the high water level.
The fish were therefore able to move freely throughout the lake.
Diagram 2 shows the same lake many years later. A drought had caused the
level of the water in the lake to drop so that the rocky island in the centre
separated the lake into two smaller lakes, A and B, for a long period of time.
1.3.1 How many types of fish species do we have in diagram (1)
………………………………………………………………………………
1.3.2 Which diagram 1 or 2 where there is a gene flow? (1)
………………………………………………………………………………
1.3.3 State the reason for your answer in QUESTION 1.3.2. (1)
………………………………………………………………………………
………………………………………………………………………………
1.3.4 Define population. (2)
………………………………………………………………………………
………………………………………………………………………………
76
1.3.5 State FOUR possible causes of the variation in the fish population in (4)
Diagram 1
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………..
1.3.6 Eventually, as shown in Diagram 2, lake A and B contained two
different species of fish.
(a) Name the process that resulted in the fish population becoming (1)
two different species.
………………………………………………………………………………
………………………………………………………………………………
(b) Explain how the new species was formed using the above (6)
diagram
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………. (16)
77
HUMAN EVOLUTION
Activity 4
4.1. There are different explanations for evolution.
4.1.1 Describe the TWO laws used by Lamarck to explain evolution. (4)
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
4.1.2 Describe punctuated equilibrium. (4)
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
4.1.3 Tabulate TWO differences between artificial selection and natural
selection. (5)
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
……………………………………………………………………………… (13)
78
Activity 5
5.1 Study the diagram below and answer the questions below.
5.1.1 (a) What is the name given to this diagram (1)
……………………………………………………………………………..
5.1.2 (a) When did Australopithecus evolved? (1)
………………………………………………………………………………
(b) When did Australopithecus become extinct? (1)
………………………………………………………………………………
(c) How long does Australopithecus robustus survived? (1)
………………………………………………………………………………
(d) Which species competed with Australopithecus boisei for the
resources? (1)
………………………………………………………………………………
5.1.3 (a) Which species is more closely related to Homo sapiens? (1)
………………………………………………………………………………
79
(b) How many genera are involve in these diagram (1)
………………………………………………………………………………
(c) How many human species are involve in this diagram (1)
………………………………………………………………………………
(d) Name family for human species (1)
…………………………………………………………………………….
5.1.4 (a) Which of the hominids in the diagram above is considered to have (1)
been the first to use tools?
………………………………………………………………………………
(b) Name TWO Australopithecus fossils found in South Africa.
……………………………………………………………………………… (2)
(12)
Activity 6
6.1 Study the diagram below and answer the questions that follow.
6.1.1 Label part X and the type of teeth at Y. (2)
………………………………………………………………………………
………………………………………………………………………………
80
6.1.2 Explain the significance of the location of the structure X in organism C. (3)
………………………………………………………………………………
………………………………………………………………………………
………………………………………………………………………………
6.1.3 Which of the skulls ( A, B or C) belongs to:
(a) An Australopithecine (1)
………………………………………………………………………………
………………………………………………………………………………
(b) A quadrupedal primate (1)
………………………………………………………………………………
………………………………………………………………………………
6.1.4 Describe the significance of the shape of each of the following as a
trend in human evolution:
Shape of the spine (2)
………………………………………………………………………………
………………………………………………………………………………
Shape of the pelvis (3)
………………………………………………………………………………
………………………………………………………………………………
(12)
81
ESSAY QUESTION
Activity 7
7.1
The formation of new species contributes to an increase in biodiversity.
Describe how speciation occurs through geographic isolation and
describe FOUR reproductive isolating mechanisms that keep species
separate by completing the missing words.
SPECIATION
7.1.1 Speciation due to a geographical barrier
Speciation – population split by a___________________ (river,
landslide, mountains, volcanoes) – geographic isolation.
The population will split up into two groups, cannot_____________,
no gene flow.
Each group adapts to the
_____________________factors/develops separately.
Each group undergoes natural selection ________________ as
environmental conditions are different.
Each group may become _______________ and phenotypically
different, which might prevent them from ___________/ become
reproductively isolated leading to the formation of a new
______________ - speciation has occurred.
7.1.2 Reproductive isolation
Reproductive isolation mechanisms isolate the gene pool of a
species resulting in the formation of new species.
Examples of reproductive isolation mechanisms___________ at
different times of the year – seasonal isolation.
o Species-specific ____________ behaviour (animals) –
behavioural isolation.
o Prevention of fertilisation – gamete isolation or mechanical
isolation – _________ offspring (e.g. mules, 63 – cross
between a horse, 64, + a donkey, 62).
o Cross-species hybrid, liger (cross between a lion + a tiger).
o Adaptation to ____________ ____________ (plants) – no cross
pollination (see diagram
82
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