IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 1 Cells and Cell Processes Nutrition
Recommended Prior Knowledge Students can come to this Unit with very little prior knowledge. In order to understand diffusion and osmosis, they will need
some understanding of particle theory. Some knowledge of catalysts will also be helpful, and they should know a little about simple chemical reactions and
how to represent these by word equations. The concept of pH should also be understood at a simple level.
Context This Unit covers some fundamental topics that will be drawn on in all the Units that follow, and therefore the majority of it is covered by both Core
and Extension candidates.
Outline The Unit first considers the special features that make living things different from non-living objects, and then looks at the structure and functions of
animal and plant cells, which leads into the organisation of cells into tissues. Some particular examples of specialised cells are considered, which introduces
the idea of structural adaptations for particular functions. Movement of substances within living organisms by diffusion, osmosis and active transport (the latter
for extension candidates only) is considered. A simple treatment of enzyme function and some applications completes the Unit. Note that section I, parts 2
and 3, are not included here, but have been placed in Unit 9. However, some teachers may prefer to cover these topics in this unit.
I1
II 1
II 1
Learning Outcomes
List and describe the characteristics of
living organisms
Define the terms nutrition, excretion,
respiration, sensitivity, reproduction,
growth and movement
Identify and describe the structure of a
plant cell (palisade cell) and an animal
cell (liver cell) as seen under a light
microscope
Describe the differences in structure
between typical plant and animal cells
Relate the structures seen under the light
microscope in the plant cell and the
animal cell to their functions.
Suggested Teaching Activities
Ask students to suggest characteristics that
are shared by plants and themselves but
not by non-living objects.
Palisade cells can be seen using prepared
slides or transparencies of leaf sections.
Freshwater filamentous algae can be
mounted in a drop of water on a slide and
viewed with a microscope.
Liver cells are difficult to observe, but it
may be possible to make temporary
mounts of stained cheek cells.
Extension candidates should consider
functions of features that are common to
plant and animal cells, and those that are
found in plant cells only. They should
consider how the differences between
animal and plant cells relate to their
different methods of obtaining nutrients.
Online Resources
Illustrations of cells
http://www.cellsalive.com/
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II 2
II 3
II
4.1
Learning Outcomes
Define tissue and relate the structure of
the following to their functions:
Ciliated cells – in respiratory tract
Root hair cells – absorption
Xylem vessels – conduction and support
Muscle cells – contraction
Red blood cells – transport
Define organs and organ systems as
illustrated by examples covered in
Sections II and III
Calculate the magnification and size of
biological specimens using millimetres as
units
Define diffusion as the movement of
molecules from a region of their higher
concentration to a region of their lower
concentration down a concentration
gradient.
Describe the importance of gaseous and
solute diffusion and of water as a solvent.
Suggested Teaching Activities
Examine a temporary mount of epidermal
tissue peeled from the inner surface of an
onion bulb.
The coverage of these examples of cells
and of organs and organ systems could
come later when they can be dealt with in
context.
Online Resources
Examples of differentiated
cells:
http://www.iacr.bbsrc.ac.uk/n
otebook/courses/guide/organ
.htm
Use the temporary mount of epidermal
tissue peeled from the inner surface of an
onion bulb and appropriate scale to
determine the size of cells.
Microscope magnification
specifications & field of view
http://www.microscopemicroscope.org/advanced/m
agnification-1.htm
Use a simple demonstration of diffusion, for
example a potassium manganate IV crystal
in a gas jar of water (diffusion of a solute),
or ammonia and hydrochloric acid placed
at opposite ends of a long glass tube, or
simply a perfume container opened in one
corner of the room (gaseous diffusion)
Diffusion and osmosis
animation and text:
http://www.bbc.co.uk/scotlan
d/revision/biology/investigatin
g_cells/cells_and_diffusion_r
ev.shtml#diffusion
Emphasise the random motion of particles.
Consider the relevance of thjs to living
organisms – for example, the diffusion of
oxygen and carbon dioxide into and out of
a plant leaf or across the surface of the
alveoli in the human lungs.
Diffusion and osmosis
interactive animations:
http://physioweb.med.uvm.ed
u/bodyfluids/osmosis.htm
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
4.3
Learning Outcomes
Define osmosis as the passage of water
molecules from a region of their higher
concentration to a region of their lower
concentration, through a partially
permeable membrane.
Describe the importance of osmosis in
the uptake of water by plants and its
effects on plant and animal tissues.
Suggested Teaching Activities
Osmosis should be treated as a special
case of diffusion, in which only water
molecules are able to move from one side
of a partially permeable membrane to
another. Ensure that students understand
what a solution is in terms of particles, so
that they are able to imagine the water
molecules and solute particles behaving
independently of each other.
Use visking tubing to demonstrate osmosis.
Investigation of changes in mass or length
of potato chips placed in a range of
different sugar solutions provides good
opportunity for quantitative treatment of
results, as well as enhancing
understanding of osmosis.
Discuss differences in the effects of water
uptake and loss on animal cells and plant
cells in terms of the absence and presence
of the plant cell wall. Turgor as an
important mechanism of support in plants
could be discussed. Relate water uptake by
osmosis back to the structure of root hair
cells covered earlier in this Unit.
II
4.3
Understand the concept of a water
potential gradient.
Explain water potential as the tendency for
water to leave a solution. The more water
(that is them more dilute the solution) the
higher the water potential. Water moves
from a high water potential to a low water
potential – that is, down a water potential
gradient. Do not introduce the idea of
negative water potentials at this level.
Online Resources
Visking tubing expt –
interactive
http://www.mhhe.com/biosci/
esp/2001_gbio/folder_structu
re/ce/m3/s3/cem3s3_3.htm
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
4.2
II 5
Learning Outcomes
Define active transport and discuss its
importance as an energy-consuming
process by which substances are
transported against a concentration
gradient, e.g. ion uptake by root hairs
and uptake of glucose by epithelial cells
of villi.
Define enzymes as proteins which
function as biological catalysts.
Suggested Teaching Activities
No detail of the molecular mechanism of
active transport needs to be considered.
Students should understand that energy for
this process is provided by respiration.
Describe the effect of changes in
temperature and pH on enzyme activity.
Revise the meaning of the term ‘catalyst’.
Ensure that students understand that
enzymes are simple molecules, not living
organisms. They cannot, therefore, be
‘killed’.
Simple experiments with catalase are an
excellent introduction to enzymes.
Investigate the effect of temperature on the
effect of enzyme activity, for example using
starch and amylase, or pepsin and milk
powder. Explain the rise in activity with
temperature in terms of kinetic theory, and
the fall as temperature rises in terms of
denaturation of the enzyme molecules.
Consider the different optimum
temperatures of different enzymes, not only
those in humans.
Online Resources
Simple account of how
enzymes work:
http://www.activesciencegsk.com/miniweb/content/en
zymes/how_do.htm
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II 5
Learning Outcomes
Describe the role of enzymes in the
germination of seeds and their uses in
biological washing products and in the
food industry.
Outline the use of microorganisms and
fermenters to manufacture enzymes for
use in biological washing powders.
Suggested Teaching Activities
The role of amylase in the breakdown of
starch to maltose in seeds provides an
example of enzymes in plants. Germinating
barley seeds, dipped into a sterilising
solution to destroy any micro-organisms on
their surfaces, can be placed on sterile
starch agar in a petri dish, which can later
be tested for starch with iodine solution.
Proteases, lipases and amylases, often
with high optimum temperatures, are all
used in biological washing powders.
Investigations can be carried out into the
effectiveness of these in removing different
types of stains.
Simple experiments on the effect of
pectinase on the yield of juice from crushed
apples can be carried out.
Online Resources
Downloadable booklet
'Practical Biotechnology',
with practical investigations
using a variety of
enzymes
http://www.ncbe.reading.ac.u
k/NCBE/PROTOCOLS/pracb
iotech.html
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 2: Animal Nutrition
Recommended Prior Knowledge Students can come into this Unit with very little biological knowledge. However, they do need to understand the concepts
of elements and compounds, and of atoms, molecules and ions, and should be familiar with simple chemical reactions.
Context The molecules that make up the bodies of living things are introduced here, and will be referred to in all of the subsequent Units.
Outline This Unit considers the molecules from which living organisms are made, and then looks in detail at how animals acquire the materials that they need
to form the structure of their bodies, and also to supply energy. The way in which small molecules can be used to make larger ones is briefly considered,
before thinking about how such large molecules need to be broken down again before they can be absorbed through the wall of the alimentary canal. The
functions of the main digestive enzymes are considered, linking back to the work on enzymes in Unit 1. The use of food to supply energy will be covered in
more detail in Unit 4, and the functions of the liver in glucose and amino acid metabolism, touched on very briefly here, will be treated in more depth in Units 5
and 6.
II 6
II 6.1
Learning Outcomes
Define nutrition as the obtaining of
organic substances and mineral ions
from which organisms obtain their
energy and their raw materials for
growth and tissue repair.
Suggested Teaching Activities
Discuss the need for materials to build
bodies, and for energy to maintain their
activities. A simple definition of an organic
substance is one whose molecules contain
carbon and hydrogen.
List the chemical elements which make
up:
carbohydrates
fats
proteins
Describe the synthesis of large
molecules from smaller basic units, i.e.
simple sugars to starch and glycogen
amino acids to proteins fatty acids and
glycerol to fats and oils.
Ensure that students have some
understanding of the terms element, atom
and molecule. Beads that string together,
or simple chemical modelling kits, can be
used to illustrate the idea of small
molecules joining together to make larger
ones.
They should understand that starch is
found only in plants, never in animals.
Online Resources
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
Learning Outcomes
Describe tests for starch (iodine
solution), reducing sugars (Benedict's
solution), protein (biuret test) and fats
(ethanol)
Suggested Teaching Activities
Students should have the opportunity to
carry out each of these tests on a range of
foods. This can also give useful practice in
recording results and conclusions in a
clearly presented results chart.
Online Resources
II 6.1
List the principal sources of, and
describe the importance of:
carbohydrates, fats, proteins, vitamins
(C and D only), mineral salts (calcium
and iron only), fibre (roughage) and
water
- Describe the deficiency symptoms for
vitamins (C and D only) and mineral
salts (calcium and iron only).
Diets in most countries depend on a staple
food such as bread or rice, which is usually
the main source of carbohydrate. Students
should be aware of the main sources of
each type of nutrient in their own country,
but also be prepared to consider how diets
differ in other parts of the world. The
Association for Science Education. College
Lane, Hatfield, Herts, AL10 9AA, England,
has a project called Science Across
Europe, which includes a unit on diet, and
which encourages schools in different parts
of the world to share information.
US Agency for International
Development’s
information on the nutritional
contents of a wide
variety of foods:
http://www.usaid.gov/hum_re
sponse/crg/fssfcor
nmeal.htm
II
6.3.1
Understand the concept of a balanced
diet describe:
a balanced diet related to age, sex and
activity of an individual
the effects of malnutrition in relation to
starvation, coronary heart disease,
constipation and obesity
Students can keep a record of the food that
they eat during one day, and then consider
whether they are obtaining the nutrients
that they need. The booklet 'Food Tables',
Bender and Bender, published by Oxford
University Press, is a good source of
information about energy and nutrient
contents of a very wide range of foods.
Balanced diet
http://www.sambal.co.uk/diet.
html
II 6.1
Malnutrition should be considered as the
result of eating an unbalanced diet, not just
the lack of a particular type of nutrient.
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
Learning Outcomes
Discuss:
the problems of world food supplies
the problems which contribute to famine
(unequal distribution of food, drought
and flooding, increasing population)
Suggested Teaching Activities
Material to illustrate this topic, and to form
the basis of discussion, can be collected
from newspaper and television reports.
Students may like to consider whether new
technologies, such as the development of
genetically modified varieties of crops, are
likely to improve the situation or exacerbate
it.
Online Resources
Technology to Feed the
World
http://www.nationalacademie
s.org/webextra/crops/
A discussion of the problems
of feeding the world's
growing population, with
excellent links to many other
site
II 6.1
Describe the use of micro-organisms in
the food industry, with reference to
yoghurt, bread and single cell protein.
There is plenty of opportunity for practical
work involving yoghurt production, and the
use of yeast for bread-making. A good
source of ideas for this is the booklet
'Practical Biotechnology'.
downloadable booklet
'Practical Biotechnology',
with practical investigations
into yoghurt production and
bread-making
http://www.ncbe.reading.ac.u
k/NCBE/PROTOC
OLS/
II 6.1
Describe the uses, benefits and health
hazards associated with food additives
including colourings.
The health benefits of preservatives, in
terms of greatly reduced risk of food
poisoning, should be emphasised.
Antioxidants also increase storage times
for many foods. Flavourings and flavour
enhancers increase palatability. A few
artificial colourings, such as tartrazine,
have been associated with problems such
as hyperactivity.
II
6.3.1
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
6.3.2
II
6.3.3
Learning Outcomes
Identify the gross structure of the
alimentary canal and associated organs
(mouth, oesophagus, stomach, small
intestine: duodenum and ileum, large
intestine: colon and rectum, anus,
pancreas, liver)
Define ingestion, digestion, absorption,
assimilation and egestion
Describe the functions of the alimentary
canal's various parts in relation to
ingestion, digestion, absorption,
assimilation and egestion of food
Suggested Teaching Activities
Students often do not understand that the
alimentary canal is a long tube - albeit a
coiled one - through which food passes.
They also need to understand that food
cannot be considered to have entered the
body until it crosses the wall of the canal.
Identify the types of human teeth and
describe their functions.
State the causes of dental decay and
describe the proper care of teeth
describe the processes of chewing and
peristalsis.
Students can think about the functions of
the different types of teeth as they eat.
Chewing increases the surface area of
food, making it easier for enzymes to act
on it during the later stages of digestion.
Dental decay should be thought of as the
result of bacteria producing acids, which
damages enamel.
It should be made clear that peristalsis
happens all through the alimentary canal,
not just in the oesophagus.
The need for digestion before absorption
can take place can be investigated using
Visking tubing (to represent the alimentary
canal) containing a mixture of glucose,
starch and water. This is placed in a beaker
of water (to represent the blood), and left
for long enough for the glucose to diffuse
across the tubing. The contents of the
tubing and of the beaker can be tested for
starch and for glucose
Online Resources
http://borg.com/~lubehawk/h
digsys.htm
Includes a quiz on the parts
of the alimentary canal
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
6.3.3
II
6.3.4
II
6.3.5
II
6.3.5
II
6.3.6
Learning Outcomes
Explain the probable action of fluoride
in reducing tooth decay and present
arguments for and against its addition
to public water supplies.
Suggested Teaching Activities
Although most health professionals
strongly support the addition of fluoride to
water supplies, there are also some
arguments against this.
Describe:
Digestion in the alimentary canal, the
functions of a typical amylase, protease
and lipase, listing the substrate and
end-products.
Identify the small intestine as the region
for absorption of digested food.
Describe the significance of villi in
increasing the internal surface area.
Describe the structure of a villus
including the role of capillaries and
lacteals.
Indicate the role of the hepatic portal
vein in the transport of absorbed food to
the liver.
Describe: the role of the liver in the
metabolism of glucose and in the
destruction of excess amino acids, the
role of fat as a storage substance.
This topic should be linked with earlier
work on enzymes, in Unit 1 (section II.5).
Students should also know in which parts
of the alimentary canal these enzymes are
found.
Core students do not need any detail of the
villus structure.
The absorption of glucose should be linked
with earlier work on active transport, in Unit
1 (section II.3).
For Core students, no detail of the
hormonal control of glucose levels is
required. They should, however, know that
the liver stores excess glucose as
glycogen (link back to section II 6.1) and
converts this back to glucose again if blood
glucose levels fall. The conversion of
excess amino acids to urea should be
dealt with very simply; this will be covered
again in Unit 5.
Online Resources
Fluorides and fluoridation
http://www.ada.org
The American Dental Association's site
dealing with the fluoride issue.
The Story of Fluoridation
http://www.nidcr.nih.gov/Healthinforma
tion/OralHealthInformationIndex/Fluori
de/StoryFluoride.htm
A history of the introduction of fluoride
into water supplies in the USA, from
the National Institute of Dental and
Craniofacial Research.
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 3: Plant Nutrition and Transport
Recommended Prior Knowledge Students should know something of carbohydrates and proteins, the structure of a plant cell, and osmosis, all of which
were dealt with in Units 1 and 2. They should have an understanding of energy transfers from one form to another.
Context This Unit builds on ideas from Units 1 and 2. Concepts from this Unit will be revisited in Units 9 and 10.
Outline This Unit covers most of the plant physiology topics. There is a considerable range of practical work that can be carried out, much of which can be
used to develop or to assess practical skills. Teachers working in countries where there are marked seasons will need to take this into consideration when
planning the timing of this Unit. The Unit begins by looking at the way in which plants manufacture organic substances using sunlight and inorganic molecules
as their raw materials. Extension candidates look a little more deeply into the way in which environmental factors affect the rate of photosynthesis, and how
these factors can be controlled in glasshouse cultivation. Knowledge of cell structure, covered earlier in Unit 1, is extended to look more fully at the structure
and function of cells and tissues in a leaf, and the idea of adaptation of structure to function is re-emphasised. The movement of water from soil to air in
xylem, and of organic products of photosynthesis in phloem, is considered. Extension candidates should think about a range of examples of adaptations of
plants to living in extreme conditions. Some wider issues relating to this Unit, such as the position of plants as producers in an ecosystem, and problems
associated with the use of fertilisers and pesticides, will be considered in Unit 10.
II
6.2.1
Learning Outcomes
Define photosynthesis and state the
equation for the production of simple
sugars and oxygen in either words or
symbols describe the intake of the raw
materials, the trapping and storing of
energy (conversion of light energy into
chemical energy) and the formation of
food substances and their subsequent
storage.
Suggested Teaching Activities
Plants can be considered as 'food
factories', in which all the food in the world
is initially made. Students should compare
the needs of animals for organic nutrients
(covered in Unit 2) with those of plants,
which only require inorganic ones such as
carbon dioxide and water.
Online Resources
Photosynthesis
http://eduref.org/cgibin/printlessons.cgi/Virtual/Less
ons/Science/Botany/BOT0046.h
tml
Simple photosynthesis
experiments
The initial products of photosynthesis are
sugars (such as glucose) which can then
be converted to large, insoluble molecules
such as starch for storage.
Investigating the behaviour of
leaf discs
http://wwwsaps.plantsci.cam.ac.uk/worksh
eets/activ/prac5.htm
Instructions for a slightly
different way of investigating the
production of starch during
photosynthesis, using leaf discs.
The process of photosynthesis should be
considered at a fairly basic level; there is
no need to introduce the ideas of lightdependent and light-independent stages.
The important point to get across is the
Other Resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
conversion of light energy to chemical
energy. Chlorophyll absorbs light energy
and enables it to be used to drive the
reactions. (Ensure that students do not
think that chlorophyll attracts light!)
II
6.2.1
Define the term limiting factor, interpret
(as limiting factors which affect
photosynthesis) the effects of light
intensity and carbon dioxide
concentration explain the use of carbon
dioxide enrichment, optimum light and
optimum temperatures in greenhouse
systems.
There is a wide variety of practical work
that can be carried out. Students should
know how to test a leaf for starch, and
carry out simple experiments into the need
for light and chlorophyll for photosynthesis.
Limiting factors should be dealt with
relatively simply, as anything which limits
the rate of photosynthesis if it is in short
supply. Simple graphs can be sketched
showing the effect of increasing light
intensity or carbon dioxide concentration on
the rate of photosynthesis, and students
should be able to explain why such a graph
initially rises and then flattens out. They
can use Elodea or other water plants to
investigate the effects of light intensity on
the rate of oxygen production.
Greenhouse systems are most widely used
in temperate countries, and students living
in countries where their use is not
widespread should be prepared to consider
the need for them in relatively cool
climates.
Various teacher and student
resources on photosynthesis
(register to use site)
http://www.riverdeep.net
(/science/biology_explorer/be_a
ctivity_pages/catn.activityi_393.j
html;$sessionid$1RXTXLJNJV
MGACQFAGMCIIQKAUA
ZOI5G)
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
6.2.2
Learning Outcomes
Identify the cellular and tissue structure
of a dicotyledonous leaf, as seen in
cross section, and demonstrate the
significance of these features in terms
of functions, i.e. distribution of
chloroplasts – photosynthesis stomata
and mesophyll cells – gaseous
exchange vascular bundles (xylem and
phloem) - transport
Suggested Teaching Activities
Before considering the appearance of a
section through a leaf, students should look
at entire leaves and consider how they are
adapted for photosynthesis. A transparency
of a section through a leaf can be projected
and discussed, before a simplified diagram
is made of a leaf section. Students should
already be familiar with the structure of a
palisade cell, and can now consider it as
part of tissue that is specialised for
photosynthesis.
It can be helpful to think of a leaf as a food
factory, and then to consider how the raw
materials are brought to it, and how the
products are removed for distribution.
Drawings of leaves, and comparisons
between two or more different kinds of
leaves, make good practice or assessment
material for the practical skills of
observation and recording, and also for
magnification calculations.
It is probably best not to go into any detail
at this point about xylem and phloem
function; they will be dealt with a little later.
II
6.2.3
Describe:
the importance of nitrate ions for protein
synthesis and magnesium ions for
chlorophyll synthesis.
Students should be reminded that
carbohydrates contain carbon, hydrogen
and oxygen only; plants can therefore
make these from carbon dioxide and water.
However, proteins also contain nitrogen, so
a nitrogen source is necessary before
some of the carbohydrate can be converted
to protein. Nitrate ions from the soil are the
main source of nitrogen for plants. For
Online Resources
Photomicrograph of Eleagnus
leaf TS with vascular bundle
http://images.botany.org/set13/13-063v.jpg
Other Resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
extension candidates, a link can be made
back to the uptake of ions by root hairs
(II.3).
It may be best not to deal with the use of
nitrogen fertilisers here, but rather to cover
this fully in Unit 10 (IV.5.1).
II
6.2.3
II
7.1.1
Explain the effects of nitrate ion and
magnesium ion deficiency on plant
growth.
Identify root hair cells as seen under
the light microscope and describe their
functions describe the passage of water
through root, stem and leaf.
This should be dealt with simply,
considering the effects on a growing plant
of a shortage of proteins or chlorophyll.
Root hair cells may already have been
covered in Unit 1 (section II.2) as an
example of a specialised cell, but here they
are dealt with in the context of the whole
plant. Osmosis should be revised, before
discussing the uptake of water through the
soil, across the root, and up through xylem.
Xylem, also, may have already been
discussed in Unit 1 (section II.2) and Unit 2
(II.6.2.2). Here it is considered in the
context of water transport from root to
leaves. If the structure of xylem vessels
has not already been dealt with, then it
should be simply covered here. No detail is
required other than the idea that a xylem
vessel is made of a long column of dead,
empty cells with lignified walls, stacked end
to end.
Students will find the path taken by the
water easier to understand if they have a
simple knowledge of the position of the
vascular bundles in the plant. Simple
diagrams can be made of a TS of a root
and of a stem, showing the xylem and
phloem.
Roots
http://www.ffp.csiro.au/research/
mycorrhiza/root.html
Diagrams & descriptions of root
structures
IGCSE BIOLOGY 0610 SCHEME OF WORK
Large and semi-transparent stems, such as
the leaf petioles of celery, can be placed
with their bases in a solution of a watersoluble dye. After some time, the dye can
be seen in the xylem vessels, spreading
out into the veins in the leaves. If thin
sections are cut, the positions of
the xylem vessels show up clearly.
II
7.1.2
Define transpiration
Describe:
How water vapour loss is related to cell
surfaces, air spaces and stomata.
The effects of variation of temperature,
humidity and light intensity on
transpiration rate.
How wilting occurs.
It is important to understand that
transpiration involves the loss of water
vapour from the leaf, mostly through open
stomata. Water in the cell walls of
mesophyll cells evaporates, and diffuses
through the air spaces and out of the leaf.
Experiments using potometers not only
help students to understand the effects of
environmental factors on the rate of
transpiration, but also provide good
opportunities to improve, or to be assessed
on, all four experimental skills. It is
important, however, that it is understood
that a photometer measures water uptake,
which is not absolutely the same as water
loss. There is no need for elaborate
potometers; all that is needed is a long
piece of capillary tubing with a length of
rubber tubing at one end into which the cut
end of a shoot is pushed. Keep everything
under water while assembling the
apparatus, to avoid air locks.
If students are shown a wilting plant, they
can think about why it is only the leaves
that wilt. This can introduce the idea of
xylem vessels, present in vascular bundles
Transpiration described &
experiment to carry out
http://www.mcgrawhill.ca/school
/booksites/sciencefocus+8/stud
ent+resources/by+resource+typ
e/cool+stuff+to+see+and+do/uni
t+2+topic+5+hands+on+activitie
s.php
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
7.1.2
Describe the mechanism of water
uptake and movement in terms of 'pull'
from above, creating a water potential
gradient through the plant.
II
7.1.2
Describe the adaptations of the leaf,
stem and root to different environments,
with emphasis on local examples.
in leaves and stem, helping with support.
Wilting is a good way for a plant to avoid
further water loss, by reducing the leaf area
from which evaporation can occur.
Extension candidates will probably already
have met the term 'water potential', in Unit
1 (section II.4). In normal conditions, the
water potential in the air is lower than that
in the soil solution. Thus water moves
down a water potential gradient as it moves
from soil to air, through the plant.
The effect of transpiration in pulling water
up xylem vessels can be compared to the
effect of sucking a liquid up a straw.
Although students should look at examples
of plant adaptations using plants that grow
locally, it is also very useful to think about
plants that grow in especially wet or dry
environments, such as rain forest or desert.
Desert plant survival
http://www.desertusa.com/du_pl
antsurv.html
Good descriptions of plant
adaptations for survival in hot,
dry regions.
Plant adaptations
http://www.microscopyuk.org.uk
/mag/articles/anne1.html
Microscope images of
xerophytes and hydrophytes
(plants that live in water),
emphasising their adaptations.
TS Marram grass
photomicrograph
http://www.microscopyuk.org.uk
/schools/mainscol.html#plant
II
7.1.3
Define translocation in terms of the
movement of sucrose and amino acids
from regions of production or of storage
to regions of utilisation in respiration or
This idea will probably already have been
met earlier in this Unit, when discussing the
functions of leaves. Here it should be
reemphasised that carbohydrates are
IGCSE BIOLOGY 0610 SCHEME OF WORK
growth.
II
7.1.3
Describe translocation, throughout the
plant, of applied chemicals including
systemic pesticides.
transported through a plant in the form of
sucrose, through phloem. No detail of
phloem structure or function is required. It
should be made clear that substances can
be transported in any direction in phloem,
for example from photosynthesising leaves
down to roots, or from storage organs
such as root tubers upwards to leaves and
flowers.
Consideration of the effects of 'ringing' a
tree can help students to bring together
their knowledge of stem structure and
function. Ringing removes the phloem,
which is near to the surface of a stem. If
the ring is cut below the leaves, then all the
cells beneath the ring are deprived of
products of photosynthesis from the leaves,
and eventually die.
Students should understand that systemic
pesticides are sprayed onto the plant, and
then absorbed by it. They move through
the plant in the phloem, and are taken in by
any insect eating the plant or sucking up
phloem sap.
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 4: Respiration and the human transport system
Recommended Prior Knowledge: Students need to have some knowledge of energy transfer, and be able understand simple chemical equations.
Context: Respiration is a fundamental process that will be referred to in most of the subsequent units.
Outline: This Unit covers the important topic of respiration, which will be met again when the carbon cycle is dealt with in Unit 9. Gas exchange in humans,
and the effects of cigarette smoke lead on from this. In animals, unlike plants, the transport system is involved in the carriage of gases between the gaseous
exchange surface and the body tissues, and so coverage of this leads on naturally from a consideration of gas exchange. Some teachers, however, may
prefer to deal with transport first, and then respiration; there are sound arguments for either sequence. There is considerable opportunity for practical work in
the respiration topics, but it is much less easy to carry out much practical work in the transport sections.
II 8
II 8.1
Learning Outcomes
Define respiration as the release of
energy from food substances in all
living cells.
Define aerobic respiration state the
equation for aerobic respiration, using
either words or symbols name and
describe the uses of energy in the body
of humans.
Suggested Teaching Activities
Ensure that, right from the start, students
understand that respiration is a reaction (or
series of reactions) that takes place inside
living cells. A very common error is to
confuse it with 'breathing', and to think that
it takes place only in the lungs. They
should also realise that every cell respires,
even plant cells.
Emphasise that the function of respiration
is to release energy from food (usually
glucose) in a form that the organism can
use. Students should not state that
respiration 'produces' energy! A class
discussion will probably pick out a good
range of uses of energy in the human
body, such as muscle contraction, nerve
impulses and keeping warm.
It can be helpful to compare respiration
with combustion - the overall equation is
the same, but respiration occurs in a series
of small reactions that do not suddenly
release large amounts of heat energy. The
energy content of a food, such as a nut,
can be estimated by allowing it to heat a
Online Resources
Introduction to respiration
http://wow.nrri.umn.edu/wow/
student/photo/cellintro.html
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
II 8.2
Define anaerobic respiration
state the equation for anaerobic
respiration in muscles and yeast using
either words or symbols
describe: its role in brewing and
breadmaking the production of lactic
acid in muscles during exercise
compare aerobic respiration and
anaerobic respiration in terms of
relative amounts of energy released.
II 8.3
List the features of gaseous exchange
surfaces in animals.
known volume of water as it burns in air.
(This investigation is often done using
peanuts, but teachers should be very
aware that an increasing number of
children are allergic to peanuts. A cube of
bread makes a safer alternative food to be
burnt.)
Anaerobic respiration can be investigated
using a suspension of yeast in boiled,
cooled water. Boiling drives off all dissolved
oxygen. The carbon dioxide released can
be detected by passing it through lime
water or hydrogencarbonate indicator
solution.
Extension students may already have
investigated the use of yeast in breadmaking, in Unit 2 (section II 6.1). If not, this
is a good opportunity for all students to
investigate, for example, whether adding
amylase or ascorbic acid, affects the rate at
which dough rises.
Anaerobic respiration in muscles will be
revisited later in this Unit, when oxygen
debt is considered.
The idea of gaseous exchange may
already have been thought about in Unit 3,
in the context of the intake and loss of
gases from leaves. A gaseous exchange
surface can be defined as a surface across
which gases pass as they enter or leave
the body. For animals, oxygen enters as
carbon dioxide leaves. Students should be
reminded of what they know
about diffusion, and then suggest features
of a surface that would enable diffusion to
take place as quickly as possible.
IGCSE BIOLOGY 0610 SCHEME OF WORK
II 8.3
State the differences in composition
between inspired and expired air.
Describe a test for carbon dioxide.
II 8.3
Describe the effects of physical activity
on rate and depth of breathing.
II 8.3
Describe the effects of tobacco smoke
and its major toxic components on the
respiratory system.
The differences between expired and
inspired air, in terms of carbon dioxide
content and water vapour content, should
be investigated experimentally. Lime water
or hydrogencarbonate indicator may be
used to test for carbon dioxide. Students
should be able to use their knowledge of
gas exchange and respiration to explain
these differences.
This should be investigated experimentally.
A simple, repeatable form of exercise, such
as step-ups, is the most useful for
generating quantitative results. Students
should use their knowledge of aerobic and
anaerobic respiration to explain why
breathing rate does not drop immediately to
normal when exercise stops.
Students will need some basic knowledge
of the structure of the breathing system trachea, bronchus, bronchioles and alveoli,
and of ciliated and goblet cells, before
thinking about how these structures are
affected by tobacco smoke.
They should understand that cilia become
less active, and goblet cells more active,
when exposed to cigarette smoke, so that
mucus collects in the lungs. Bacteria are
likely to breed in it, leading to bronchitis
and other infections. Alveoli lose their
elasticity, and coughing may damage their
walls, leading to emphysema.
Cancer can be triggered by exposure to
many of the chemicals in tar.
The lungs - an overview of
how they work
http://www.lungnet.org.au/fra
me_learnhealth.htm
Emphysema
http://www.lungusa.org/site/a
pps/s/content.asp?c=dvLUK9
O0E&B=34706&ct=67284
IGCSE BIOLOGY 0610 SCHEME OF WORK
II 8.3
Describe the role of ribs, internal and
external intercostals muscles and
diaphragm in ventilation of the lungs.
II
7.2.1
Describe:
The gross structure and function of the
heart.
The double circulatory system
The effect of exercise on heart beat
II
7.2.1
List the likely causes of hear attack
(diet, smoking, stress), and
preventative measures.
II
7.2.2
Describe the structure and functions of
arteries, veins and capillaries.
Explain how structure & function are
related in arteries, veins and capillaries.
Students often find this topic difficult, and it
is a good idea to use a model of some kind
to illustrate how increasing the volume of
the thorax leads to a reduction in pressure.
The 'balloons in a bell jar' model shows this
effectively.
Diagrams of the heart, showing both
external and internal structure, need to be
known. Ensure that students realise that
both sides of the heart beat together. The
direction of blood flow through the heart,
the separation of oxygenated and
deoxygenated blood, and the functions of
the valves should be understood. It is
recommended that the idea of a double
circulatory system, in which blood passes
twice through the heart during one
complete circuit of the body, is covered
here, as this helps to make sense of the
structure and function of the heart. The
effect of exercise on heart beat relates
closely to the effects of physical activity on
rate and depth of breathing, dealt with
earlier in this Unit.
Students may already have some ideas
about factors that increase the likelihood of
suffering from heart disease, and class
discussion will probably bring out most of
the major influences. A person's genes are
also thought to play a major role in this.
Transparencies or microscope slides of
sections through an artery and a vein can
be used to help students to understand the
differences between them. They should be
able to explain the differences in terms of
the high, pulsing blood pressure in arteries,
and the much lower pressure and smoother
flow in veins. Emphasise that arteries do
not pump blood.
Structure of your heart
http://www.wehealnewyork.or
g/services/cardiology/structur
e.html
Animation of heart beat
http://web.ukonline.co.uk/we
bwise/spinneret/circuln/anca
d.htm
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
7.2.3
Identify blood cells as seen under a
light microscope, describe:
the components of blood
the functions of blood, including clotting
(no details of clotting required)
the transfer of materials between
capillaries and tissue fluid
Again, students should see transparencies
or microscope slides of stained blood
samples, and be able to distinguish red
cells, white cells and platelets. They should
understand that red cells transport oxygen
and also carbon dioxide, and know that
they contain haemoglobin. Links can be
made back to Unit 2, and the need for iron
in the diet. This is a good place to discuss
the adaptations of red blood cells to their
functions, if this has not already been
covered in Unit 1.
White cells, on the other hand, protect the
body from invading pathogens. No detail of
this is required by Core students. Clotting
should be mentioned, as a mechanism to
prevent loss of blood and entry of
pathogens, but Core students need no
detail at all of how it takes place, other than
that platelets are involved.
II
7.2.3
Describe the process of clotting
(fibrinogen to fibrin only).
II
7.2.3
Describe the immune system in terms
of antibody production, tissue rejection
and phagocytosis.
Tissue fluid can be thought of simply as
plasma that has leaked out of capillaries.
Diffusion can be revised, and students
should be able to use their knowledge of
respiration to suggest substances that
move from blood to tissues and vice versa.
Extension students need to understand
that fibrinogen is a soluble protein, which is
converted to the insoluble fibrin when a
blood vessel is damaged. Calcium is
required for this, so links can be made back
to Unit 2.
A relatively simple approach to this
complex topic is required. Some white
blood cells are phagocytes, and the
process of phagocytosis should be
understood. Lymphocytes, however,
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
7.2.3
Describe the function of the lymphatic
system in circulation of body fluids and
the production of lymphocytes.
secrete antibodies (which are proteins) in
response to contact with their particular
antigen, which may be an invading
pathogen or a foreign tissue that has been
transplanted. Students may be interested
to learn how immunity to a disease can be
conferred by vaccination. This topic also
links with kidney transplants, covered in
Unit 5.
This is another potentially difficult topic,
which should be dealt with simply. Tissue
fluid (dealt with earlier in this Unit) drains
into lymph vessels, which carry it slowly
back to the main circulatory system through
vessels with valves. It is worth pointing out
that lacteals, dealt with in Unit 2, are part of
the lymphatic system.
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 5: Coordination, Response and Homeostasis
Recommended Prior Knowledge: Knowledge of cell structure, osmosis, respiration and enzyme activity will help students to understand why homeostasis is
important in mammals. It will also be helpful if they have some understanding of the behaviour of light, lenses, and how to draw simple ray diagrams before
beginning work on the human eye. Extension candidates need a simple knowledge of the immune response in order to discuss the difficulties associated with
kidney transplants.
Context: This Unit provides numerous opportunities to revisit ideas and facts covered in earlier Units.
Outline: The theme running throughout this unit is communication within the body, both through chemicals and the nervous system. Both plants and animals
are dealt with, and students encouraged to see how similar are the mechanisms by which they achieve responses to stimuli. Once the basic function of the
nervous system has been covered, the effects on it of drugs such as alcohol and heroin are considered. Homeostasis is illustrated for all candidates by
temperature regulation in humans, while extension candidates take these ideas further, looking at the control of blood glucose concentration and taking an
overview of how negative feedback is involved in control mechanisms. A simple treatment of excretion in humans completes the Unit.
II
10.1
Learning Outcomes
Define hormone.
Describe the chemical control of
metabolic activity by adrenaline.
II
10.1
Discuss the use of hormones in food
production.
Suggested Teaching Activities
Adrenaline makes a good introduction to
the idea of hormones, as everyone is
aware of its effects. Discussion will bring
out most of these, and students should be
able to suggest how they help to prepare
the body for 'fight or flight'. A hormone can
be defined as a chemical that is secreted
from ductless (endocrine) glands, and that
is transported in the blood system all
around the body, where it has an effect on
its target organs.
This is also a suitable point at which to
discuss the general need for
communication systems in the body, and
the ideas of receptors and effectors.
The use of BST in milk and meat
production can be discussed.
Online Resources
Bovine Somatotropin
http://project.bio.iastate.edu/course
s/Gen308SS99/BIOTECH_INFO/n
cr488.html
A balanced description of the use
and effects of BST
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
Posilac - an introduction
http://www.monsantodairy.com/abo
ut/index.html
A view from the firm that makes
and sells BST
II
10.2
Define geotropism and phototropism.
II
10.2
Describe geotropism and phototropism
in terms of auxins regulating differential
growth describe the chemical control of
plant growth by auxins and the effects
of synthetic plant hormones used as
weedkillers.
II
10.2
Describe simple behaviour in terms of
the taxic responses of invertebrates.
Having dealt with the idea of how animals
may respond to stimuli (with respect to
adrenaline), students can now think about
how plants do this. Geotropism and
phototropism should be investigated with
simple experiments. It should be made
clear that these are growth responses,
in which the direction of growth is related to
the direction of the stimulus. Once again,
as in animals, receptors and effectors can
be identified.
There is still some controversy over just
how geotropism and phototropism are
regulated. A relatively simple possible
mechanism, involving unequal distribution
of auxin, should be considered. If it is
possible to obtain IAA, then simple
investigations can be carried out into its
effects.
Students should also consider the
similarities and differences between animal
hormones such as adrenaline, and plant
hormones such as auxins.
It is quite a jump from thinking about plant
hormones to looking at simple behavioural
responses in animals, but again the
common factors of receptors and effectors,
stimulus and response, can be
Investigating plant growth
regulators
http://wwwsaps.plantsci.cam.ac.uk/worksheet
s/activ/prac4.htm
An experiment involving the use of
IAA on mustard seedlings.
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
10.3
Describe the human nervous system in
terms of the central nervous system
(brain and spinal cord as areas of
coordination) and the peripheral
nervous system.
II
10.3
Define sense organs as groups of
receptor cells responding to specific
stimuli: light, sound, touch, temperature
and chemicals.
emphasised. A taxic response in an animal
is in many ways like a tropic response in
plants, in that the direction of the response
is related to the direction of the stimulus.
The main difference is that in plants the
response is growth, while in animals it is
movement. Maggots (fly larvae) can be
used for simple experiments investigating
their directional response to light. (Note
that the responses by woodlice, for
example in choice chambers, do not
illustrate taxis but kinesis; the response is
the rate of movement or rate of turning, not
a directional response.) Students need to
be encouraged to think about these
responses as automatic ones, that do not
involve any 'thinking' by the animals.
Diagrams or models can be used to
illustrate the positions of brain, spinal cord
and peripheral nerves in the human body.
Ensure that there is no confusion between
spinal cord and vertebral column. Lamb
chops often have a small piece of spinal
cord on them, lying in the groove of a
vertebra, and this can be used to show
students what the cord looks like, and also
how it is protected by the surrounding
vertebrae.
The idea of receptor and effector is
returned to now, with a detailed look at
what receptors do, and one example of a
receptor in humans. Models of the eye are
helpful in aiding understanding of its
Neuroscience for kids
http://faculty.washington.edu/chudl
er/neurok.html
Despite the title, some of the
material at this site is a little
advanced for IGCSE students.
IGCSE BIOLOGY 0610 SCHEME OF WORK
Describe the structure and function of
the eye including accommodation.
II
10.3
II
10.3
Distinguish between rods and cones in
terms of function and distribution.
Describe effectors in terms of muscles
and glands describe the action of
antagonistic muscles in terms of biceps
and triceps and associated bones.
II
10.3
Identify motor and sensory neurones
from diagrams.
Describe a simple reflex arc in terms of
sensory, relay and motor neurones and
a reflex action as a means of
integrating and coordinating stimuli with
responses.
Describe the pupil reflex.
II
10.3
Distinguish between voluntary and
involuntary actions.
structure and function. A round flask of
fluorescein with a convex lens at the front
can be used to show how light is focussed
on to the retina (the back of the flask).
It may be possible to dissect an eye, for
example from a sheep. Students can also
draw and interpret views of their own eyes,
using a mirror.
Rods and cones should be considered as
examples of receptor cells.
As for receptors, one example of effectors
is considered in detail. They can feel the
biceps and triceps muscles in their own
arm, and think about what each of them is
doing as the arm is bent and straightened.
It is important to understand that muscles
can contract and relax, but cannot make
themselves shorter - hence the need for
two antagonistic muscles to work together.
Having looked at receptors and effectors,
the way in which communication is
achieved between them through the
nervous system is now considered.
Students can think about examples of
reflex actions, in each case identifying the
stimulus and response, and the receptor
and effector that are involved. The pupil
reflex is a good example of a reflex action,
and students can see this in their own
eyes, by covering one or both eyes with
something dark and then allowing light to
fall on them.
By now, a number of simple responses
have been covered, and extension
candidates should begin to realise that
many of these are involuntary. They should
be able to suggest a number of voluntary
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
10.3
Compare nervous and hormonal control
systems.
II
10.5
Describe the effects of alcohol and
heroin and the dangers of their misuse.
and involuntary actions, listing stimulus and
response in each case.
Students can now be asked to think back
over the work covered so far in this Unit,
and to identify similarities and differences
between the examples they have dealt with
involving communication by hormones, and
by them nervous system. A table
summarising these can be built up.
Most of the effects of alcohol and heroin
involve the nervous system, although they
do both affect other body organs.
Describe the personal and social
problems arising from drug abuse, by
reference to alcohol and heroin.
Alcohol
http://www.health.org/features/kids
area/funstuf/brain/default.aspx
Despite the title, some of the
material at this site is a little
advanced for IGCSE students.
FAQs on alcohol abuse
http://www.niaaa.nih.gov/faq/faq.ht
m
II
10.4
Define homeostasis as the
maintenance of a constant internal
environment.
II
10.4
Describe temperature regulation and
explain the effects of sweating,
vasodilation and vasoconstriction only.
For most cells in the human body, their
immediate environment is the tissue fluid
that surrounds them. Students should think
about why it is important to keep this
environment relatively constant, and what
features of it are controlled. Thinking back
to earlier work on osmosis, enzyme activity
and respiration will help with this.
This can be introduced as an example of
homeostasis, in which communication is
achieved through the nervous system. A
simple diagram of the skin can be drawn,
showing the responses of sweat glands,
arterioles and capillaries when the body
temperature is too high and too low. Make
sure that students do not think that the
blood capillaries move up and down in the
skin! Emphasise that the cooling effect of
sweating is due to the evaporation of water.
Homeostasis
http://www.bbc.co.uk/schools/gcse
bitesize/biology/humansasorganis
ms/6homeostasisrev1.shtml
IGCSE BIOLOGY 0610 SCHEME OF WORK
II
10.4
Describe the control of the glucose
content of the blood by the liver and by
insulin and glucagon from the
pancreas.
II
10.4
Discuss the general role of negative
feedback in homeostasis.
II 9
Define excretion as the removal of toxic
materials, the waste products of
metabolism and substances in excess
requirements from organisms.
II
6.3.6
Define deamination as removal of the
nitrogen containing part of amino acids
as urea, followed by release of energy
from the remainder of the amino acid
Describe the formation of urea and the
breakdown of alcohol, drugs and
hormones in the liver.
Describe the function of the kidney
simply in terms of removal of urea and
excess water and reabsorption of
II 9
II 9
Extension candidates now look at another
example of homeostasis, in this case with
hormones achieving coordination between
receptor and effector. They may also like to
know something of diabetes, a relatively
common disorder in many countries. They
should consider why it is important to
control blood glucose content, thinking
back to what they know about osmosis and
respiration. Correct spelling is essential to
distinguish between glycogen and
glucagon.
Negative feedback will have featured in
both temperature regulation and control of
glucose content. Teachers could explain
the role of negative feedback in one of
these, drawing a flow diagram to show how
it is achieved. Students can then draw a
similar flow diagram to illustrate negative
feedback in the second example.
Excretion can be considered as another
way in which the environment of cells is
controlled, by removing waste products of
metabolism. Ensure that they understand
the difference between egestion (the
removal of substances from the alimentary
canal, that have never been part of the
body at all) and excretion.
Only a simple understanding of the
formation of urea from excess amino acids
is required.
The role of the liver in breaking down
alcohol and drugs may already have been
touched on earlier in this Unit.
This, too, should be dealt with very simply
as even extension students will find details
of nephron structure and function
Understanding diabetes
http://www.diabetes.org.uk/diabete
s/index.html
IGCSE BIOLOGY 0610 SCHEME OF WORK
glucose and some salts (details of
kidney structure and nephron
not required)
confusing.
The relative positions of ureters,
bladder and urethra in the body.
II 9
II 9
Describe the function of the kidney as
the filtration of water, glucose and salts
out of the blood, followed by reabsorption of glucose, most of the
water and some of the salts back in to
the blood, leading to the concentration
of urea in the urine, and loss of excess
water.
Explain dialysis and discuss its
application in kidney machines.
Discuss the advantages and
disadvantages of kidney transplants,
compared with dialysis.
The importance of retaining glucose must
be emphasised and it is excess water and
salts which are excreted in urine. This will
link back to section II 10.4 earlier in the unit
which considers diabetes.
Extension students will need to remember
what they know about osmosis and
diffusion in order to understand how
dialysis works. They will also need to think
back to their earlier work on the immune
system and tissue rejection, when
considering kidney transplants.
About kidney disease and dialysis
http://www.kdf.org.sg/health.htm
The treatment of kidney failure
http://www.kidneypatientguide.org.
uk/site/dialysis.html
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 6: Reproduction in plants
Recommended Prior Knowledge: A basic knowledge of cell structure will be helpful, but otherwise the Unit requires very little previous knowledge.
Context: This Unit introduces the concept of reproduction that will be developed further in Unit 7.
Outline: In this Unit, general features of both asexual and sexual reproduction are considered, before looking in detail at sexual reproduction in plants. The
Unit should therefore be covered at a time of year when suitable flowers are likely to be available. It is suggested that mitosis and meiosis are briefly dealt
with here, as they help with the interpretation of the distinction between asexual and sexual reproduction, although some teachers may prefer to leave this
until genetics is covered. This Unit could be combined with Unit 7, Reproduction in humans.
III
1.1
Learning Outcomes
Define asexual reproduction
Describe asexual reproduction in
bacteria, spore production in fungi and
tuber formation in potatoes.
III
3.2
Describe mitosis simply, in terms of the
exact duplication chromosomes
resulting in identical daughter nuclei
(details of stages are not required).
Suggested Teaching Activities
Ensure that students understand that
'asexual' means 'not sexual'. Asexual
reproduction involves only one parent,
which produces new organisms by mitosis.
Fungal spores can be easily seen on bread
moulds or mushroom gills, if these are
allowed to develop well past the edible
stage.
Forethought is required to demonstrate
asexual reproduction in potatoes, but apart
from the time factor it is easy to
demonstrate that planting one potato
results in the production of many more.
Although students have no knowledge of
genetics yet, they will probably be aware
that the nucleus of a cell contains
chromosomes, and that these carry genes.
Mitosis is a type of cell division that
produces cells with identical chromosomes
and genes to the parent cell. A simple
series of diagrams showing how
chromosomes behave during mitosis, with
no names of stages, or details of spindles
and so on, is all that is required.
Online Resources
Mitosis
http://www.iacr.bbsrc.ac.uk/n
otebook/courses/guide/mitosi
s.htm
Rather more detailed than is
required at this level, but
nevertheless students may
enjoy visiting this site.
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
1.2
Define sexual reproduction.
III
3.3
Describe the production of gametes by
meiosis simply, in terms of halving of
chromosome number leading to
variation (details of stages not
required).
III
1.2.1
Describe the structure and functions of
the flower of a named dicotyledonous
plant.
Define pollination and name the agents
of pollination.
Compare the different structural
adaptations of insect-pollinated and
wind-pollinated flowers.
Sexual reproduction should be described
as a process in which gametes fuse
together in a process called fertilisation,
producing a zygote. Make sure that
students understand that this need not
always involve two parents – selffertilisation, which is not uncommon in
plants, is still sexual reproduction. Unlike
asexual reproduction, sexual reproduction
introduces genetic variation amongst the
offspring.
Students should think about how
chromosome number can be kept constant
during sexual reproduction, and discussion
will probably bring out the idea that
gametes must have only half the normal
number of chromosomes if the zygote is to
end up with the right number. The
description of meiosis should be kept as
simple as possible, concentrating on its
results rather than any details of the
process itself.
It is probably best for extension candidates
not to attempt to compare sexual and
asexual reproduction until they know a little
more about the latter process.
Students should look closely at the
structure of a simple, radically symmetrical
insect-pollinated flower. They can dissect it
to find all the different parts, and think
about their functions. This is a good
opportunity to develop or assess the
practical skills of observation and
recording.
Samples of insect-pollinated and windpollinated flowers (grasses and cereals are
What is a flower? Pollination
http://www.thinkquest.org/libr
ary/lib/site_sum_outside.html
?tname=3715&cid=2&url=37
15/flower.html%3ftqskip1=1&
tqtime=0812
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
1.2.1
Describe the growth of the pollen tube
and the process of fertilisation.
Describe the formation of seed and fruit
and the structure of a non-endospermic
seed.
good examples of the latter) can be studied
and compared.
Students could try growing pollen tubes.
Fertilisation should be dealt with simply,
There is no need for details of embyrosacs
or all the different nuclei involved.
However, do try to avoid the common
misconception that the entire pollen grain
moves down the style, or that the pollen is
the male gamete.
If possible, students should be able to
watch a flowering plant through all the
stages from flowering through to fruit and
seed development. This helps them to
understand how fruits and seeds develop
after fertilisation.
III
1.2.1
Define dispersal of seeds and fruits.
Describe seed and fruit dispersal by
wind and by animals.
III
1.2.1
Discuss the advantages and
disadvantages to the species of
asexual reproduction.
Discuss the advantages and
disadvantages of sexual reproduction.
The structure of seeds should be
investigated practically. Soaked bean
seeds are large and easy to see.
A range of fruits should be looked at and
the ways in which they are dispersed
considered. A very common error is to
confuse pollination with seed or fruit
dispersal and care should be taken to
avoid this.
Now that they have looked at examples of
both asexual and sexual reproduction,
extension candidates should be able to
consider the advantages and
disadvantages of each process.
Pollen tube growth
http://wwwsaps.plantsci.cam.ac.uk/work
sheets/ssheets/ssheet4.htm
A method for investigating
the growth of pollen tubes.
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
1.2.1
Discuss the implications to a species of
self pollination and cross pollination.
III 2
Describe the environmental conditions
affecting germination.
III 2
Define growth in terms of increase in
dry mass.
Define development in terms of
increase in complexity.
This topic is difficult to deal with at this
level, especially as genetics and evolution
are yet to be covered. However, extension
candidates should be able to consider
them in terms of the degree of variation
amongst offspring, and begin to think about
the effects this might have on populations.
Ensure that the emphasis is on the species
itself, not on advantages or disadvantages
to farmers or gardeners who grow the
plants.
This is an excellent opportunity for
candidates to design a simple investigation
for themselves. Note that most of the seeds
that are used in laboratories are derived
from crop plants, and these do not normally
require light for germination. However, light
is commonly required for the germination of
the seeds of other plants.
The germination and subsequent growth of
seedlings can be used as an illustration of
growth and development, and students
could carry out simple investigations into
this.
Investigating seed
germination
http://wwwsaps.plantsci.cam.ac.uk/work
sheets/ssheets/ssheet5.htm
Morphology and growth of
the rice plant
http://www.riceweb.org/Plant.
htm
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 7: Human Reproduction
Recommended Prior Knowledge: Students should have knowledge of the basic principles of sexual reproduction, which has been covered in Unit 6. They
should also understand the nature of hormones, dealt with in Unit 5.
Context: this Unit builds on the work on sexual reproduction covered in the early part of Unit 6. This Unit and Unit 6 lay the foundations for the study of
genetics, to be covered in Unit 8.
Outline: This Unit considers the biological aspects of human reproduction, and also provides the opportunity to discuss some of the social and ethical issues
associated with birth control, artificial insemination and fertility drugs. It is a relatively short Unit, with no real opportunities for practical work. Some teachers
may therefore like to combine it with Unit 6, or with Unit 8.
III
1.2
.2
III
1.3
III
1.3
III
1.2
.2
Learning Outcomes
Describe the structure and function of
human male and female reproductive
systems, including the menstrual cycle.
Describe the roles of testosterone and
oestrogen in the development and
regulation of secondary sexual
characteristics at puberty.
Describe the sites of production and the
roles of oestrogen and progesterone in
the menstrual cycle.
Describe sexual intercourse, fertilisation
and implantation.
Suggested Teaching Activities
Diagrams and models can be used to
illustrate the structure of the male and
female reproductive systems. Students
should be able to interpret either front or
side views.
For Core students, there is no need to
know anything about the hormonal control
of the menstrual cycle.
The general characteristics of hormones
will already have been covered, and here
two others are introduced.
Extension candidates should be aware of
the cyclical secretion of oestrogen and
progesterone from the ovary. They do not
need to know any detail of the
development of follicles within the ovary,
nor the roles of FSH and LH.
Students will already have met the idea of
gametes and fertilisation, and these ideas
should be revisited here before considering
how they occur in humans.
Online Resources
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
1.2
.1
Describe the development of the foetus
in terms of placenta, maternal and foetal
blood supplies and exchange of
materials.
Describe ante-natal care in terms of
dietary requirements and maintaining
good health birth.
III
1.2
.2
Indicate the functions of the amniotic sac
and amniotic fluid.
III
1.3
Describe the sites of production and the
roles of oestrogen and progesterone in
pregnancy.
Describe the advantages of breast
feeding compared with bottle feeding.
III
1.2
.2
III
1.4
Discuss the social aspects of artificial
insemination and the use of hormones in
fertility drugs.
Diagrams should be drawn to show the
relationship between the foetus, umbilical
cord and placenta. The large surface area
of the placenta villi can be compared to that
of the lungs or small intestine; in each
case, the large surface area helps to
maximise the rate of exchange across it.
Make sure that students understand that
maternal and foetal blood do not mix. They
should be precise in naming materials that
cross the placenta, for example mentioning
glucose and amino acids rather than
'nutrients', and also understand that they
may cross by diffusion. The effects of
smoking on health, first met in Unit 4, can
be looked at again here in relation to
pregnancy.
The idea of protection of the embryo must
be emphasised. The amniotic fluid
produces a cushioning effect from physical
damage. The amniotic sac provides
protection against infection. (Details of the
composition of the fluid are not required)
This can be linked with the roles of these
hormones in the menstrual cycle.
This topic can be dealt with through
discussion, perhaps after students have
done a little research of their own. The
biological advantages of breast-feeding are
incontrovertible, but students should also
be aware of social or other reasons why
some mothers find this difficult and prefer
to use formula milk.
A simple factual treatment of what artificial
insemination is, and the use of fertility
drugs, will be required before students can
discuss the social and ethical issues
Benefits of breast feeding
http://www.cyberparent.com/
bfeed2/
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
1.4
Name and describe the following
methods of birth control:
natural, chemical, mechanical and
surgical
III
1.5
Describe the symptoms, signs, effects
and treatment of gonorrhoea.
Describe the methods of transmission of
human immunodeficiency virus (HIV) and
the ways in which it can be prevented
from spreading.
associated with it. These issues regularly
find their way into the news, and it would
be useful to collect a range of articles from
newspapers and magazines that could
form the basis for discussion.
A simple description of the biological basis
of the different types of birth control is
required. Students should also understand
the relative effectiveness of each, and may
want to discuss the ways in which religious
or cultural beliefs can affect their use. The
advantages of condoms in reducing the risk
of transmitting diseases should also be
considered.
Gonorrhoea is used as an example of a
relatively common sexually-transmitted
disease caused by a bacterium, readily
treated with antibiotics. HIV, on the other
hand, is caused by a virus, and as yet no
cure is available.
Although no detail is expected of the
symptoms of AIDS, it could be useful to
deal with these briefly, with reference back
to the functions of white blood cells in Unit
4.
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 8: Inheritance and Evolution
Recommended Prior Knowledge: Knowledge Basic knowledge of cell structure is required, and also an understanding of the processes involved in sexual
reproduction.
Context: This Unit builds on the topic of sexual reproduction, covered in Units 6 and 7.
Outline: The Unit begins with the introduction of several new terms, before moving on to genetics and inheritance. Variation, affected by both genotype and
phenotype, is investigated, before considering the ideas of natural selection and evolution.
III
3.1
III
Learning Outcomes
Define the following terms: chromosome;
gene; allele; haploid and diploid nuclei
Define the following terms: genotype;
Suggested Teaching Activities
Students should know that a chromosome
is a length of DNA, and that each
chromosome carries a large number of
genes. They may be interested to discuss
the human genome project, which is
mapping all the genes on the human
chromosomes.
They may already have met the terms
haploid and diploid when considering the
processes involved in sexual reproduction.
A haploid cell is one with a single set of
chromosomes (for example a gamete)
while a diploid cell has two complete sets.
Meiosis produces haploid cells from diploid.
It is important to use the terms 'gene' and
'allele' correctly right from the start. If this is
done, students find them easy to use, and
there is no reason for confusion! At IGCSE
level, it is enough to define a gene as a
length of DNA giving instructions for a
certain characteristic. However, you may
prefer to say that a gene carries
instructions for making a particular protein.
An allele is a variety of a gene, and many
genes have many different alleles.
Online Resources
The Human Genome Project
http://www.genome.gov/page
.cfm?pageID=10001694
It is best to consider the meanings of these
Genotype and phenotype
Introduction to chromosomes
http://gslc.genetics.utah.edu/
units/basics/tour/
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
3.4
phenotype; homozygous; heterozygous;
dominant; recessive
terms before thinking about inheritance.
They can best be illustrated and explained
with reference to a particular characteristic.
Choose something simple, and that is likely
to appeal to students, such as coat colour
of an animal. The example does not have
to be real. It should involve a gene with two
alleles, one dominant and one recessive.
Students should learn that one letter is
used to represent these alleles, with an
upper case letter for the dominant allele
and a lower case letter for the recessive
allele.
They will already know that most cells are
diploid, so should be able to understand
that they therefore carry two copies of each
gene. They can work out for themselves
the three possible combinations of alleles,
and think about what colours will result
from them. Hence the terms genotype,
phenotype, homozygous and heterozygous
can be introduced and defined.
It is a good idea to spend some time with
such examples, and ensure that students
are thoroughly confident using the
terminology, before beginning to think
about how inheritance occurs.
http://www.brooklyn.cuny.edu
/bc/ahp/BioInfo/GP/Definition
.html
III
3.4
Calculate and predict the results of
monohybrid crosses involving 1 : 1 and 3
One or more of the examples used to
illustrate the meanings of the above terms
The genetics of PKU
http://www.ess.sunysb.edu/tr
IGCSE BIOLOGY 0610 SCHEME OF WORK
: 1 ratios
can now be taken further. Use correctly
drawn genetic diagrams right from the start,
and do not let students take short cuts! The
correct way to set out a genetic cross is
shown on page 20 of the syllabus.
Students should be reminded that gametes
are haploid cells, and therefore carry only
one copy of each gene. They can be asked
to work out what kind of gametes will be
produced by organisms with a range of
different genotypes.
It is good practice, and avoids confusion, if
a circle is drawn around each gamete
genotype when writing out a genetic cross.
Discourage students from automatically
writing down two gametes from each
parent. This is only necessary if the parent
is heterozygous and producing two
different kinds of gamete. If it is
homozygous, then only one kind of gamete
is made, and only one needs to be written
down.
Next, they can be introduced to the idea of
random fertilisation, in which any kind of
gamete from the male parent can fuse with
any kind of gamete from the female parent.
The offspring now have two copies of each
gene again. Drawing lines from gamete to
gamete often causes errors to be
introduced, and a simple
diamond or square, with gametes along the
sides and offspring genotypes in the boxes,
is more likely to avoid errors.
Ensure that students understand that what
they have worked out is the probability of
particular genotypes being produced. The
fact that, for example, four different
genotypes are present amongst the
offspring does not mean that the parents
acy/genetics.html
Inheritance patterns in
monogenic disorders
http://www.gig.org.uk/educati
on2.htm
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
3.4
Explain codominance and inheritance of
A, B, AB, O blood groups (IA, IB and 1O).
III
3.1
Describe the inheritance of sex in
humans (XX, XY).
III
3.5
Describe continuous and discontinuous
variation as influenced by the
environment and genes, illustrated by
height and A, B, AB and 0 blood groups
in humans.
will have four children!
Codominance is, in many ways, easier to
deal with than dominance. It is easy for
students to imagine that a combination of
two different alleles will produce an effect
that is a mixture of both of them. The
correct use of symbols should be
encouraged; where codominance exists,
the gene is shown with an upper case
letter, with superscripts to represent the
different alleles.
The genetics of the A, B, AB and O blood
groups is a good example of codominance,
but it is also more complex than what has
gone before because there are now three
different alleles of the gene to consider,
rather than just two. It is therefore helpful to
write down a list of all the possible
genotypes and the resulting phenotypes
before attempting to deal with any crosses.
Ensure that the correct symbols, as used in
the syllabus, are automatically used by
students. They should not take the easy
way out by writing A and B instead of IA
and IB.
The inheritance of sex can be dealt with in
the same way as the inheritance of genes,
but this time the symbols X and Y are used
to indicate whole chromosomes, not alleles
of a gene. Students should be able to draw
genetic crosses to show that you would
expect equal numbers of males and
females to be born.
Extension students will already be familiar
with the A, B, AB and O blood groups, but
these will need introducing for Core
students. They are a good example of
discontinuous variation. Students can draw
bar charts to show the relative proportions
Coat colour in Great Danes
http://www.greatdanerescuei
nc.com/PrimaryColor.html
ABO genetics
http://www.people.virginia.ed
u/~rjh9u/abo.html
Variation – continuous and
discontinuous
http://www.bbc.co.uk/scotlan
d/revision/biology/inheritance
/variation_and_genetics_and
_society_rev.shtml
IGCSE BIOLOGY 0610 SCHEME OF WORK
of people with these four blood groups.
They will not find it difficult to understand
that everyone fits into one of these four
categories, with no in-betweens, and this is
therefore an example of discontinuous
variation. They could then be asked to think
of other examples of discontinuous
variation, and may think of gender.
Continuous variation can be illustrated by
almost anything that is measurable on a
human - height, length of middle finger or
wrist circumference will each give a good
range of results and not cause any
embarrassment! Leaves or other plant
material can also be used to generate a
range of results. Students will realise that
they are dealing with something that
behaves differently from blood groups; now
there are no clear-cut categories, but a
whole range of values. To show them
graphically, they will need to decide on 6 or
7 ranges and then draw up a tally chart to
show how many values fit into each range.
These can then be plotted on a histogram.
A common misconception is that
'continuous variation' means something
that changes through your life. Although
this is true of the measurements students
are likely to have made to illustrate this, it is
not the correct meaning of the term. Use
other features, such as hair or eye colour,
to emphasise the real meaning of
continuous variation.
Students should be able to work out for
themselves that, while discontinuous
variation is caused purely by genes,
continuous variation often involves
influence by the environment as well.
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
3.5
Define mutation.
Describe mutation as a source of
variation, as shown by Down's syndrome.
Outline the effects of radiation and
chemicals on the rate of mutation.
III
3.5
Describe sickle cell anaemia and explain
its incidence in relation to that of malaria.
Mutation can be defined as an
unpredictable change in the DNA content
of a cell. It can affect a single gene, or
whole chromosomes, and can happen at
any stage, not only during cell division.
Ionising radiation and mustard gas can
be given as examples of factors that may
cause mutations.
Down's syndrome is used to illustrate a
mutation that occurs during cell division,
and that affects the number of
chromosomes in a cell. Students could look
at karyotypes of people with Down's
syndrome, and compare them with
karyotypes of males and females with the
normal number of chromosomes.
Sickle cell anaemia can be explained as
the result of a mutation in the gene that
codes for the production of haemoglobin.
The effects of this on the carriage of
oxygen, and the consequences for
respiring cells in body tissues, can be
discussed. Its inheritance can also be
considered. Students will need to know a
little about malaria. They can then look at
maps showing the distribution of malaria
and of sickle cell anaemia, and begin to
think of why these should be so similar.
The story is not a simple one, and will give
plenty of food for thought for Extension
students. It is a good way to introduce the
ideas of selection pressures, and natural
selection.
Down’s syndrome as an
example of mutation
http://www.bbc.co.uk/scotlan
d/revision/biology/inheritance
/variation_and_genetics_and
_society_rev.shtml
Sickle cell disease
http://www.cuhk.edu.hk/med/
paf/slides/hematolo/xv19.htm
Inheritance of sickle cell
anaemia
http://www.sicklecellsociety.o
rg/education.htm
IGCSE BIOLOGY 0610 SCHEME OF WORK
III
3.6
Describe the role of artificial selection in
the production of varieties of animals and
plants with increased economic
importance.
III
3.6
Define natural selection as the passing
on of genes by the best adapted
organisms
Assess the importance of natural
selection as a possible mechanism for
evolution
Describe variation and state that
competition leads to differential survival
of, and reproduction by, those organisms
best fitted to the environment
Students are already aware that variation
occurs within populations of organisms,
and they will not find it difficult to think how
humans may choose a particular variety of
an animal or plant, and use this to breed
from. Real or imaginary examples can be
used to illustrate this. It should be made
clear that this selection needs to continue
for many generations, and does not
produce immediate results.
If students have already considered the
sickle cell anaemia story, they will already
have thought about the ideas of differential
survival and selection. Here, they can think
a little more widely, perhaps using
imaginary examples to think about how
competition for scarce resources could lead
to some individuals being more likely to
survive and breed than others. These will
pass on their alleles to their offspring,
so that the alleles that confer the
advantageous characteristics gradually
become more common. Over time, this
could lead to a change in the overall
characteristics of the species.
Simulated evolution
http://home.pacbell.net/smax/scott/simevol.html
III
3.6
Describe the development of strains of
antibiotic resistant bacteria as an
example of natural selection
The development of antibiotic-resistant
strains of bacteria makes a good example
to illustrate the ideas in the previous
section.
Antibiotic resistance
http://www.hpa.org.uk/infecti
ons/topics_az/wfhfactsheets/
WFHantib.htm
III
3.7
Define genetic engineering as taking a
gene from one species and putting it into
another species
Use simple diagrams of bacteria containing
circular DNA to show how a section of
human DNA can be inserted into the
bacterial DNA.
Explain that DNA can be cut in certain
places using different restriction enzymes
to select the correct gene. If the same
Description of human insulin
production
http://www.tiscali.co.uk/refere
nce/encyclopaedia/hutchinso
n/m0007839.html
Explain why, and outline how, human
insulin genes were put in to bacteria
using genetic engineering
IGCSE BIOLOGY 0610 SCHEME OF WORK
restriction enzyme is used to cut the
bacterial DNA then the ends of the human
and bacterial DNA will stick together.
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 9: Organisms and Environment
Recommended Prior Knowledge: Students should have knowledge of photosynthesis and respiration, and understand something of energy transfers. They
should know the elements from which biological molecules are made, in order to understand nutrient cycles.
Context: This Unit brings together ideas from several earlier Units and lays the foundations for Unit 10.
Outline: It is hoped that students will be able to visit a local habitat, even if only in the school grounds, during this Unit. The Unit begins with the naming and
classification of living organisms, with some thought being given to their adaptations to their environment. Keys are used to help to identify them. The flow of
energy and cycling of nutrients through ecosystems is covered. This Unit sets the scene for a consideration of how human activities can affect ecosystems, in
Unit 10.
I2
Learning Outcomes
Define and describe the binomial
system of naming species.
I2
Classify the five main classes of
vertebrates using visible, external
characteristic features only.
I2
List the main features used in the
classification of the following groups:
flowering plants (monocotyledons and
dicotyledons), arthropods (insects,
crustaceans, arachnids and
myriapods), annelids, nematodes and
molluscs,
using visible, external characteristic
features only.
Suggested Teaching Activities
Students will probably already know a few
binomials, such as Homo sapiens, and this
makes a good starting point for discussing
why Latin names are used and how they
are constructed. Take care that the name
of the genus is always given a capital letter,
and that of the species a lower case letter.
Photographs or specimens of the five
groups of vertebrates can be used to
illustrate their external features. Students
could be given a blank chart to complete,
observing and recording for themselves
relevant features for each group, such as
body covering. A definitive table can then
be built up from their observations.
A similar approach can be taken here. All
of these organisms, with the exception of
nematodes, can be easily observed in
almost any habitat. It is excellent if students
can observe them within an ecosystem,
and not just as pictures or preserved
specimens. Students should be able to
describe features that are characteristic of
all arthropods, and also those that
distinguish each of the four arthropod
Online Resources
Species diversity
http://www.seaworld.org/infoboo
ks/Biodiversity/speciesbio.html
Photographs and descriptions of
a range of mammals, reptiles,
amphibians and fish.
Monocots vs.dicots
http://www.csdl.tamu.edu/FLOR
A/201Manhart/mono.vs.di/mono
svsdi.html
Understanding arthropod
classification and
identification
http://members.aol.com/YESed
u/arthrocl.html
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
I2
List the main features used in the
classification of the following groups:
viruses, bacteria, fungi, and their
adaptation to the environment, as
appropriate.
I3
Use simple dichotomous keys based on
easily identifiable features.
IV 1
State that the Sun is the principal
source of energy input to biological
systems.
Describe the non-cyclical nature of
energy flow.
groups listed.
This is also an excellent opportunity to
consider how particular animals are
adapted to their environment. Adaptations
of plants to different environments have
already been considered in Unit 3, so it
would be sensible to concentrate on animal
adaptations here.
Viruses and bacteria are too small for
students to be able to examine real
specimens, so they will need to use
photographs and diagrams. Fungi,
however, are easily visible. Note that here
all features that enable the classification of
these groups are required, not just
externally visible ones.
Teachers will need to devise or select
simple keys that can be used to identify a
range of specimens available to students. It
is strongly recommended that this is done
with living specimens within a habitat that
the students can visit - for example,
identifying trees in the school grounds,
using keys to their leaves.
Extension students could also try devising
dichotomous keys of their own.
Having looked at the range of different
types of organisms that live in a habitat,
students now consider the relationships
between them. The concept of energy is
not an easy one, and students who have
not met with it in either physics or
chemistry courses will need an opportunity
to think about what it means.
Photosynthesis and respiration have
already been dealt with, so what is needed
here is a link to be made between the two,
Introduction to the annelida
http://www.ucmp.berkeley.edu/a
nnelida/annelida.html
The Virtual Virus Experience
http://library.thinkquest.org/1337
3/intro/intro.htm
IGCSE BIOLOGY 0610 SCHEME OF WORK
IV 2
Define the following:
food chain; food web; producer;
consumer, herbivore, carnivore,
decomposer; ecosystem, trophic level
IV 2
Describe energy losses between
trophic levels and the advantages of
short food chains.
Describe and interpret pyramids of
biomass, numbers and energy.
IV 2
Recognise that there is an increased
plus the idea that animals obtain energyrich nutrients from plants.
If students have an opportunity to visit a
habitat, even if only in the school grounds,
then they should be able to construct food
chains and food webs for themselves.
Emphasise that the arrows in a food chain
represent the direction of energy flow.
Definitions of each of these terms can be
built up once students are comfortable with
the concept of food chains.
Students who have studied physics may
already understand that energy transfers
are never 100% efficient, and that some
energy is always lost as heat when energy
is transferred from one form to another.
They will best understand the concept if
encouraged to think about a particular
example, such as energy transfer from
grass in a field and cattle that are eating it.
Once energy losses are understood, it
should become apparent that food chains
cannot go on for ever.
Pyramids of numbers, biomass and energy
can be drawn for particular food chains or
webs. Students can think of them as a kind
of graph, in which the areas of the boxes
represent values for whatever is being
plotted.
The concepts being dealt with here are not
easy for most students to comprehend, and
adequate time should be allocated to
ensure that they are not rushed in
absorbing these ideas.
Extension students can now take the ideas
Trophic pyramids and food
webs
http://www.geog.ouc.bc.ca/phys
geog/contents/9o.html
IGCSE BIOLOGY 0610 SCHEME OF WORK
efficiency in supplying green plants as
human food and that there is relative
inefficiency, in terms of energy loss, of
feeding crop plants to animals.
IV 3
Describe the water cycle.
IV 3
Describe the carbon cycle.
IV 3
Discuss the effects of combustion of
fossil fuels and cutting down of forests
on the balance between oxygen and
carbon dioxide.
IV 3
Describe the nitrogen cycle in terms of
the role of micro-organisms in providing
usable nitrogen-containing substances
by decomposition and by nitrogen
fixation in roots; the absorption of these
substances by plants and their
conversion to protein, followed by
passage through food chains, death,
decay and the return of nitrogen to the
soil or the atmosphere (Names of
of energy flow and losses between trophic
levels a little further, and think of their
implications for human populations. They
may also like to consider why, if it is
inefficient in terms of energy, so many
human populations use animals for food.
This is likely to be revision for many
students. The roles of trees and other
plants in returning water vapour to the air,
through transpiration, should be
emphasised.
Rather than simply presenting students
with a complete diagram of a carbon cycle,
it can be very useful to build it up together.
They will know enough of photosynthesis,
respiration and combustion to be able to
think of most of the steps that should be
included.
Human influences on the carbon cycle are
now considered. Fossil fuels and trees
contain huge amounts of carbon, and when
burnt this is released into the air. Students
will probably already be aware that
increased amounts of carbon dioxide in the
atmosphere are likely to lead to global
warming. Take care to avoid confusion
between this and the damage to the ozone
layer - a common source of confusion.
The nitrogen cycle is considerably more
difficult for students to understand than the
carbon cycle. It is important that they
understand the different forms in which
nitrogen occurs – as nitrogen gas in the air,
nitrate ions in the soil and proteins in
animals and plants. They also need to
realise that nitrogen gas is unreactive,
and must be converted to something more
reactive before plants can make use of it.
The water cycle
http://wwwk12.atmos.washingto
n.edu/k12/pilot/water_cycle/grab
ber2.html
IGCSE BIOLOGY 0610 SCHEME OF WORK
individual bacteria are not required).
Avoid using the term 'nitrogen' alone,
always specifying the particular compound
that is being discussed.
IGCSE BIOLOGY 0610 SCHEME OF WORK
UNIT 10: Human influences on the environment.
Recommended Prior Knowledge: Students should have covered Unit 9 before beginning this Unit.
Context: This Unit builds on ideas studies in Unit 9, and brings together knowledge from many other areas of the syllabus.
Outline: General features of population growth are first considered, before looking in particular at problems associated with human population growth. A
number of different effects of the growing human population on the environment are then considered. Some of these are complex issues, with no
straightforward answers, and students should be encouraged to discuss and debate them.
IV 4
Learning Outcomes
State the factors affecting the rate of
population growth, and describe their
importance (e.g. food, supply, predation
and disease)
Identify the phases of a sigmoid curve
of population growth resulting from the
action of a limiting factor.
Explain the factors that lead to the lag
phase, exponential phase and
stationary phase in the sigmoid curve of
population growth.
IV 4
Describe the increase in population size
in the absence of limiting factors
(human population growth) and the
social implications of current human
survival rate interpret graphs and
diagrams of human population growth.
Suggested Teaching Activities
The term 'population' will need to be
defined before thinking about how
populations grow.
Ideas about how populations grow can be
built up by discussion, concentrating on
examples that are likely to be familiar to
students – for example they could imagine
what might happen if a few rabbits were
introduced onto an island where none have
previously existed. Simple sketch graphs
should be drawn to illustrate population
growth, and possible factors that might
cause a levelling off in population growth
can be considered.
The ideas developed in the previous
section are now applied to human
population growth. Graphs showing how
the human population has changed in the
past, and predictions for the future should
be drawn. Students could also be
introduced to population pyramids and their
interpretation. They should discuss the
possible implications of continued growth of
the world human population, if possible
with reference to particular examples,
collected from newspapers and other
sources of up-to-date information and data.
Online Resources
Other resources
IGCSE BIOLOGY 0610 SCHEME OF WORK
IV
5.1
Discuss, using suitable examples, ways
in which the use of modern technology
has resulted in increased food
production.
IV
5.1
Describe the undesirable effects of
deforestation.
IV
5.1
Describe the over-use of fertilisers on
the land.
IV
5.2
Describe the undesirable effects of
water pollution by sewage and chemical
waste, air pollution by sulphur dioxide
and pollution due to pesticides and
herbicides and nuclear fall-out.
Where possible, this should be related both
to the students' own country, and also to
other countries in the world. Ideas to
consider are the introduction of machinery
(tractors to replace draught animals, for
example), and the increasing use of
pesticides and fertilisers, as well as the
breeding of new high-yielding crop
varieties. At least one specific example
should be looked at in some detail.
Deforestation may already have been
considered in relation to the carbon cycle,
and now more wide-ranging effects can be
considered, such as loss of habitat and
increased soil erosion and flooding. Again,
it is a good idea to try to introduce at least
one specific example, as well as discussing
the problems in general.
The use of fertilisers containing nitrate can
be concentrated on here, and related back
to the nitrogen cycle (dealt with in Unit 9).
Ensure that students realise that both
organic (for example manure) and
inorganic fertilisers can cause problems,
but do avoid creating a completely negative
attitude towards farmers. Leaching into
waterways, and subsequent eutrophication,
should be described and explained.
Pollution of waterways by raw (untreated)
sewage can be considered to cause the
same problems as fertilisers, plus the risks
to health from water-borne pathogens (e.g.
cholera). Problems caused by pesticides
could be dealt with by considering a
particular example, e.g. DDT, and the
Two sites explaining what is
being done in the UK to
reduce pollution from
fertilisers:
Nitrate Vulnerable Zones
http://www.environmentagenc
y.gov.uk/yourenv/eff/water/210
440/
Nitrate Sensitive Areas
http://www.defra.gov.uk/news/
newsrel/1998/980122a.htm
DDT a banned insecticide
http://www.chem.ox.ac.uk/it_le
ctures/chemistry/mom/ddt/ddt.
html
DDT - a replacement is
necessary before a ban
IGCSE BIOLOGY 0610 SCHEME OF WORK
debate for and against its continued use in
countries where malaria is a major
problem. This example demonstrates
that these issues are not simply matters of
right and wrong, but involve complex
evaluation and careful decision making.
Make sure that students realise that not all
pesticides are long-lasting and accumulate
up food chains.
Non-biodegradable materials will be
detrimental to the environment if they are
put in land fill sites. They will produce air
pollution if they are burnt in an incinerator.
The environmentally friendly option is to
recycle materials such as paper, glass,
metal etc. This reduces environmental
pollution and saves energy in production
costs.
Students should understand that acid rain
is caused by sulphur dioxide (released from
the burning of oil and coal, for example in
power stations) and nitrogen oxides
(present, for example, in car exhausts.
They should know something of the
biological effects of acid rain.
http://www.malaria.org/teachin
gmodules/ddt.html
IV
5.2
Assess the significance of nonbiodegradable plastics and other
materials used in the manufacturing
industry.
IV
5.2
Discuss the causes and apparent
effects on the environment of acid rain
and the measures which might be taken
to reduce its incidence.
IV
5.3
Describe the need for conservation of
species and their habitats and of
natural resources.
It is best to look at some specific examples
here, either relating to the students' home
country, or of international importance
(such as tigers in India, elephants in Africa
or orang-utans in Borneo).
Tigers in the wild
http://www.panda.org/about_w
wf/what_we_do/species/show
species.cfm?SID=25&LID=1&
FH=E
IV
5.3
Describe the principle of recycling of
materials including sewage (water) and
paper.
Students should learn how sewage is dealt
with in their own local area, and there may
be an opportunity to visit a sewage
treatment plant, or at the very least to
obtain information from the water company
responsible for this.
Plastics recycling
http://www.plasticsresource.co
m/
http://www.alupro.org.uk/
Facts and information about
recycling and environmental
projects or schools.
FAQ's on acid rain
http://www.ns.ec.gc.ca/aeb/ss
d/acid/acidfaq.html