Download 1A Human Biology – Food, Digestion and Associated Body Systems

Science
Junior Cert
Biology Revision Notes
By Peter Jackson
Junior Cert Science -Biology
Peter Jackson
Author
These notes were brought to you by Peter Jackson. Peter is the Head of Science at St Columbas College,
Whitechurch, Co Dublin. Peter has over 30 years teaching experience and has corrected Biology papers for the
Department of Education for over 25 years and also marks appeals for the Department. Peter teaches Science at JC
and Biology and Chemistry at LC. Peter has also recently written a book for Leaving Certificate students 'Essentials
Unfolded - Chemistry ' specifically to help students studying Chemistry at LC. He has also given numerous courses on
Lab Safety and IT in Teaching.
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Science – Biology Revision Notes Peter Jackson
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Junior Cert Science -Biology
Contents
Human Biology – Food, Digestion and Associated Body Systems ................................................................................ 4
Food .............................................................................................................................................................................. 4
Digestion ....................................................................................................................................................................... 5
Enzymes ........................................................................................................................................................................ 6
Aerobic Respiration....................................................................................................................................................... 6
Breathing System .......................................................................................................................................................... 7
Circulatory System ........................................................................................................................................................ 8
Excretion ....................................................................................................................................................................... 9
The Skeletal/Muscular System, the Senses and Human reproduction ....................................................................... 10
Muscular System ......................................................................................................................................................... 10
Sensory System ........................................................................................................................................................... 13
Reproductive System ................................................................................................................................................. 14
Genetics ...................................................................................................................................................................... 16
Animals, Plants and Micro-organisms......................................................................................................................... 17
The Light Microscope .................................................................................................................................................. 18
Plant Structure ............................................................................................................................................................ 20
Transport in Plants ...................................................................................................................................................... 20
Photosynthesis ............................................................................................................................................................ 21
Reproduction and Germination in Plants ................................................................................................................... 21
Flower Structure ......................................................................................................................................................... 22
Ecology ........................................................................................................................................................................ 23
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Human Biology – Food, Digestion and Associated Body Systems
Food

Food is one of the basic human needs and the digestive system enables the body to convert it into a
form that is more suitable for use.
Food is
 A necessary source of energy
 A growth material for the body
Balanced Diet: the correct proportion of each food type in your daily diet
Constituents of a Balanced Diet:
Food Type
1. Carbohydrates
2. Proteins
3. Fats
4. Vitamins
5. Minerals
6. Water
Function
Sugars – quick energy source
Starch – slower longer lasting source of energy
Fibre – absorbs water, aids peristalsis, prevents
constipation
Growth and Repair
Energy Store, insulation
C – prevents scurvy (bleeding gums)
D – prevents rickets (soft bones)
Iron – used to make haemoglobin for red blood cells
Calcium – strong teeth and bones
Solvent – carries glucose and other substances around
the body
– Medium for chemical reactions to take place in
Source
Fruit, jam
Bread, pasta,
Vegetables, brown
bread
Lean meat, fish
Butter, oils,
Oranges
Dairy products
Red meat, green veg.
Water
Food Pyramid

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The food pyramid shows us the relative amounts of each kind of food that we should eat
At each level there are a number of examples of typical foods of that type
Food

Tests
Starch: e.g. potato, bread and pasta.
o
o
o
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Add iodine solution
If starch present it turns blue black
If no starch present it stays brown.
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Junior Cert Science -Biology
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Lipid [Fat or Oil]: e.g. butter or vegetable oil
o
o
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Reducing Sugar: e.g. glucose
o
o
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Rub on brown paper,
If lipid present brown paper remains translucent
Mix with Benedict’s Solution and heat gently (do not boil)
If reducing sugar present turns from blue to red
Protein: e.g. egg white
o
o
Add Biuret Solution and shake
If protein present turns from blue to violet
Food Labels
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Energy values are given in kilojoules (kJ) or kilocalories
(kcal) for each food group
They are given per 100g (or as a %) and often per typical
serving
This enables one to compare different foods
Women need 2000 kcal and men 2500 kcal per day
Digestion
Digestion: The breakdown of food to make it suitable to be absorbed into the body

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Physical – teeth and churning in the stomach
Chemical – by enzymes in the mouth, stomach and small intestine
Structure and Function of Digestive System
Part
Mouth
Oesophagus
Stomach
Liver
Pancreas
Small Intestine
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Functions
 Teeth chop food
 Saliva lubricates
 Amylase starts digestion of
carbohydrates
 Pushes food to stomach by peristalsis
Mixes food with
 HCl to kill bacteria
 Pepsin to break down protein
 Produces bile to neutralise acid from
stomach
Produces
 Amylase to digest carbohydrates
 Lipase to digest fats
 Protease to digest proteins
 Insulin to control blood sugar levels
 Absorbs digested food
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Junior Cert Science -Biology
Large Intestine
 Water balance
 Vitamins B and K produced by symbiotic
bacteria
Teeth
Type
Incisors
Canines
Pre-Molars
Molars
Function
Flat and sharp for cutting food
Pointed for tearing food
Flat and ridged for crushing and grinding food
Flat and ridged for crushing and grinding food
Enzymes

Enzyme: a biological catalyst

Catalyst: substance that speeds up a chemical reaction but is not used up in the reaction
The Action of Amylase on Starch
 Substrate: the substance the enzyme works on e.g. starch in potato
 Enzyme: e.g. amylase in saliva
 Product: e.g. glucose
 Take two samples of starch dissolved in water
 Mix one sample with amylase
o
 Place both in a water bath at 37 C for ten minutes
 Test both for glucose using Benedict’s solution
 Result: glucose present in tube containing amylase
 Conclusion: amylase breaks starch down to glucose
Aerobic Respiration
Respiration: the release of energy from digested food
Investigate the Conversion of Chemical Energy in Food to Heat Energy
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Put some cold water in a test tube
Take its temperature
Light a crisp and hold it under the test tube of water
After is has burned take the temperature of the water
o
o
The temperature of the water has risen from 16 C to 28 C
Conclusion
o Food contains lots of energy as chemical potential energy
o This can be converted to heat energy by burning
Aerobic Respiration: The process of releasing energy from food using oxygen
Glucose (food) + Oxygen = Carbon Dioxide + Water + Energy
Demonstrate the Products of Aerobic Respiration
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Tests to Compare the Carbon Dioxide Levels of Inhaled and Exhaled Air
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Using the apparatus shown to the right
Breathe in through one sample of limewater
Breathe out through another sample of water
Results
Limewater
 goes milky with exhaled air
 Stays clear with inhaled air
Conclusion
 Exhaled air contains more CO2
 Take careful note of the positions of the pipes
Breathing System
The breathing and circulatory systems
 Enable the transport of
o oxygen
o digested food around the body
 To provide energy and growth materials where
they are required.
Structure and Function
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Nasal hairs filter incoming air
Epiglottis stops food entering the airways
Larynx [Voice box] produces sound by vibration
of the vocal cords
Trachea windpipe allows air to enter lungs
Rings of cartilage keep the trachea open
Bronchi first division of trachea
Bronchioles further divisions of bronchi
Alveoli air sacs covered in a network of capillaries
oxygen enters and carbon dioxide leaves blood
Ribs protect lungs and heart and play an
important role in breathing
Diaphragm sheet of muscle that separates the
lungs and intestines. Helps draw air into lungs
when it contracts and flattens
Gaseous Exchange
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Occurs in the alveoli
Surrounded by a network of capillaries
Oxygen diffuses into blood
Carbon dioxide and water diffuse out of blood
Moist surfaces make this easier
Breathing Rate is the number of breaths per minute
Effects of Smoking
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Smoke irritates the lungs causing inflammation making lungs less efficient
Increases breathing rate
Causes bronchitis, cancer and heart disease
Circulatory System
Composition and Functions of Blood
Component
Plasma
Description
Liquid part of blood – straw
coloured
Red Blood cells
Biconcave discs, no nucleus,
contain haemoglobin
Larger tan red cells,
Fragments of cells
White Blood Cells
Platelets
Function
Transports food, hormones, blood cells,
Oxygen and carbon dioxide
Salts and urea
o
Heat ( Helps regulate body temperature at 37 C)
Carry oxygen around the body
Involved in defence (fight infections)
Involved in clotting blood
Structure and Function of the Heart

Left ventricle is stronger and thicker because it has to
pump blood further (round the whole body) than the
right ventricle which only has to pump it to the lungs and
back
Note left and right are that of the owner of
the heart not as you look at it
Passage of Blood through the Heart
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Deoxygenated blood enters right atrium from vena
cava
Right atrium then contracts
Enters right ventricle through valve
Contracts and passes into pulmonary artery through
valve
Passes through lungs – picks up O2, loses CO2
Enters left atrium from Pulmonary vein
Enters left ventricle through valve
Contracts and into Aorta through valve
Around body
Differences between Arteries, Veins and Capillaries
Artery
Pulse
Carries Blood away from heart
No valves
Thick walls
Small lumen
High pressure
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Vein
No pulse
Carries blood towards heart
Valves to prevent backflow
Thin walls
Large Lumen
Low pressure
Science – Biology Revision Notes Peter Jackson
Capillaries
Connects arteries to veins
Walls leak tissue fluid
Walls on cell thick
Very narrow
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Junior Cert Science -Biology
The products of digestion are absorbed into the bloodstream and are thus circulated around the body
Factors Affecting Human Pulse Rate

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Exercise
o Increases heart rate
o The fitter one is the lower heart rate tends to be and the faster it returns to normal
Health
o Illness tends to increase pulse rate
Stress
o Increases pulse rate
The Effect of Exercise on the Pulse and Breathing Rate.


Record pulse at rest using first and second fingers on wrist
Count number of pulse in 15 seconds and multiply by four to get rate per
minute
 Average pulse rate for an adult at rest is 70 b.p.m.
 Record the breathing rate at rest
 Count the number of breaths in 15 seconds and multiply by four to get rate
per minute
 Do vigorous exercise
Taking a Pulse
 Record the pulse and breathing rates as before
Results: Exercise increases both pulse and breathing rates

A balance of both regular exercise and diet promotes good health
 Exercise results in increased pulse and breathing rates to supply extra oxygen for the increase in respiration
required to release the extra energy needed for the exercise
Body Temperature


Normal human body temperature is 37 °C
Illness may cause an increase in body temperature as the body requires extra energy to fight the infection
Excretion
Excretion: the removal of metabolic wastes from the body
Egestion: the removal of undigested food from the body as faeces
Products of Excretion: CO2, water and urea
Organ
Lungs
Kidneys
Skin
Substances Excreted
Carbon dioxide and water in breath
Water, salts and urea in urine
Salt and water in sweat
Urinary System

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Renal Artery brings blood with impurities from heart to
kidney
Renal Vein brings purified blood to the vena cava and
thence back to the heart
Kidney Filters the blood and removes urea and excess water
Ureter brings urine from the kidney to the bladder
Bladder stores urine
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Junior Cert Science -Biology
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Urethra carries urine from the bladder to outside the body
The Skeletal/Muscular System, the Senses and Human reproduction
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Our basic body shape is formed by our skeleton, which is made up of over two hundred bones.
The skeleton provides support and protection for the body and the arrangement of the bones,
together with the associated ligaments and muscles, allows for movement.
Our senses enable us to be aware of, and respond to, our immediate surroundings.
The human species is continued through the process of sexual reproduction.
The reproductive system develops to maturity during adolescence, and males and females have
different roles in reproduction.
Children inherit many characteristics from their parents.
Role of the skeleton
 Support
Gives the body shape and structure
 Movement
Allows movement using bones, muscles and joints
 Protection
Encases vital organs in solid framework
o Skull protects brain
o Ribs protect heart and lungs
o Vertebral column protects spinal chord
Structure of the skeleton
 You have to be able to identify the bones shown in the
diagram opposite.
Muscular System
Muscles
 Muscles can only contract (or relax)
 They cannot expand
 Cause movement by contracting and using bones as levers
Tendons
 Join muscle to bone
 They are tough and inelastic
Ligaments
 Join bone to bone
Cartilage
 Prevents friction between moving bones
 Cushion joints by acting as a shock absorber
Joints

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Joints are where bones meet
Some do not allow any movement e.g. in the skull
Some allow different degrees of movement
Synovial fluid lubricates the joint
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Joint Type
Where Found
Degree of Movement
Fixed
Skull
None
Hinge
Elbow and Knee
In one plane
Ball and Socket
Shoulder and Hip
In all directions
Gliding
Ankle, Wrist, Spine
Slight in all directions
Antagonistic Muscle Pairs
 When one muscle contracts the other relaxes and is stretched
back to its original length.
 Muscles that work against each other in this way are called
antagonistic pairs
 In the elbow the biceps contracts and pulls the forearm up
towards the body
 As this happens the triceps relaxes and is stretched
 When the triceps contracts it straightens the arm and stretches
the biceps
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Junior Cert Science -Biology
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Sensory System
Sense Organs

Allow us to be aware of and respond to our surroundings
Sense
Organ
Sight
Eye
Hearing
Ear
Smell
Nose
Taste
Tongue
Touch
Skin
Eye Structure and Functions of Parts
Central Nervous System
 Consists of brain and spinal cord
 Co-ordinates responses to stimuli from our sense organs
Peripheral Nervous System
 Consists of pairs of nerves connected to spinal cord
 Sense organs collect information about our surroundings and pass them to the brain
 Sensory Nerves carry impulses from receptors to brain via spinal cord
 Motor Nerves carry impulses from brain muscles and glands via spinal cord
 Stimulus is an electrical message passed along a nerve
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Junior Cert Science -Biology
Reproductive System
Male Reproductive System
 Testis produces sperm
 Sperm is the male gamete
 Epididymis stores sperm
 Sperm Duct carries sperm to the urethra
 Seminal Vesicles add fluid to sperm producing semen
 Urethra carries sperm (and urine) out of the body
 Penis places the sperm at the top of the vagina for the best
chance of fertilization
Female Reproductive System
 Ovary produces an egg every 28 days after puberty until the
menopause
 Oviduct (Fallopian Tube) carries egg to the uterus.
 Fertilisation occurs in the oviduct
 Uterus (womb) holds the developing baby
 Cervix is the opening of the uterus
 Vagina is where the penis deposits sperm
 Egg is the female gamete
Menstrual cycle
 This begin at puberty (sexual maturity)
 It is a series of events that happens every 28 days (on average) in the human female
Days 1 - 5
 Lining of uterus breaks down
 Passed out of the body with some blood.
 Called menstruation of having a period
Days 6 - 13
 New lining of uterus develops
Days 14
 Ovulation an egg is released
Days 15 - 28
 Lining of uterus stays in place
 Fertilization stops the menstrual cycle
Fertile Period
 Days 11- 18
o Sexual intercourse is the act of placing the penis into the vagina
o Intercourse during this period has the best chance of producing a pregnancy
Fertilization and Pregnancy
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Fertilisation is the fusing of the male and female gametes (sperm and egg)
The resulting cell is called a zygote
The zygote undergoes cell division many, many times to become a foetus in the uterus
The baby continues to grow
After about 40 weeks the baby is fully developed
The baby passes out through the cervix and vagina at birth
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Birth
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Labour is when the uterus contracts rhythmically
The waters break (protective fluid around the baby)
Delivery is when the baby comes out
Afterbirth is when the placenta is expelled
Contraception
 Is the prevention of pregnancy
 Methods e.g. condom, contraceptive pill, diaphragm and rhythm method prevent fertilisation
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Birth
Junior Cert Science -Biology
Genetics
Genetics is the study of inherited characteristics
Inherited Characteristics
 Are passed from parents to children e.g. eye colour, hair colour, blood group
 These are controlled by genes
Non-inherited Characteristics
 NOT passed on from parents to children e.g. musical skills, ability to play chess
 These are acquired during one’s lifetime
Chromosomes
 Are found in the nucleus of all cells
 These are long strands of DNA (deoxyribonucleic acid) wrapped
around clumps of protein
 Human cells have 23 pairs of chromosomes
o Except sperm and egg cells which have 23 single
chromosomes
 Each chromosome has many genes along its length
 Each gene controls a particular characteristic e.g. eye colour, hair
colour, blood group
 At fertilisation the sperm and egg cells each provide 23
chromosomes to make up 23 pairs (46 chromosomes in total)
 When cells divide exact copies of each chromosome are formed
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Human Chromosomes
(Stanford University)
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Junior Cert Science -Biology
Animals, Plants and Micro-organisms
Through photosynthesis plants use the sun’s energy to make food, which is stored in the form of
carbohydrates.
At the same time, they replenish the supply of oxygen in the atmosphere and remove carbon
dioxide.
Plants have systems that enable them to function and survive, and to respond to their environment.
Competition and interdependence occur within an ecosystem.
Living Things
There is a tremendous variety of living things
Classification: is placing living things in groups with common characteristics
 Plants
 Animals
o Vertebrates animals with backbones
o Invertebrates: animals without backbones
Identifying Common Animals

Key: a series of simple questions used to identify organisms
1
2
3
4
5
6
(a)
Animal with backbone ………………………
Go to 2
(b)
Animal without backbone ……………………
Go to 3
(a)
Covering of feathers ………………………….
Go to 4
(b)
Covering of hair ………………………………...
Go to 5
(a)
Tough hard outer body ……………………….
Go to 6
(b)
Soft body ……………………………………......
Go to 7
(a)
Red feathers on chest ………………………….
Robin
(b)
Black and white feathers..……………….........
Magpie
(a)
Long bushy tail………………………………....
Fox
(b)
Long ears, short white tail…………………….
Rabbit
(a)
3 pairs of legs……………………………….......
Ground
beetle
7
(b)
Four pairs of legs………………………………..
Spider
(a)
Segmented body………………………………...
Earthworm
(b)
Un-segmented body……………………………..
Slug
Answers
A = Earthworm
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B = Slug
C = Ground Beetle
Science – Biology Revision Notes Peter Jackson
D = Spider
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Junior Cert Science -Biology
E = Robin
F = Magpie
G = Fox
H = Rabbit
Characteristics of Living Organisms
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Nutrition they need food to live, grow and reproduce.
Respiration how they get energy from food
Excretion how they get rid of their waste products
Growth is an increase in the size or number of cells of an organism
Reproduction is the ability of an organism to make new organisms
Movement They need to be able to move.
Response is how an organism interacts with its environment
Remember these using a Mnemonic such as Nine Raging Elephants Got Really Mad Recently
Organisation within living Organisms
All living things show different levels of organisation which increases as they become more complex
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Cell: the basic unit of life, the smallest independent part of an animal or plant
Tissue: a group of cells with a common function e.g. muscle
Organ: a group of tissues working together e.g. heart made up of muscle, valve, artery and vein
tissues
System: a group of organs working together e.g. respiratory system consisting of trachea, lungs
and capillaries
The Light Microscope
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Objective Lens – magnifies
Eyepiece lens – magnifies
Stage – holds slide
Coarse Focus Knob – to focus roughly
Fine Focus Knob – to focus accurately
Light – Illuminates object to see it clearly
Cells as seen under the Light Microscope
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Junior Cert Science -Biology
Prepare a Slide from Plant Tissue and Sketch the Cells under Magnification
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Cut onion in half
Pull out a layer of the onion (a leaf)
Remove the thin layer on the surface
Cut a small square of this and place on a slide
Add a drop of iodine solution to stain it so the
structures can be seen more clearly
Cover with a cover slip
Examine using microscope
Prepare a Slide from Animal Tissue and Sketch the Cells under Magnification
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Rub your finger along the inside of your cheek
Rub this scraping onto a slide
Add some methylene blue stain
Cover with a cover slip
Examine under high power with a microscope
Draw what you see
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Junior Cert Science -Biology
Plant Structure
Root
 Anchors plant
 Absorbs water and minerals
 Stores food [carrot]
 Vegetative reproduction [dahlia]
Stem
 Transports water and minerals up stem
 Transports food up and down stem
 Stores food
 Holds leaves and flowers in place
Leaf
 Photosynthesis
 Stores food [cabbage]
 Vegetative reproduction [Bryophyllum]
 Water transport by transpiration
Flower
 Sexual Reproduction
 Attracts pollinators
 Produces seeds
Seed
 Production of new plants
 Dispersal to colonise new areas and avoid
competition
Transport in Plants
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Water is carried through the plant as a result of transpiration from the leaves
Transpiration is the evaporation of water through the stomata (pores) in the leaf surface
Xylem transports water and minerals up the plant
Phloem transports food in the form of glucose solution
The Path of Water through Plant Tissue,
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Cut a stick of celery
Place in a beaker of water containing red food dye
Leave for two days
Cut the stem half way up
Note the coloured areas these are the xylem vessels
Note also the lines of red up the stem
Show that Water Evaporates from the Surface of a Leaf by Transpiration
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Cover a potted plant with a dry plastic bag and seal the bottom
Leave for a day
Examine the plastic bag
Note the condensation on the inside
Test the liquid with cobalt chloride paper
The paper turns from blue to pink showing that the liquid is water
The water has got there by transpiration
Transpiration is the evaporation of water from a leaf through the stomata
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Junior Cert Science -Biology
Photosynthesis
The process by which plants use chlorophyll to make glucose (food) from carbon dioxide and
water in the presence of sunlight
Phototropism is a Growth Response to Light
 Set up the apparatus s shown in the diagram
 Place cress seeds on moist cotton wool
 Place the box near a window with the opening facing the
window
 Leave for a few days
 Result the seedling grow towards the light
 Conclusion: Plants grow towards light
Geotropism is a Growth Response to Gravity
 Set up the apparatus s shown in the diagram
 Germinate some bean seeds until radicals appear
 Arrange at random on the cotton wool
 Place seeds on moist cotton wool
 Place Petri dishes vertically
 Leave for two days
 Result the seedling grow downwards
 Conclusion: Roots grow towards gravity
Show that Starch is Produced by a Photosynthesising Plant
 Take a leaf from a plant kept in bright light
 Dip it in boiling water to kill it
 Place it in hot alcohol for ten minutes to remove the chlorophyll
 Place in boiling water again to soften it
 Place it on a white tile
 Add some brown iodine solution
Result: The iodine turns blue/black showing that starch is present
Conclusion: a photosynthesizing plant converts light energy to
chemical energy (starch)
Reproduction and Germination in Plants
Asexual Reproduction
 Does not involve gametes
 All plants produced are identical to the parents
 Strawberries produce runners and where these touch the ground a
new plant forms
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Strawberry
Junior Cert Science -Biology
Sexual Reproduction
 Reproduction involving gametes (pollen and eggs)
 Results in plants which are all different in some respects
 The flower is the agent of sexual reproduction
Flower Structure
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Sepals: protect the flower before it opens and when it closes up at night time
Petals: brightly coloured to attract insects for pollination
Carpel (female part)
o Stigma: catches pollen
o Style: holds stigma in a suitable position
o Ovary: produces the egg cell(s)
o Egg cell: produces the female gamete
Stamen (male part)
o Filament: holds the anther in a suitable position
o Anther: produces pollen
o Pollen: produces the male gamete for
fertilisation,
Pollination: Transfer of pollen from an anther to a stigma
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Insect pollination
o Transfer of pollen by insect
o Petals brightly coloured
o Scented
o Have nectar
Insect Pollination
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Wind Pollination
o Wind carries the pollen
o No petals or very small dull petals
o Large amounts of light pollen
o Stamens and stigmas stick out to catch the wind
Fertilisation: fusion of male and female gametes
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Wind Pollination
Fused male and female gametes form a zygote
Zygote develops into a seed
Ovary wall can become the fruit
Petals and sepals wither
Seed Structure
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Testa hard outer coat protects the seed and its food supply
Food Supply is mainly starch
Plumule forms the shoot
Radicle forms the root
Micropyle allows water to enter the seed
Seed Dispersal getting the seeds away from the parent plant
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Rowan – Animal
Pea – Self (explosive)
Coconut - Water
Dandelion - Wind
Germination: is when the seed starts to grow
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Normally after a period of dormancy (no growth)
It is necessary to produce a new plant
Seed absorbs water through micropyle
Radical
o Emerges first
o Grows downwards
o Becomes the root
Plumule
o Emerges second
o Grows upward
o Becomes the shoot
Conditions Necessary for Germination
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Set up 4 test tubes as shown in diagram
Examine tubes after 3-4 days
Results
Tube B – germination
Tubes A, C and D no germination
Conclusion
Heat, water and oxygen all needed for
germination
Ecology
Ecology is the study of the relationships between plants, animals and their environment
Ecosystem an area where a group of different plant and animal species live and their interactions
with the environment
Habitat place where a plant or animal species lives e.g. Woodland
Producers
 Green plants - make their own food by photosynthesis e.g. grass, primroses and oak tree
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Are eaten by herbivores
Consumers
 Primary Consumers are herbivores i.e. eat plants e.g. snails, rabbits,
 Secondary Consumers are carnivores i.e. eat animals e.g. fox, thrush and Sparrow hawk
Decomposers break down dead plants and animals for food e.g. fungi and bacteria
 Return valuable nutrients back into the soil
Adaptation – changes in structure or behaviour in a species which help it to survive.
 Rabbits have big ears to help the hear predators coming
 Primroses flower early to get enough light before the leaves come on the trees
Competition struggle between organisms for resources in short supply
 Plants compete for light
 Animals compete for food and mates
Dependence One species needs another to survive
 Rabbits need grass to survive but grass does not need rabbits to survive
Interdependence two species that need each other to survive e.g. bees and primroses,
 Bees need wallflowers for food (nectar and pollen)
 Wall flowers need bees for pollination
 Living things are affected by their environment and respond to changes that occur in that
environment
 Their numbers depend on availability of food and presence or absence of other organisms
Food Chain is a list of organisms where one organism is eaten by the next organism in the chain
Food Web is two or more interconnected food chains.
Examples from a woodland habitat
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Study a Local Habitat to show the Variety and Distribution of Named Organisms
Quadrat
Beating Tray
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Place the quadrat at random in the habitat
Record the number of each plant or animal inside the square
Repeat a number of times (say eight times)
Calculate the number of each plant or animal per square metre
To show primroses and bluebells in a woodland
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Hold the beating tray under a branch
Beat the branch with a stick
small insects fall from the branch onto the tray
Collect the insects with a pooter
Identify the insects e.g. ladybirds and greenflies
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Bury jar in ground with neck level with ground surface
Cover with a flat stone to keep out the rain
Leave for 24 hours
Collect insects and identify them
e.g. ground beetles and centipedes
Pitfall Trap
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Line Transect
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Place line knotted at 1 m intervals across habitat
Identify the plant that touches each knot
Record the plant that touches each knot
e.g. primroses and bluebells
Pooter
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Hold the plastic tube beside the insect you wish to capture
Suck sharply on the other tube
Insect is drawn into the jar
Gauze stops insects entering your mouth
Identify the insects e.g. ladybirds and greenflies
Conservation is management of the environment
to maintain populations at a sustainable level
to increase numbers if they are too rare
to reduce numbers if they are too plentiful and are causing damage to other species
to help scarce raw materials last longer
Pollution is any harmful addition to the environment
 Air Pollution from car exhausts pumping carbon monoxide into the air, and sulphur dioxide
causing acid rain.
 Water Pollution by fertilizers being washed from farmland into rivers
 Soil Pollution from dumping old car batteries into the ground causes lead pollution
Waste Management is the proper disposal of waste materials to prevent pollution
 Proper disposal of wastes
 Reduce the amount of packaging, or the amount of heating by turning down thermostats
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Reuse materials e.g. wood to help save the rainforests
Recycle metals such as aluminium to conserve raw materials
Effects of Human Activity on the Environment
Positive
 Wildlife Reserves help protect endangered species
 Increasing insulation in homes helps conserve valuable oil reserves
Negative
 Using mahogany causes rain forests to be cut down
 Using fossil fuels causes global warming
Microbiology is the Study of Microscopic Living Things
There are three main groups of micro-organisms
Fungi
 Do not have any chlorophyll and so cannot make their own food
 Some mushrooms are edible i.e. can be used as food
 Some mushrooms are poisonous
 Many fungi are decomposers i.e. break down dead material and return
valuable nutrients to the soil. Some of these can spoil food
 Some cause diseases such as Athletes Foot
 Some can be used to make antibiotics e.g. penicillin
 Yeast is used to make alcohol and to make bread rise
Bacteria
 Are very small and primitive cells
 Many are decomposers and some cause food to rot
 Many cause diseases see table on next page
 Some cause tooth decay
 Some are used to make yoghurt and cheese
Edible Mushroom
Tuberculosis Bacteria
Viruses
 Are incredibly small and can only be seen with an electron microscope
 Many cause diseases see table on next page
 Antibiotics do not affect viruses
 Antibodies are needed to fight viruses
 Vaccines are used to help the body fight viral diseases e.g. mumps and
measles
Mumps virus
Common Bacterial and Viral Illnesses
Illnesses caused by Bacteria
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Illnesses caused by Viruses
Typhoid
Smallpox (has been eradicated)
Tuberculosis
Influenza
Strep Throat
Polio
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Junior Cert Science -Biology
Investigate the Presence of Micro-organisms in Air and Soil
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Take three nutrient agar Petri dishes
Open one to the air for five minutes
Rub a sample of soil on the other
Leave the third unopened as a control for comparison
Seal both and Incubate at 25oC for two days
Results
 Both exposed plates are covered in colonies of bacteria and fungi
 Control has nothing growing on it
Colonies on Agar Plate
Conclusion soil and air contain micro-organisms
Biotechnology is the use of micro-organisms to make useful substances
In Industry
 Yeast fungus is used to make alcohol e.g. beer and wine
 Bacteria are used to make yoghurt
In Medicine
 Bacteria are used to make insulin to treat diabetes
 Penicillin fungus is used to make antibiotics
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