Keeping Healthy - 1.4
Pathogens and Disease
Pathogens are micro-organisms (Viruses and bacteria) that cause infectious diseases.
When Bacteria or Viruses enter the body they reproduce rapidly.
Bacteria produce toxins this is what makes you feel ill.
Viruses reproduce in your cells and the damage this causes them makes you also feel ill (as well as the toxins produced).
Learn their repoduction paths.
- Discovered pathogens in his hospital. Told his Staff to wash hands inbetween helping patients. Noticed a decrease in the amoount of child bed fever.
- Other doctors did not take him seriously.
Keeping Healthy - 1.5
List of Defence Mechanisms -
- Skin. Forms a protective, impentrable barrier around body. (Unless it breaks)
- Mucuus. Traps pathogens and 'wafts' them out.
- Stomach Acid. Any pathogens consumed are burnt out
White Blood Cells
- Part of the Immune System.
- They ingest Pathogens (digest and destroy)
- Copy their DNA and on finding another pathogen of that particular type, they send out antibodies to attack the antigens on a pathogen. Destroying antigens kills the pathogen
- Produce Antitoxins to destroy the toxins produced by pathogen. This does not kill the Pathogen, it only neutralises it.
Medicine and Drugs - 3.6
Drugs in Sport
Some Athletes use drugs illegally to increase their performance.
Steroids are drugs that are used to increase muscle mass, however other drugs increase stamina.
Strong painkillers are also banned becasue if the athlete suffers an injury he may not feel it and cause further damage.
Most drugs are very expensive, giving an unfair advantage over those who can't afford them.
Using the drugs can permanently damage the body and leead to death.
Many feel it is unethical to use the drugs to improve performance
Keeping Healthy - 1.2
- It is important for good health to get the energy balance correct
- Mass stays same if energy used equals energy taken in.
- Eating too much causes obesity
- Long-term obesity can cause severe health problems like Type 2 Diabetes (high-blood sugar)
- These can be reduced by less carbohydrate intake and increasing exercise.
- Some people have too little food (starvation). They'll suffer from difficiency diseases due to lack of minerals and vitamins.
Keeping Healthy - 1.6
Using Drugs to Treat Disease
Antibiotics kill infective bacteria in the body.
Penicillin (a common antibiotic) was first discovered by Alexander Flemming in 1928. Discovered in his laboratory after he noticed a substance killing the amount of bacteria in his petri dish.
- Viruses are difficult to kill because they reproduce inside the cell
Painkillers and other drugs, relieve symptoms but do not kill pathogen.
Your immune system will voercome the viral pathogens.
Antibiotics - Penicillin, Amoxicillin
Painkillers - Paracetemol
Keeping Healthy - 1.9
Vaccines - Formed from dead or inactive forms of a pathogen. They are injected into the body, causing white blood cells to ingest them and memorise them. This means they can destroy the pathogen without the body having to suffer from it first. This is called Immunity.
- This is a triple protection vaccine for Measles, Mumps and Rhubella.
It is better to vaccinate children (and adults) because Viruses are hard to kill because they reprouce in cells.
(PAGE 7 Diagram)
Keeping Healthy - 1.10
How Do We Deal With Disease
People in a population need to be vaccinated to prevent epidemics of a serious disease.
Measles for example can lead to long-term damage to your body such as deafness and occasionally death (well that certainly is long term damage...)
Disadvantages of Vaccinations
- Some can cause side-effects.
Overuse of anitbiotics can lead to the developement of new strains of bacteria so Doctors don't subscribe antibiotics to minor infections like sore throats. Scientists are researching new ways to treat disease.
(PAGE 7 diagram)
Co-ordination and Control - 2.1
Responding to Change
- Has recpetors that respond to detect stimuli. These are found in sense organs
- Light stimulates in eye, Sound in the ear, Chemical in the tongue and nose, Temperature, touch and pain in the skin
- The Brain and Spinal Cord form the CNS (Central Nervous System)
- Nerves contain Neurones. Sensory Neurones carry impulses from receptors to the CNS. Motor Neurones carry impulses from the CNS to the Effector Organs (muscle or glands). These respond by contracting - muscles - or secreting chemicals - glands.
Seven Way Path
Stimulas - Receptor - Sensory - Co-ordinator (CNS) - Motor - Effector - Response
Impulse in Neurone - Scas contaain chemicals - Chemicals released between neurone - Receptor Site - Chemicals form a new electrical impulse
Keeping Healthy - 1.7
Growing and Investigating Bacteria
- Pure cultures of non-pathogenic bacteria can be used for laboratory investigations.
- A culture of micro-organisms can be used to find the effect of antibiotics on bacteria
- Investigations need uncontaminated cultures of micro-organisms
- Contaminations might come from your skin, the air, the soil, or the water around you
- If the culture is contaminated other bacteria could grow including pathogens
Culture Growing (Petri Dish Experiment)
- Provide warmth and oxygen. These conditions pathogens like the best.
- Give a liquid or gel containing nutrients - a culture medium. Agar Jelly in a petri dish. It will contain carbohydrates and various other minerals.
- Keep them incubated at 25 degrees c in schools and 35 degrees c in industries.
To keep it pure all the mixture must be killed of all previous baacteria by passing metal loops through a flame and boiling the solutions and agar. You can also prevent microorganism getting into the jelly from the air.
Co-ordination and Control - 2.2
Reflex actions happen without us having to think about it - they arerapid automatic responses to a stimulas, e.g pupils dilating. This means there is a shorter process fro the response to occur.
- Recpetor detects stimulas
- Sensory neuron transmits impulse to CNS
- A relay neuron passes the impulse on
- A motor neuron is stimulated
- The impulse passes to an effector (muscle or gland)
Relay Neurons - Carry impulse from one part of the CNS to the other.
Medicine and Drugs - 3.2
How Effective are Medicines?
- Used in the elderly to lower the amount of 'bad' cholestral.
- Taken daily
- Trials show that incidence of heart disease and strokes has gone down by 40%.
St John's Wort
- A herb which can be taken to counteract depression
- Some people prefer using it over anti-depressants such as Prozac.
- However the only way to be sure it works is to do a double-blind trial.
Co-ordination and Control - 2.7
- Contraceptive Pill. Can plan families
- Others use hormones to become pregnant
- Sometimes used to help older women have babies. May involve using an egg donor.
- Taking hormones for a long time can lead to side effects
- Plant hormones can be used by farmers and gardeners
- Weedkillers kill unwanted plants on lawn
- When cuttings are taken from plants, hormones are used to encourage roots to grow before the cutting is planted
- Hormones encourage fruit to ripen
- If hormones are used incorrectly they can cause damage to the environment e.g weedkillers can harm useful plants.
Co-ordination and Control - 2.5
Body controls the following internal environments -
- Water content
- Ion content
- Blood Sugar Level
We lose water via breath, sweat and urine (excess and produced by Kidneys). We also lose ions in our sweat and urine.
Temperature must be constant otherwise enzymes in the body won't work as efficiently.
Sugar levels must be maintained because they are the energy source for our cells. The level of sugar in our blood is controlled by the pancreas.
Co-ordination and Control - 2.6
Hormones and the Control of Plant Growth
Plants are sensitive to light, gravity and moisture;
- Plants grow towards light. This response is Phototropism
- Plants grow down towards gravity. This response is Gravitropism
- Roots also grow towards water
- There is a positive and negative for all of these. Positive = towards. Negative = away.
- Auxin is the hormone which controls phototropism and gravitropism. An unequal distribution of auxins causes unequal growth. This results in bending of the root or shoot.
- Plant growth hormones can be used as weed killers and to stimulate root growth
- Plant turned on tis side. The auxins instead all sink to 'bottom' of plant. In root, the non-auxin side grows more, so the root bends down. In stem the auxin side grows more so it bends upwards. (Look at diagram on p13)
- Phototropism only happens in stem. It is positive
Adaptation for Survival - 4.8
The Impact of Change
- Changes in environment affect the distribution of species andn organisms. However determining what this change is is difficult.
- Birds may fly further North if the weather gets hotter. This could cause new competition between other birds.
- A large fall in the bee population may have been caused by several factors. These include the use of chemical sprays by farmers, a viral disease or possibly changes in flowering patterns in plants due in turn t oclimate change.
Co-ordination and Control - 2.4
The Artificial Control of Fertility
- Contains oestrogen and progesterone. Oestrogen stops FSH production so no egg is matured. Progesterone lowers side-effects.
- For people who don't want child
- Reduce family size and poverty in some areas. Can plan families
- Can cause side-effects
- Ethical/religious reasons
Fertility Treatment and In Vitro Fertilisation
- For people who cannot produce LH and FSH, it is given. FSH causes eggs to mature, LH causes ovulation.
- For people who want child
- Egg is taken from woman. Sperm donations from man. Fertilized in laboratory. Placed back inside woman.
- Infertile couples can have child
- Expensive and considered unethical. Also low success rate.
Medicine and Drugs - 3.1
Developing New Medicines
A large amount of substances are tested to see if they can cause diseases.
- First tests are in science labs on cells/tissues/organs. Then on animals, then healthy human volunteers, then on patients.
- Healthy people are given low doses
- In some trials placebo's are used. Placebo's do not contain a drug. Half the patients have the drug and the other half don't - this checks if the drug really does have an effect. In a double-blind trial neither doctor nor patient know who has the drug.
Which - check traditional - check synth. chemicals - test cell - animal - h. humans - s. humans - tested on large groups - government - long term human trials continue.
This was a sleeping pill, that some doctors realised helped morning sickness in pregnant women. The pill was pescribed without checking it. The babies were all born with deformities. The drug was banned.
More recently the drug has been used to cure leprosy but never to pregnant women.
Medicine and Drugs - 3.3
When we develop new drugs, we have to test them on people for long periods of time to make sure there are no side effects. nUseful drugs have been used for centuries.
Recreational drugs are used by people for pleasure e.g Heroin and Cocaine. They are not only highly addictive and dangerous but illegal.
Cannabis is also illegal as it is considered a gate way drug to harder substances. It also contains chemicals which can cause mental damage. If you try to stop consuming addictive drugs you will suffer withdrawal symptoms.
Illegal and legal (alcohol, tobacco) drugs can cause harm to your body.
Medicine and Drugs - 3.4
Legal and Illegal Drugs
Medicinal Drugs - These are drugs used to cure illness and disease in people. THey are often only atainable via a prescription from a Doctor and have been developed for years and years.
Recreational Drugs - These drugs are used for pleasure. Often they are illegal due to hazardous health affects and short-term actions on the body whilst under the influence.
They affect the brain and nervous system and slow down responses. It is very easy to become addicted to recreational drugs.
However some are legal. Alcohol, nictoine and caffeine are legal drugs that are used recreationally. However these can still cause problems. Alcohol poisoning, lung cancer.
Some medicinal drugs can be used illegally - steroids in sport.
Medicine and Drugs - 3.5
Does Cannabis Lead to Hard Drugs?
- Cannabis can cause mental illness among some.
- Teenagers who smoke Cannabis increase their risk of getting depression
- Cannabis is illegal
- Because it is illegal, it means that buyers are more likely to become addicted to harder drugs. Cannabis is a gateway drug.
- Not all Cannabis users get on hard drugs, however many do.
- Most Heroin users started by taking Cannabis.
Co-ordination and Control - 2.3
Hormones and the Menstrual Cycle
- FSH (Follicle Stimulating Hormone) is made in the Pituitary Gland and it travels throught the bloodstream and causes an egg in an ovary to mature and Oestrogen to be produced.
- Oestrogen is produced by the Ovaries and inhibits the production of FSH. It starts the production of LH (Luteinising Hormone) and also stimulates the womb lining to deevelop to receive fertillised egg.
- LH is made by the Pituitary Gland (located near the brain) and stimulates the mature egg to be released from the ovary. This is ovulation.
- Progesterone produced by the empty follicle stops LH maintains the lining. If not ferilized then this level will fall. If fertillized it will be continued.
Corpus Luteum - Continues to produce Progesterone and Oestrogen
This cycle last 28 days.
Nervous - Fast acting, short-term effects, travels through nerves as impulses, produced by sensory organs
Hormonal - slow acting, long-term effects, travels through blood stream, produced by glands
Keeping Healthy - 1.8
Mutation - A pathogen (bacteria or virus) that has changed. Very few people are immune to these pathogens so disease spreads quickly. Diseases that spread within a country are called an epidemic. Those that spread internationally are called pandemic.
Antibiotic Resistant Bacteria
The MRSA Super bug is a bacterium that haas evolved through natural selecton. MRSA and other bacteria have become resistant to the common antibiotics.
- Mutations of pathogens produce new strains, some are resistant to anitbiotics
- Anitbiotics kill individual pathogens of the no-resistant strain
- The resistant strain survive and reproduce rapidly and a whole population of a resistant strain developes. This is natural selection.
- Anitbiotics should not be used for mild infections in order to slow down the rate of developement of resistant strains.
Adaptation for Survival - 4.1
Adapt and Survive
Organisms adapt so they can survive their constantly changing habitat. They need materials from their surroundings to survive.
Plants need light, carbon dioxide, soil, water, oxygen and nutrients
Animals need food, water and oxygen
Micro-organisms need different things depending on the species. Some are like plants, some are like animals and some don't need oxygen or light to survive.
Special features of an organism are called ADAPTATIONS.
Plants are adapted to obtain light and food efficiently through photosynthesis.
Animals have mouth parts depending on their diet (carnivore or herbivore).
Most organisms live at temperatures below 40 degrees C so their enzymes do not denature.
Extremophiles are micro-organisms who can survive in extreme temperatures, enzymes don't usually work in these areas.
Adaptation for Survival - 4.3
Adaptation in Plants
Plants need to collect and store water. They can then lose water as water vapour through stomata in the leaves.
Plants have extensive root systems to collect water. Water can be conserved if the plant has small or waxy leaves or a large stem.
Hot Conditions - Cacti
Waxy bodies to retain water. Pins as leaves so as to allow minimal water to escape, and to keep off predators. Extensive root systems.
To prevent animals from eating them, some plants have adpated thorns, poisonous chemicals and warning colours to put animals off.
Adaptation for Survival - 4.4
Competition in Animals
Animals are constantly competing each other for water, space, food and breeding mates.
An animals territory will be large enough to accomodate these things.
Predators compete with prey as they want to eat them. They are both usually camouflaged so as to avoid detection. Prey animals compete with each other to escape from predators and to find food for themselves.
Some animals e.g caterpillars may be poisonous and have warning colours on their bodies.
This is pretty much it.
Adaptation for Survival - 4.5
Competition in Plants
- All plants compete for water, space, light and nutrients. Eg in some woodlands, some plants flower before a tree leaves so as to get maximum light (Snowdrops)
- Plants with deep roots can ensure they get more nutrients and water than those with short roots.
- Some plants spread their seeds over wide areas to ensure they don't compete with themselves.
Some of them are spread via animals.
Some plants use the wind (sycamore) or mini explosions (broom)
Variation, Reproduction and New Technology - 6.1
The nucleus of a cell contains thread-like strucures called Chromosomes - these carry genes.
In the nuclei of Gametes there is only a single set of chromosomes - therefore male and female sex cells only contain one set of genes.
A parents genetic informaton is passed on to the child during reproduction. The offspring contains two sets of inherited genes one from each parent.
In most body cells the chromosomes are in pairs. One set came from the female gamete and one from the male gamete.
Different genes control the growth and development of different characteristics
Adaptation for Survival - 4.2
Adaptation in Animals
- Thicker fur
- Fat under the skin (blubber)
- Some (arctic fox) are white in Winter and brown in the Summer so they camouflage.
- Animals are usually large with small surface area : volume ratios.
- Adapted to conserve water
- Stop them getting too hot
- Can hunt or feed at night when the temperatures are cooler.
- May have a large surface area : volume ratio.
Adaptation for Survival - 4.6
How Do You Survive?
Some animals have very unusal adaptations, particularly suited to their species
- Females have specially shaped heeads for getting into fig tree flowers
- Oviposters that allow them to place the egg deep inside the flower.
- Some male fig wasps wait their entire lives for a female inside a flower.
- Lives undergound and so is blind, it doesn't need sight because there is no light.
- Very sensitive to touch and smell though.
Venus Fly Traps
- Insect eating plants. Sweet, sticky nectar and are bright red to attract flies.
Energy in Biomass - 5.3
All organisms that take up nutrients must eventually release them.
This is the process of Decay
- Detritus Feeders - (types of worm) thesse start decay by eating dead animals or plants and producing waste materials.
- Decomposers - These are Decay Organisms (micro-organisms - bacteria and fungi) that break down the waste or dead palnts and animals. This part of Decay is faster in warm and wet conditions with high amounts of oxygen.
- All of the materials are recycled, sending the nutrients back to the soil.
- Humans can recycle waste in Sewage Treatment Plants and Compost Heaps.
Energy in Biomass - 5.4
The Carbon Cycle
The recycling of Carbon involves Photosynthesis and Respiration.
Photosynthesis removec CO2 from the atmosphere. Green plants as well as animals respire this returns CO2 to the atmosphere.
When trees are cut down and burnt CO2 is released into the atmopshere.
When animals or plants die, micro-organisms release the CO2 trapped in their bodies back into the atmosphere.
A stable community recycles all of the nutrients it takes up.
Look at Diagram p 26 I seem to be doing a lot of that.
Energy in Biomass - 5.5
Recycling Organic Waste
We can recycle organic waste (waste vegetables, peelings, grass cuttings, tree clippings). This can be composed in many ways.
The most efficient is allowing the waste to be mixed with oxygen and moisture. This allows energy to escape by heating the surroundings. We can do this in a Compost Heap
The rate of decomposition in a compost heap can be sped up by the addition of detritus feeders and decomposers. Limestone is added to counteract the acidity of these conditions.
Councillors also colelct garden waste and use shredders and large bins to compose the material.
Look at diagram on p26 again. but you pretty much know it off by heart anyway!
Energy in Biomass - 5.1
Pyramids of Biomass
Biomass is the mass of living material in plants and animals. A Pyramid of Biomass represents the mass of each level in a food chain. Often it is more accurate than a Pyramid of Number.
Green Plants transfer Solar Energy into Chemical Energy and that is passed through the food chain.
(PAGE 24 diagram)
Variation, Reproduction and New Technology - 6.2
Types of Reproduction
- Does not involve the fusion of gametes
- All of the genetic info comes from one parent
- Does not require two organisms
- Little variety because all of the offspring are identical to parent
- Produces clones
- Involves fusion of gametes
- Two organisms required
- Offspring are variated due to mixing of genetic information
- Sex cells are egg and sperm in animals
- Offspring cannot be identical to either parent due to combination of genes.
- The variation of genes is imporant for survival. Some characteristics may give offspring a better chance of survival.
Evolution - 7.2
Accepting Darwin's Ideas
Natural selection was only eventually accepted for these reasons
- The theory of natural selection challenged the idea that God made all the animals and plants on Earth.
- Many weren't convinced because they didn't think there was sufficient evidence.
- Darwin couldn't explain the organism variety or how inheritance worked. 50 years later enes and genetics were discovered.
- Darwin had tried to show that birds (finches) on the Galapagos Islands could change over time if they lived under different environmental conditions. However he could not explain in his lifetime, in terms of genes, why the offspring inherited the useful adaptations.
Insert diagram of birds heads on p34. Two more to go!!
Variation, Reproduction and New Technology - 6.4
Offspring that are genetically identical to the parent are called clones. Plants are very easy to clone unlike animals. Cloning is used to produce new individuals that are useful in farming and agriculture.
In plants the process of cloning can be cheap and effective . Plants can be cloned by taking cuttings and growing them.
Taking small groups of cells from part of a plant and growing them under special conditions (tissue culture) is more expensive. Tissue culture can be used to reproduce large numbers of a rare or top quality plant.
Embryo transplants are used to clone animals. An embryo with unspecialised cells is split into smaller groups of cells. Each group of genetically identical cells is transplanted and allowed to develop in a host animal.
Sometimes animals or plants are genetically modified to produce usefl substances before they are cloned.
Variation, Reproduction and New Technology - 6.5
Adult Cell Cloning
1) First the nucleus is removed from an unfertilised egg cell. The nucleus is removed from the skin cell and placed inside the empty egg cell.
2) The new cell is given an elecric shock which causes it to start to divide. The ball of cells forms an embryo. The mbryo is genetically identical to the skin cell of the adult.
3) Once the embryo has developed into a ball of cells it is inserted into the womb of the host mother. Dolly the sheep - 1997. Look at diagram p 30
- Valuable proteins in the genetically cloned animals milk. Uses in medicine
- Save animals from extinction
- Ethics of cloning
- Limits the variation of a population, natural selection can't occur
- Concerns about using the technique to clone humans in the future.
Variation, Reproduction and New Technology - 6.6
Genetic Engineering - This involves changing the genetic make-up of an organism.
Genes can be transferred to the cells of animals, plants or micro-organisms at an early stage in their development.
- A gene is 'cut out' of the chromosome of an organism using an enzyme. The gene is then placed in the chromosome of another organism.
- The genes may be placed in an organism of the smae species to give it a desired characteristic.
- Sometimes genes are palced in a different species, such as bacterium. For example, the gene to produce insulin in humans can be placed in bacteria. then the bacteria can produce large quantities of insulin to treat diabetes.
New genes can be transferred to crop plants. These are called Genetically Modified (GM) plants. These may be insect - or herbicide - resistant and usually have an increased yield.
Keeping Healthy - 1.1
Diet and Exercise
Carbohydrates, fat and protein are used by the body to release energy and to build cells.
Mineral ions and vitamins are needed to keep the body healthy. An unbalanced diet causes Malnourishment, hence why the United States is the most malnourished country in the world.
The Eatwell Plate - Learn it, but you pretty much know it anyway.
- If you exercise more often, you increase your metabolic rate and you also increase the amount of energy you use. This means that the chemical reactions in cells work faster.
- The proportion of muscle to body fat and your inherited factors can also affect your metabolic rate.
Variation, Reproduction and New Technology - 6.3
Genetic and Environmental Differences
Differences in Characteristics of Individuals of Same Species may be because -
- Difference in inherited genes
- Conditions in which they developed
- Combination of both of these genetic and environmental causes
Genes are the most important factor in controlling an individuals appearance.
Plants are affected by light, nnutrients and space. This can affect the strength between two plants even if they have the same genes
Human developent can be altered in pregnancy if the mother smoke's or drinks excessive alcohol. This can cause a small birth weight.
Amount of ocan alter a humans growth .E.g someone might have the genes to be a good athlete but if they don't have food there will be stunted growth.
Variation, Reproduction and New Technology - 6.7
Making choices about Technology
Advantages of Chlone Engineering
- Cloning cattle can produce cattle with useful characteristics
- Can be used to make copies of the best animals
- If a person has a faulty gene they can have genetic disorders, they can be cured with the correct gene.
- Several medical drugs (Insulin, Antibodies) have been produced.
- GM crops are resistant to Herbicides or to insects
Disadvantages to Chlone and Genetic Engineering
- GM crops have a bigger yield but farmers have to buy new GM seed every year because crops are infertile.
- Some are concerned about accidentally intorducing genes into wild flower populations
- Insects which are not pests may be affected by GM crops
- Effect on human health after eating GM crops
- Ethical? Long-term effecs? Will we create new organisms we don't know anything about? Are these processes ethically correct?
Evolution - 7.3
The organisms most suited to the environment due to particular characteristics are the ones who will survive the longest e.g best camouflage, best eyesight, stronges, quickest, best suited to current climate.
Since all organisms breed, the ones that survive are the most likely to breed successfully - these genes then being passed on to the offspring.
Someetimes a gene accidentally changes a forms a new form of gene. These changes are called mutations. If the mutated gene controls a characteristic which makes the organism better adapted to the environment then it will be passed on to the offspring.
Mutations may be particularly important if the environment changes. For example when the rabbit disease myxomatosis killed most of the rabbits in the UK a few rabbits had a mutated gene which gave them immunity. The rabbits with the mutated gene survived to breed.
Evolution - 7.4
Classification and Evolution
Classificaton - The process of putting organisms into groups. We do this so we can identify the relationships between them. The system we use is called the 'Natural Classification System'.
The largest group is called Kingdoms (Animal Kingdom, Plant Kingdom and Kingdom which contain Micro-organisms).
The smallest groups are Species. Members of a species are very similar and can breed together.
Evolutionary Trees - Models that can be drawn to show the relationships between different groups of organisms. Evolutionary Relationships can be modified if new evidence is found.
Ecological relationships tell us how species have evolved together in an environment.
Adaptation for Survival - 4.7
Measuring Environmental Change
If the environment of an animal changes, then organisms may not be able to live their anymore.
Non-living Factors - Temperature, Rainfall, Light and Oxygen Levels
Living Factors - Arrival of New Predator, Disease, Introduction of new Plants which might provide more food or habitats.
Pollution Indicators and Monitoring
- Lichens. These indicate the level of air pollution (particularly sulfur dioxide). The more lichen, th cleaner the air. They are an indicator species.
- Freshwater Invertebrates. Indicate level of water pollution, in same way as lichens. In particular the concentration of dissolved oxygen in water. The wider the range, the cleaner the water. Some however only live in polluted waters
- Equipment such as rain gauges, thermometers, pH and oxygen sensors and data loggers can be used to monitor non-living changes in the environment.
Evolution - 7.1
Theories of Evolution
Inheritance of Acquired Characteristics
- Jean-Baptiste Lamarck
- Characteristics which develop through an organisms lifetime will be passed on.
- Not believable
- e.g. if parents built up muscle in the gym, the child wouldn't necessarily be muscly. Or go to the gym
- Charles Darwin (afer journey to the Galapagos Islands)
- Small changes in organisms took place over long period of time. Al species vary and so some are more likely to survive than others. Those that are best adapted pass on their characteristics.
- We can now say that 'the best adapteed organisms survive to breed'. It is the better varied that pass on the genes.
Energy in Biomass - 5.2
Bewteen each stage of the food chain there is energy wasted - this means that not all energy taken in by an organism results in the groth of that organism.
- Since not all food can be digested, faeces and urea contain quite a large proportion.
- Some of the energy is used in respiration which releases energy for living purposes
- Movement requires energy. THe more an object moves the less energy available for growth.
- Animals that need a constant temperature use energy simply to complete this.
- Most energy released in respiration is tranfered to the surroundings.
We can use a Sankey Diagram to show how the energy is being used. So take a peek at the Sankey Diagram examples on p 25 if you get chance! ;)