1. Topic 3 – Problems of and solutions to a changing environment
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Topic 3 – Problems of and solutions to a changing environment

2. Introduction to Drugs
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Drugs are classed as “a substance that affects the central nervous system, causing changes in psychological behaviour and possibly addiction”. Some examples:
Type of drug
Effects
Examples
Painkiller
Block nervous impulses
Morphine, aspirin
Hallucinogen
Distort sense perception
LSD
Stimulant
Increase reactions
Caffeine
Depressant
Slow down brain activity
Alcohol

3. Investigating Reaction Times
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Task: Design an experiment that investigates the affect of caffeine on reaction times.
Variables: What are the independent, dependant and control variables?
Results: Draw your own results table:
Conclusion: What do your results show you?

4. Smoking Cigarettes contain 3 harmful things:
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Cigarettes contain 3 harmful things:
NICOTINE, which is an ___________ drug that raises the heart beat, narrows the arteries and so causes ____ _____ _____. This leads to heart _________.
TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause ______________.
CARBON MONOXIDE, which is a _______ ____ which joins up with ____ blood cells making them incapable of transporting _____________ around the body. In pregnant women it can cause oxygen deprivation, leading to low birth ______.
Words – high blood pressure, oxygen, red, addictive, disease, poisonous gas, lungs, cancer, mass

5. Tobacco and Lung Cancer
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Smoking has existed in Western culture since the 16th Century. However, scientists only proved the link between it and various diseases shortly after the Second World War.
Sir Richard Doll,
Over 50 years I proved the link between smoking and lung cancer. I published my first findings in 1950, based on patients in London hospitals, and then studied 40,000 doctors and proved a link in a paper published in 1954.

6. Cancer Research UK statistics
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What do these statistics imply?

7. The spread of infection
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Ignaz Semmelweiss
Guten tag. In the mid-19th century I realised that many deaths in hospitals could be avoided by insisting on clean hands and equipment. As a result of my work deaths in my wards fell from 12% to 1%.
More people die due to infections from hospitals than on the roads in Britain. Hospitals have been trying to improve hygiene standards:
Year
Amount of hand wash solution used (litres per 1000 patient days)
MRSA infections per 100 patients
1993
3.5
0.50
1995
6.9
0.48
1997
10.9
0.25

8. Vaccinations
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Some people argue that the MMR vaccine is a good idea, others think it is a bad idea. Briefly summarise each side of the argument:
MMR vaccine
For
Against

9. Tuberculosis
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Tuberculosis is a bacterial disease caused by “mycobacterium tuberculosis”. It usually affects the lungs and the bacteria are spread in coughs and sneezes.
TB bacteria can cause cavities or lumps in the lungs
No. of cases of TB in Britain
Year
140,000
1953
National vaccination starts

10. Researching new medicines
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Before new drugs can be approved they have to go through three stages:
1. Is it toxic? Tests are done on animals
2. Is it safe for humans? Human volunteers trial the drug
3. Does it work? People with the illness are tested on

11. HIV and AIDS
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HIV stands for Human Immunodeficiency Virus, and can be undetected for years before developing into....
AIDS, which stands for Acquired Immune Deficiency Syndrome.
Graph showing HIV and AIDS trends in the UK.

12. Is the infection a big risk?
Vaccination Policies
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Is the infection a big risk?
Is the vaccine safe?
Factors to consider
about vaccinations
Who is at risk?
How much does it cost?

13. Developing new drugs
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Before a new drug can be approved it has to go through a strict testing process. Consider the example of thalidomide:
Date
Event
Mid 1950s
Late 1950s
Early 1960s
Mid 1960s
Animal testing using thalidomide was undertaken. Tests showed that it was safe but the tests were “inadequate” – no tests were done on pregnant animals
Thalidomide prescribed to pregnant mothers to help sleep and morning sickness problems
Babies are born with birth defects and the drug was banned worldwide. Around 12,000 deformed Thalidomide babies born, 4,000 die in first year.
Tests show that Thalidomide can help leprosy sufferers and it is still used today for this purpose.

14. Placebos Clinical trials can be done in different ways:
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Clinical trials can be done in different ways:
1) Blind trials
Patients do not know which drugs they are taking – a real drug or a “placebo”
2) Double blind trial
Neither the doctors or the patients know if they are taking the real drug
Placebos offer anethical dilemma as a patient might be sick and still be given a “dummy” pill. Also, you might notice if you had a placebo as you wouldn’t get the side effects of normal drugs...

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Malaria

16. Drugs Research Project
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Explain and give examples for the following:
Why do people use legal drugs?
What are the drawbacks of legal drugs?
Alchohol is a legal drug. What does it do to the human body?
Why do people use illegal drugs?
What are the drawbacks of illegal drugs? What can they cause?
Find out which drugs are in which classes

17. The Effects of Alcohol Time Effects Short term Long term
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Time
Effects
Short term
Long term
Blurred vision, lowering of inhibitions, slowing of reactions
Liver cirrhosis, brain damage

18. Organ Transplants
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It is possible to perform transplants of major organs, including:
I don’t think organ transplants should be allowed because if people damage their lungs by smoking then it’s their fault.
The lungs
The heart
What do you think?
The liver

19. Pathogens
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Pathogens are microbes (micro organisms) that can cause diseases. They can enter the body in a number of ways:
They can be breathed in through the mouth or nose
They can enter through cuts or bites in the skin
…or other natural openings…

20. Spreading of Pathogens
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Diseases and pathogens can be spread by a number of means, including:
Salmonella bacteria, found in food
Cholera bacteria, spread in water
Athlete’s foot, a fungus spread through contact
Influenza virus, spread through the air
HIV, spread through body fluids
Malaria, spread through “vectors”, e.g. mosquitoes

21. Microbes: our defence against them
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Our bodies have defence mechanisms against invading microbes:
The breathing organs have hairs and produce mucus to cover the lining of these organs and trap the microbes
Tears contain lysozyme, an enzyme that kills bacteria
The skin acts as a waterproof barrier
The stomach contains hydrochloric acid, which kills bacteria
If our skin is cut platelets seal the wound by clotting

22. Rainforest medicines
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Many plants contain chemicals that have natural antibiotics effects in order to defend themselves. Many of these substances can be used by humans.

23. Using Antibiotics
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1) Overuse of antibacterials can lead to bacteria becoming resistant (e.g. the MRSA “superbug”). This means that antibiotics must be used sparingly.
2) Antifungals can be used to treat fungal infections like Athlete’s foot

24. Resistance to antibiotics
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Although vaccinations and antibiotics are useful in the fight against pathogens, bacteria and virii can mutate to form a new, resistant “strain”:
Mutation – some strains of bacteria can develop _______ to the antibiotics.
The non-resistant bacteria are _____ by the _______.
The resistant bacteria _______ and pass on their mutations to their ______. Don’t use antibiotics unless you need to!!
Bacteria
No effect!!
Penicillin
Words – offspring, resistance, killed, antibiotics, reproduce

25. The rise of MRSA
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No. of MRSA cases
Year

26. Growing micro organisms
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Method:
1) Sterilise the inoculating loop
2) Dip the loop in the bacteria and spread it across the agar
3) Secure (but don’t seal) the lid with tape
Questions:
Why are you sterilising the loop?
What does the agar do?
Why is the lid not sealed all the way around?
What can you now do to investigate the affect of antibiotics?

27. Food chains
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A food chain shows where the biomass or energy goes in a food chain (in other words, “what gets eaten by what”):
Rabbit
Cabbage
Fox
Stoat
The arrows indicate where the energy is going
Plants convert the sun’s energy into food through photosynthesis

28. Pyramids of biomass
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In this food chain we can see that the mass of organisms in each stage is less than in the previous stage:
Cabbage
Rabbit
Stoat
Fox
We can draw a “Pyramid of Biomass” to show this pattern:
Mass of foxes
Mass of stoats
Mass of rabbits
Mass of cabbages

29. Energy flow in a food chain
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Consider the energy flow in this food chain:
100%
10% 1%
0.1%
Cabbage
Rabbit
Stoat
Fox
Clearly, not all of the ___’s energy that becomes stored in the _______ will end up in the fox. Only around ______ is passed on to the next stage in each food chain.
Energy is lost to the surroundings at each stage because of a number of reasons:
Each organism has to ____, keep warm etc
Energy is lost through faeces (______)
Words – 10%, move, sun, waste, cabbage

30. Interdependent Relationships
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1) Parasitic relationships
Parasites take food from another living host _______. For example, if a human eats pork infected with bladderworm the worms attach themselves to the ___ wall and a young tapeworm grows, which _______ food from the gut.
Mutualistic relationships are when two organisms benefit from each other. For example, pea plants have nitrogen-fixing ______ which convert nitrogen into nitrates for plant _____. The bacteria benefit by taking sugars from the plant for ___________.
Words – growth, respiration, organism, gut, bacteria, absorbs
2) Mutualistic Relationships

31. Interdependent Relationships
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Task: Find out about other examples of parasitism and mutualism. Find two further examples of each and explain how each of the organisms depends on the other.

32. Global Population Changes
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Q. What do you think the following graph would look like?
10,000BC
8,000BC
6,000BC
4,000BC
2,000BC
2000AD
Global Population

33. Global Population Changes
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Statistics from Wikipedia:
The world’s population is currently growing by 1,000,000,000 people every years

34. Population and Pollution
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Population
Time
The human population is growing exponentially:
This has a number of effects on the environment:
Farming –
less land available for crops
Building –
more buildings needed
Bigger population means…
Pollution –
More phosphates, nitrates, CO2 and SO2
Waste –
more waste needs to be disposed of

35. Eutrophication
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Yet another example of pollution, eutrophication is when lakes become stagnant due to careless use of fertiliser. There are six steps:
1) Inorganic fertilisers used on fields are washed into the lake
3) This growth causes overcrowding and many plants die due to lack of enough light or food
2) The fertiliser causes increased growth in water plants

36. Eutrophication Can’t…breathe…
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4) Microorganisms and bacteria increase in number due to the extra dead material
6) The lack of oxygen causes the death of fish and other aquatic animals
Can’t…breathe…
5) These microorganisms use up the oxygen in the lake during respiration

37. Eutrophication
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4) Microorganisms and bacteria increase in number due to the extra dead material
6) The lack of oxygen causes the death of fish and other aquatic animals
5) These microorganisms use up the oxygen in the lake during respiration

38. Pollution Indicators Lichens can be used as air pollution indicators:
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Lichens in very clean air
Lichens can be used as air pollution indicators:
Lichens in clean air
Lichens in slightly dirty air

39. Pollution Indicators
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In dirty water leeches and midges will survive
The quality of water can be monitored by looking at the species of insect in the water:
In average water more species (like the dragonfly and cranefly) will survive
In clean water a lot more species (like the mayfly and caddisfly) will survive

40. Reducing Pollution by Recycling
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Reasons why recycling is good
Reasons why recycling is bad
Still requires energy
Reduces demand for raw materials
Recycling
Paper, metal and plastic can be recycled
Requires money to sort and recycle
Reduces the amount of rubbish going to landfill sites

41. Recycling ourselves Eating Waste Death Absorption Broken down
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Eating
Waste
Death
Absorption
Broken down
Microbes are the key to this – they break down waste and dead bodies so that the products can be used by plants for growth. Microbes work best in warm, moist conditions where there is plenty of oxygen.

42. The Carbon Cycle CO2 in air
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2. Plants and algae release CO2 through respiration
Burning fossil fuels also releases CO2
CO2 in air
1. CO2 is taken in by plants and algae for photosynthesis and turned into carbohydrates, fats and proteins
6. These microbes also release CO2 through respiration
4. Animals release CO2 through respiration
5. Animals (and plants) die and their remains are fed on by microbes and detritus feeders
3. The carbon taken in by plants is then eaten by animals and the animals that eat them

43. The Nitrogen Cycle N2 in air
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4. Denitrifying bacteria convert nitrates and ammonium compounds into atmospheric nitrogen
N2 in air
1. Nitrogen-fixing bacteria convert N2 in the air into nitrates
1. Fertilisers
Denitrifying bacteria
Lightning
Waste and dead animals
5. Nitrifying bacteria convert ammonium compounds into nitrates
6. Nitrates taken in by plants
Nitrates in the soil
3. Decomposers break down waste products and dead animals and plants to form AMMONIUM COMPOUNDS
2. Plants are then eaten by animals – the nitrogen becomes PROTEIN