Science - Year 9 Pupil Tracks 1 and 2

1. Living things compete with each other for things that the need, these things are food, water, shelter, and mates. There are two different types of competition, the first is inter-species (competition between species), and intra-species (competiton between two animals of the same species.

2. Organisms are interdependent and interrelated. They have an effect on each others population; e.g. The prey numbers start to rise and so do the predator numbers, then the prey numbers fall again as the predator numbers have risen, then the predator numbers fall again and this causes the prey numbers to increase again. This is called the predator-prey cycle.

3. Data from samples can be used to estimate population sizes, but this won't be accurate.

4. Environments are effected by economic, industrial and population changes. Examples of this would be the expansion of industry and population needing more space.

5. Pyramids can show the numbers, biomass or energy in different levels of food pyramids.

6. Darwin's theory of natural selection was as follows: 1) All organisms over-produce. 2) But populations remain fairly constant, so some offspring must die. 3) All organisms show variation. The ones who are best adapted to their environment are more likely to survive and breed. 4) Some characteristics are inherited. Well-adapted parents may pass on useful characteristics to future generations, which eventually evolve into a new species.

7. Fossils provide evidence for evolution.

8. Scientists classify living things in a specific way. By kingdom, phylum, class, order, family, genus, and species.

1. Genes are made of DNA (Deoxyribonucleic Acid). They are parts of chromosones and instruct our cells what to do. DNA effects hair colour, eye colour and earwax texture.

2. Organic crops are those grown without the presence of artificial fertilisers or chemicals. GM crops contain genes that have been altered or taken from another organism.

3. Genes for something like hair colour come in two different forms. E.g. 1 gene tells the cells to make brown hair, whereas the other tells the cells to make black hair. Different forms of these genes are called alleles. As each childs recieves a different combination of these genes from the parents, variation occurs.

4. A genetic disorder is caused by faulty genes. These are mutated alleles.

5. Some genetic disorders, such as cystic fibrosis can be inherited. This would occur when alleles are inherited from your parents, and these alleles would be faulty.

6. The Human Genome Project determined the the 3 billion base pairs that make up the human DNA. We now have a greater understanding of our bodies and concerns about genetic disorders have been raised. However, people say it is an invasion of privacy.

7. Gene therapy can be used to treat diseases such as cystic fibrosis. It is sometimes possible to treat genetic disorders by replacing faulty genes by healthy ones. This is known as gene therapy.

8. Cloning is the creation of an organism which is an exact genetic copy of another. This is very controversial as a lot of ethical issues surround this such as the fact that the clone will not be unique and God did not intend for it to happen. 

9. Deisgner Babies are those whose genetic make-up has been altered before birth.

1. Different elements have different properties dependent on where they are in the periodic table. The elements of the periodic table are organised by period and group. Metals are on the left of the staircase and take up 3/4 of the table, on the right of the staircase are the non-metals.

2. Uses of transistion metals: Iron: tools, cars Copper: Pipes, wires Silver: Electronic appliances, jewelry Gold: Jewelry, Aerospace.

3. An atoms consists of sub-atomic particles. These are Protons with a mass of 1  and a charge of +1, Neutrons with a mass of 1 and a charge of 0, and Electrions with a mass of 0 and a charge of -1.

4. Alkali metals become more reactive as their atomic number increases. E.g. Francium is more reactive than Lithium. 

5. Noble gases are chemically inert, i.e. they are totally unreactive.

6. Halogens have low melting and boiling points, they are poor conductors of heat and electricity, they are coloured gases and form coloured vapours, melting and boiling point decrease as you go down the group, reactivity decreases are you go down the group.

7. 2NaX + Y^2 ---> 2NaY + X^2 is the displacement reaction for halogens.

1. The test for oxygen is the glowing splint test, which will reignite when placed into a test-tube. The test for hydrogen is the pop when placing a burning splint in a test-tube. The test for carbon dioxide is when you bubble it through limewater, if it turns a cloudy white than carbon dixoide is present.

2. Oxidation refers to the reactions where elements gain oxygen. Oxidation can happen slowly (rust), or quickly (combustion).

3. Metals which are less reactive than carbon in the reactivity series can be purified by displacement from their ore with carbo.

4. See attached sheet

5. There are 4 major types of base when making salts: Metals which are more reactive than hydrogen produce a salt and water. Metal oxides produce a salt and water. Metal hydroxides produce a salt and water. Metal carbonates produce a salt, water and carbon dioxide. 

1. Amplitude - Amplitude is loudness/volume and this is how high the wave is above the baseline. Wavelength - Wavelength is the distance between two peaks of a wave. Frequency - Frequency is pitch and high frequency means the particles are vibrating very fast which equates to the waves being very close together. 

2. In a transverse wave, the direction of movement of the particles is at right angles to the direction the wave is travelling. In a longitduinal wave, the particles move parallel to the wave.

3. Waves can be reflection from different surfaces.

4. Reflection - The angle of incidence =  The angle of reflection Refraction - The density of the object determines the angle of refraction.

5. P-waves are longitudinal, S-waves are transverse. The Earth's liquid core refracts the wave. P-waves more quicker than S-waves. Both waves are detected by a seismograph.

6. All electromagnetic waves travel at the speed of light. These waves are Radio Waves, Micro Waves, Infrared, Visible Light, Ultraviolet, X-Rays, and Gamma Rays. Electromagnetic waves are generally transverse, travel at the speed of light, carry energy, and can travel in a vacuum.

1. Mass is how big you are, Weight is how much force pulls you towards the centre of the Earth.

2. Earth is 150,000,000km from the Sun. The Moon is 385,000km from the Earth. It takes the Earth 365 days to orbit the Sun. It takes the Moon 27 days to orbit the Earth.

3. A comet has an olliptical orbit whereas a planet has a regular orbit.

4. Conditions are difficult for astronauts in space, causing them to need a spacesuit. There is little gravity in space, so astronauts come back feeling weak. The heart also gradually weakens in space. Astronauts are also at high risk from radiation.

5. The lfie cycle of an average star is as follows: Nebula --> Protostar --> Star --> Red Giant --> White Dwarf. The life cycle of a massive star is as follows: Nebuka --> Protostar --> Massive Star --> Super Red Giant --> Supernova --> Neutron Star or Black Hole.

6. The universe began with the Big Bang. Then atoms began to from (mainly Hydrogen and Helium). Protostars and protogalaxies then fromed. Stars and galaxies then fromed. Today we have stars, galaxies, nebulas and black holes.