Science Notes by: Unknown

Topic 1 – Atomos: Inner Space

• Atoms: Elements and compounds made up of atoms. 1 element = 1 type of atom. COMPOUND is 2 or more types of atoms.


• Atoms: ELECTRONS, NEUTRONS AND PROTONS.

If there are the same number of protons and electrons, the atom is neutral.

• Atomic Number: number of protons


• Mass Number: sum of number of protons and neutrons.


• Atomic mass unit: proton = 1, neutron = 1, electron = 0


• Isotopes: atoms of the same element which have a different number of neutrons. E.g. Argon 36, 38, 40. Lithium 6, 7. Bromine 79, 81.


• Ions: atoms which are negatively or positively charged. Combine to form new compounds.


• Electrons: matter = mass and volume.

                              Same charge = repel
                              Unlike charge = attract

• Shells: 1 = 2 max.

                  2 = 8 max.
                  3 = 18 max.
                  4 = 32 max.

• Periodic Table: The arrangement of elements in order of increasing atomic number. Includes, metals, non-metals, semi-metals.


• Radioactivity: The spontaneous decay of unstable nuclei, releasing matter and energy in the process. As nucleus breaks down it emits radiation in particles or rays. Marie Curie discovered radio activity.


• Radioactive decay: (Alpha, Beta and gamma radiation)


• ALPHA PARTICLES – 2 protons, 2 neutrons, positive, travel few cm’s in air, stopped by thickness of a sheet of paper.


• BETA PARTICLES – electron, negative, travel few m’s in air, stopped by sheet of aluminium, 1 cm thick wood.


• GAMMA RAYS – high energy, not charged, travel few km’s, stopped by thick concrete wall, 2 – 3 cm’s thick lead.


• Background Radiation: the radiation which surrounds a particular area. E.g. school lab. It is measured in sieverts. ( 1 million msv = 1 sv)


• Half-Life: Impossible to predict exactly when nucleus will decay. Half life is the time it takes for exactly half the nucleuses present to decay. Its rate is constant.


• Effects of Radiation: Alpha, beta and gamma rays and x-rays = ionizing radiation. They disrupt atoms as they pass through       changing them to ion. Large doses of radiation can kill cells. Sever radiation exposure = immediate death. Lower dose of radiation can damage body, chance of cancer. 1 msv per year is recommended (excluding background and medical).


• Radioisotopes: Unstable isotopes emit radiation.


• TRACERS – Used to follow path of atoms. Can reveal structure/ functioning of organs.


• GAMMA RADIATION – Used to sterilize food, medical supplies, treat cancer.


• NUCLEAR REACTOR – Device for making radioisotopes.


• CYCLOTRON

- Phosphorus 32 (leukaemia)        - iron 59 (blood diseases)
- Cobalt 60 (cancer)                    - Barium 137 (digestive illnesses)
- Iodine 131 (Thyroid)                 - Carbon 14 (artefacts). When a plant  
                                                      dies, it takes in no more C 14 and
                                                     present C 14 decays.    

• Nuclear Fission: Nuclear energy is released when changes occur in nucleus. Nuclear fission is splitting heavier atoms into lighter atoms. When this occurs 2 or 3 neutrons, heat energy and gamma radiation is released.

• Advantages and Disadvantages of Nuclear Energy:

Advantages

• PRODUCING POWER – electricity, ships, submarines


• MEDICINE – * radioactive isotopes (tracers) for organs, tumours, cancers

                           * nuclear medication
                                 * radiation services for human bones, tissue                      

• INDUSTRY – Radiation – how fast it wears off moving tyre, thickness of metal strips, how fast liquid/ gas flows through pipes

                             - Lucas Ht Reactor – radiate large crystals of silicon into wafers (video cameras, fax, and air conditioning)

• AGRICULTURE – Isotopes (tracers) – animals/ plants


• ENVIROMENT – Monitor pollution and erosion

Disadvantages

• WEAPONS – war


• RADIATION – cause damage to humans (cancer)


• NUCLEAR WASTE – need safe methods of disposal

Topic 2 – Shaking All Over

Layered Structure of the earth

• Crust: thin layer of rock. Forms continents and islands. Thickest under continents (60 km) and thinnest under ocean (10km).


• Mantle: Thick layer (2800km) of rocks. Upper part is in a ‘plastic state’ (magma) which comes to surface when volcanoes erupt.


• Core: Consists of large ball like shape in middle. Two parts: the inner core (solid) and the outer core (liquid).

Plate Tectonic Theory: Based on theory that earth’s crust is broken into 12 plates which slowly move. ‘Tectonic’ means forces which lead to movement. This is determined using satellites. Forces come from the ASTHENOSPHERE, region below the solid lithosphere. CONVENTION CURRENTS cause the movements from here.
Surface Features created from Plate Collisions: Collide on land or under sea.

• Deep Sea Trench: When 2 plates collide under sea and one plate pushes under another. Slipping between plates earthquakes. As plate is pushed deeper, rock melts.


• Volcanoes/Earthquakes: when a plate with a continent on it collides with a plate under sea. Friction of plate, melts rocks. Melted rock pushes up forming mountains eg. Andes Mountains.


• Fold Mountains: when two plates both with continents collide and rock material piles up.


• Faults: When plates slide by each resulting in earthquakes. Comes in jerks e.g. San Andreas Fault in CA, U.S.A.


• Mid Ocean Ridge: Found in the Atlantic Ocean, almost all around the world. Deep trench found in the middle and molten material forced up forming new crustal material.

Earthquakes:Natural phenomena caused by movements of earth’s crust. (compression or tension). Caused by slipping between plates and plates sliding by each other. Located usually on edge or near plates.
Detecting an Earthquake: energy released causes waves that spread out in all directions.

• P Waves: Primary, monitored first. Compression waves (shake in wave direction). Fastest waves at 5-13 km/s. Can travel through solid and liquid. Least destructive.


• S Waves: Secondary, monitored second. Transverse waves (shakes across the wave direction). Faster than L waves- 3-8 km/s. Travels through solid only.


• L Waves: Long, monitored last. Transverse waves. Slowest waves at 3-4 km/s. Surface waves only and most destructive.

Earthquake waves recorded on SEISOMETERS to form SEISMOGRAMS.
Scales: MERCALLI – (what happens and how people respond). Roman numerals.
                RICHTER – (measurement of size, amplitude)

• Locating Earthquakes:


• FOCUS – the place where the slip occurs. Small area or a long line.


• EPICENTRE – the point or line directly above the focus


• Three seismographs at 3 different places. 3 arcs drawn on a map using distances derived from time-travel curve (difference between P and S waves). Radius of arc is the distance to the earthquake. Point where arcs intersect is the location of earthquake (epicentre).

Effects of Earthquakes:

• shaking of ground


• horiznyal warping


• cracks in surface


• changes to stream course


• tsunamis


• land/mud/ice slides


• damage to buildings, roads rails and fencing.


• Fires from pipes


• Loss of life

Evidence for Continental Drift:

• Wegener’s Ideas:

Many of the continents ‘fit’ together, just like a jigsaw puzzle (movement of continents)

• ‘Pangaea’ – super continent


• North America, Europe and Asia form ‘Laurasia’


• Antarctica, Australia, India, Africa, and South America formed ‘Gondwanaland’.


• Both split into separate continents

Many rock types and ages are similar between continents (glaciation and tillite). There are a number of ancient climatic zones in lands which are very different to their climates today. There is a certain distribution of many fossil plants and animals across different climates. These similar or identical fossils occur on continents now far away.

Volcanoes: various types of eruptions. Depends on plate boundary.

• Explosive Eruptions: where plates collide, periods of violent and quite activity, mainly ash, lava bombs and gases.


• Quieter Eruptions: lava moves out flows down         steep cone with layers of ash and lava called COMPOSITE CONE.


• Cinder Cones: steep cones made entirely of ash and rock.


• Shield Volcanoes: low, flat cones with little ash formed from lava of large volcanoes which have built up from the seafloor.


• Mid-Ocean Ridge Volcanoes: located where plates separate on ocean floor. Quieter eruptions.


• Volcanic Island Chains: form as the plate moves over a hot spot or magma chamber in the upper mantle.


• Intrusions: movement of magma up through structures.


• ####: cuts across bedded rock.


• Sill: parallel to beds of rock. Form between beds.


• Batholith: large dome shape.

Joints: (tectonic plate movement can result in joints) Joints are cracks in the earths crust

• Faults: formed when compression/ stretching forces cause blocks to move or   against each other.


• Joint: cracks are joined up and level.


• Normal Fault: when right side of block moves up and the left side moves down, both stretching forces.


• Reverse Fault: when right side moves down and left side moves up, both by compression forces.


• Normal Fault: earth’s crust increases.


• Reverse Fault: earth’s crust decreases.


• Folding: Changes in crust cause folding, faulting and tilting. Folding results from sideways pressure on rock layers.


• Strata: horizontal layers.

Topic 3 – Chemistry in the Home

• Matter: particles which can be arranged in different ways.


• Elements, Compounds and Mixtures:

Elements: Substances that are made up of one type of atom only. Sulphur, lead, mercury, copper.
Compounds: substances which are mad up of at least 2 different kinds of atoms joined together by chemical bonds. Hydrochloric acid, ammonia, sodium chloride.
Mixtures: made up of at least two elements. Washing powder, sodium hydroxide 0.2H

• Atoms and Molecules:

Atoms: Simplest form of matter, smallest unit of an element. Consists of a single particle.
Molecules: Made up of 2 or more atoms joined together by chemical bonds.

• Common Chemical Properties:

Acids: All acids are substances that contain hydrogen that can be released as hydrogen gas when a metal is corroded by the acid. Antaciols neutralize or destroy the properties of the acid to produce a neutral solution.
Bases: compounds with properties opposite of acids

• Alkalis: soluble bases that contain a group of charged atoms called the hydroxide ion (OH  )


• Salts: sodium chloride= table salt. Ionic compounds formed when acids and bases react together (neutralization).

Acid + base              salt + water. Properties of acid and base are destroyed, new substance formed. Salt formed can be recovered by evaporation and filtration (precipitate formed).
RULE: Salt = 1st part of base and 1st part of acid.
E.g. Sodium hydroxide + hydrochloric acid        sodium chloride + water.

• Carbonates: Ion = CO (valency is -2).


• Hydrocarbons: Molecules that are only made up of hydrogen and carbon.


• Compound Groups:

Molecular Compounds: (covalent: both non-metals).

• don’t conduct electricity in solution/


• aren’t uncharged


• solutions of molecular compounds are non-electrolytes


• Prefixes used e.g. Carbon dioxide, water.


• E.g. Nitrogen monoxide, methane.

Ionic Compounds: (metal and non-metal)

• ion – charged atom


• atoms of metallic elements usually form positive ions


• atoms of non-metallic elements usually form negative ions


• charge of an ion = valency


• POLYATOMIC IONS = when some ions consist of groups of atoms such that the group as a whole has gained/ lost 1 or more electrons. E.g. nitrate, sulphate.


• Ionic compounds formed from an ionic bond, when oppositely charge ions are attracted to each other.


• E.g. sodium carbonate, aluminium nitrate.

• Chemical Bonds: Bonds are strong forces that hold atoms of elements together

Covalent Bonding: Atoms share one or more of each other’s outer electrons. Two or more NON-METALS combine to form compounds that have MOLECULES.
Ionic Bonding: When a nucleus with a stronger attraction COMPLETELY takes over one or more outer electrons orbiting another nucleus. Results in a positive and negative ion which then attract each other. They are formed when METALS and NON-METALS react to usually produce an ionic crystal lattice.

• Equations/ Formulas:


• writing formulas for ionic compounds: charges of ions (valencies). Sum total of charges = 0. Positive ions symbol written first. The number following the symbol = number of atoms/ ions of the element.


• Remember to BALANCE equations!!! Put in brackets. Number to be placed only at FROMT of formula.


• Chemical reactions = reactants                products

• Combustion and Fire: fuel + oxygen                carbon dioxide + water


• fuel combines with oxygen to release energy.


• Requirements: ignition source, oxygen, fuel


• Extinguishing fires: * remove/ separate unburnt fuel, remove ignition source, remove oxygen supply


• Common fuels: wood, petrol, methane


• Common ignition sources: frictional heat, matches, cooking appliances

Aborigines used fire for:

• driving animals from bush


• cooking


• regeneration


• prevent natural fires

Bushfires in Australia:

• dehydrated foliage ignites and releases burst of heat radiation


• oils and waxes in eucalyptus leaves readily ignite and cause green leaves to burn.

• Corrosion: fuel + oxygen            carbon dioxide + water


• slow decay/ degradation of metal resulting from contact with gases and liquids in enviroment (rust)


• protection: coat with protective barrier to keep out moist air using substances like vaseline

• Precipitation: soluble salt + soluble salt               insoluble salt + soluble salt


• insoluble compounds which form when solutions containing positive and negative ions are mixed


• when one compound is INSOLUBLE and the other is SOLUBLE


• compounds switch around

eg.  silver    +   potassium          silver       +    potassium
       nitrate         chloride           chloride           nitrate
         (aq)             (aq)                  (s)                   (aq)

Aqueous = not pure liquid

• Acids on Metals: metal + acid              salt + hydrogen


• Aim: observe the reaction of acids on metal


• Results: metal dissolved and hydrogen was produced.


• Conclusion: when metals react with acids. Hydrogen gas and a salt is produced.


• Eg. zinc + hydrochloric acid                zinc chloride and hydrogen

• Neutralization: acid + base               salt + water


• when bases and acids react together and form salts


• see ‘salts’ 3 pages back.

• Indicators and Colour changes:


• indicators are chemicals which change colour according to acidity/ basicity of enviroments


• use acid/ base indicators to test level of acidity/ basicity of chemicals.

Litmus:

• red in acidic solutions


• blue in basic solutions (alkali)


• doesn’t change in neutral solutions

Phenolpthalien:

• magenta in basic solutions


• colourless in acidic and neutral solutions

• Acids on Carbonates: acid + metal carbonate             salt + carbon dioxide + water

• Decomposition: compounds can be decomposed by heat.

Topic 4 – Field Studies

• Biotic: the biological components of the environment.

Biotic factors that affect an ecosystem:
- competitors – food – shelter – predators (2nd order consumers) – producers (make food by photosynthesis)  
- 1st order consumers (herbivores)

• Abiotic: parts of the environment which are non living. Includes physical and chemical.

Abiotic factors that affect an ecosystem:
- air/water temp.    - wind speed/ direction   - humidity
- depth/ speed of water    - characteristics of the soil    
- acidity of water/ soil    - salinity of soil/ water    - light penetration in water    - light penetration of canopy

• Balance of Nature: an ecosystem is an area and the community that lives in it. The system involves giving and taking between living and non-living. In nature, ecosystems are in BALANCE. Enough light energy is taken in to replace the energy lost in heat, and matter is cycled between the community and its surroundings.


• Methods to estimate plant and animal pop.


• QUADRANT SAMPLING: sample square placed at random and the population is measured within the squares. Cons: not good for animals that move.


• CAPTURE RECAPTURE: involves tagging a sample of the pop. Then calculations are made of the proportion of marked animals in a recaptured sample.

Total Pop. =       # of tagged animals x # recaptured  
                       Average # of tagged animals recaptured
Cons: trapping techniques are hard to master

• Impact of Human Activity on Australian ecosystems


• removal of trees and clearing of land for agriculture


• introduced species.


• Clear land for cities- destroy ecosystems


• Dams are built


• Transportation systems built e.g. roads, rail


• Disposal of waste – sewage system, garbage removal


• Removal of other man-made materials


• Photosynthesis: occurs in producers.

Two outcomes (a) light energy stored             stored chemical energy
                        (b)  carbon dioxide and water                  sugar and oxygen

• Respiration: a process where sugar is broken down for the energy it contains


• Australian Ecosystems:

-DESERT- widely spaced grasses, salt bush, high temp., low rain
-GRASSLANDS- spinifex grasses, very low coverage >30%  
  < 500mm rainfall, temperate or tropical
- SHRUBLANDS- mallee, mulga 30%-70% coverage, low rain, high
   temp.
- WOODLANDS- trees, shrubs, grasses, widely spaced canopy, low
   coverage w/ shrubs, high rain in tropical, temperate or tropical.
- ALPINE- snow gums, heaths, continuous cover, variable rainfall (or snow), temp. increases with altitude.
- SCLEROPHYLL FOREST- trees (jarrah, blue gum), shrubs, grasses, open canopy but ground cover, rain depends, no distinct seasonal rain, warm temp.
- RAINFOREST- trees (cedars, southern beach), lianas, ferns, dense canopy, distinct layers within, high rain, temperate or tropical (little season variation)
- REEFS & MARSHES- mangroves, reeds, dense growth, temp. and rain vary at different spots on the coast

• Key Vocabulary

PIGMENT: a chemical that absorbs light energy
BIOSYNTHESIS: a process which the chemical of the body are built from other (simpler) chemicals.
REDUCER: organism that breaks down other organisms into simpler things.

Topic 5 – Seeing is Believing

• Sight: sight is caused by rays of light which are reflected of an object. These rays carry with them an image that enters our eye.


• Light: light travels in straight lines and at a constant speed as long as the medium it travels through doesn’t change. Light travels at 300’000 kms -1 in a vacuum but slows when entering more dense mediums. Light may change direction (refract) when passing through different mediums leading to optical illusions. Light is a form of energy that travels as a transverse wave.


• Transverse Wave: as it travels, the particles themselves oscillate along a path that is at a right angle to the direction of motion of the wave. E.g. light or radio waves.


• Longitudinal Waves: The particles of the medium oscillate in the same direction as the waves travel. Also know as compression waves. E.g. sound waves.


• V = f    used to work out measurement in a wave.

                       Wavelength=
                       Frequency = f Hz (hertz)
                       Amplitude   = a metres
                       Velocity       = v ms-1
                       Period/ wavelength = T
                       f = 1/ T     T = 1/f    

• Laws of Reflection: Governed by two laws.

(1) The angle of incidence is equal to angle of reflection
(2)  The incidence ray and reflected ray are in the same plane a, and on opposite sides of, the normal.

• Refraction: The bending of light rays as they travel from one medium to another.

GLASS RECTANGULAR PRISM:  as it passes through the prism, the light travels away from the normal.
CONCAVE LENS: the rays of light diverge
CONVEX LENS: the rays of light converge

• Translucent Objects: A translucent object let light through, but the direction changes. E.g. frosted glass


• Transparent Objects: allows light through with very little change to direction. E.g. clear glass


• Opaque Objects: doesn’t allow light to pass through. E.g. wood, bricks. Colour is caused by some of the waves that make up visible light being absorbed and some reflected. Black: all absorbed   White: all reflected.


• Human Eye:

RETINA: layer at back which detects image. Contains sensitive nerve endings which detect light.
CORNEA: transparent bulge at front. Window that allows light to enter.
LENS: convex lens. Tough, flexible and transparent. Helps focus light rays on retina.
CILIARY MUSCLES:  muscles that control the curvature and shape of the lens thus power of the lens.
CHLORIOD: thin black layer on the inside of the sclerotic coat. Absorbs all light after it’s passed through the retina.

• Short Sightedness: can see near objects clearly but not distant ones. Corrected with concave lens.


• Long Sightedness: can see distant objects clearly but not near ones. Corrected with convex lens.


• Dispersion: the spreading out and separation of light rays as they are dispersed. Into separate colours.


• Different forms of Electromagnetic Radiation

Wavelength (m)                       Type                 Uses
100                                      Radio waves         radio
                                              Microwaves

1                                                                       microwave ovens
  
1/ 1000
                                              Infra Red              electric fires

1/ million
                                              Light                    electric lighting
                                              Ultra violet           ultra violet lamps/                                                                                                                        
                                                                          Sunbathing
1/ 1000 mil.
                                             X-rays                 x-ray photographs

1/ Mil. Mil.                          Gamma rays            radio activity


Topic 6 – The Body Under Attack

• Microbes: microscopic organisms


• Pathogens: Microbes that cause disease.


• Kingdom Monera: Bacteria and cyanobacteria belong in this category. Their cells do not have a nucleus with a membrane. A cyanobacterium is 20 um in size. A bacterium is approx. 5 um in size (types include spirillum, bacillus and coccus). Tuberculosis and tetanus are both members of this kingdom.


• Kingdom Protistia: Many unicellular organisms as well as algae belong in this kingdom. Their cells have membrane- bound nuclei. They are approx. 50 um in size. The kingdom includes amoeba, ciliates and flagellates. Protozoa that cause malaria and sleeping sickness are part of this kingdom.


• Kingdom Fungi: Fungi are organisms that do not contain chlorophyll but their cells are surrounded by cell walls and have membrane bound nuclei. They are approx. 100 um in size and include yeast (which is beneficial to us), bread mould and penicillin. Tinea and thrush are examples of pathogenic fungi.  


• Viruses and Prions: Viruses are bodies much small than cells which are composed of some genetic material (codes required for reproduction and control) surrounded by a protein coat. Viruses cannot reproduce unless they first invade a host cell. Influenza, polio, mumps and AIDS are caused by viruses. They are approx. 100 nm in size. Prions are protein particles that cause disease such as Creutz- Jakob disease and Mad Cow Disease.


• Resisting/ fighting Micro-organism Infection

- SKIN: microbes can not penetrate unbroken skin. Harmless bacteria live on your skin and use the oil from your pores to create acids that prevent other bacteria and fungi from growing.
- ACID IN YOUR STOMACH: if pathogens enter your body as you eat, they usually are killed by your stomach acidic gastric juices.
- MUCUS IN YOUR AIRWAYS: the cells of the membranes that line your trachea and bronchi produce a sticky mucus. It traps pathogens you breathe in. Microscopic hairs transport these trapped particles back out you mouth when they are coughed out or swallowed and destroyed.
- STERILE, ACIDIC URINE: urine constantly flushes the bladder, ureters and urethra. Because urine is acidic, microbes cannot readily grow.
- WHITE BLOOD CELLS: your body produces white blood cells called phagocytes that consume and destroy microbes that enter the bloodstream.
- ANTIBODIES: these are proteins produced by the body that attach themselves to pathogens or foreign substances and allow the phagocytes to destroy them.
- IMMUNITY: when the body has experience a disease and fought it off successfully, they often become immune to it. That means that now that your defence system has killed the invading pathogen, they now have ready antibodies to fight it off again if necessary.

• Antibiotics: Antibiotics are a form of medicine that kills many disease organisms. Antibiotic drugs have saved many lives. Unfortunately, some microbes have become resistant to their effects. Antibiotics can not cure viral diseases.


• Hygiene: Hygiene is a very effective way to resist infection or disease. If your body is kept clean, then you make the risk of contracting a disease much lower.  By washing your hands regularly you can stop yourself from contracting many diseases which are transferred through your dirty hands.


• Immunization: an active process that seeks to protect you before you are attacked by certain microbes. Scientists have developed vaccines from dead or ineffective microbes. If these vaccines are injected into your blood, you develop immunity to that disease. Active immunizations have been developed for bacterial and viral infections.


• Non-Infectious Diseases: not all diseases are caused by microbes. Non- infectious diseases include genetic diseases (e.g. Down syndrome), nutritional diseases (e.g. anorexia), environmental diseases (e.g. lead poisoning) and organ and tissue diseases (e.g. cancer, heart disease). Some environmental diseases are caused by factors in the environment, such as heavy lead poisoning and radiation.


• Cancer: cancer is caused by abnormal cell division, which creates abnormal cells which don’t function properly. The defence system usually removes these cells, but if it can’t the cells continue to divide forming a mass of cells called a tumour or cancer. There are two types of tumours, benign and malignant. Benign tumours grow within a membrane, but malignant do not and often invade other tissues and organs. Cancer is caused by cells being exposed to an agent called a carcinogen. This causes the genetic code in the chromosomes to change (mutation). This leads to their abnormal behaviour. Some common carcinogens include tobacco smoke, benzene, hep. B virus, HIV, x-rays and Gamma rays.


• SKIN CANCER- Caused by exposure to UV rays, which are invisible.

Topic 7 – Multiplication

• Life Cycle: the cycle of a certain organisms life, including birth, growth, reproduction and death.


• Fertilization: the combination of the sperm and the egg to create a new living cell.


• Sexual Reproduction: involves the production of specialized sex cells called gametes. The male gamete (sperm) must meet the female gamete (egg) at FERTALIZATION to produce the first new call of the next generation. Examples of sexually reproducing organisms include humans, mammals, lizards, frogs, fish and some flowers. Many organisms sexually reproduce differently. For example, fish and frogs reproduce EXTERNALLY, where the female eggs and the male sperm meet and unite in the water. Mammals reproduce INTERNALLY, yet monotreme mammals such as the platypus lay eggs which are held in a skin fold till the young is ready to be born. Marsupials are born at an immature stage of their development and are held in a pouch until they have fully grown. Placental animals, such as cows and horses and humans, give birth to their live young at a late stage in development.


• Asexual Reproduction: asexual reproduction is the reproduction of an organism without the help of another organism. Many simple protests and bacteria reproduce asexually by making IDENTICAL copies of their cell through normal cell division. Examples include bacteria, protozoa, fungi, and many types of plants.

Fission: simple cell division to produce identical cells that are approx. the same size. Some yeasts or hydra reproduce this way yet the new cells are smaller and called BUDS.
Spores: produced by field mushrooms, moulds etc., they are grown in spore sacs and opened to spread around.
Vegetative Reproduction: RUNNERS: new stems that grow along the soil surface and produce new shoots e.g. strawberries. BULBS: onion and daffodil bulbs produce buds that develop into new plants. TUBBERS: potatoes are swollen stems called tubers that grow vegetatively underground.  RHIZOMES: underground branching stems. E.g. couch grass, irises. CUTTINGS: a small part of a plant which is cut off and replanted. Roots grow from where it was cut. E.g. roses, apple trees.

• Organisms that reproduce both sexually and asexually: some organisms can reproduce both sexually and asexually, such as onions, potatoes, roses, grass, hydra, irises and daffodils. Often plants reproduce asexually because it leads to a higher success rate but sexually reproduction is important because it can create new varieties, some of which could survive sudden changes in the environment.


• Pollination: Fertilization of plants using pollen. Pollination occurs when the pollen of a male plant (with the sperm in it) enters the stigma of a female flower and they unite in the ovary to create a new seed.


• Human Reproduction: Once an egg is release into the fallopian tube during OVULATION a woman is ready to be fertilized. When a man and a woman have sexual intercourse, the man ejaculates sperm in to the woman. It travels into the uterus and to the fallopian tubes and fertilizes the egg. The new zygote moves into the uterus and implants itself into the wall. It grows for approx. 9 months, and then is delivered live and developed from the woman’s uterus through the vagina.


• Menstruation: Menstruation occurs in the female only. It is the cycle which prepares the body for fertilization.  Firstly FSH stimulates the growth of an egg in the follicles within the ovary. After so many days, LH stimulates ovulation, where the egg is released from the follicle into the fallopian tube. LTH stimulates the growth of the corpus luteum. Once it is developed, it produces oestrogen which continues building up the lining of the uterus. The oestrogen also stops the production of FSH. Progesterone also stimulates the lining of the uterus to grow. However if the egg is not fertilized, the lining is shed and a new cycle begins.


• Puberty:

Males: Begins on at average 12-14 and lasts about 4 years. Hormones stimulate secondary sex characteristics to begin. These include: growth of hair (pubic, body, underarm, facial); enlargement of the testes and penis; increased muscle development; deepening of the voice; stimulations of the sweat and oil producing glands; sexual desire; growth spurt.
Females: Begins on average between 11 and 13 and lasts about 4 years. Hormones begin secondary sex characteristics which include: growth of pubic and underarm hair; growth of breast; change in bones, especially the widening of the hips; redistribution of fat on the hips and thighs, the development of sexual desire; growth spurt; and the beginning of menstruation.