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iGCSE Double award Biology Part 2 Key word challenge…… What happens when you have a vaccination? • • • • • • Antigen Immunity Immunisation Immune response Vaccination Pathogen How many keywords can you include in your explanation? What are antibiotics and how do they work? • Can you name any antibiotics? • Do you know who discovered penicillin? Antibiotics • Antibiotics, including penicillin, are medicines that help to cure BACTERIAL diseases by killing the infective BACTERIA inside the body. Why don’t antibiotics work when you have a virus e.g. a cold? Antibiotics There are 2 reasons why you can’t take antibiotics for a viral infection e.g. a common cold. 1. Most Antibiotics work by destroying the cell wall of the pathogen- viruses don’t have a cell wall. 2. Viruses live and reproduce inside your living cells. It is very difficult to develop a drug that kills viruses without damaging the body’s cells What about painkillers? What do they do? Painkillers help to relieve the symptoms of infectious disease but they DO NOT kill the pathogens. Have we always protected ourselves against disease in the same way as we do today What happens when pathogens mutate? Pathogen Infectious disease Bacteria Salmonella, cholera, tuberculosis, tetanus, MRSA Virus Flu, chicken pox, AIDS, Hepatitis B, Measles Fungus Thrush, athletes foot Protozoa Malaria, dysentery Finnish your medicine!!! • What happens inside your body when you take antibiotics? • What happens if you don’t finish the course? What is a mutation? How and why do mutations happen? Mutation • The word mutation means a change in the genetic composition of a cell. Mutations can be divided into two main groups. • The first group is gene mutations. • The second is chromosome mutations. What causes mutation? • • • • • Spontaneous Increases caused by environmental factors UV light X-rays Mutagens – chemicals such as benzene, formaldehyde, carbon tetrachloride Antibiotic resistant bacteria • Many strains of bacteria – INCLUDING MRSA – have developed RESISTANCE to antibiotics as a result of a mutation, leading to natural selection. • Why is this a problem? • What must we do to prevent more strains of bacteria becoming resistant? – Not overuse antibiotics – Don’t use to treat mild infections like sore throat – Ensure that people complete their whole course of antibiotics. MRSA Methicillin Resistant Staphylococcus Aureus Staphylococcus aureus is a bacterium often found in 20-30% of the noses of normal healthy people and is also commonly found on people's skin. Staphylococcus aureus which are resistant to an antibiotic called methicillin are referred to as methicillin-resistant Staphylococcus aureus or MRSA. Many commonly prescribed antibiotics are not effective against these bacteria www.mrsa.uk.com MRSA MRSA may occasionally get into the body (eg through breaks in the skin such as abrasions, cuts, wounds, surgical incisions or indwelling catheters) and cause infections. These infections may be mild (eg pimples or boils) or serious (eg infection of the bloodstream, bones or joints). Why is MRSA causing such a problem in our hospitals? How can we help reduce these problems? Pandemics, Epidemics Pandemic: A disease prevalent throughout an extensive region, country, or continent, or throughout the world. E.g. SARS, Swine flu http://www.cdc.gov/vhf/ebola/outbreaks/2014-westafrica/ Epidemic: The occurrence of disease within a specific geographical area or population that is in excess of what is normally expected. E.g. Foot and Mouth, Plague Why did Swine flu cause such a scare across the world, even to those people who have had the flu vaccine? Why is it so hard to stop the spread of a new, mutated disease? Whiteboards at the ready……. How can we find out more about pathogens which cause diseases? Step by step method • Hints – How do you keep everything sterile? – Why do you need to let the inoculating loop cool? – Why should you not take the lid completely off the agar plate? – Why do you secure the lid with 3 pieces of selotape? – Why can you not incubate above 25oC in school laboratories? – Why do they incubate at a higher temperature in industry? Photosynthesis……? ☼ What do you already know? Learning Objectives: • To give the equation for photosynthesis • To explain why plants are green • To describe where the energy comes from and how it is used Plant cell • To explain why plants are green Why am I green? Think Find out Discuss Photosynthesis • Photosynthesis is summarised by the following equation: ………………. + …………….. …………....+ …….……….. Formula equation (2 minute challenge for 10 VIVOs) Where do plants get their energy from and how do they use it? What factors limit the rate at which photosynthesis takes place? • The rate of photosynthesis may be limited by: – Low temperature – Shortage of carbon dioxide – Shortage of light • Annotate these graphs to describe what is happening • Working with your given partner, you need to give a clear EXPLAINATION of each graph Is the rate of photosynthesis in a normal plant effected by just one of the factors? • No • Light, temperature and availability if carbon dioxide interact and, in practice, any of them may be the factor that limits photosynthesis. If you were a crop farmer using a greenhouse, what would you do to increase your yield? • • • • Artificial light Artificial heat Additional Carbon Dioxide ….Why would paraffin lamps be good to use? • What are the pros and cons of your approach? Used for respiration Converted into fats, oil or protein in storage organs e.g. nuts & seeds Converted into starch & stored in fruits and roots Converted into cellulose & used in cell walls Become nitrates which are used to make proteins Where do I store my starch? • STARCH????? What is it? What is it made from …… • How could we test for starch? • Predict – where do you think you would find the most starch in a plant? If you were a crop farmer using a greenhouse, what would you do to increase your yield? • • • • Artificial light Artificial heat Additional Carbon Dioxide ….Why would paraffin lamps be good to use? • What are the pros and cons of your approach? How are plants specially adapted to be good at obtaining the substrates they need? Guard Cells make a pore called a stomata. Carbon dioxide enters the leaf through the stomata by diffusion. Inside the leaf= lower concentration of carbon dioxide Outside the leaf= higher concentration of carbon dioxide Can you label the cross section of this leaf? What do the different transport tissues carry? Ext - Which parts of the leaf are important to consider for transpiration? Why is it important that plants have guard cells? Where would you find the most stomata? WHY? What happens to the water once it has been absorbed via the roots? • What has happened to your celery? Plant hormones • What are they? • What effect do they have on plants? Plant hormones • • • • What are plant growth hormones called? What are plant growth hormones used for in agriculture? What are the pros and cons of using plant hormones as a weed killer? What are the pros and cons of using plant hormones to help roots develop artificially? Why are we like we are? 5 key words you must include….. • Gametes • Fertilisation • Chromosome • Environment • Genes Chromosomes, genes and DNA • Chromosome – rod shaped body found in the nucleus of cell which contains genetic information (DNA). Humans have 46 chromosomes. All animals and plants have a different number of chromosomes. • Gene - A gene is a section of DNA that carries the code for a particular protein. Different genes control the development of different characteristics of an organism. Many genes are needed to carry all the genetic information for a whole organism. Chromosomes, which are found in the nucleus of the cell, contain many genes. • DNA – Deoxyribonucleic Acid. What so these cells have to do with inheritance? Human Karyotype • Look at the human karyotype. • How many individual chromosomes are there? • How many pairs of chromosomes are there? – Note that one chromosome from each of the pairs comes from the mother and one from the father. What are the causes for the differences between us? • Genetics (i.e. our DNA coding) • Environmental • You need 3 examples of each of these causes. What causes these hairstyles? http://www.telegraph.co.uk/news/health/318 3666/Genetic-link-to-baldness-discovered.html Could you apply this to plants? Variation Variation can come about for two reasons: 1. Some features can be inherited. That means that you get them from your parents and they are controlled by genes 2. Other features are affected by the environment. 3. Lots of features are a combination of both Examples? –To recall and explain the 2 factors which influence who and what we are Genetic or environment? Inherited from parents Big muscles fashion sense Eye colour Caused by environmental factors Natural hair colour Lung cancer Sickle cell anaemia 23 chromosomes Egg cell from mother containing exact replica of 50% of mothers DNA 23 chromosomes Sperm cell from father containing exact replica of 50% of fathers DNA 23 chromosomes 1 from each homologous pair 23 chromosomes NOTE - the parental chromosomes carry the genes which determine the characteristics of the child. 1 from each homologous pair 46 chromosomes 23 chrom. from mother + 23 from father giving 46 chromosomes which carry the DNA for the new person. Reproduction!!!??!! • Sexual reproduction vs. Asexual reproduction Sexual Reproduction – Where a male and female gamete fuse together. The genetic information from the two parents are mixed together leading to variety in the offspring. Asexual Reproduction – Only one individual is needed as the parent. There is no fusion of gametes and therefore there is no mixing of genetic information. As there is no mixing of genetic information all the offspring are exactly the same, these genetically identical individuals are known as CLONES • What type of reproduction does this picture show? • What can we call the offspring? • What could we conclude about the offspring? What are the benefits of sexual and asexual reproduction? Sexual Asexual From Mendel to DNA Starter • What can you tell me about Mendel? Keywords for the topic! 1. 2. 3. 4. 5. 6. 7. 8. 9. Chromosome Gene Allele Dominant Recessive Genotype Phenotype Homozygous Heterozygous Find an expert! You have 2 mins to familiarise yourself with these words before we begin! Terms to know A GENE is a section of DNA which codes for a specific protein and therefore characteristic. There are different versions of one gene and these are called ALLELES When there is more than 1 version of a gene the cell will have a preferred choice which is called the DOMINANT gene (allele) and the unused allele is called the RECESSIVE GENE. •For the recessive gene to be expressed, the individual must be homozygous for that gene (both alleles the same). •If a person has two different alleles then they are heterozygous for that gene. •What you see (is expressed) is the PHENOTYPE e.g. Tall •What the genes are is the GENOTYPE e.g. TT or Tt Why does sexual reproduction give rise to variation? The Work of Gregor Mendel What does this show? x F1 F2 Crossed together a tall pea plant and a dwarf pea plant The resulting offspring are all tall F2 generation were present in the ratio 3:1 tall to short From this experiment Mendel made three important conclusions: 1. That the inheritance of a trait is determined by units (now called genes) that are passed to descendents. 2. An individual inherits one unit from each parent for each trait. 3. That a trait may not show up in an individual but can still be passed on to the next generation. GENE- is a small section of DNA, an inheritable unit of information coding for a particular trait e.g. height This experiment also show us the tall gene is dominant (will be expressed) over dwarf gene. Different forms of the same gene are called alleles. Inheritance in action! • • • • • • Write a sentence on your whiteboard which contains AT LEAST one of the words below. ** 10 VIVOS if you can include them all!** Chromosome DNA Gene Allele Dominant Recessive COPY A Chromosome Each gene codes for a particular Gene with different alleles (Heterozygous) combination of amino acids which makes a Attachment point (not a specific gene): Centromere protein. Therefore genes are responsible Gene with identical for your alleles (Homozygous) different features Dominant and recessive • An allele that controls the development of a characteristic when it is present on only 1 of the chromosomes is a DOMINANT ALLELE • An allele that controls the development of characteristics only if the dominant allele is not present is a RECESSIVE ALLELE. Do a genetic cross diagram for the following situation. Black is the dominant allele Parent One: Black mouse, Genes: BB Parent Two: Brown mouse, genes bb What are the ratios of the offspring coat colour? Do a genetic cross diagram for the following situation. Parent One: Black mouse, Genes: Bb Parent Two: Brown mouse, genes bb What are the ratios of the offspring coat colour? Dimples are controlled by a dominant gene The father has dimples but the mother does not. The father is heterozygous for dimples. What is chance of their first child having dimples? What is the chance that their second child will have dimples? Another couple, who both have dimples, have a baby, which does not have dimples. What are the genotype of the parents? Why does sexual reproduction give rise to variation? How is the sex of a baby determined? Human Chromosomes Humans have 46 chromosomes (23 pairs) one set of 23 inherited from their mother another set of 23 from their father. 22 pairs are autosomal chromosomes this mean they contain genes to all the body. The 23rd pair are the sex chromosomes for determination of sex. In females, the sex chromosomes are the same (XX), in males the sex chromosomes are different (XY). Is this person male or female? Sex Determination Parents Phenotype: Male x Female Genotype: XY x XX What are the chances of having a boy? Father gametes X Y XX= female XY= Male Mother X XX XY X XX XY 50% Chance of having either a boy or girl The sex of a baby is determined by the father DNA Fingerprinting…? Genetic Crosses Mother is homozygous for blue eyes, Father is heterozygous for green eyes, other allele is for blue eyes. Green is dominant over blue. Calculate the ratios of their children’s eye colour Parents Phenotype: Let = green = blue Parents Genotype: gametes Mother Father Polydactyly disease • • • • Cause – Which system in the body does it effect? Symptoms Outcome - Having extra fingers and/ or toes, caused by an dominant allele of a gene. It can therefore ONLY be passed on by a parent who has the disorder If 1 parent is heterozygous for the disease, what is the percentage chance the children will have it? Cystic Fibrosis • • • • Cause – Which part of the body does it effect? Symptoms Outcome - Disorder of cell membranes. Must be inherited from both parents and is caused by a recessive allele of a gene. It can therefore be passed on from parents, neither of whom have the disease. Parents can be CARRIERS of the disease. Sickle-cell anaemia • • • • Cause – Which part of the body does it effect? Symptoms Outcome - An inherited condition affecting red blood cells. Must be inherited from both parents and is caused by a recessive allele of a gene. It can therefore be passed on from parents who are CARRIERS of the disease. Heterozygous people will have some protection against malaria. Down’s syndrome • • • • Cause – Which part of the body does it effect? Symptoms Outcome - Extra copy of chromosome 21 so that the baby has 47 chromosomes. Can cause developmental problems in many different areas including the brain, heart and muscles If both parents are heterozygous for the Cystic Fibrosis gene, what is the percentage chance of their children having the disease? Exam questions (3 marks) • Mr and Mrs Smith both have a history of cystic fibrosis in their families. Neither of them has cystic fibrosis. Mr and Mrs Smith are concerned that they may have a child with cystic fibrosis. • Use a genetic diagram to show how they could have a child with cystic fibrosis. • Use the symbol A for the dominant allele and the symbol a for the recessive allele. Inheritance of Colour (red-green) Blindness- Sex Linked Sex linked genes only present on X chromosome Y X XX= Female 8% men affected but only 0.5% women Gene for colour blindness is carried on the X-chromosome, it is a recessive gene. XY= Male X1 = X-chromosome with the affected allele for colour blindness So… why is it more common for boys to be colour blind? Inheritance of Colour (red-green) Blindness- Sex Linked X 1Y Colour blind XY Normal Vision XX Normal Vision X 1X Carrier Father M o t h e r X1 Y X X1 XY X X1 XY Daughters are carriers, sons are unaffected Now carry out a cross if this daughter were to have children with a normal man. Cloning!!! • 5 minute find out…. Success Criteria: • To give a step by step method for each different cloning technique • To explain why it may be advantageous to clone certain certain individual plants or animals. • To evaluate the economic, social and ethical concerns surrounding cloning Tissue Culture Method Embryo Transplants Adult Cell Method Why and when would you use it? Why and when would you use it? Evaluation Evaluation Method Why and when would you use it? Evaluation • • • • Adult cell cloning https://www.youtube.com/watch?v=Vvz0tfFe9CI Tissue culture https://www.youtube.com/watch?v=6y13hYGPi8 Q • Embryo transplants • https://www.youtube.com/watch?v=bJ_zFG_NWi M Success Criteria: • To give a step by step method for each different cloning technique • To explain why it may be advantageous to clone certain certain individual plants or animals. • To evaluate the economic, social and ethical concerns surrounding cloning Cloning • The good……………………. The bad……………………. • The conclusion! Learning Intention – to learn about the different types of genetic manipulation Genetic Engineering • What is it? • How do we do it? Success criteria: • To give a step by step method for how to genetically engineer something • To explain the different ways in which GM can be used • To evaluate the use of GM Process of genetic engineering Genetic Modification • Give 5 ways in which GM is / has been used • When, in the development of an organism, does GM have to happen? • http://www.bionetonline.org/english/content/ff_ cont3.htm • http://listverse.com/2013/07/26/top-10-gmanimals-you-can-buy-or-eat/ Evaluate the use of genetic engineering Spec link DNA to protein • Gene is copied • Copy leaves the nucleus • Ribosome readys copy of DNA. • Bases are read in 3s • 3 bases = amino acid • A string of amino acids is produced = protein You are a dormouse! • What are the 4 essential things that you need to survive and reproduce 3 minute find out How would these things change if you were a plant? How are animals adapted to ensure that they can get these things? Adaptation Define - 5 minute find out Success Criteria: • To be able to define the term Adaptation. • To be able to give an example of an animal and explain how it is adapted to suit its environment. • Explain why certain animals have certain adaptations and features using ideas such as volume to surface area ratio. Animal adaptation • Animals have physical adaptations which enable them to survive in the conditions in which they normally live. • Write down 3 examples of physical adaptation. • Animals may also have special features e.g. spines, which help them to deal with specific aspects of their environment. • Can you think what these aspects may be and give 3 examples of specialised features of named animals. Why are polar bears and walruses so big? In the arctic is it better to be large or small??? Is it only size which matters? • What other factors are important when surviving in freezing conditions? Oh dear….. elephants are huge – why don’t they die in the sweltering heat? Plant adaptations Success Criteria * To give an example of a plant and explain how it is adapted to survive in its environment. * To give 3 ways in which desert plants are adapted to survive in extreme conditions * To explain what an extremeophile is and give an example Plant adaptations • Plants may be adapted for survival in the conditions they normally live e.g. desert and arctic • Plants may be adapted to cope with specific features of their environments e.g. thorns, poisons and warning colours. What is the biggest threat faced by plants in the desert? What adaptations do desert plants have to survive such hot weather? * Draw a typical desert plant and annotate it to show how it is adapted to survive! * To give 3 ways in which desert plants are adapted to survive in extreme conditions What adaptations do desert plants have to survive such hot weather? • • • • • Few/no leaves Deep roots Thick, waxy cuticle Spines Deep and few stomata Specialised Plant Cells: Guard Cells •Kidney bean shaped cells. •Mostly found in the lower epidermis. •Can open and close. •Allow gases e.g. carbon dioxide in and oxygen and water vapour out. •Flaccid= Closed •Turgid (Swollen)= Open Guard Cells make a pore called a stomata. Carbon dioxide enters the leaf through the stomata by diffusion. Inside the leaf= lower concentration of carbon dioxide Outside the leaf= higher concentration of carbon dioxide Competition in Animals • Success Criteria: To be able to answer the following questions: – What do animals compete for? – How do different animals compete and display? Review and build • Thinking of both plants and animals… • Around the room are 3 boards, please go to each in turn and write examples of organisms which have specific: – Structural adaptations – Behavioural adaptations – Functional adaptations • Please explain what the adaptation is and why they have it. What do animals compete for? Being fit! • For animals the distinction of being ‘fit’ is how many offspring they have. • I.e. how many set of their genes they pass onto the next generation. • Finding the ‘fittest’ mate is therefore extremely important. • Thus animals compete in various ways to mate with the fittest. E.g. display or fight. Something to think about…. • What is the difference between intra-specific competition and inter- specific competition? • What makes a successful competitor? • What is it most important to compete for food, territory or mate? WHY? Competition in plants • Success Criteria: – To review why plants compete with each other. – To state what plants compete for – To apply your knowledge to explain how plants compete. How do all of these plants survive? Competition in plants • What do plants compete for? • How do they compete? Seed dispersal • How do plants disperse their seeds? • https://www.youtube.com/watch?v=buZV0h4vfmQ • Why is it important for plants to be good at seed dispersal? Distribution of organisms Success Criteria: • List the physical factors which affect the distribution of living organisms • Explain the different ways in which you could sample an area • Apply your knowledge of sampling techniques to correctly select the appropriate method to use in different situations What readings could we take to give us information about this environment? What readings could we take to give us information about this environment? Biotic Abiotic What would happen if we greatly reduced or increased one of these factors? Suggest an explanation for why How could you gather quantitative data How couldare you sampleat this the trees growing thearea about the distribution of organisms? to collect some back of this areadata? and not in the middle? Collecting data on the distribution of organisms • Random sampling • Sampling along a transect *When would you use this method of sampling? *How EXACTLY do you carry out this method? *What sort of data would you collect? What do these words mean??? Valid Dependant variable Accurate Can you come up with: 1) A valid method for gathering information about how the distribution of daisies alters as you move away from a tree. 2) A non-valid method for gathering information about how the distribution of daisies alters as you move away from a tree. Think….. • Give at least 4 different possibilities: – Why does the population of rabbits in Sandringham woods vary from 800 in year 1 of sampling to 1000 in year 2 to 300 in year 3? How can environmental change be measured? • • • • • Rainfall Oxygen levels Temperature pH levels Living factors……. – Living organisms can be indicators of pollution – give 3 examples of this – 5 minute find out 5 minute find out…. • What is the ‘biotic index of water cleanliness’? The impact of change Environmental changes have an affect on the distribution of organisms. • You have 15 minutes to research and report back to the rest of the class on this question with reference to: – – – – – – – – Bluebells European birds Dartford warbler Honey Bees Polar bears Killer Whales Snowshoe Hares Coral Exam Question • How repeatable, reproducible and valid do you think the data on change in an environment provided by living indicators might be? Evolution Survival of the fittest What can you already tell me about these words? Natural Selection Darwin Theories of evolution • Lemark and Darwin both constructed theories of evolution. • What did they believe happened? • 5 minute find out! • https://www.youtube.com/watch?v=gIoqci8xcNU • http://www.cornell.edu/video/darwinian-revolutions-3lamarcks-theory Lamarck Darwin • How did they come up with their theories? • What were their theories of evolution? Lemarck vs. Darwin Explain that theory! Darwins theory of evolution • https://www.youtube.com/watch?v=iKz01UB8QrY • https://www.youtube.com/watch?v=vnktXHBvE8s • The theory of evolution states that all species of living things which exist today have evolved from simple life forms which first developed more than three billion years ago. Why was Darwin’s theory not accepted by all at the time of publishing? Natural Selection • What are you examples?? • Working as a group, put together a flow diagram to explain how natural selection works • Can you create a model to demonstrate this to another group? • http://peppermoths.weebly.com/ Natural Selection • Favourable genes are passed on to the next generation • Variation in a population • Mutation of a gene • Most ‘well adapted’/ fittest breed • Certain genes give advantages to survival * Some individuals have genes which mean that they are better suited to their environment Why is mutation important in natural selection? • • • • What is a mutation? Increases variation Could be good or bad If helps organisms to be better adapted to its environment then the frequency of it will increase Timescales of evolution • Does evolution take place over the same length of time for every species? – Discuss and explain your answer (4 marks) – The timescale for evolution depends upon the life cycle and complexity of an organism • Simple life forms eg bacteria can evolve much faster than more complex organisms such as mammals Classification and evolution • What is classification? • What do we look for when we are classifying organisms? • What is the ‘natural classification system’? • What are evolutionary trees and how to they help us to work out evolutionary and ecological relationships? (4 marks) Formation of fossils • Why are we not certain about the origins of life on Earth? • What is a fossil? • What are the 4 ways in fossils can be formed? • Why are fossils useful to us? • Why is the fossil record incomplete? Y11 – Period 1 Extinction! • 5 minute find out…. Causes of extinction! Living organisms causing Environmental changes Extinction Extinction *New Predators * New Diseases * More successful Competitors * Changing climate and environment over geological time * Catastrophic event Please give an example for each one! How are we doing with this? • Please answer these questions in the back of your book – Give 4 causes of extinction in species of living organisms – Give 2 possible causes of mass extinction events – Why is extinction and important part of evolution? What are the ways in which populations can become isolated? Specification link New species arise as a result of: isolation: two populations of a species become separated, eg geographically genetic variation: each population has a wide range of alleles that control their characteristics natural selection: in each population, the alleles that control the characteristics which help the organism to survive are selected speciation: the populations become so different that successful interbreeding is no longer possible. Can you make a mnemonic to help you remember this? Pyramids of Biomass! • Success Criteria – To define the key terms for this topic and use them within your work – To construct a pyramid of biomass – To peer assess a pyramid of biomass with reference to marking criteria – To extend… you will use your knowledge to consider WHY the biomass decreases at each tropic level. Key terms • What are they for this topic? – – – – – – Biomass Consumer Producer Herbivore Carnivore Trophic level • Lets define… 5 mins – To define the key terms for this topic and use them within your work If I told you that the biomass of the oak tree is 10kg, what would the biomass of the caterpillars be? Why is the biomass at each level of the pyramid not the same? Where does the energy come from initially? –To extend… you will use your knowledge to consider WHY the biomass decreases at each tropic level. Pyramids of Biomass • The mass of living material (biomass) at each stage in a food chain is less than it was at the previous stage. • Radiation from the Sun is the source of energy for the most communities of living organisms. Green plants capture a small part of the solar energy which reaches them. This energy is stored in the substances which make up the cells of the plants. Pyramids of biomass • We can draw a pyramid of biomass where the length of each box shows the total mass of organisms at each trophic level. • Task: • Can you draw a pyramid of biomass to show 100Kg of grass, eaten by 40kg of grasshoppers, eaten by a 15kg snake which dies and is decayed by 1.5kg of bacteria. • Extension – Explain why each box is smaller! – To construct a pyramid of biomass – To extend… you will use your knowledge to consider WHY the biomass decreases at each tropic level. Rules of drawing a pyramid of Biomass! • • Lets mark out of 5: A pyramid of biomass must 1. 2. 3. 4. Be drawn with a pencil and ruler Be drawn to scale (with the scale indicated) Each box must be the same height Each box must be a different length and correctly drawn according to the scale given 5. Each box must be labelled with organism and mass • WWW and EBI • Student response and improvement * To peer assess a pyramid of biomass with reference to marking criteria Review: • What is a pyramid of biomass and what does it show? • Where does the energy come from initially and why do we not end up with the same amount of energy? Pyramid of biomass • Please draw a pyramid of biomass for the following data: • 1000kg of Oak tree is eaten by • 200kg of aphid, which is eaten by • 30kg of Great tits, which is eaten by • 3kg of Sparrow hawk Why is the biomass of organisms less at each successive level? If the sun gives 1000Joules of light, why does the plant only have 400 Joules? Success Criteria: • To state and explain 3 ways in which energy is lost from an organism. • To apply your ideas to help you explain why different organisms lose different amounts of energy • To explain where all the nutrients go at successive levels in the food chain How much of the energy was lost at each stage? • How was the energy lost? •To state and explain 3 ways in which energy is lost from an organism. Sun Corn Cattle Burger Energy Losses • The amount of material and energy contained in the biomass of organisms is reduced at each successive stage in a food chain because: – Some materials and energy are excreted as waste materials – Respiration releases a lot of energy which is eventually lost as heat – Endotherms loose a lot of energy as they have to maintain their constant body temperature, which is often higher than their surroundings. Where did last years leaves go? Learning Objectives: • To review our experiment/ look at progress to explore what factors cause decay • To explain what happens to the products of decay • To give at least 3 stages in the carbon cycle Decaying food • Why does food decay? • What causes it? • What conditions are best for decay to occur? • What has happened to your bread? •To review our experiment/ look at progress to explore what factors cause decay Decaying Food • Materials decay because they are digested (broken down) by microorganisms. • Microbes digest food faster when it is: – Moist – Warm – ..and usually when there is plenty of oxygen (why?.......) In nature, what happens to the products of decay? • They are released into the soil and used by plants to grow. •To explain what happens to the products of decay What does this antelope give to and take from the environment during its life time? Recycling in nature?........ How does it work? • Living things remove materials from the environment for growth and other processes. These materials are returned to the environment either in waste materials or when living things die and decay. • In nature, the processes which remove materials, are balanced by processes which return materials – the materials are constantly recycled • CAN YOU THINK OF ANY EXAMPLES? • 5 minute find out…… Where could I find carbon containing compounds? Success Criteria • To state at least 5 Carbon containing compounds • To explain how carbon is transferred from one organism to another nature • To construct a cycle to show this transfer between living and non-living parts of the world THE CARBON CYCLE What is it, what happens? 5 mins – find out as much as you can •To explain how carbon is transferred from one organism to another The carbon cycle • .. Is the constant cycling of carbon! Use the pictures to help you construct you own cycle * Use arrows to show the direction of the carbon flow * Label the arrows to name the processes * Explain exactly what is happening to the carbon in each transfer (what is it being turned into?) •To explain how carbon is transferred from one organism to another