B6 Inheritance Variation and Evolution

Transcription

1 B6 Inheritance Variation and Evolution 35 Questions Name: Class: Date: Time: Marks: Comments: Page of 04

2 Figure shows a fish called a carp. Figure The characteristics of an animal can be a result of: only genetic causes only environmental causes both genetic and environmental causes. (a) Give one characteristic shown in Figure for each different cause. Only genetic causes Only environmental causes Both genetic and environmental causes (3) Page 2 of 04

3 (b) Two alleles control the body colour of carp: brown ( B) blue ( b). The brown allele is dominant to the blue allele. The genetic cross from breeding two carp is shown in Figure 2. Figure 2 Complete Figure 2. (c) Draw a ring around one blue offspring shown in Figure 2. (2) () (d) What is the probability that the offspring from this genetic cross will be brown? Tick two boxes () Page 3 of 04

4 (e) Carp can produce large numbers of offspring. The two carp crossed in Figure 2 had offspring. Approximately how many offspring are expected to be brown? Brown carp offspring = () (f) A pond contains carp used for breeding. The carp for breeding are brown or blue. A red carp has been seen. The red carp was not added to the pond. Suggest what might have caused the red carp to appear. () (Total 9 marks) 2 Living things can be classified into groups. (a) Scientists look at structures inside cells to classify living things. Suggest one structure found in cells that can be used to classify living things. () Page 4 of 04

5 (b) The table below shows one system for classifying humans. X Phylum Class Order Family Genus Species Animalia Chordata Mammalia Primates Hominidae Homo Sapiens Who devised this system of classification? Tick one box. Darwin Linnaeus Wallace Woese () (c) Look at the table above. X is the largest category in this classification. Name category X. () (d) Give the binomial name of humans. Use information in the table above. () Page 5 of 04

6 (e) Suggest one way that classification systems are useful to scientists. 3 (a) Some antibiotics work by destroying the cell membranes of bacteria. Suggest why these antibiotics may have side effects in the animals that are given these antibiotics. () (Total 5 marks) () (b) Each arrow on the figure below shows the date of discovery of each new type of antibiotic. In which 0 year period were most new types of antibiotic discovered? () (c) The figure above shows 22 new types of antibiotic. These were discovered before 200. Determine the percentage of types of antibiotic that have been discovered between 980 and 200. Use information from the figure above. Give your answer to 2 significant figures. % (2) Page 6 of 04

7 (d) Bacteria can evolve rapidly. Many bacteria can develop into new strains which are resistant to antibiotics. Complete the table below to show if each action is more likely or less likely to help bacteria to become antibiotic resistant. Put a tick in each row. Action More likely Less likely Take painkillers for headache Washing with antiseptic hand gel Adding antibiotics to food for cows Giving antibiotics for colds and flu Stopping antibiotics as soon as you feel better (4) (Total 8 marks) Page 7 of 04

8 4 Starfish can split in half. Each half can then grow new arms to form offspring. This process is shown in the figure below. (a) What process produces the starfish offspring? Tick one box. Asexual reproduction Fertilisation Selective breeding Sexual reproduction () (b) More cells are produced as the starfish grows more arms. What process will produce more cells in the starfish as they grow? () (c) All the offspring produced are genetically identical. What name is given to genetically identical organisms? () Page 8 of 04

9 (d) Each body cell of the parent starfish contains 44 chromosomes. How many chromosomes are in each body cell of the offspring? () (Total 4 marks) 5 Moose are animals that eat grass. Figure shows a moose. Figure Wildnerdpix/iStock/Thinkstock Figure 2 shows a food chain. Figure 2 Grass Moose Wolves (a) Name the secondary consumer shown in Figure 2. () Page 9 of 04

10 (b) Figure 3 shows how the moose population and wolf population have changed in one area. This is a predator-prey cycle. Figure 3 In 2004 the line on Figure 3 for wolves is above the line for moose. How does Figure 3 show that there are more moose than wolves in 2004? () (c) Suggest why the moose population decreased between 2002 and Use information from Figure 3. () (d) The number of wolves is one biotic factor that could affect the size of the moose population. Give two other biotic factors that could affect the size of the moose population.. 2. (2) Page 0 of 04

11 (e) Moose have distinct characteristics such as antlers. Describe how moose may have evolved to have large antlers. (5) (Total 0 marks) 6 Different antibiotics destroy bacteria in different ways. Some antibiotics disrupt the bacterial cell membrane. Some antibiotics disrupt the bacterial cell wall. (a) Antibiotics that disrupt the bacterial cell membrane often cause more side effects in humans compared with antibiotics that disrupt bacterial cell walls. Suggest why. () (b) Some antibiotics prevent ribosomes functioning. Suggest how this damages the bacterium. () Page of 04

12 (c) Drug manufacturers are spending less on research into new antibiotics. One reason why is because new antibiotics are rarely prescribed. Some people think that governments should pay drug manufacturers to develop new antibiotics. Suggest why. (3) (Total 5 marks) 7 The figure below shows a carp. (a) A mutation causes a blue colour in some carp. What is a mutation? () (b) Suggest how a mutation could cause a different colour in carp. () Page 2 of 04

13 (c) Two alleles control the body colour of carp: brown ( B) blue ( b). The brown allele is dominant to the blue allele. Two carp that are heterozygous for colour are crossed and produce offspring. Approximately how many of the offspring are expected to be blue? Draw a genetic diagram to explain your answer. Give your answer in standard form. Number of offspring expected to be blue = (5) (d) A scientist wanted to find out whether a brown carp has the genotype BB or Bb. Describe what genetic cross a scientist could do to determine this. (2) (Total 9 marks) Page 3 of 04

14 8 In the 8th century a binomial system of grouping similar organisms was developed. Before the binomial system was developed the common briar rose had the following names: Rosa sylvestris inodora seu canina Rosa sylvestris alba cum rubore folio glabro. In the binomial system, the same rose is called Rosa canina. (a) One advantage of the binomial system is that the name is shorter than the names used before this system. Suggest two other advantages of the binomial system.. 2. (2) (b) Classification systems have changed in the last 50 years. Give one reason why we now have more information to classify organisms. () (c) Archaea is one of the groups in the three-domain system of classification. Give two features of the domain Archaea.. 2. (2) (Total 5 marks) Page 4 of 04

15 9 Sexual reproduction in humans involves the joining together of an egg cell and a sperm cell. The sex of an embryo is decided by the chromosomes they inherit from their mother and father. (a) Where in the cell are the chromosomes? Tick one box. Cell membrane Cytoplasm Nucleus Ribosomes () (b) Draw one line from each type of cell to the number of chromosomes in the cell. Type of cell Number of chromosomes 23 Sperm cell Embryo cell (2) Page 5 of 04

16 (c) A man and a woman decide to have a child. Complete the genetic diagram in the figure below. (d) (e) On the figure above, circle a male child. What is the chance of the man and woman having a boy? Tick one box. (2) () in 2 in 3 in 4 in 8 () (Total 7 marks) Page 6 of 04

17 0 A person s characteristics can be due to: environmental causes genetic causes both environmental and genetic causes. (a) Complete Table. Put a tick to show what each characteristic is due to. Table Characteristic due to Characteristic Environmental causes Genetic causes Both environmental and genetic causes Eye colour A scar Weight (3) (b) Draw one line from each key term to the correct definition. Key term Definition The set of alleles for a characteristic Genotype The genus of an organism The inheritance of chromosomes Phenotype The mutation of genes The physical characteristic of an organism (2) Page 7 of 04

18 (c) Farmers use selective breeding to control the characteristics in cows. Table 2 shows the stages of selective breeding in cows. Complete Table 2 to show the correct order of the stages. The first stage has been numbered for you. Table 2 Stage in selective breeding Order of stage Cows are bred over many generations Parents are bred together Cows with the desired characteristics are chosen Calves with the most desired characteristics are bred together (2) (d) Farmers selectively breed cows for many different reasons. Suggest two characteristics that cows may be bred for. Do not suggest coat colour.. 2. (2) (e) Selective breeding can lead to problems. Suggest how problems caused by selective breeding in cows can have negative financial effects for the farmer. (2) (Total marks) Page 8 of 04

19 Bacteria can cause disease. Figure shows some features of a Salmonella bacterium. Figure (a) Draw one line from each feature of the Salmonella bacterium to the function. Feature Function Cell membrane Controls the movement of substances into and out of the cell Carries genetic information Plasmid DNA Provides support and protection The site of protein synthesis (2) Page 9 of 04

20 (b) How is Salmonella spread between people? Tick one box. Animal bites Contaminated food Sneezing Sexual contact () (c) Give two ways you could stop Salmonella from spreading.. 2. (2) Page 20 of 04

21 (d) Harmful bacteria can also be useful. Scientists are doing research to find out if Salmonella can be used in a vaccine to treat cancer. The Salmonella vaccine can be injected into the blood or swallowed in a tablet. One benefit of injecting the vaccine is that it gets to the cancer quickly in the blood. What is another benefit? Tick one box. All cancers can be treated by the injection It will not cause sickness and diarrhoea side effects The injection is not painful to the patient The injection introduces cancer cells into the body () Page 2 of 04

22 (e) The Salmonella bacterium used in the vaccine is genetically modified using part of a virus. Look at Figure 2. Figure 2 Complete the sentences. Use the letters from Figure 2. Bacteria reproduce quickly in part DNA with the desired gene is removed from the virus in part The chosen gene is inserted into the plasmid in part (3) (Total 9 marks) Page 22 of 04

23 2 Humans can use different methods to produce animals and plants with desired characteristics. The figure below shows some different breeds of horse. GlobalP/iStock/Thinkstock (a) All breeds of horse are of the same species. Suggest what you could do to show this. (2) Page 23 of 04

24 (b) Horse racing is an ancient sport. Selective breeding has been used for centuries to produce racehorses. Describe the steps involved in selective breeding to produce a racehorse. (3) (c) Another way of producing organisms with desired characteristics is genetic engineering. Bt cotton is a variety of cotton that has been genetically engineered to produce a poison. The poison kills several different species of insect that feed on cotton plants. The poison is naturally produced by a soil bacterium called Bacillus thuringiensis. Describe how cotton plants can be genetically engineered to produce the Bt poison. (3) Page 24 of 04

25 (d) Describe the advantages and disadvantages of growing Bt cotton. (4) (Total 2 marks) 3 Huntington s disease is an inherited disorder that affects the nervous system. It is caused by a dominant allele. A man is heterozygous for Huntington s disease. His partner is healthy and does not have the allele that causes Huntington s disease. (a) What are the genotypes of the man and the woman? Use: H for the allele that causes Huntington s disease h for the healthy allele. Man s genotype Woman s genotype () (b) The couple want to have a child. Use a Punnett square to determine the probability of the child having Huntington s disease. Circle the genotypes of any children that will have Huntington s disease. Probability of child having Huntington s disease = (4) Page 25 of 04

26 (c) The couple visit a genetic counsellor, who gives them the following options.. Adopt a child. 2. Gamete donation uses sperm from another man to fertilise the woman s eggs by in vitro fertilisation (IVF). 3. Conceive naturally. 4. Use pre-implantation genetic diagnosis (PGD). Many embryos are produced by IVF using gametes from the man and woman. Embryos are tested for Huntington s disease and a healthy embryo is implanted into the woman s uterus. The risk of implanting an embryo with the allele for Huntington s disease is 0.2%. Costs the NHS about Conceive naturally and use prenatal diagnosis (PND) once the woman becomes pregnant. A sample of the placenta is taken at 0 weeks of pregnancy or a sample of fluid is taken from around the developing baby at 6 weeks of pregnancy. The sample is tested for the Huntington s allele. A 0.5.0% risk of miscarriage. About % of samples collected are unsuitable for testing. Costs the NHS about 600. The couple decide they want to have a healthy baby that is their own biological offspring. Evaluate the options. Suggest which option would be best for the couple. Page 26 of 04

27 4 (a) (6) (Total marks) Which of the following is the best definition of a species? Tick ( ) one box. Organisms with many features in common Organisms that live in the same habitat and eat the same food Organisms that reproduce together to form fertile offspring () Page 27 of 04

28 (b) Figure is a photograph of the Grand Canyon. The layers of rock contain fossils. Sumikophoto/iStock/Thinkstock Scientists found five fossils of different species of animal, P, Q, R, S and T, at the positions shown in Figure. (i) What is the evidence in Figure that animals P and Q were alive at the same time? () (ii) Was animal R alive at an earlier time or at a later time than animals P and Q? Give the reason for your answer. () Page 28 of 04

29 (iii) Which two of the following would be evidence that animal T may have evolved from animal S? Tick ( ) two boxes. The fossils of animals S and T have many features in common, but T is more complex than S. The fossils of animals S and T are the same size. The fossils of animals S and T have the same skin colour. The fossil of animal S was found in a deeper layer of rock than the fossil of animal T. The fossil of animal T is more similar to the fossil of animal R than to the fossil of animal S. (2) Page 29 of 04

30 (c) Figure 2 shows two species of ground squirrel, W and X. Squirrel W lives on the high ground to the south of the Grand Canyon. Squirrel X lives on the high ground to the north of the Grand Canyon. The land to the north of the Grand Canyon is about 300 metres higher than the land on the south side. The north side also has lower winter temperatures and has more rain and snow than the south side. (i) The two species of squirrel are very similar. Describe one way, which you can see in Figure 2, in which squirrel X is different from squirrel W. () Page 30 of 04

31 (ii) The Grand Canyon was formed about 6 million years ago. Explain how the two different species of squirrel could have developed from a common ancestor. (6) (iii) Squirrels W and X are separate species, but they are still very similar. Suggest why the two species have not become more different over time. (2) (Total 4 marks) Page 3 of 04

32 5 Glyphosate is a herbicide. Crop plants have been genetically modified to make them resistant to glyphosate. (a) Why is it an advantage to make crop plants resistant to glyphosate? (3) Page 32 of 04

33 (b) Figure shows how scientists produce genetically modified (GM) crop plants. The scientists use a GM-bacterium that can invade plant cells. (i) The ring of DNA shown in Figure acts as a vector for the resistance gene. What is the scientific name for this ring of DNA? () Page 33 of 04

34 (ii) At step in Figure, the ring of DNA is cut open. How do scientists cut open the ring of DNA? () (iii) At step 5 in Figure, plant cells and GM-bacteria are put on agar containing glyphosate. Explain why the scientists add glyphosate to the agar. (2) Page 34 of 04

35 (c) Some people disagree with the use of GM herbicide-resistant crop plants. Figure 2 shows data published on a website in 203. A journalist used the data to claim: Scientists show that GM crops cause kidney disease in humans. Use information from Figure 2 to evaluate the evidence for this claim. Page 35 of 04

36 (4) (Total marks) 6 Genetic disorder E is a condition caused by a change in the chromosomes. (a) Figure shows the chromosomes from one cell of a person with genetic disorder E. (i) How do you know this person is female? Use information from Figure. () (ii) Describe how the chromosomes shown in Figure are different from the chromosomes from a person who does not have genetic disorder E. (2) Page 36 of 04

37 (b) As a woman gets older, the chance of her having a baby with genetic disorder E increases. Figure 2 shows this. (i) The chance of a 35-year-old woman having a baby with genetic disorder E is 2 per 000 births. What is the chance of a 40-year-old woman having a baby with genetic disorder E? per 000 births () (ii) A 40-year-old woman is more likely than a 35-year-old woman to have a baby with genetic disorder E. How many times more likely? times () Page 37 of 04

38 (c) A 4-year-old woman wants to have a baby. A 4-year-old woman has an increased chance of having a baby with genetic disorder E. Doctors can screen embryos for genetic disorder E. The table gives some information about two methods of embryo screening. Method Method 2. The woman is given hormones to cause the release of a few eggs. The eggs are taken from her body in a minor operation. The eggs are fertilised in a glass dish. 2. One cell is taken from each embryo when the embryo is 3 days old. 3. Cells are screened for genetic disorder E. 4. An unaffected embryo is placed in the woman s uterus. Embryos that are not used are destroyed or used in medical research.. The woman gets pregnant in the normal way. 2. Cells are taken when the embryo is 0 weeks old. 3. Cells are screened for genetic disorder E. 4. An unaffected fetus is allowed to develop. If the fetus has genetic disorder E, the woman can choose to have an abortion. 5. This method costs about This method costs about 600. Use information from the table to give two advantages and one disadvantage of Method compared with Method 2 for detecting genetic disorder E. Advantages of Method :. 2. Disadvantage of Method : (3) (Total 8 marks) Page 38 of 04

39 7 Fossils give us information about organisms from a long time ago. (a) Amber is a solid, glass-like material. Amber is formed from a thick, sticky liquid which oozes out of pine trees. The image shows two fossil insects in amber. fkienas/istock/thinkstock (i) Suggest how the insects came to be preserved in the amber. (2) (ii) Give two other ways fossils are formed.. 2. (2) Page 39 of 04

40 (b) The fossil record shows that many organisms, including the dinosaurs, became extinct 65 million years ago. One theory was that volcanic activity might have caused this mass extinction. Many scientists believe that this extinction was caused when an asteroid collided with the Earth. (i) A new scientific theory may replace an old theory. Why might this happen? Tick ( ) one box. Evidence from amber is unreliable. Internet evidence is more reliable than fossil evidence. New technology provides more valid evidence. () (ii) Give three reasons, other than volcanic activity and collision with an asteroid, why a species may become extinct (3) (Total 8 marks) Page 40 of 04

41 8 DNA is the genetic material of human cells. Figure shows the structure of part of a DNA molecule. (a) (i) Describe where DNA is found in a human cell. (2) (ii) When a cell divides by mitosis the new cells are genetically identical. What causes the cells to be genetically identical? () (b) Many genes have different forms called alleles. (i) A person has polydactyly (extra fingers or toes). Polydactyly is caused by a dominant allele. What is the smallest number of copies of the dominant allele for polydactyly that could be found in a body cell of this person? () (ii) Another person has cystic fibrosis. Cystic fibrosis (CF) is caused by a recessive allele. How many copies of the recessive CF allele are there in a body cell of this person? () Page 4 of 04

42 (c) A burglar broke into a house. The burglar cut his hand on some broken glass. Scientists extracted DNA from the blood on the broken glass. The scientists analysed the DNA from the glass and DNA from three suspects, A, B and C. The scientists used a method called DNA fingerprinting. Figure 2 shows the scientists results. Which suspect, A, B or C, is most likely to have been the burglar? Tick ( ) one box. A B C () (Total 6 marks) Page 42 of 04

43 9 (a) Evidence about extinct species of animals and plants comes from fossils. Below is a photograph of a fossil of a bird-like animal called Archaeopteryx. Archaeopteryx lived about 50 million years ago. Wlad74/iStock/Thinkstock (i) Suggest how the fossil of Archaeopteryx was formed. (2) (ii) Scientists have found other fossils of the ancestors of modern birds, but the fossil record is very incomplete. Suggest two reasons why there are gaps in the fossil record.. 2. (2) Page 43 of 04

44 (b) There are many different species of bird on the Earth today. Describe how these different species may have evolved from an ancestor such as Archaeopteryx. (4) (Total 8 marks) 20 The photograph shows a fossil of a prehistoric bird called Archaeopteryx. By Ghedoghedo (own work) [CC-BY-SA-3.0 ( or GFDL ( /fdl.html)], via Wikimedia Commons; By Steenbergs from Ripon, United Kingdom (Small Fishing Boat In North Sea) [CC-BY-2.0 ( via Wikimedia Commons. Page 44 of 04

45 (a) Describe three ways fossils can be made. (3) (b) The drawing shows what an Archaeopteryx might have looked like when it was alive. Scientists think that Archaeopteryx was a predator. Page 45 of 04

46 (i) Look at the drawing. Write down three adaptations that might have helped Archaeopteryx to catch prey. How would each adaptation have helped Archaeopteryx to catch prey? Adaptation How it helps Adaptation 2 How it helps Adaptation 3 How it helps (3) (ii) Archaeopteryx is now extinct. Give two reasons why animals may become extinct.. 2. (2) (Total 8 marks) 2 Some genetic disorders are caused by alleles inherited from the parents. (a) What are alleles? () Page 46 of 04

47 (b) Describe how embryos can be screened for the alleles that cause genetic disorders. (4) (c) Polydactyly is a genetic disorder that leads to extra fingers or toes. Polydactyly is caused by a dominant allele, D. The photograph shows the hand of a person with polydactyly. Adem Demir/Hemera. Page 47 of 04

48 A man has polydactyly. His wife does not have polydactyly. This couple s children have a 50% chance of having polydactyly. Draw a genetic diagram to explain why. (3) (d) Cystic fibrosis is another genetic disorder. It is caused by a recessive allele. The diagram shows the inheritance of cystic fibrosis in one family. Page 48 of 04

49 Woman 5 is pregnant with her fourth child. What is the probability that this child will have cystic fibrosis? Draw a genetic diagram to explain your answer. Use the following symbols. N = allele for normal health n = allele for cystic fibrosis (4) (Total 2 marks) 22 The diagram shows part of a DNA molecule. (a) (i) In which part of an animal cell is DNA found? () Page 49 of 04

50 (ii) Complete the following sentence. The letters A, C, G and T in the diagram represent four different compounds called. () (iii) One strand of the DNA, in the section labelled X, contains the following sequence of these compounds: T A T G G G T C T T C G How many amino acids would this section of the DNA code for? () (iv) The section of DNA described in part (a) (iii) is a small part of a gene. The sequence of compounds A, C, G and T in the gene is important. Explain why. (2) Page 50 of 04

51 (b) Read the following information about genetic engineering. The caterpillar of the European Corn Borer moth feeds on the fruits of maize (sweet corn). There is a chemical called Bt-toxin which is poisonous to the corn borer caterpillar but not to humans. Scientists carried out the following steps.. The Scientists made a bacterial plasmid to which they added two genes: Bt gene, which coded for production of the Bt-toxin kan r gene, which coded for resistance to an antibiotic called kanamycin. 2. They used this plasmid to produce genetically modified bacteria which could invade plant cells. 3. They mixed these genetically modified bacteria with pieces cut from maize leaves. 4. They placed the pieces of maize leaf on agar jelly in a Petri dish. The agar jelly contained the antibiotic, kanamycin. The kanamycin killed most of the pieces of maize leaf, but a few survived. 5. They took some cells from the surviving pieces of maize leaf and grew them in tissue culture. The result was maize plants that now contained the Bt gene, as well as the kan r gene, in all of their cells. (i) What is a plasmid (Step )? (2) (ii) Why did the scientists add kanamycin to the agar jelly (Step 4)? (2) Page 5 of 04

52 (iii) The scientists grew each Bt-maize plant from a single cell which contained the Bt gene. Explain why all the cells in the Bt-maize plant contained the Bt gene. (2) (iv) Kanamycin is an antibiotic. Some scientists are concerned that the gene for kanamycin resistance has been put into maize. Suggest why. (2) (Total 3 marks) 23 CRAM is an inherited condition which causes muscle breakdown. The breakdown products enter the urine, making it dark-coloured. The diagram below shows the inheritance of CRAM in one family. Page 52 of 04

53 CRAM is caused by a recessive allele, n. The allele for normal health is N. (a) (i) What is an allele? () (ii) What does recessive mean? () (iii) Give evidence from the diagram that CRAM is caused by a recessive allele. () (b) (i) Person 2 is homozygous for CRAM. What does homozygous mean? () (ii) None of person 2 s children have CRAM. Explain why. (2) (c) Persons 7 and 8 want to have another child. (i) What is the probability that this child will have CRAM? Draw a genetic diagram to explain your answer. Probability = (4) Page 53 of 04

54 (ii) To avoid having another child with CRAM, persons 7 and 8 may decide to use embryo screening. Two ways of doing this are: PGD (pre-implantation genetic diagnosis) CVS (chorionic villus sampling). PGD involves IVF (in vitro fertilisation) of a few eggs, then taking a cell from each embryo when it is 3 days old. The image below shows how the cell is removed. Rtimages/iStock/Thinkstock The DNA in the cell can then be tested. An unaffected embryo can be implanted in the woman s uterus. The possibility of a false positive result is around in 6. The procedure costs about Affected embryos would be discarded. Extra unaffected embryos might be frozen and kept for later implantation. Alternatively, the extra embryos might be used in scientific research. CVS involves taking a sample of blood from the placenta a few weeks into pregnancy. DNA from white blood cells can then be tested. If an affected embryo is detected, the parents then have to decide whether to terminate the pregnancy or allow it to continue. CVS has a percent chance of giving an incorrect result and a 0.9 percent chance of causing a miscarriage. CVS costs about 600. Page 54 of 04

55 Evaluate the benefits of these two methods of embryo screening. You should include a conclusion to your evaluation. (5) (Total 5 marks) 24 This question is about evolution in humans. The graph shows: the estimated brain volume of different species of humans the time when the different species existed on Earth. The data is plotted for modern humans (Homo sapiens) and for three types of extinct ancestors of humans. Page 55 of 04

56 Millions of years ago Key Each point plotted on the graph shows the estimate for one human. (a) (i) As humans evolved, their brain volume changed. What has happened to human brain volume over the past 4 million years? () (ii) Why is the evidence for estimated brain volume for Homo sapiens stronger than the evidence for Australopithecus afarensis? () (b) In a book, the brain volume of a different species, Australopithecus africanus, is stated to be about 600 cm 3. Use evidence from the graphic above to estimate when Australopithecus africanus lived on Earth. Estimate = million years ago () Page 56 of 04

57 (c) Scientists believe that modern humans evolved by natural selection from Australopithecus afarensis. (i) Complete the following sentence. In the nineteenth century, the scientist who suggested the theory of evolution by natural selection was Charles. () (ii) In the nineteenth century, many people did not accept this scientist s theory. Give one reason why. () (Total 5 marks) 25 Read the information. Insects can be both useful and harmful to crop plants. Insects such as bees pollinate the flowers of some crop plants. Pollination is needed for successful sexual reproduction of crop plants. Some insects eat crops and other insects eat the insects that eat crops. Corn borers are insects that eat maize plants. A toxin produced by the bacterium Bacillus thuringiensis kills insects. Scientists grow Bacillus thuringiensis in large containers. The toxin is collected from the containers and is sprayed over maize crops to kill corn borers. A company has developed genetically modified (GM) maize plants. GM maize plants contain a gene from Bacillus thuringiensis. This gene changes the GM maize plants so that they produce the toxin. (a) Describe how scientists can transfer the gene from Bacillus thuringiensis to maize plants. (3) Page 57 of 04

58 (b) Would you advise farmers to grow GM maize plants? Justify your answer by giving advantages and disadvantages of growing GM maize plants. Use the information from the box and your own knowledge to help you. (4) (Total 7 marks) 26 Figure shows a fossil of a sea animal called a Plesiosaur. The Plesiosaur was alive about 35 million years ago. Figure By Andy Dingley (Own work) [CC-BY-SA-3.0 ( via Wikimedia Commons Page 58 of 04

59 (a) How can fossils give evidence for evolution? Tick ( ) one box. Newer fossils are simpler than older fossils. Fossils show change over time. All fossils show the bones of animals. () (b) Plesiosaurs lived in the sea. There was mud at the bottom of the sea. Suggest how the fossil shown in Figure may have been formed after the animal died. (3) (c) Figure 2 shows what scientists think a living Plesiosaur may have looked like. Figure 2 Andreas Meyer/Hemera/Thinkstock Page 59 of 04

60 Scientists think that the Plesiosaur had smooth skin, with no scales. The scientists cannot be certain what the skin of a Plesiosaur was like. Suggest why. () (d) Plesiosaurs are now extinct. Give two possible reasons why.. 2. (2) (Total 7 marks) 27 In sexual reproduction, an egg fuses with a sperm. (a) (i) Draw a ring around the correct answer to complete the sentence. cloning. An egg and a sperm fuse together in the process of fertilisation. mitosis. () (ii) Egg cells and sperm cells each contain the structures given in the box. chromosome gene nucleus List these three structures in size order, starting with the smallest. (smallest) 2. 3 (largest) (2) Page 60 of 04

61 (iii) The egg and the sperm contain genetic material. Draw a ring around the correct answer to complete the sentence. carbohydrate. The genetic material is made of DNA. protein. () (b) The diagram below shows the inheritance of X and Y chromosomes. (i) Draw a tick ( ) on the part of the diagram that shows a sperm cell. () (ii) What is the chance of having a female child? Give the reason for your answer. (2) (Total 7 marks) 28 Phenylketonuria (PKU) is an inherited condition. PKU makes people ill. (a) PKU is caused by a recessive allele. (i) What is an allele? () Page 6 of 04

62 (ii) What is meant by recessive? () (b) The diagram below shows the inheritance of PKU in one family. (i) Give one piece of evidence from the diagram that PKU is caused by a recessive allele. () (ii) Persons 6 and 7 are planning to have another child. Use a genetic diagram to find the probability that the new child will have PKU. Use the following symbols in your answer: N = the dominant allele for not having PKU n = the recessive allele for PKU. Probability = (4) (c) Persons 6 and 7 wish to avoid having another child with PKU. A genetic counsellor advises that they could produce several embryos by IVF treatment. (i) During IVF treatment, each fertilised egg cell forms an embryo by cell division. Name this type of cell division. () Page 62 of 04

63 (ii) An embryo screening technique could be used to find the genotype of each embryo. An unaffected embryo could then be placed in person 7 s uterus. The screening technique is carried out on a cell from an embryo after just three cell divisions of the fertilised egg. How many cells will there be in an embryo after the fertilised egg has divided three times? () (iii) During embryo screening, a technician tests the genetic material of the embryo to find out which alleles are present. The genetic material is made up of large molecules of a chemical substance. Name this chemical substance. () (d) Some people have ethical objections to embryo screening. (i) Give one ethical objection to embryo screening. () (ii) Give one reason in favour of embryo screening. 29 (a) () (Total 2 marks) Complete the sentences about evolution. Draw a ring around the correct answer to complete each sentence. artificial (i) Darwin suggested the theory of evolution by natural selection. asexual () Page 63 of 04

64 (ii) Darwin s theory of evolution says that all species of living things have artificial evolved from complex life forms. simple three billion () (iii) Most scientists believe that life first developed about three million years ago. three thousand () (b) Darwin s theory of evolution was only slowly accepted by other people. Give two reasons why. 2 (2) (c) Diagram shows one model of the relationship between some animals. Diagram (i) Complete the sentence. The model shown in Diagram is an evolutionary. () Page 64 of 04

65 (ii) Which two of the animals in Diagram are most closely related? and () (iii) Diagram 2 shows a more recent model of the relationship between the animals. Diagram 2 Suggest one reason why scientists have changed the model of the relationships between the animals shown in the diagram. Draw a ring around the correct answer. more powerful computers new evidence from fossils new species discovered () (Total 8 marks) Page 65 of 04

66 30 Peas grow in pods on pea plants. A gardener grew four varieties of pea plants, A, B, C and D, in his garden. The gardener counted the number of peas in each pod growing on each plant. The table shows his results. Variety Range of number of peas in each pod Mean number of peas in each pod A B C D (a) Give one environmental factor and one other factor that might affect the number of peas in a pod. Environmental factor Other factor (2) (b) The gardener thinks that he will get the largest mass of peas from his garden if he grows variety D. Why is the gardener not correct? Suggest one reason. () Page 66 of 04

67 (c) It is important that carbon is cycled through living things. After he has picked the peas, the gardener puts the dead pea plants onto a compost heap. Over the next few months, the carbon in the carbon compounds from the pea plants is returned to the air. Describe how. (4) (Total 7 marks) 3 Darwin suggested the theory of natural selection. (a) Explain how natural selection occurs. (3) Page 67 of 04

68 (b) Latitude is a measure of distance from the Earth s equator. Scientists investigated the effect of latitude on: the time taken for new species to evolve the number of living species. The table shows the scientists results. Latitude in degrees North of equator Time taken for new species to evolve in millions of years Relative number of living species 0 (at the equator) (in the Arctic) As latitude increases environmental conditions become more severe. (i) Describe the patterns shown by the data. (2) Page 68 of 04

69 (ii) Suggest explanations for the patterns you have described in part (b)(i). (2) (Total 7 marks) 32 When humans reproduce, chromosomes and genes are passed on to the next generation. In each of the following questions, draw a ring around the correct answer to complete the sentence. cellulose. (a) A gene is a small section of DNA. protein. () X and X. (b) The sex chromosomes in the human male are X and Y. Y and Y. () 23 chromosomes. (c) (i) Most human body cells contain 46 chromosomes. 92 chromosomes. () Page 69 of 04

70 (ii) The number of chromosomes in a human gamete (sex cell) the same number as is half the number in body cells. twice the number () fertilisation. (d) Gametes are produced by meiosis. mitosis. () (Total 5 marks) 33 The photograph shows a fossil footprint. The fossil was found in a rock at the bottom of a shallow river. Scientists believe this is the footprint of a dinosaur. The dinosaur was alive 0 million years ago. Pearl Jackson/iStock (a) (i) Suggest how the fossil shown in the photograph was formed. () (ii) Fossils may also be formed by other methods. Describe one other method of forming a fossil. () Page 70 of 04

71 (b) Dinosaurs are now extinct. Give two factors that can cause extinction.. 2. (2) (c) How can fossils give evidence for evolution? () (d) Scientists are uncertain about how life began on Earth. Why? () (Total 6 marks) 34 In each question, draw a ring around the correct answer to complete the sentence. (a) Our understanding of how genes are inherited is mostly because of Darwin. the work of Lamarck. Mendel. () Page 7 of 04

72 (b) A scientist investigated inheritance in pea plants. The scientist crossed tall pea plants with short pea plants. Diagram shows the results. Diagram Some tall offspring Some short offspring In the rest of this question, the following symbols are used to represent alleles. T = allele for tall t = allele for short (i) The st cross in Diagram produced 20 offspring. All of these offspring were tall. TT. This shows that plant contained the alleles Tt. Page 72 of 04

73 tt. () a dominant allele. (ii) Plant 3 is tall because of the environment. a recessive allele. () (c) Diagram 2 gives more information about the cross between plant 3 and plant 4. Diagram 2 This cross produced some tall offspring and some short offspring. :. The ratio of tall to short offspring in Diagram 2 is 2:. 3:. () (d) Two short plants were crossed. This cross produced 00 offspring. 00 short plants. The expected offspring would be 50 tall plants and 50 short plants. 75 tall plants and 25 short plants. () (Total 5 marks) Page 73 of 04

74 35 The diagram shows some of the cell divisions that occur during human reproduction. (a) (i) Name the type of cell division that produces cell D from cell B. () (ii) Which organ in the male body produces cell C from cell A? () (b) (i) Cells A and B each contain 46 chromosomes. How many chromosomes would there be in the nucleus of cell C? () (ii) Why is it important that cell C has this number of chromosomes? (2) (Total 5 marks) Page 74 of 04

75 Mark schemes (a) only genetic causes any one from: pattern of scales number of fins eye colour only environmental causes: scar both genetic and environmental causes: length (b) B b b bb b Bb bb (c) any bb circled allow 2 correct for mark 2 (d) 0.5 allow ecf from 04.2 (e) ( / 2 =) allow ecf from 04.4 (f) mutation allow change in diet / hormones / DNA [9] 2 (a) Relevant organelle found in cells such as nucleus, mitochondria (b) Linnaeus (c) Kingdom Page 75 of 04

76 (d) (e) Homo Sapiens Any one from: ignore underlining, italics or not, capitals or not to know which species are closely related or study evolution to monitor biodiversity to identify different organisms such as two different species [5] 3 (a) animal cells also have cell membrane (b) allow or (c) 9. (%) allow 9.09 (%) or 9 (%) with no working shown for mark allow 9. (%) with no working shown for 2 marks (d) More likely Less likely allow 3 marks for 4 correct allow 2 marks for 3 correct allow mark for 2 correct more than one tick in a row negates a mark 4 [8] 4 (a) asexual reproduction Page 76 of 04

77 (b) (c) mitosis clones (d) 44 [4] 5 (a) wolves (b) moose and wolves are on different scales (c) wolf population has increased so more moose are eaten do not accept there are more wolves than moose (d) any two from: (other) predators allow correct examples allow humans hunting moose (new) pathogens allow diseases competition 2 (e) any four from: variation (within species) of antler size allow description relating to antlers (caused by) different genes as a result of sexual reproduction / process of meiosis / mutation (phenotype) most suited to environment most likely to survive and breed ignore natural selection unqualified genes for large antlers (more likely to be) passed on to next generation 4 reference to mate selection or fighting or gaining territory or competition for mates or avoiding predation [0] Page 77 of 04

78 6 (a) human cells have cell membrane or human cells have no cell wall (b) can no longer synthesise proteins (c) antibiotics are being developed at a slower rate than emergence of new resistant strains resistant strains mean we cannot treat (common) infections reduce (future) cost of antibiotic resistant infections [5] 7 (a) a change in the DNA / gene (b) produces a different protein / enzyme that is responsible for colour (c) parents genotype both Bb allow correctly derived gametes offspring genotypes correctly derived bb identified as blue allow ring around bb only allow ecf or (d) cross with bb / blue carp allow annotated Punnett square diagram(s) of cross with bb carp if any offspring are blue, the parent was Bb / heterozygous allow converse allow cross with known Bb carp if any offspring are blue, other parent was Bb / heterozygous [9] 8 (a) same name to everyone Page 78 of 04

79 (genus) part gives information on ancestry (b) any one from: (c) DNA / RNA analysis improvements to (electron) microscopes improved understanding of biochemical processes evidence of internal structures being more developed primitive bacteria / prokaryotes (often) from extreme environments / extremophiles [5] 9 (a) Nucleus (b) Type of cell Number of chromosomes extra lines from left cancel the mark 2 (c) X X X XX XX Y XY XY all three correct for 2 marks one or two correct for mark allow XY or YX in correct places 2 Page 79 of 04

80 (d) X X X XX XX Y either circled (e) in 2 [7] 0 (a) Characteristic Environmental Genetic Both Eye colour A scar Weight 3 (b) Key term Definition extra lines from the left negate the mark 2 Page 80 of 04

81 (c) Stage in selective breeding Order of stage Cows are bred over many generations 4 Parents are bred together 2 Cows with the desired characteristics are chosen Calves with the most desired characteristics are bred together 3 (d) (e) all 3 correct for 2 marks or 2 correct for mark beef / meat allow hardiness, disease resistance milk yield higher veterinary costs max. 2 less income from sale of (milk and meat) products [] (a) Feature Function (b) Contaminated food extra lines from the left negate the mark 2 Page 8 of 04

82 (c) any two from: (d) (e) cook food (thoroughly) pasteurise food wash hands properly disinfect work surfaces keep raw and cooked foods separate only drink clean water It will not cause sickness and diarrhoea side effects E B 2 D [9] 2 (a) cross / breed / mate different breeds of horse if the offspring are fertile then the two breeds are of the same species (b) select the fastest male and female to cross / mate allow any relevant characteristic, eg stamina select the fastest offspring and breed them repeat over several generations to produce faster horses (c) gene for the Bt poison is cut from the bacterial DNA / plasmid / chromosome ignore characteristic accept Bacillus thuringiensis using enzymes(s) and transferred to cotton plant cells / DNA / chromosome do not allow to cotton plant plasmid Page 82 of 04

83 (d) any four from: must have both advantages and disadvantages for full marks advantages increased yield as less eaten by insects fewer pesticides need to be used (so) producer can make more money Disadvantages: this point may only be gained if linked to one of the points above gene (for poison) could be passed on to wild plants may kill useful insects allow named insect eg bees ecosystem / food chain could be affected gene pool of cotton plants could be reduced allow less variation in cotton plant population max. 4 [2] 3 (a) Man s genotpe Hh both needed for the mark Woman s genotype hh (b) gametes correctly derived from parents genotypes in 05. offspring genotypes correctly derived from gametes all Hh circled Man s gametes Woman s gametes h h H Hh Hh h hh hh Page 83 of 04

84 (Probability =) any one from: 50% ½ 2 / in 2 2 in 4 : 2:2 (c) Level 3 (5 6 marks): A detailed and coherent evaluation is provided which considers a range of relevant points and comes to a conclusion consistent with the reasoning. Level 2 (3 4 marks): An attempt is made to relate relevant points and come to a conclusion. The logic may be inconsistent at times but builds towards a coherent argument. Level ( 2 marks): Discrete relevant points made. The logic may be unclear and the conclusion, if present, may not be consistent with the reasoning. 0 marks: No relevant content Indicative content adoption / gamete donation unsuitable as offspring not biologically theirs natural conception too risky / only 50% chance of healthy offspring natural conception would cause worry whether baby would be healthy or not (therefore) choice is between PGD and PND pros of PGD baby would be theirs results obtained at an early stage high chance baby produced would be healthy parents would have confidence of having a heathy baby from start of pregnancy lower risk of miscarriage compared to PND frozen embryos can be used to have another healthy child PGD occurs before pregnancy / implantation PGD does not involve abortion so less trauma / less pain / ethical comparison spare healthy embryos may be used for research / medical treatment cons of PGD slight / 0.2% chance of misdiagnosed embryo expensive procedure cost to NHS of non-essential procedure (unhealthy) embryos might be destroyed large number of embryos produced so healthy embryos may be destroyed ethical issues of using embryos for research some people are opposed to IVF due to their religious beliefs Page 84 of 04

85 pros of PND natural conception less invasive for mother psychological benefit of producing child naturally 99% / high chance that result of test will be conclusive cons of PND sampling technique invasive to mother risk of miscarriage risk of infection long wait before test can be carried out 50% chance baby will have allele for Huntington s disease parents will have a difficult decision to make if baby is unheathly baby may be aborted ethical / religious issues of abortion a justified conclusion 6 [] 4 (a) organisms that reproduce together to form fertile offspring (b) (i) fossils of P and Q in same stratum / layer / level / height (ii) (iii) earlier fossil in deeper layer / further down the fossils of animals S and T have many features in common, but T is more complex that S the fossil of animal S was found in a deeper layer of rock than the fossil of animal T Page 85 of 04

86 (c) (i) X has white tail / shorter tail allow other points eg X has furrier tail / smaller feet / is furrier or W has sharper claws / W has larger claws (ii) two (ancestral) populations separated / isolated (by geographical barrier / by canyon / river) genetic variation (in each population) / different alleles / different genotypes / (different) mutation(s) different environmental conditions / example described allow abiotic or biotic example the better adapted survive / natural selection occurs allow survival of the fittest ignore they adapt to the environment so (different / favourable) alleles / genes passed on (in each population) eventually two types cannot interbreed successfully allow to produce fertile offspring (iii) any two from: environments similar / described allow example, e.g. similar predator(s) / food / climate therefore similar adaptations / features / phenotypes suit accept suitable named feature original ancestor already well adapted ignore reference to not enough time for evolution. 2 [4] 5 (a) kills weeds among crops / does not kill crops (kills weeds) so less competition for named factor eg light / water / ions ignore space crops grow better / higher yield Page 86 of 04

87 (b) (i) plasmid (ii) (iii) use an enzyme allow correct example only some cells become GM / take up the plasmid / take up resistance gene allow idea of transfer of gene / plasmid to some plant cells from bacteria GM cells survive / non-gm cells are killed (c) Pro: (positive) correlation between use of glyphosate and number of cases of kidney disease allow mark for justified conclusion that the claim is not justified + any three from: Con: lack of controls / control group correlation does not prove a causal link some other factor could be the cause accept obesity / infection no evidence that kidney patients actually consumed GM crops / crops treated with glyphosate / no evidence about amount consumed or graph shows amount of herbicide not amount of GM crops grown or graph shows data only for maize and soya / not for other (GM) crops data have been manipulated by carefully chosen scales to make it look like they coincide data from some years is missing no data for the dosage of herbicide used allow kidney disease has been around for much longer than GM crops / better diagnosis of kidney disease. 3 [] 6 (a) (i) (female) has XX / only X s / no Y allow has X chromosomes ignore ref to genes / cells (ii) extra chromosome / has 47 chromosomes / one set has 3 copies no. 8 ignore reference to chromosome numbers other than 47 or no. 8 Page 87 of 04