BIOLOGY
Living things
All living things have 7 features that make
them different from non living things. These
are called the characteristics of life.
A general name for a living thing is an
organism.
The characteristics
of living things
Movement
Respiration
Sensitivity
Feeding
Excretion
Reproduction
Growth
The microscope
Living things are classified: into plants and
animals
Plants are In a fixed position. They make their
own food by photosynthesis. They are identified
by their shape leaves and flowers
Animals can move around. They cannot make
their own food. They are divided into 2 groups:
vertebrates and invertebrates;
Vertebrates: have a backbone: e.g. fish, frogs,
snakes and humans
Invertebrates: do not have a backbone e.g.
worms, insects, spiders, crabs, jellyfish and
snakes
The Cell: Animal and Plant cells
All living things (organisms) are made up of tiny units called cells.
Plant cell have cell walls and chloroplasts. Animals cells do not have these.
To Examine Onion Bulb Cells (PlantCells)
1. Place a drop of water on the slide (to
prevent the cells drying out.
2. Get onion skin and transfer one piece into
the drop of water on the slide.
2. Apply the cover slip. The cover slip is added
at an angle to avoid trapping air bubbles.
3. Iodine can be used to stain the nuclei orange
To Examine check Cells (Animal cells)
For animals cell. Scrap cells from inside your
cheek. Apply in the water on the slide. Stain
with methyhlene blue.
•
Groups of cells of the same type working
together are called a tissue e.g. muscle tissue.
•
Several different types of tissue working
together form an organ e.g. a stomach.
•
A number of organ working
together form a system
e.g. a digestion system.
Growth results from cells dividing.
Food
Functions of food:
• Provide energy
• Provide material
for growth
,rice, cerceals
, fats, oils,
butter, cheese
A balanced diet
consists of 6 food
types (see table).
A balanced diet is
one that contains the
right amount of food
all food types needed
to stay healthy.
F
o
o
d
A food pyramid shows how much of each food type is needed for a healthy diet.
Food packets give nutritional
information and energy content
of 100g of the food.
Energy content is measured in kJ
(kilojoules).
Nutrtional and energy values of
different food can be compared
using their labels.
To Test for the presence of starch
Add iodine to the substance to be tested.
If the iodine turns blue black starch is present
To Test for the presence of reducing sugar (glucose/maltose)
Add Benedict’s solution (blue) and heat in boiling water for 3
min.
If the Benedict’s solution turns brick red reducing sugar is
present
To Test for the presence of protein
Add Sodium hydroxide. Then add copper sulfate.
Mixture turns violet if protein is present
To Test for the presence of fat
Rub the substance to be tested on a
brown paper bag.
A translucent (see through) spot
indicates fat is present.
To investigate the conversion of chemical energy
in food to heat energy
Food is burned. The heat energy released from
this burning is used to raise the temperature of
water. The rise in temperature is measure using a
thermometer.
The Digestive system
The digestive system is a group of organ working together to breakdown food into molecules that
the body can use for respiration, growth and repair.
•
Physical digestion: chewing of the food into smaller piece by the teeth
•
Chemical digestion: chemical breakdown of the food using enzymes.
•
This digested food in then absorbed into the blood stream and
transported around the body by the circulation system.
The function of an enzyme is to speed up a chemical reaction inside
a cell. Enzymes are often referred to biological catalysts
An enzyme acts on a
substrate (starch) to
break it down into a
product (maltose):
Starch is broken down by
the enzyme amylase into
maltose.
Enzyme
Substrate
Product
To show the action of amylase on starch
2 test tube are set up
A contains starch only
B contains starch and amylase.
Both are incubated at 37C for 15 min.
Samples of each are then remove and tested for
starch (iodine goes blue/black)
and reducing sugar (Benedict’s solution and heat goes
brick red).
Starch in present in tube A.
Starch is no longer present in B. Reducing sugar is.
In B starch has been broken down into maltose
(reducing sugar) by the amylase
Aerobic Respiration (Aerobic = needs oxygen)
Respiration is the release of energy from digested food. Our body breaks our food
down into glucose during digestion. This glucose is the fuel our bodies use to produce
energy in a process of respiration. Respiration required oxygen. Waste produce of
respiration are carbon dioxide and water.
The characteristics
Burning:
Fossil Fuel + O2 -> Energy+ CO2 + H2O
Respiration : Glucose + O2 -> Energy+ CO2 + H2O
Respiration: Energy conversion from chemical energy (food) to heat energy.
All living organism respire. Human get glucose from
our diet. We take in oxygen in the lungs and we
excrete carbon dioxide and water form the lungs
To show that respiration produces energy (heat)
Use respiring peas:
2 flasks are set up
1) live peas
2) dead peas (control; dead organism do not respire)
Result:
The temperature in flask A will rise after 3 days as
the respiring peas produce heat.
To show that respiration produces CO2
Use respiring woodlice:
2 test tubes are set up
1) live wood lice
2) empty (control)
Result:
Limewater will go milky in the tube with the lice.
Only carbon dioxide turns lime water milky.
of living things
Movement
Respiration
Sensitivity
Feeding
Excretion
Reproduction
Growth
To show that respiration produces H2O
Use respiring woodlice:
2 test tubes are set up
1) live wood lice
2) empty (control)
Result:
Cobalt Chloride paper will turn pink in the tube
with the lice.
Only water turns Cobalt Chloride paper pink.
To Show that expired air has more carbon dioxide than
inspired air
In A air from the lungs is blown through lime water. It turns
the lime milky very fast.
In B air from the room is sucked through the lime water. The
lime water goes milky slowly.
Together these indicate that there is more CO2 in exhaled
air. Humans produce CO2 during respiration.
The Lungs
Function of the breathing system:
• Take in oxygen____ O2
• Excrete carbon dioxide ___ CO2
• Excrete water vapour ____H2O
Glucose + O2
-> Energy+ CO2 + H2O
Gaseous exchange takes place in the alveoli
• Oxygen/ O2 crosses out of the alveoli and
into bloodstream.
• This oxygen is carried in the blood to all the
cell of the body for use in the process of
respiration.
• The blood carries carbon dioxide/ CO2
(waste product of respiration) back to the
lungs.
•
In the alveoli CO2 the moves
out of the blood into alveoli
and gets exhaled
Inhalation is another word for breathing in
Exhalation is another word for breathing out.
Breathing rate is a measure of how many
times you inhale in one minute. On average
the human breathing rate , at rest is 17
breaths per minute
Smoking prevents efficient gas exchange:
• Tar in smoke causes mucus production in the lungs
leading to bronchitis.
• Carbon monoxide in smoke replaced oxygen in the
blood so the smoker does not get enough oxygen.
• Smoking during pregnancy reduces the amount of
oxygen the baby gets and so causes stunted growth
The circulatory system: consists of the blood, arteries, veins and capillars and the heart
The functions of the blood are:
1. Transport: blood transports oxygen, digested food, hormones and waste materials around the body.
2. Defence against disease: the blood destroys invading bacteria and viruses.
3. Maintains body temperature. The blood transfers heat around the body
Blood Parts
Function
Plasma
(watery liquid)
Carry dissolved
substance
Red blood cells
Carry Oxygen
White blood cells
Fights infection
Platelets
Clot the blood
The function of the heart is to pump blood
around the body
Right ventricle
Blood cells are
made in the bone
marrow
Blood from all around the body (carrying CO2)
arrives in veins to the right atrium. It then moves
to the right ventricle. The right ventricle pumps it
to the lungs where gaseous exchange occurs
(CO2 is swapped for O2). The O2 rich blood
returns to the left atrium. It then moves to the
left ventricle. The left ventricle pumps it all
around the body.
The 3 main types of blood vessel are:
Arteries: carry blood away from the heart.
They have thick wall to take the pressure of
the fast moving blood
Veins: carry blood to the heart.
Left
The have valves to prevent backflow of
atrium
slow moving blood.
Capillaries: link arteries and veins.
They have thin wall to allow substance
Left ventricle
to move through them.
The left ventricle pumps blood all around
the body hence the wall is very thick and
muscular. The right ventricle pumps to
the lung only.
The normal heart rate is about 70 beats per minute. During exercise we require more energy.
Energy is produced during respiration from food and oxygen. Glucose + O2 -> Energy+ CO2 + H2O
During exercise the heart beats faster (pumps blood faster) and we breath faster (exchange gases
faster) to speed up the rate at which food and oxygen are circulated around the body for respiration.
A balance of rest and exercise is required for good health.
To Demonstrate the effect of exercise on pulse and breathing rate.
Take your pulse while you are at rest (found at wrists or neck). Take 3 reading over 3 min and average.
Exercise for 2 min, stop, retake pulse.
Pulse will increase with exercise and then return to normal over time.
Count breaths while at rest. Take 3 reading over 3 min and average.
Exercise for 2 min, stop, retake breath count.
Number of breaths will increase with exercise and then return to normal over time.
Normal bogy temperature is 37˚C. Illness may cause this to rise. This rise in
temperature is often called a fever.
The Excretory system
• Excretion is the removal of waste products that are made in the body. The waste products
include:
• carbon dioxide and water produced during respiration and
• Urea produced by the liver as it breaks down extra protein from the diet (Kidneys will remove this
urea from the blood).
Waste products are transported in the blood to the excretory organs:
Lungs (excrete CO2 and H2O)
Skin (excretes sweat which is salt and water)
Kidneys (excretes urine which is urea, salt and water)
The urinary system includes:
Function: to remove urea (produced during
the breakdown of protein in the liver)
Renal artery: Brings blood to the kidney
Kidney: filters the blood to remove urine
and to regulates amount of
water in the blood
Renal vein: Filtered blood leaves the kidney
in the renal vein
Ureter: urine travels to the bladder in the
ureter
Bladder: urine is stored in the bladder.
Urethra: urine passes out of the body
through the urethra
The sensory system
5 Senses
Organ
Sight
Eye
Hearing
Ear
Smell
Nose
Taste
Tongue
Touch
Skin
The system in the body which receives information
from the sense organs, and allows us to react to
the information is called the nervous system.
The nervous system consists of the brain and spinal
cord (called the central nervous system: CNS) and
the nerves that run out to all parts of the body.
Nerves are made up of bundles of nerve cells called
neurons. There are 2 types of neurons.
1) Sensory neurons collect information from the
sense organs and pass it to the brain.
2) Motor neurons pass information from the brain
to the body.
The eye structure and functions:
As no light is reflected back out of the eye the pupil appears black.
The skeletal system
Plants do not need a skeletal system as they have a cell wall.
The skeletal system has 3 functions:
1. Support; skelton support the body and gives it shape.
2. Protection; The skull protect the brain. The ribs protect the lungs and the heart.
3. Movement; muscle are attached to the bones. Contraction of muscles allow us to move.
Bone is a living tissue so it can repair itself. It is composed of a flexible living part and a hard mineral
(calcium) part. This is why we need calcium in the diet. Together these give the bone strength. Blood
cells are made in the bone.
Joints: A joint is where one bone meets another
bone. In general the function of joints is to allow
movement. There are different type of joint:
Fused joint: immoveable e.g. the skull.
Ball and Socket
Ball and socket joints: allow movement in all
direction e.g. the shoulder and the hip
Hinge joints: movement in one direction only- like a
door e.g. the knee and the elbow.
Structure of movable joints:
Ligaments join bone to bone.
To prevent bone damage(friction) by bones
rubbing off each other synovial fluid
(lubrication) is present in movable joints.
Cartilage is also present in these joints, it
acts as a shock absorber.
Tendons join muscle to bone.
Muscles work in pairs to cause movement. Pairs
of muscles pull in opposite directions.
Pairs which pull in opposite direction are called
antagonistic muscles. The bicep of triceps of the
upper arm are as antagonistic pair.
The biceps contracts (shortens) the lower arm is
raised. The triceps contracts (shortens) and the
arm is lowered.
Hinge joint
The Reproductive system
The menstrual cycle
Lasts about 28 days.
Days 1-5: Menstruation (period) lining breaks down.
Days 6-12 New lining builds up
Days 13-15 Ovulation (release of an egg)
Days 16-28 Lining stays in place.
If fertilisation does not occur the cycle starts again.
The fertile period occurs during the cycle (Day 11-18 approximately in a regular 28 day cycle)
Steps in human reproduction
Sexual intercourse: the man’s penis fills with blood and hardens. It is inserted into the vagina.
Semen (mixture of sperm and seminal fluid) is release. Sperm swim to the fallopian tube
Fertilisation: Fusion of the sperm (male gamete) and the egg (female gamete) to form a
fertilised egg (zygote) occurs in the fallopian tube. The women is now pregnant.
Cell division and pregnancy: lasts approximately 40 weeks.
The fertilised egg divides and travel from the fallopian tube to the uterus (womb).
The group of cells implant themselves in the lining of the uterus (the placenta)
and continue to grow. Group of cells-> embryo->foetus.
Nutrients pass from mother to baby through the placenta,
waste passes from baby to mother through the placenta.
The baby is attached to the placenta by the umbilical cord
The baby is protected inside a bag of fluid called the amniotic fluid.
Birth:
At birth the muscle of the uterus contract (labour). The bag of fluid burst
and the baby is pushed out. The umbilical cord is clamped and cut (belly button).
The placenta is also pushed out (after birth).
Growth and puberty: Boys: Starts between 10 and 16.
Sex hormones released. Voice deepens. Hair grows around the sex organ, face, chest
and underarms. Penis and testes grow and enlarge. Testes produce sperm (male gamete)
Girls: (Starts between 9-15)
Sex hormones released. Breasts develop, hips widen and hair grows.
First egg is released from the ovary and menstruation (periods) begin.
An egg (female gamete) will be released every month until menopause in middle age.
Family Planning: Contraception if the prevention of fertilisation and/or implantation.
Abstinence from sexual intercourse means no fertilisation can take place.
Natural method: no sexual intercourse during the women’s fertile period.
Condoms: cover the penis, prevent sperm entering the vagina and so prevent fertilisation.
The “pill”: stops the egg been produced and so prevent fertilisation.
Genetics
Is the study of inheritance of characteristics.
Characteristics which we inherit from our parents are called inheritable characteristics.
E.g. Hair colour, eye colour, shape of face.
Characteristics which we learn during our lives are called non-inheritable characteristics
e.g. ability to speak a language or ride a bike
Inheritable characteristics are controlled by genes past
down from our parents to children.
Genes are located on chromosomes.
Chromosomes are thread like structures made of DNA
and protein and are found in the nucleus of cells.
Humans have 23 pairs of chromosomes in their cells.
The flowering plant
Photosynthesis: Is the process by which plants make food.
Plants use a green pigment called chlorophyll to trap light energy from the sun. Plants then
convert this light energy into chemical energy in the form of starch.
Energy conversion: Light energy -> Chemical energy
Photosynthesis occurs in the green parts of the plant (mainly leaves) where chlorophyll is present.
Photosynthesis is the opposite to respiration:
Respiration: Glucose + O2 -> Energy+ CO2 + H2O
Photosynthesis: Energy+ CO2 + H2O -> Glucose + O2
Glucose is either used by the plant for respiration or
converted to starch and stored.
To test a leaf for starch/to show starch is produced during photosynthesis.
1) Place the leaf in boiling water for one minute. This kills and softens the leaf.
2) Place the leaf in hot alcohol. (This removes the green chlorophyll so results
can be seen).
3) Rinse the leaf in hot water. This softens the leaf.
4) Place the leaf on a white tile and test for starch: Add iodine. Blue black
colour indicate that starch in present.
If a leave that has been left in the dark is use no starch is present as the leaf
needs light to photosynthesis and make starch.
Plant Reproduction: Plants can reproduce by sexual and asexual reproduction.
Asexual reproduction involves only one parent. A leaf cutting can be taken from a plant and placed
in soil where it will grow into a new plant e.g. A geranium. Strawberry plants send out runner that
form new separate plants.
Scented and colourful to
Sexual Reproduction in plants in done using flowers.
attract insects
The anther
produces pollen
(male gamete)
The ovary
produces the
egg cell
(female gamete)
Reproduction involves 5 stages. 1 Pollination. 2 Fertilisation, 3. Seed and fruit formation, 4. Seed
dispersal and 5. germination.
Pollination is the transfer of pollen. This can be done to 2 ways:
• Wind: Pollen is carried by the wind
• Insect: Insects who visit the plant for nectar transfer the pollen on there bodies.
Fertilisation is the fusion of the male and female gamete to form a zygote.
Seed and fruit formation follows fertilisation.
Seed dispersal: Plants spread their seeds out to avoid competition for resource like nutrient and space.
Dispersal is done by animal, wind, water and self- dispersal.
• Animals: eat the seeds, move away and drop the seeds in their droppings e.g. plants with fruits
• Wind: the wind carries the seeds e.g dandelion (have parachutes)
• Self-dispersal: some plants have pods that explode
sycamore (have wings)
e.g. peas
• Water dispersal: some plants produce seeds that float e.g. water lily and coconut
Seed Structure
Germination is the growth of a seed/zygote into a new plant.
Water, oxygen and heat are needed for germination.
To show that Water, oxygen and heat are needed for
germination.
Will become
the shoot
Will become
the root
Seeds are left for a week.
Only the seeds is A will germinate.
This proves that Water, oxygen and
heat are needed for germination.
4 test tubes with seeds (cress seeds) are set up.
Tube A gets: Water, Oxygen and heat (This is the control)
Tube B gets: Oxygen and heat (no water is added)
Tube C: gets water and heat (no oxygen. Water is boiled to
remove dissolved oxygen and oil is used to
keep oxygen out)
Tube D: Get water and oxygen (no heat. Tube is left in fridge)
Plant transport and response
Plants use their transport systems to carry
water (with dissolved minerals) from the roots to the leaves and
Food (made in the leaves) around the plant.
Plants have 2 types of transport vessels:
Xylem vessels: carry water and minerals
Phloem vessels: carry food
The plants loses water vapour through the leaves: water moves up from the roots through the stem
and is lost through the leaves. This flow of water is called the transpiration stream.
Transpiration is the loss of water vapour from the leaves of a plant.
Functions of transpiration:
To carry water and mineral from the roots.
To keep the plant cool by allowing the evaporation of water from the leaves.
To show plant roots absorb water
Set up apparatus as shown.
Oil is used to stop loss of water by evaporation.
The water level in the tube with the plant will go down.
• This water was absorbed by the roots and lost through the leaves by
transpiration.
To show the path of water through plant tissue
A stick of celery is place in a beaker containing water
with food dye and left for a week.
The stem is then cut and examined. The dyed water
in visible in the xylem vessels.
To show that water evaporates from the
surface of leaves by transpiration.
Place a plastic bag over a live transpiring plant.
Water the soil well.
Drops of liquid form inside the bag. Test this liquid
with cobalt chloride paper.
Cobalt chloride paper goes from blue to pink
indicating the liquid is water.
A dead plant (or a plant with no leaves) can be used
as a control.
Plant Response
Living things are sensitive to what is around them. Plants are
sensitivity to water, light and gravity and will grow towards them.
A tropism is the growth of a plant in response to a stimulus.
Phototropism is growth is response to light:
Plant stems grow towards light allowing their leaves
to get more light for photosynthesis
Geotropism: Plant roots grow down towards gravity allowing the
roots to get more water and minerals for the plant.
Plant stem grow away from gravity ensuring the
leaves are above the ground.
The characteristics
of living things
Movement
Respiration
Sensitivity
Feeding
Excretion
Reproduction
Growth
To show phototropism in plants:
Cress seed are left to germinate (grow) in boxes with windows cut in
different sides. The seeds will grow towards the light demonstrating
phototropism.
To show geotropism in plants:
Broad beans are placed at different angle in a beaker with moist blotting paper and left to
germinate and grow for a week. All of the roots will grow down. All of the stems will grow up.
Introduction to Ecology
Ecology is the study of living things and how they interact with one another and with their
environment.
The environment is everything that surround an animal or plant.
A habitat is the name given to the place a plant or animal lives. Each habitat has its own
community of plants and animals. Example of habitats include: woodland, riverbank, meadow and
seashore.
The plants and animals (organisms) in a habit are affected by and respond to changes in their
environment.
Food chain: A food chain shows how organism are linked by what they eat. All food chain start
with green plants because they are the only organism that can produce their own food (by
photosynthesis). Green plant are know as producers, e.g. grass, trees.
Everything else in know as a consumer as they do not make food but only consume it.
Example of a meadow food chain.
Grass is the producer (it produces food by photosynthesis)
Rabbit is a consumer (it consumes grass).
Fox is a consumer (it consumes rabbit).
The numbers of organisms in a habit
depend on each other. In the meadow
if the grass disappears, the rabbits will have
nothing to eat and their numbers will drop. If
the numbers of rabbits drops the numbers of
foxes will also drop.
A food web is a number of interconnected food
chains.
Decomposers: Are organism that break down
dead animals and plants. Examples include
bacteria, fungi, earthworms and dung beetles.
Meadow habitat
Meadow food web
Interdependence: The organisms in a habit are interdependent on one another: In a
meadow bees rely on plants/flowers for food. The plants in turn rely on the
bees to carry their pollen.
Competition: Occurs when 2 or more organisms seek something that is in limited supply.
Example: in a meadow grass and dandelions compete for water
Adaptation: is how an organism adapts (changes) to be able to compete in its environment.
Grass has adapted shallow roots to collect surface water. The dandelion has
adapted deep roots to collect deeper water.
Habit Study
5 Stages of a habitat study include:
1) Make a simple map: include the direction north, a scale and a legend.
2) Measure environmental factors: Air, water and soil temperature are measured with a thermometer.
Light intensity is measured with a light meter
3) Collect samples: using a pooter, quadrat, pitfall trap, beating tray, line transect.
4) Identify and list samples
5) Estimate the number of organism present
The lid prevents the jar
filling with water
A line transect is used to show changes in plant numbers
across a boundary in a habit
Use of a quadrate:
1) The quadrat in thrown randomly 10 times.
2) The presence or absence of a particular organism is recorded
(Example: in 10 throws buttercups were inside the quadrate 4 time)
3) The frequency of the particular organism is calculated.
(Example: Buttercup was 4 out of 10 which is 40%)
Plants and animals in the habitat may be identified by
using keys.
A key is a set of question which are asked about the
organism you are trying to identify. Your answers leads you
to another question and so on until you have identified the
organism.
Pollution and Conservation.
Pollution is the addition of harmful material to the environment.
• Air pollutions is caused by smoke, dust and harmful gases.
• The burning of fossil fuel causes the release of carbon dioxide and sulfur dioxide. These dissolve in rain
water to cause acid rain. Acid rain damages plants, kills fish and dissolves stonework.
• Increasing levels of carbon dioxide also add to the greenhouse effect and cause a rise in temperature
(global warming).
• Soil pollution is caused by pesticides, fertilisers and acid rain.
• Water pollution is caused by fertilisers, slurry and oil.
Waste management techniques include landfill, incineration and recycling.
Conservation is the protection, preservation and sensible use of the earth’s natural resources, allowing
them to be passed on to future generations.
Individual Conservation:
• Do not create litter
• Use energy wisely (turn of lights)
• Recycle
• Compost
• Plant trees (trees use carbon dioxide and produce oxygen)
Community Conservation projects include:
• National parks: spaces where habitat and flora (plants) and fauna (animals) are protected
• Hedgerow conservation
• Bog land conservation
• Listing of threatened species: these plants and animals are given legal protection e.g lizards and frogs
• Plant trees
• Zoos and wildlife parks: breed endangered species.
Two negative effects of human on the environment are
1) Air pollution
2) Habitat destruction
Two positive effects of humans on the environment are:
1) Tree planting
2) Protection of endangered species
Microbiology and Biotechnology
Microbiology is the study of micro-organisms. Micro-organism include bacteria, viruses and fungi.
Bacteria are single cell organisms. They are found almost everywhere. They are present in the human
gut where they make vitamins for us. They are present in the soil where they breakdown dead matter.
Some bacteria cause disease like TB, Food poisoning, tetanus and meningitis.
Viruses are a piece of DNA surrounded by a protein. They causes diseases like swine flue, measles,
common cold and AIDS.
Fungi include mould (like bread mould) and mushrooms. They cause food to spoil. People can get fungal
infections e.g. athlete’s foot.
Biotechnology is the use of living things (micro-organism) to make useful substances.
Biotechnology in industry:
• Bacteria are used to make cheese.
• Yeast (a fungus) is used to brew alcohol.
Biotechnology in medicine:
• Bacteria are used to make insulin for diabetics.
• Fungus is used to produce antibiotics.
To show the presence of micro-organism in air.
1. Leave an agar dish open in the air for 20 min. Control: unopened
dish.
2.
Close and incubate both dishes upside down in an oven at 20˚C for
2 days.
3.
View the dishes.
Result: Bacteria and fungi from the air are growing on the dish that was
opened. The unopened dish has no growth.
To show the presence of micro-organism in Soil.
1. Sprinkle some soil on an agar dish. Control: unopened dish.
2.
Incubate both dishes upside down in an oven at 20˚C for a
week.
3.
View the dishes.
Result: Bacteria and fungi are growing on the dish with the soil. The
unopened dish has no growth.