4.13

how human activity adds to the greenhouse effect:

• burning fossil fuels (as well as cars, factories) leads to more CO2,NO2,SO2
• farming (cows) cause methane (CH4)
• evaporation of water -> water vapour (clouds)
• refrigeration/ solvents/ propellants
--> CFC chlorine, fluorine, carbon C(CL3)F

4.12 - green house effect

4.11

• combustion of fossil fuels (as well as vehicle combustion) gives off sulphur dioxide (SO2)
• When the SO2 combines with H2O in the atmosphere, sulphuric acid is made which leads to acid rain.
• Trees and plants are affected by the acid rain by getting burned
• Ca2+ and mag 2+ are leached from the soil, meaning plants cannot obtain calcium or magnesium that they need to grow
• the ph of lakes is reduced which releases Al3+ ions, which means more fish die. The aluminum forms as a mucus to the fishes gills which decreases the ability for oxygen to get in


• Fossil fuels are burned with an insufficient amount of oxygen resulting in carbon monoxide
• Carbon monoxide is toxic as it attaches to your haemoglobin cells inside your red blood cells which blocks oxygen getting around your body
• does not smell, cannot be seen, can lead to death

4.7

• A pyramid of energy is used
• Reasons for loss of energy:
- respiration
- excretion (energy which has not been able to be digested)
- heat loss
• Since the mouse can only use 10% of the energy from the producer, this would suggest that the owl can only use 1% of the energy it gets from eating the mouse
• When the organisms eventually die, when they will be broken down by micro organisms, which are called decomposers

4.6 : Energy and substances in food chains

producer = Bush grass
primary consumer = Impala
secondary consumer = Leopard
tertiary consumer = Lion

• producer converts light energy into chemical energy
• CE takes the form of different organic molecules such as:
- carbohydrates
- proteins
- lipids

These molecules (called food) consist of
C-H
C-O
C-C
O-H
C-N
bonds
• These bonds represent energy and carbon, hydrogen, oxygen and nitrogen are the matter(substances)

• The substance (the energy in the bonds) is passed down at each stage in the food chain

4.5a: Food chain & 4.5b: Food webs

• Producer -> Primary Consumer -> Secondary Consumer -> Tertiary Consumer

• Only one organism per trophic level
• In a food chain you cannot show an animal as an omnivore (eating at more than one level)
• food chains show the flow of matter and energy

• provides us with a better description of the ecosystem (in this case, feeding)
• Can show feeding at different trophic levels. This can have consequences:
- multiple predators
- feeding on multiple prey
-results in food chains being linked

4.4 Trophic levels

• Trophic = feed


For example: 
A carrot plant (producer) is doing photosynthesis, turning light energy into chemical energy


The carrot fly (a herbivore) is eating the carrot plant, which is called a primary consumer. It takes in the CE of the plant and turn it into CE of the fly


The fly catcher eats the carrot fly (a carnivore), a secondary consumer. It changes the CE once again from one form to another


The sparrow-hawk (top carnivore) eats the fly catcher, a tertiary consumer. It changes the CE again to suit itself


• All these die at some point, where decomposers break the molecules into nitrates and phosphates
• examples of decomposers: fungi, bacteria