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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. We at mocks.ie are delighted to bring you these excellent notes at an affordable price. Mocks.ie Science – Biology Revision Notes Peter Jackson Page 2 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 3 Junior Cert Science -Biology 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 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 Mocks.ie Add iodine solution If starch present it turns blue black If no starch present it stays brown. Science – Biology Revision Notes Peter Jackson Page 4 Junior Cert Science -Biology Lipid [Fat or Oil]: e.g. butter or vegetable oil o o Reducing Sugar: e.g. glucose o o 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 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 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 Mocks.ie 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 Science – Biology Revision Notes Peter Jackson Page 5 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 6 Junior Cert Science -Biology Tests to Compare the Carbon Dioxide Levels of Inhaled and Exhaled Air 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 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 7 Junior Cert Science -Biology 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 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 Mocks.ie 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 Page 8 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 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 9 Junior Cert Science -Biology Urethra carries urine from the bladder to outside the body The Skeletal/Muscular System, the Senses and Human reproduction 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 10 Junior Cert Science -Biology 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 11 Junior Cert Science -Biology Mocks.ie Science – Biology Revision Notes Peter Jackson Page 12 Junior Cert Science -Biology 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 13 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 14 Junior Cert Science -Biology Birth 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 15 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Human Chromosomes (Stanford University) Page 16 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 Mocks.ie B = Slug C = Ground Beetle Science – Biology Revision Notes Peter Jackson D = Spider Page 17 Junior Cert Science -Biology E = Robin F = Magpie G = Fox H = Rabbit Characteristics of Living Organisms 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 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 18 Junior Cert Science -Biology Prepare a Slide from Plant Tissue and Sketch the Cells under Magnification 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 19 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 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, 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 20 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 21 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 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 Insect pollination o Transfer of pollen by insect o Petals brightly coloured o Scented o Have nectar Insect Pollination 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 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 22 Junior Cert Science -Biology Rowan – Animal Pea – Self (explosive) Coconut - Water Dandelion - Wind Germination: is when the seed starts to grow 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 23 Junior Cert Science -Biology 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 24 Junior Cert Science -Biology Study a Local Habitat to show the Variety and Distribution of Named Organisms Quadrat Beating Tray 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 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 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 Line Transect 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 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 25 Junior Cert Science -Biology 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 Mocks.ie Illnesses caused by Viruses Typhoid Smallpox (has been eradicated) Tuberculosis Influenza Strep Throat Polio Science – Biology Revision Notes Peter Jackson Page 26 Junior Cert Science -Biology Investigate the Presence of Micro-organisms in Air and Soil 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 Mocks.ie Science – Biology Revision Notes Peter Jackson Page 27