File - singhscience

download report

Transcript File - singhscience

07/04/2016
Topic 3 – Problems of and solutions
to a changing environment
Introduction to Drugs
07/04/2016
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
Investigating Reaction Times
07/04/2016
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?
Smoking
07/04/2016
Cigarettes contain 3 harmful things:
1. NICOTINE, which is an ___________ drug that raises the
heart beat, narrows the arteries and so causes ____
_____ _____. This leads to heart _________.
2. TAR, which coats the lining of the _______ making them
less able to take in oxygen. It also contains carcinogens
which cause ______________.
3. 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
Tobacco and Lung Cancer
07/04/2016
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.
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.
Sir Richard
Doll, 1912-2005
Cancer Research UK statistics
07/04/2016
What do these statistics imply?
The spread of infection
07/04/2016
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%.
Ignaz Semmelweiss
1818-1865
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
Vaccinations
07/04/2016
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:
For
Against
MMR vaccine
Tuberculosis
07/04/2016
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
140,000
National
vaccination
starts
1953
Year
Researching new medicines
07/04/2016
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
HIV and AIDS
07/04/2016
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.
Vaccination Policies
07/04/2016
Is the
infection a
big risk?
Is the
vaccine
safe?
Factors to consider
about vaccinations
How much
does it
cost?
Who is at
risk?
Developing new drugs
07/04/2016
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
Animal testing using thalidomide was undertaken.
Tests showed that it was safe but the tests were
“inadequate” – no tests were done on pregnant animals
Late 1950s
Thalidomide prescribed to pregnant mothers to help
sleep and morning sickness problems
Early 1960s
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.
Mid 1960s
Tests show that Thalidomide can help leprosy
sufferers and it is still used today for this purpose.
Placebos
07/04/2016
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...
Malaria
07/04/2016
Drugs Research Project
07/04/2016
Explain and give examples for the following:
1) Why do people use legal drugs?
2) What are the drawbacks of legal drugs?
3) Alchohol is a legal drug. What does it do to the human
body?
4) Why do people use illegal drugs?
5) What are the drawbacks of illegal drugs? What can they
cause?
6) Find out which drugs are in which classes
The Effects of Alcohol
Time
Short term
Long term
07/04/2016
Effects
Blurred vision, lowering of inhibitions,
slowing of reactions
Liver cirrhosis, brain damage
Organ Transplants
It is possible to perform transplants of major organs,
including:
The lungs
The heart
I don’t think organ
transplants should be
allowed because if
people damage their
lungs by smoking then
it’s their fault.
What do you think?
The liver
07/04/2016
Pathogens
07/04/2016
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
…or other
natural
openings…
They can enter
through cuts or
bites in the skin
Spreading of Pathogens
07/04/2016
Diseases and pathogens can be spread by a number of means,
including:
Salmonella
Cholera
bacteria,
bacteria,
found in food
spread in
water
Influenza virus,
spread through
the air
Malaria, spread
through
“vectors”, e.g.
mosquitoes
Athlete’s foot, a
fungus spread
through contact
HIV, spread
through body
fluids
Microbes: our defence against them
07/04/2016
Our bodies have defence mechanisms against invading
microbes:
Tears contain
lysozyme, an enzyme
that kills bacteria
The skin acts as
a waterproof
barrier
If our skin is
cut platelets
seal the wound
by clotting
The breathing
organs have hairs
and produce mucus
to cover the lining
of these organs and
trap the microbes
The stomach contains
hydrochloric acid,
which kills bacteria
Rainforest medicines
07/04/2016
Many plants contain chemicals that have natural antibiotics
effects in order to defend themselves. Many of these
substances can be used by humans.
Using Antibiotics
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
07/04/2016
Resistance to antibiotics
07/04/2016
Although vaccinations and antibiotics are useful in the fight
against pathogens, bacteria and virii can mutate to form a new,
resistant “strain”:
1) Mutation – some strains of
bacteria can develop _______
to the antibiotics.
Bacteria
No
effect!!
Penicillin
2) The non-resistant bacteria
are _____ by the _______.
3) The resistant bacteria
_______ and pass on their
mutations to their ______.
Don’t use antibiotics unless
you need to!!
Words – offspring, resistance,
killed, antibiotics, reproduce
The rise of MRSA
No. of
MRSA
cases
Year
07/04/2016
Growing micro organisms
07/04/2016
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:
1) Why are you sterilising the loop?
2) What does the agar do?
3) Why is the lid not sealed all the way around?
4) What can you now do to investigate the affect of antibiotics?
Food chains
07/04/2016
A food chain shows where the biomass or energy goes in a
food chain (in other words, “what gets eaten by what”):
Cabbage
Rabbit
Plants convert the sun’s
energy into food through
photosynthesis
Stoat
Fox
The arrows indicate where
the energy is going
Pyramids of biomass
07/04/2016
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
Energy flow in a food chain
07/04/2016
Consider the energy flow in this food chain:
100%
10%
Cabbage
Rabbit
1%
Stoat
0.1%
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:
1) Each organism has to ____, keep warm etc
2) Energy is lost through faeces (______)
Words – 10%, move, sun, waste, cabbage
Interdependent Relationships
07/04/2016
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.
2) Mutualistic Relationships
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
Interdependent Relationships
07/04/2016
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.
Global Population Changes
07/04/2016
Global Population
Q. What do you think the following graph would look like?
10,000BC
8,000BC
6,000BC
4,000BC
2,000BC
0
2000AD
Global Population Changes
07/04/2016
Statistics from Wikipedia:
The world’s population is currently growing by 1,000,000,000
people every 10-15 years
Population and Pollution
The human population is
growing exponentially:
07/04/2016
Population
Time
This has a number of effects on the environment:
Farming –
less land available
for crops
Waste –
more waste needs
to be disposed of
Bigger
population
means…
Building –
more buildings
needed
Pollution –
More phosphates,
nitrates, CO2 and SO2
Eutrophication
07/04/2016
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
Eutrophication
4) Microorganisms and
bacteria increase in number due
to the extra dead material
07/04/2016
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
Eutrophication
4) Microorganisms and
bacteria increase in number due
to the extra dead material
07/04/2016
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
Pollution Indicators
07/04/2016
Lichens can be used as air
pollution indicators:
Lichens in clean
air
Lichens in very
clean air
Lichens in slightly
dirty air
Pollution Indicators
07/04/2016
The quality of water can be monitored
by looking at the species of insect in
the water:
In dirty water
leeches and midges
will survive
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
Reducing Pollution by Recycling
07/04/2016
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
Reduces the amount of
rubbish going to landfill sites
Requires money to
sort and recycle
Recycling ourselves
07/04/2016
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.
The Carbon Cycle
Burning
fossil fuels
also releases
CO2
6. These microbes
also release CO2
through
respiration
5. Animals (and plants)
die and their remains
are fed on by microbes
and detritus feeders
CO2 in air
4. Animals
release CO2
through
respiration
07/04/2016
2. Plants and algae
release CO2 through
respiration
1. CO2 is taken in
by plants and
algae for
photosynthesis
and turned into
carbohydrates,
fats and proteins
3. The carbon taken in
by plants is then eaten
by animals and the
animals that eat them
The Nitrogen Cycle
Waste and
dead animals
N2 in air
5. Nitrifying
bacteria
convert
ammonium
compounds
into nitrates
3. Decomposers break down
waste products and dead
animals and plants to form
AMMONIUM COMPOUNDS
1. Nitrogen-fixing
bacteria convert
N2 in the air into
nitrates
1. Fertilisers
4. Denitrifying
bacteria convert
nitrates and ammonium
compounds into
atmospheric nitrogen
07/04/2016
6. Nitrates
taken in by
plants
Nitrates
in the soil
2. Plants are then
eaten by animals –
the nitrogen
becomes PROTEIN