2 In this question you will be assessed on using good English, organising information clearly and using specialist term where appropriate.

Transcription

1 B. Keeping healthy It is possile to grow microorganisms in the laoratory. List A shows some temperatures. List B shows situations for which these temperatures might e suitale. Match each temperature to the correct situation. (3) List A List B 25 C Used in industrial laoratories to grow microorganisms quickly 35 C Used in school laoratory to grow microorganisms safely 00 C Used to stop microorganisms growing without killing them Used to kill microorganisms 2 In this question you will e assessed on using good English, organising information clearly and using specialist term where appropriate. We need a alanced diet to keep us healthy. Explain the ways in which an unalanced diet can affect the ody. (6).. 3 A person s metaolic rate varies with the amount of activity they do. a Metaolic rate is... () Choose one answer. the reathing rate the rate of chemical reactions in cells the heart rate Suggest one other factor which can change a person s metaolic rate. ()

2 4 Polio is a disease caused y a virus. In the UK, children are given polio vaccine to protect them against the disease. a Choose the correct words from each list to complete the sentences elow. i It is difficult to kill the polio virus inside the ody ecause the virus... () is not affected y drugs lives inside cells produces antitoxins ii The vaccine contains an... form of the polio virus. () active infective inactive iii The vaccine stimulates the white lood cells to produce... which destroy the virus. () antiiotics antiodies drugs The graph shows the numer of cases of polio in the UK etween 948 and 968. i In which year was the numer of cases of polio highest? () ii Polio vaccination was first used in the UK in 955. How many years did it take for the numer of cases of polio to fall to zero? () iii There have een no cases of polio in the UK for many years. But children are still vaccinated against the disease. Suggest one reason for this. () AQA, 2006

3 5 Controlling infections in hospitals has ecome much more difficult in recent years. a Suggest two reasons why MRSA is causing prolems in many hospitals. (2) The pioneer in methods of treating infections in hospitals was Ignaz Semmelweiss. He oserved that women whose aies were delivered y doctors in hospital had a death rate of 8% from infections caught in the hospital. Women whose aies were delivered y midwives in the hospital had a death rate of 2%. He oserved that doctors often came straight from examining dead odies to the delivery ward. i In a controlled experiment, Semmelweiss made doctors wash their hands in chloride of lime solution efore delivering the aies. The death rate fell to aout 2% down to the same level as the death rate in mothers whose aies were delivered y midwives. Explain why the death rate fell. () ii Explain how Semmelweiss s results could e used to reduce the spread of MRSA in a modern hospital. (2) 25 C Used in school laoratory to grow microorganisms safely, 35 C Used in industrial laoratories to grow microorganisms quickly, 00 C Used to kill microorganisms 3 AQA, Marks awarded for this answer will e determined y the Quality of Written Communication (QWC) as well as the standard of the scientific response. There is a clear, alanced and detailed description referring to oth overeating and deficiency. The answer shows almost faultless spelling, punctuation and grammar. It is coherent and in an organised, logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. There is some description of a range of the ways in which the diet can e unalanced and the effects. There are some errors in spelling, punctuation and grammar. The answer has some structure and organisation. The use of

4 specialist terms has een attempted, ut not always accurately. There is a rief description of at least two ways in which the diet can e unalanced, which has little clarity and detail. The spelling, punctuation and grammar are very weak. The answer is poorly organised with almost no specialist terms and/or their use demonstrating a general lack of understanding of their meaning. No relevant content Examples of iology points made in the response: alanced diet contains all the correct nutrients in the correct amounts alanced diet has the correct amount of energy too much energy leads to mass/weight increase e.g. eating too much fat if activity increases use of energy increases too little energy leads to decrease in mass/weight can lead to anorexia/descried symptom lack of vitamins/named vitamin can lead to deficiency disease/correctly named too much carohydrate/ sugar/overweight can lead to type 2 diaetes lack of a mineral ion/named ion can lead to deficiency disease/correctly named oesity linked to e.g. heart disease/arthritis/high lood pressure, etc. 3 a the rate of chemical reactions in cells Any one from: the proportion of fat to muscle inherited factors other sensile suggestion, other than activity 4 a i lives inside cells ii inactive iii antiodies i 950 ii 8 (years) iii Any one from: e.g. disease could e reintroduced (from aroad) disease would spread ack insufficient disease would spread if it came ack protection on holiday aroad high proportion of immune people needed to prevent epidemic 5 a Any two from: resistant to (most) antiiotics contagious or easily passed on or reference to open wounds patients ill therefore less ale to comat disease i chloride of lime/hand washing killed acteria (picked up from corpses) allow disease/germs/infection/ disinfectants ii people to wash hands after contact with patient so acteria/ pathogen/mrsa not transferred to other patient 2 3

5 B.2 Coordination and Control A dog responds to stimuli. a Link the receptor descriptions to the correct part of the animal y choosing the correct letter (A, B, C or D). i Contains receptors to detect chemicals () ii Contains receptors to detect light () iii Contains receptors to detect movement of the head and sound. () The skin of a human contains receptors which are sensitive to touch. i Give one other stimulus which is detected y human skin. () ii Suggest why there are many touch receptors in a person s fingertips. () 2 a When a person touches a hot surface they move their hand away quickly. Choose the correct word to complete the sentence. This is called a... action. () learned reflex thoughtful

6 What is the importance of this type of action? () 3 This picture shows a Venus fly trap. a The Venus fly trap catches flies for food. When a fly lands on the leaf the trap closes. Choose the correct word to complete the sentence. The shutting of the trap is called a... () detector stimulus response Suggest one receptor the Venus flytrap has to detect the fly. () 4 Hormones are important chemicals which help to control conditions inside living organisms. a List A shows three hormones List B shows where some hormones are produced. Match each hormone with where it is produced. (3) List A Hormone auxin oestrogen FSH List B Where produced pituitary gland kidney plant stems and roots ovary Choose the correct answer to complete each of the following sentences. i The hormone which causes eggs to mature is.... () auxin oestrogen FSH ii The hormone which causes growth of the uterus (wom) lining is.... () auxin oestrogen FSH

7 5 When light is shone in a person s eyes they link. When a plant is placed near a lamp the stem ends towards the light. a Choose the correct answer to complete each of the following sentences. i The response of the eye to right light is called a... action. () learned reflex stimulated ii The response of the plant to light is called... () gravitropism hydrotropism phototropism In this question you will e assessed on using good English, organising information clearly and using specialist terms where appropriate. Plants respond to light and gravity. Descrie how plant hormones control the growth of roots and shoots. a i A ii C iii B i temperature/pressure/pain ii idea of increased sensitivity (for a particular task, e.g. to feel a pencil when writing) 2 a reflex prevents damage/harm OR prevents skin urning 3 3 a response any one of: touch/pressure/chemical 4 a Auxin links to plant stems and roots, oestrogen links to ovary, FSH links to pituitary gland. i FSH ii oestrogen 5 a i reflex ii phototropism There is a clear and detailed scientific description of phototropism and

8 geotropism and how auxin controls growth of oth the root and shoot. The answer is coherent and in a logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. The answer shows very few errors in spelling, punctuation and grammar. There is some description of how hormones cause the root and shoot to end. The answer has some structure and the use of specialist terms has een attempted, ut not always accurately. There may e some errors in spelling, punctuation and grammar. There is a rief description of how hormones control growth in either the root or shoot which has little clarity and detail. The answer is poorly constructed with an asence of specialist terms or their use demonstrate a lack of understanding of their meaning. The spelling, punctuation and grammar are weak. No relevant content. Examples of iology points made in the response: Correct use of phototropism Correct use of gravitropism (allow geotropism) Auxin produced in root/shoot More hormone/auxin on lower side of root More hormone/auxin on lower/dark side of shoot Hormone inhiits growth of root cells Hormone stimulates growth of shoot/stem cells Longer cells on one side Causes root/shoot to end Roots grow towards gravity Shoots grow towards light B.3 Medicine and drugs People take drugs for many different reasons. alcohol heroin penicillin statin steroid thalidomide Choose a word from aove to match the following sentences. a an illegal drug which is highly addictive () a drug used y athletes to make them perform etter () c a medical drug which is used to reduce cholesterol levels () 2 A drug company wants to test a new painkiller called PainGo2. The company hope that the new drug will cure headaches quicker than PainGo.

9 PainGo2 has to e tested in clinical trials. PainGo2 is twice as strong as PainGo. Phase trial a few healthy people will e given one or two talets of PainGo2. Phase 2 trial a small group ( ) of patients with headaches will e given PainGo2. Phase 3 trial 3 large groups (2000 in each group) of patients with headaches will e given either PainGo2 or PainGo or a placeo. a What is the purpose of the Phase trial? () Suggest why in Phase 2 the patients were asked to record how they felt after taking the PainGo2. () c What is a placeo? () d Phase 3 was done as a doule-lind trial y doctors who had patients with headaches. In a doule-lind trial who will know who is given the new drug? Choose your answer from the choices elow. the patient only the doctor only oth the doctor and the patient neither the doctor nor the patient () e Why is it important to use the placeo in the Phase 3 trial? () f Why are some patients given PainGo in Phase 3? () 3 a Give one example of:

10 i A legal recreational drug ( ii An illegal recreational drug () Some recreational drugs are addictive. i Give one example of a recreational drug that is very addictive. () ii Explain how the action of a drug makes a person ecome addicted to it. () c Some doctors think that smoking cannais causes depression. Doctors investigated the cannais smoking haits of 500 young adults. The tale shows the percentage of cannais smokers in the investigation who ecame depressed. How many times the men or women had smoked cannais in the last 2 months Percentage of men who ecame depressed Less than 5 times 9 6 More than 5 times, ut less than once per week times per week 2 3 Every day 5 68 Percentage of women who ecame depressed From the data, give two conclusions that can e drawn aout the relationship etween cannais and depression. (2) 4 In this question you will e assessed on using good English, organising information clearly and using specialist term where AQA, 2007

11 appropriate. Read the description of an investigation into the link etween smoking cannais and heroin addiction. Six teenage rats were given a small dose of THC the active chemical in cannais every three days etween the ages of 28 and 49 days. This is the equivalent of human ages 2 to 8. The amount of THC given was roughly equivalent to a human smoking one cannais joint every three days. A control group of six teenage rats did not receive THC. After 56 days catheters (narrow tues) were inserted in all twelve of the now adult rats and they were ale to self-administer heroin y pushing a lever. All the rats egan to self-administer heroin frequently. After a while, they stailised their daily intake at a certain level. The ones that had een on THC as teenagers stailised their heroin intake at a much higher level than the others. They appeared to e less sensitive to the effects of heroin. This pattern continued throughout their lives. Reduced sensitivity to the heroin means that the rats take larger doses. This has een shown to increase the risk of addiction. Evaluate this investigation with respect to estalishing a link etween cannais smoking and heroin addiction in humans. Rememer to include a conclusion to your evaluation. (6) a heroin steroid(s) c statin(s) 2 a To check for unexpected side effects with the higher dose/stronger pain killer. To see if the drug cured the headaches. c A talet which does not contain a drug/contains a harmless chemical/ a lank. d D Neither the doctor nor the patient. e To rule out psychological effects/description of this. f To see if the PainGo2/the new drug is etter (at curing headaches) than PainGo.

12 3 a i toacco/nicotine/alcohol (accept: solvent/glue/caffeine, ignore cigarettes/coffee) ii cannais/heroin/cocaine (allow: crack/weed/ecstasy/lsd/ amphetamine/speed/steroids/ GHB). i heroin/cocaine/toacco/nicotine (ignore: alcohol/cigarettes/ cannais/caffeine/coffee) ii alters ody chemistry (ignore: withdrawal symptoms/craving/ non-chemical effects on nervous system) c Any two from: increase in cannais smoking increases (%) depression greater effect in women/allow women ecome more depressed depression linked with/not directly caused y cannais/ignore cannais causes depression not all cannais smokers get depression. 4 There is a clear, alanced and detailed argument referring to oth pros and cons and a conclusion which matches the pros and cons. The answer shows almost faultless spelling, punctuation and grammar. It is coherent and in an organised, logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. The answer contains at least one pro and one con with a conclusion. There are some errors in spelling, punctuation and grammar. The answer has some structure and organisation. The use of specialist terms has een attempted, ut not always accurately. There is mention of either a pro or a con with an attempt at a conclusion or a list of pros and cons without a conclusion, has little clarity and detail. The spelling, punctuation and grammar are very weak. The answer is poorly organised with almost no specialist terms and/or their use demonstrating a general lack of understanding of their meaning No relevant content. Examples of iology points made in the response: Pros, e.g. used teenage rats as equivalent to human teenagers THC dose typical of human cannais smoking haits used control group rats allowed to choose amount of heroin Cons, e.g. sample size small/only used 2 rats heroin administration very different from human situation Conclusions rats given THC/cannais took more heroin (this) is evidence for a link etween THC/cannais and heroin (ut) rat ehaviour/ physiology not necessarily same as human ehaviour/ physiology does not prove link in humans. 0

13 B.4 Adaption for survival The picture shows a solenodon. Figure A solenodon Solenodons have lived on earth since the Age of the Dinosaurs. They are only found in forests in Haiti and are the only mammals which have a poisonous ite. They are rarely seen ecause they feed at night. They mainly eat insects and spiders. a The solenodon has adaptations which help it to survive. Match the adaptation to the correct letter (A, B, C, D or E) to answer the following questions. i This helps the solenodon to dig its urrow. () ii This helps the solenodon to detect its food. () The solenodon is at risk of dying out since new animals have een taken to the islands. Use the information and the picture to help answer the following questions. i The solenodon is not adapted to flee from predators. Suggest why. () ii If the solenodon is caught y a predator it can defend itself. Suggest how.

14 () 2 Trees which live in the rain forests are very tall and often have road leaves. This is a prolem for young trees which do not get much light. a Choose the correct answer to complete the sentence. light nutrients space Rain forest trees have road leaves so they can compete for... () Choose the correct answer to complete the sentence. larger trees large seeds with stored food Trees in the rain forest have adapted to lack of light near the ground y having... () 3 The gemsok is a large herivore living in dry desert regions of South Africa. It feeds on grasses that are adapted to the dry conditions y otaining moisture from the air as it cools at night. The tale elow shows the water content of these grasses and the feeding activity of the gemsok over a 24-hour period. Time of day % water content of grasses % of gemoks feeding a i Name the independent variale investigated. () ii Is this a categoric, ordered, discrete or continuous variale? () How does the water content of the grasses change throughout the 24 hour period?

15 () c Between which recorded times are more than 30% of the gemsoks feeding? () d Suggest three reasons why the gemsoks enefit from feeding at this time. (3) AQA, 2008 a i D ii E i Any one of: Poor eyesight, legs look awkward for running, no natural predators, other sensile suggestions. ii Poisonous ite, has poison, strong claws / description 2 a light large seeds with stored food 3 a i Time of day ii Continuous It rises during the night (some time after) 800 hours to a maximumof 25% at 0900 hours and then falls (more rapidly at first) to a minimum of 5% at 800 hours Some accurate reference to actual figures in the tale is necessary to otain the mark. c Between 2400 hours and 0600 hours. The important words here are more than. Candidates who ignore these words will include the figure of 30% and therefore give a response of 200 hours to 0900 hours. d The water content of the grasses that it eats are high over this period. It is night and the gemsoks are therefore less easily seen y predators It is cooler and therefore they are less likely to have to sweat and so this helps them conserve precious water.

16 B.5-6 Energy in iomass Raits eat very large amounts of grass. A single hawk eats a few raits. a Draw a pyramid of iomass for the raits, grass and the hawk. (2) Much of the energy from the grass is not transferred to the hawk. Suggest two reasons why. (2) 2 Choose words from elow to complete each sentence. caron dioxide cool dry insects microorganisms moi a Plant waste in a compost heap is decayed y... () c The plant waste decays faster in conditions which are... and... (2) The plant waste will also decay faster when the air contains plenty of.... () 3 The diagram shows what happens to the energy in the food a calf eats. In the calculations show clearly how you work out your answer.

17 a Calculate the % energy lost in methane (X). (2) The energy in the food the calf eats in one day is 0 megajoules. Calculate the amount of this energy that would e lost in faeces and urine. (2) c Name the process which transfers the energy from the food into movement. () d The farmer decides to move his calf indoors so that it will grow quicker. Suggest two reasons why. (2) 4 In this question you will e assessed on using good English, organising information clearly and using specialist term where appropriate. The constant cycling of caron in nature is called The caron cycle. Each autumn, trees lose their leaves. Descrie how the caron in the leaves is recycled so that the trees can use it again.

18 (6) 5 The diagram shows a pyramid of iomass drawn to scale. a What is the source of energy for the water plants? () The ratio of the iomass of water plants to the iomass of insects is 5:. Calculate the ratio of the iomass of insects to the iomass of frogs. Show clearly how you work out your answer. (2) c Give two reasons why the iomass of the frog population is smaller than the iomass of the insect population. (2) d Some insects die. Descrie how the caron in the dead insect odies may e recycled. (4)

19 a Pyramid drawn with three layers widest to narrowest either way up ut correctly laeled. Any two from: not all the grass eaten is used to make rait grow / waste in urea faeces / roots not eaten energy is lost due to movement y raits /raits run around energy used to keep raits warm hawks do not eat the whole rait 2 a microorganisms moist and warm (either order) c oxygen 3 a 0 (%) if wrong answer allow for mark 2.5 if incorrect answer allow mark for correct working. c respiration d It reduces the calf s movement ecause it won t walk aout, therefore it will use that energy for growth. It also reduces the energy the calf will need to use to keep warm and that energy can e used for growth. reduces movement/walking aout reduces energy/transferred y heating/keeps (calf )warm. 4 There is a clear and detailed description of the sequence of events in the caron cycle. The answer is coherent and in a logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. The answer shows very few errors in spelling, punctuation and grammar. There is some description of the sequence of events in the caron cycle ut there is a lack of clarity and detail. The answer has some structure and the use of specialist terms has een attempted, ut not always accurately. There may e some errors in spelling, punctuation and grammar. There is a rief description of the caron cycle, which has little clarity and detail. The answer is poorly constructed with an asence of specialist terms or their use demonstrates a lack of understanding of their meaning. The spelling, punctuation and grammar are weak. No relevant content Examples of iology points made in response: microorganisms only allow once if no mention of acteria or fungi acteria fungi digest / reak down organic matter / leaves / decompose / reference decomposers / decay / rot respiration comustion release of caron dioxide into the air CO2 can e used (y trees) in photosynthesis reference to faster in warmer weather / slower during the winter/cold weather.

20 5 a the sun / light / sunshine / solar allow radiation from the sun ignore photosynthesis / respiration apply list principle do not allow water / minerals / heat 2.5 (:) correct answer with or without working ignore rounding with correct working do not allow other equivalent ratios for oth marks evidence of selection of 0 (insects) and 4 (frogs) or 50 and 20 or and 0.4 for mark if no other working allow mark for (): 0.4 on answer line c Any two from: allow for insects or frogs allow energy for iomass some parts indigestile / faeces waste / examples of waste, e.g. urea / nitrogenous compounds / urine / excretion movement / e.g. of movement allow keeping warm heat not all eaten / e.g. of not all eaten respiration do not accept energy for respiration d Any four from: (odies) consumed y animals / named / scavengers / detritus feeders microorganisms / acteria / fungi / decomposers reference to enzymes decay / reakdown / decompose / rot ignore digest(ion) respiration caron dioxide produced photosynthesis sugar / glucose produced accept other organic molecules fossilisation / fossil fuels / named comustion / urning must e linked with fossilisation / fossil fuels (urning) produces caron dioxide allow caron dioxide produced once only B.7 Variation, reproduction and new technology Strawerries are ale to reproduce many plants from one parent plant. Choose the correct answer to complete each sentence. a Producing new plants with one parent is called... () asexual reproduction genetic engineering sexual reproduction

21 The advantage of this is that all the strawerry fruits will... () e igger all taste etter all taste the same c A disadvantage of this to the strawerry plants is that... () there is more variation they are genetically identical they cannot mate 2 Read the passage. Use the information and your own knowledge to answer the questions. At one time, the oll weevil destroyed cotton crops. Farmers sprayed the crops with a pesticide. The weevil died out ut another insect, the ollworm moth, ecame resistant to this pesticide. In the 990s large crops of the cotton plant were destroyed y the ollworm moth. The pesticides then used to kill the moth were expensive and very poisonous, resulting in deaths to humans. Scientists investigated alternative ways to control the ollworm moth. They found out that a type of acterium produced a poison which killed ollworm larvae (grus). A GM cotton crop plant was developed which produced the poison to kill ollworms. This proved to e very effective and farmers were ale to stop using pesticide sprays. Now farmers have another prolem. Large numers of other insects have multiplied ecause they were not killed when the farmers stopped using pesticides. Some of these insects have started to destroy the GM cotton and farmers are eginning to use pesticides again! a i Give one advantage of spraying crops with pesticides. () ii Give two disadvantages of spraying crops with pesticides. () iii Give one economic advantage of using GM cotton. () iv Some people oject to using GM crops. Suggest one reason why. ()

22 In this question you will e assessed on using good English, organising information clearly and using specialist term where appropriate. The GM cotton was genetically engineered to produce the same poison as the acterium. Descrie fully how this is done (6) 3 The use of cloned animals in food production is controversial. It is now possile to clone champion cows. Champion cows produce large quantities of milk. a Descrie how adult cell cloning could e used to produce a clone of a champion cow. (4) Read the passage aout cloning cattle. The Government has een accused of inexcusale ehaviour ecause a calf of a cloned American champion cow has een orn on a British farm. Campaigners say it will undermine trust in British food ecause the cloned cow s milk could enter the human food chain. But supporters of cloning say that milk from clones and their offspring is as safe as the milk we drink every day. Those in favour of cloning say that an animal clone is a genetic copy. It is not the same as a genetically engineered animal. Opponents of cloning say that consumers will e uneasy aout

23 drinking milk from cloned animals. Use the information in the passage and your own knowledge and understanding to evaluate whether the government should allow the production of milk from cloned champion cows. Rememer to give a conclusion to your evaluation. (5) AQA, 2006 Note to teachers DNA is strictly introduced in Unit BLY2. If candidates give an answer where DNA would e appropriate they will gain credit in BLY ut it is not essential knowledge. 6 a asexual reproduction all taste the same c they are genetically identical 7 a i kills insects (which eat crop) or increases yield ii Any two from: kills insects which may not e pests poisonous to humans expensive pollutes the environment other relevant suggestions e.g. is not organic iii increases crop yield or reduces cost of pesticide use iv Any one from: May lead to increased use of pesticides in the long run / description / ref to last paragraph ethical considerations e.g. alters genes of crop Do not allow not natural against genes may get into wildlife idea, religion or similar, not organic. There is a clear and detailed scientific description of the sequence of events in genetic engineering. The answer is coherent and in a logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. The answer shows very few errors in spelling, punctuation and grammar. There is some description of the sequence of events in genetic engineering ut there is a lack of clarity and detail. The answer has some structure and the use of specialist terms has een attempted, ut not

24 always accurately. There may e some errors in spelling, punctuation and grammar. There is a rief description of the genetic engineering, which has little clarity and detail. The answer is poorly constructed with an asence of specialist terms or their use demonstrates a lack of understanding of their meaning. The spelling, punctuation and grammar are weak. No relevant content Examples of iology points made in response: gene from the acterium is cut from the chromosome using enzymes gene transferred to the cotton (cotton) chromosome allow cell (the gene) controls characteristics causes the cotton (cells) to produce the poison. 8 a Any four from: nucleus / DNA / chromosomes / genetic material removed (from egg) from (unfertilised) egg / ovum linked to second point allow empty egg cell for first two marks do not allow fertilised egg allow egg from champion cow nucleus from ody cell of champion (cow) inserted into egg / ovum electric shock to make cell divide or develop into emryo (emryo) inserted into wom / host / another cow allow this point if wrong method e.g. emryo splitting 4 Any four from: Pros: Max 2 marks economic enefit e.g. increased yield / more profit clone calf not genetically engineered genetic material not altered milk safe to drink / same as ordinary milk Cons: Max 2 marks consumer resistance caused y misunderstanding process not proved that milk is safe ignore God would not like it or it s not natural ethical / religious argument reduce gene pool / e.g. Conclusion: Max marks sensile conclusion for or against, sustantiated y information from the passage and / or own knowledge conclusion at end 5

25 B.8 Evolution a This diagram shows a timeline for the evolution of some dinosaurs. The mass of each dinosaur is shown in the rackets y its name. Choose the correct answer to complete each sentence. Dinosaur evolution timeline i A dinosaur which lived etween 00 and 50 million years ago is.... () Agilisaurus Saturnalia Tyrannosaurus ii Camarasaurus evolved from.... Agilisaurus Alamosaurus Saturnalia iii The difference in mass etween Agilisaurus and the smallest dinosaur is... kg. () i The earliest life forms developed on Earth more than 3... years ago. () illion million thousand ii The earliest life forms can e descried as... () ony complex simple c Darwin suggested a theory of evolution. His theory is descried as evolution y... () acquired characteristics a god natural selection 2 Giraffes have developed their long necks over millions of years.

26 Two scientists tried to explain why the giraffes have long necks. They are called Darwin and Lamarck. Match the name in List A to the correct statement in List B. (3) List A Name Darwin only Lamark only Both Lamark and Darwin List B Statement Noticed that the neck of the giraffe changed over time Had enough evidence to prove why the giraffe s neck got longer Thought that natural selection worked on variations in neck length present at irth Thought the giraffe stretched its neck while eating leaves in trees. Then its young inherited the longer neck 3 The photograph shows a snake eating a toad. Cane toads were first introduced into Australia in 935. The toads contain toxins and most species of Australian snake die after eating the toad. The cane toad toxin does not affect all snakes the same way. Longer snakes are less affected y toad toxin. Scientists investigated how red-ellied lack snakes had changed in the 70 years since cane toads were introduced into their area. They found that red-ellied lack snakes had ecome longer y around 3 5%. Suggest an explanation for the change in the ody length of the redellied lack snakes since the introduction of the cane toads.

27 (4) AQA, 2005 a i Agilisaurus ii Saturnalia iii 7.32 i illion ii simple c Natural selection 2 Darwin only Thought that natural selection worked on variations in neck length present at irth. Lamark only thought the giraffe stretched its neck while eating leaves in trees. Then its young inherited the longer neck. Both Lamark and Darwin noticed that the neck of the giraffe changed over time. 3 Accept any four from: mutation (do not accept had to mutate / decided to mutate ) produces longer snake or there is variation in snake length (do not accept had to adapt and ecame longer ) longer snake less susceptile to toxin or longer snake survives survivors reproduce gene passed to next generation (allow characteristic passed to next generation) 3 4