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Inheritance Presentation


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inheritance, genes, chromosomes, punnet squares

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Inheritance Presentation

  1. 1. Hereditary Genetics Hereditary means something which is passed on from one generation to the next. What are we talking about?
  2. 2. What do we Inherit from our Parents?
  3. 3. What are? <ul><li>Chromosomes?
  4. 4. DNA?
  5. 5. Genes?
  6. 6. CG, AT?
  7. 7. Why can two right-handed parents have a left-handed child?
  8. 8. Why do some people look different to their parents?
  9. 9. What causes some people to be born disabled? </li></ul>
  10. 10. Chromosomes <ul><li>Most cells contain a nucleus
  11. 11. The nucleus contains long, thin strands of DNA (deoxyribonucleic acid).
  12. 12. The DNA contains the code to make every part of an organism.
  13. 13. Instructions for a particular characteristic is called a gene . </li></ul>
  14. 14. Chromosomes and DNA
  15. 15. Chromosomes in a Cell
  16. 16. A Real Photo
  17. 17. Human Chromosomes Homologous chromosomes
  18. 18. Chromosome Pairs <ul><li>Chromosomes always come in pairs. Humans have 23 pairs.
  19. 19. Each chromosome in the pair contains instructions for the same genes. The instructions may be the same or different, eg 'blonde hair' and 'black hair', or 'right handed' or 'left handed'.
  20. 20. In organisms which undergo sexual reproduction, one chromosome is inherited from each parent. Sex cells (eg sperm, egg, pollen) contain one chromosome from each pair, so 23 chromosomes. </li></ul>
  21. 21. Spotlight Science <ul><li>Page 7. </li></ul>
  22. 22. Mitosis Mitosis is for growth and repair of tissue.
  23. 23. Meiosis Meiosis produces sex cells, or gametes (sperm and egg) Each gamete has half the number of chromosomes – one from each pair. Each allele is stored on one chromosome. l
  24. 24. Mendel Mendel was an Austrian Monk who worked with peas. Where's Austria?
  25. 25. Mendel Used Peas Mendel studied characteristics. A characteristic is something which can change. Mendel studied five characteristics in peas.
  26. 26. Pollination and Flowers
  27. 27. Cross Pollination
  28. 28. First Generation Plants Image from a Japanese textbook:
  29. 29. Third Generation Plants The second generation plants' flowers were all pink. When the second-generation flowers were self-pollinated, three quarters of the third-generation had pink flowers and one quarter and white flowers. From this Mendel determined that each of the second-generation pea plants contained one pink gene from one of their parent plants, and one white gene from the other parent. Since they were all pink, he determined that the pink gene would always show up if present; he called this the dominant gene. The recessive gene 'recedes' and can remain hidden for several generations, and only appears when no dominant gene is present.
  30. 30. Vocabulary A characteristic is a feature which can take different forms, eg hair colour, handedness. A trait is a possible form of a characteristic, eg blonde hair, left handed. A gene is the instruction for an inherited characteristic. Different forms of a gene are known as alleles, which are written as letters. A dominant allele will always show up. It's written as a capital letter. A recessive allele will only show up if there is no dominant. It's written as a lowercase letter.
  31. 31. MORE vocabulary Everyone has two alleles for each gene, with one from each parent. A gen otype is the the gen es, written as two letters. A ph enotype is the ph ysical characteristic that we can see. HH
  32. 32. Punnet Squares A punnet square is used to calculate the probability of outcomes. Probability does not mean it will happen. There is a one in two chance of a head when I flip a coin, but this doesn't mean I will always get half heads.
  33. 33. Discontinuous Human Characteristics All these are controlled by one gene in humans. These show more variation in Europeans. Why? Images in my presentation from class included a European sailing ship, the Josean Empire (Korean) logo and the Great Wall of China.
  34. 34. Tongue Rolling
  35. 35. Hitchhikers Thumb
  36. 36. Hair Colour Dark (brown / black) hair is dominant to light-coloured hair (blonde, ginger etc). Like all these examples, this is a simplification as hair colour is controlled by many different genes.
  37. 37. Eye Colour Dark (brown / black) eyes are dominant to light-coloured eyes (blue, hazel etc).
  38. 38. Punnet Squares Example Right handedness (H) is dominant to left handedness (h). A right handed parent who also carries the left handed allele has four children with a left handed parent. a) draw a punnet square for this cross. b) what is the probability that each child will be right handed? c) how many of the six children would you expect to be left handed?
  39. 39. More Vocabulary Homozygous means both alleles are the same. 1. Homozygous dominant means both alleles are dominant. 2. Homozygous recessive means both alleles are recessive. 3. Heterozygous means both alleles are different. Which one will have a recessive phenotype? Which one will have all children the same?
  40. 40. <ul>1. Ayumi, who is homozygous right handed, has four children with Satoshi, who is left handed. A) Write down the genotypes and phenotypes of Ayumi and Satoshi. B) Draw a punnet square to calculate the genotype and phenotype of their offpsring. C) Explain why all of the children are right handed. 2. One of Ayumi and Satoshi's children, Atsumi, has children with a Yuuto, who is heterozygous. Determine the phenotype ratio for Atsumi and Yuuto's children. 3. Black hair B is dominant to blonde hair, b. Mary, who has black hair, has five children with Bill, who has blonde hair. All the children have black hair. a) What is Mary's genotype most likely to be? Explain why we can't be certain. b) What is the genotype of Mary and Bill's children? c) One of Mary and Bill's children has children with a blonde haired person. What percentage of their children do you expect to have blonde hair? </ul>
  41. 41. Punnet Squares Worksheets In-class work
  42. 42. Male/Female difference Males have an x and a y chromosome. Females have two x chromosomes. Which sex chromosome (x or y) does sperm have? Which sex chromosome do eggs have? Draw a punnet square of this cross.
  43. 43. King Henry VIII King Henry the VIII had a lot of wives.,_Traitors_Gate.jpg
  44. 44. Colour Blindedness Colour blindedness is recessive on the x chromosome. Which gender is more liky to be colourblind?
  45. 45. Explain... Explain why colourblindedness is more likely to occur in males than females. Your explanation should be suited to a fifth grade child. It should explain: 1. dominant and recessive. 2. X and Y chromosomes and their role in gender 3. Why boys are more likely to be colourblind than girls. 4. It should also give an example of what is required for a girl and boy to be born colourblind.
  46. 46. Pedigree Charts
  47. 47. Sex Chromosome Problems Sometimes errors occur during meiosis (the production of gametes) and the zygote (sperm and egg combined) have the wrong number of sex chromosomes. In class we looked at a few of the more common syndromes that result from sex chromosome abnormalities, however I do not expect you to remember what they all are.
  48. 48. Quick Review <ul>1. Who was Mendel? 2. Mendel found that smooth peas are dominant to wrinkled peas. Mendel crosses two pea plants which are both heterozygous for pea texture. Draw a punnet square to show the cross, and determine the phenotype ratio of the offspring. 3. Tall pea plants are dominant to short pea plants. A pure-breeding (homozygous) short pea plant is crossed with a heterozygous pea plant. Determine the phenotype ratio of the offspring. </ul>
  49. 49. Pedigree Charts
  50. 50. Pedigree Charts <ul><li>A pedigree chart is a diagram which shows the phenotypes for one gene through generations.
  51. 51. A female is represented by a circle and a male a square.
  52. 52. A filled in (black) shape represents the presence of one phenotype and an empty (white) shape represents the other phenotype.
  53. 53. The dominant trait can be determined because two parents with the ____________ trait can have offspring with the __________ trait, but not vice versa. </li></ul>
  54. 54. The Cryptogram The human genome contains over three billion base pairs, about one and a half percent of which stores codes for twenty three thousand proteins, and the rest stores other information, including controversial &quot; junk DNA &quot; which has no known purpose. The total amount of data is about six hundred megabytes. Each cell copies this entire code during mitosis , and it only takes about eighty minutes to copy the entire genome. Cells very rarely copy any of the code incorrectly, but if a mistake is made, it is called a mutation , and can be good, bad or have no effect.
  55. 55. Poster Design an A3 poster to show your family's genotypes and phenotypes. 1.Include as many people as possible. 2. It should be a pedigree chart, but style can vary. (eg it doesn't need to use squares and circles if it's obvious) 3. It may include photos or pictures. 4. If possible, show them with the phenotype, eg rolling their tongue or holding a pen in one hand. Be creative.
  56. 56. DNA DNA = Deoxy--ribo--nucleic Acid It stores the code to make all living things. It is like a recipe book. It's shape is a double helix, like a twisted ladder. Image source: wikipedia
  57. 57. Nucleotides DNA is made of four different nucleotides joined together. Each one has a sugar, a phosphate and a base. The base is the only part that is different. A always pairs with T. G always pairs with C. Please only learn the above; don't memorise the structure of the DNA molecule. This image is included because it is licensed under Creative Commons.
  58. 58. How the Code is Stored The order of the base pairs stores code for proteins. Every part of our body is made of protein, and the code is in our DNA. Our DNA has some differences but is mostly the same. It is also similar to other primates. It is the ORDER of the base pairs which is the same or different.
  59. 59. Proteins Proteins make up all living things. Hair, toenails, skin etc are all made of proteins. Proteins are made of amino acids. There are twenty different amino acids used by animals. A good diagram here:
  60. 60. Quick Review <ul><li>Explain the terms DNA, chromosome, gene, genotype, genome, phenotype, dominant, recessive.
  61. 61. In pea plants, green pea pods are dominant to yellow pea pods. Karina cross-pollinates a heterozygous plant with a plant with yellow pods. a) What colour are the pods of the heterozygous plant. b) Draw a punnet square for the cross. c) Determine the phenotype ratio of the next generation.
  62. 62. Explain how our DNA stores code to make an organism. You should consider how it is coded and what the information tells. </li></ul>
  63. 63. Incomplete Dominance <ul><li>Incomplete Dominance occurs when the phenotype of the heterozygous genotype shows some of each of the homozygous phenotypes.
  64. 64. For example, the Snapdragon flower can be: RR = red rr = white Rr = pink </li></ul>
  65. 65. A good diagram here:
  66. 66. Problems <ul><li>A Snapdragon plant with pink flowers is self-pollinated. A flower gardener plants 100 seeds from it. How many can she expect to have: a) Red flowers? b) Pink flowers? c) White flowers? Draw a punnet square to illustrate your answer. </li></ul>
  67. 67. Co-dominance <ul><li>Co-dominance occurs when both alleles contribute to the phenotype. Blood type follows co-dominance.
  68. 68. The four phenotypes are A, B, AB and O.
  69. 69. A produces A antigens and B produces B antigens; AB produce both. O produces none and is recessive to the others.
  70. 70. Can a parent with blood type A and a parent with blood type O have? a) children with A? b) children with B? c) children with AB? d) children with O? </li></ul>
  71. 71. Blood Types
  72. 72. Replication What does 'replicate' mean?
  73. 73. DNA Replication This image from wikipedia is to show that in order to make a copy of itself, the DNA strand unravels itself and the two strands separate into what will become two new strands. Extra base pairs fill in the missing half of the two new strands. Main idea: The other half of the DNA molecule exists so that the DNA molecule can easily and efficiently copy itself, while rarely making a mistake. When it does make a mistake, this is called a mutation. This diagram is for visual purposes only; please do not learn any of the terms on it – they are well above Grade 8 level!
  74. 74. Replicating Class DNA <ul><li>Cut the DNA in half and give half to another student. Cut the DNA strand in half, and insert new base pairs to show how the DNA replicates. Then answer the following: </li></ul><ul><li>During what process does DNA replication occur?
  75. 75. What could or would happen if a) One base pair was incorrectly placed? b) Several base pairs were incorrectly placed? c) One base pair was chopped off during the process?
  76. 76. How might this be good for the individual? Bad for the individual? Good for the species? Bad for the species? </li></ul>
  77. 77. Mutations <ul><li>The human genome is about three billion base pairs long, and it is usually copied without error.
  78. 78. If an error does occur the genes are changed. This is called a mutation.
  79. 79. Mutations usually have no effect, are sometimes harmful and occasionally beneficial.
  80. 80. Blue eyes in humans are a recent mutation, therefore all blue-eyed people share a common ancestor. </li></ul>
  81. 81. Adaptation An adaptation is a change which helps an organism survive and reproduce in its environment. Images:wikipedia
  82. 82. Evolved Animals Choose an interesting environment. I want you to 'design' an animal that is well-adapted to that environment. Make an A4 poster of it. You may do the whole thing by hand, draw the animal by hand and the words on a computer, or if you are good at art programs on a computer, design the whole thing
  83. 83. Part 2 Takumi is going on a holiday to the desert in Australia, and, worried that his hotel might not be clean, he takes a box of cleaners with him. When he arrives in his hotel, a sinkoism runs out, and despite Takumi chasing it, within a few minutes he has escaped into the desert. Not long later, Ben returns to Australia, taking with him his cleaning supplies. Low and behold, a sinkosim makes a run, and with a few minutes she has escaped. The two fall in love and produce many offspring, however they must adapt to their new environment.
  84. 84. From Niagra to the Vatican
  85. 85. From the Deep Dark Ocean to The City <ul><li>Shion is holidaying in a dark and deserted pacific island, and while swimming during the daytime a winged stinger-fish climbs into her suitcase to escape the bright pacific sun. Shion doesn't realise until her next stopover, in ____________, at which time she runs off into the city.
  86. 86. Not far behind her is another tourist, who also releases a stinger fish.
  87. 87. The two meet up, fall in love and produce lots of winged stinger-fish. How will they adapt and survive in their new environment? </li></ul>
  88. 88. From Alaska to Narnia Narnia picture:
  89. 90. We discussed how similar skeletons of mammals are, as can be shown at the link below, and what scientists believe this tells about our origins (that we are related). We also discussed the existence of the tailbone, and how that suggests that humans once had a tail.
  90. 91. Species If two organisms can produce fertile offpsring, they are considered a species. Image source: Wikipedia (Poodle and German Shepherd)
  91. 92. Infertile Offspring?
  92. 93. Mule <ul><li>A horse and a donkey can produce a mule, but the mule is infertile (cannot produce offspring).
  93. 94. Therefore horses and donkeys are different species. </li></ul>
  94. 95. Our Crazy Pictures Life evolves anywhere it can, and where selection pressures are strong (it's harder to survive) evolution is faster. Our pictures were funny, but some were quite realistic.
  95. 96. Where's This? Tubifex tubifex
  96. 97. Flagellum Bacteria have evolved a flagellum to help them move towards food or water. It works like a motor.
  97. 98. Human Influence on Evolution We have studied how species adapt to their natural environment, and those that survive are likely to have more offspring. This is called n________ s__________. Humans change the gene pool of many other species by selecting which ones reproduce. This is called selective breeding . Selective breeding is different from g________ e_______ in that organisms can only be genetically combined if they are of the same or similar species.
  98. 99. Carrots It is believed that the carrot was first found growing in present-day Afghanistan around 5000 years ago, in colours of white, black and purple. It is believed that this cave drawing Egypt from 2000 years ago is of a purple carrot. We looked at historical drawings of carrots, but of course I don't expect you to remember them! Main idea: humans have selectively bred plants and animal species to the point that most look little like their ancestors from thousands of years ago before humans began farming them.
  99. 100. Greeks on Carrots Theophrastus (371-287bc, Greece), the “father of Botany” reports of carrots being found in Greece and Asia. Archaeobotanists have analyzed plant DNA in Greek-made pills from a 130 BC shipwreck, and found that the pills appear to contain carrot, parsley, radish, alfalfa, chestnut, celery, wild onion, yarrow, oak, and cabbage.
  100. 101. Cows Cattle (cows) have been domesticated by humans since the neolithic period. They are unusual in that they rarely exist in the wild anymore. We have selectively bred cows to produce a lot of milk (and meat?).
  101. 102. What's Not Good about Selective Breeding Selective Breeding of can cause food to be less healthy than old varieties. We get more food faster, but it's not necessarily better. Through selective breeding of cows (and often the use of drugs) the average annual production of milk has increased from 3,300kg per year to 8,500 kg per year in a century.
  102. 103. Evidence for Evolution The fossil record Observable changes within recordable human history, or even smaller times. What is something which evolves very fast, and why? ANS: things with shorter lifespans evolve faster.
  103. 104. How did Life Begin? Evidence of very simple life on Earth called protobionts dates back to around 1 Billion years after the formation of the Earth. It is believed these formed naturally, and became more and more complicated, evolving into prokaryotic and then eukaryotic cells, and then eventually plants, animals etc.
  104. 105. What evolution can't explain (yet?) 1. How the first replicating molecules formed. Experiments have created some components (called RNA) of early life forms , but nothing advanced enough to copy itself. 2. How replicating molecules first formed into a cell. 3. How higher forms of life became conscious. We discussed whether plants, insects, monkeys, cats and babies were conscious.
  105. 106. Carbon 14 Most carbon is carbon-12, which means that it has ________ protons and ______ neutrons. Carbon-14 has an extra two ____________. In the atmosphere, the ratio of carbon-14 to carbon-12 is about 1 : 7 * 10 11 . Carbon 14 has a half life of 5730 years. This means that every 5730 years, exactly half of the carbon 14 will change into carbon-12. In the atmosphere, more carbon-14 is made. But in dead things, it is not, so the amount of carbon-14 slowly decreases over time. By measuring the amount of carbon-14 in something we can estimate how long since it died.
  106. 107. Simulation
  107. 108. Fossilised Dinosaur 'Dakota' is a fossilised Hadrosaur dinosaur. This means that small particles of rock went into its body, including skin, internal organs etc, and set into rock.
  108. 109. Extension: Dating a Dinosaur The dinosaur was 65 million years old. If a piece of its bone contained 1 billion C-14 atoms, calculate how many are left. Note: extension exercise beyond Grade 8 math level Hint 1: the half-life of C-14 is 5730 years. Answer: 0 Instead, scientists can use half lives of minerals to determine how old a layer of rocks is which contain the fossils.
  109. 110. What Assumption Does Carbon Dating Make? Radiometric dating assumes that the ratio of isotopes (eg C-14 to C-12) was the same thousands or millions of years ago as it is today. Most (but not all) scientists consider this a safe assumption.
  110. 111. Geologic Time Scale At this level I only expect you to remember the order (using PreCambrian, Paleozoic, Mesozoic and Cenozoic) and which types of organisms appeared in each.
  111. 112. Mass Extinctions Many species become extinct if they can not adapt to changes in their environment fast enough. At some times during history, many species become extinct. Scientists believe this is due to changes in climate, which may be caused by meteorites.
  112. 113. Pangea It is believed that all the continents were once together in one landmass. Pangea means “all Earth”. As the continents drift apart, their climate changes, so species must adapt.
  113. 114. Why Did they Die? Dinousaurs died out about 65.5 million years ago. Why? Heat generated caused fires, and the smoke and dust blocked out the sunlight, so the plants all died out, leaving the dinosaurs with nothing to eat.
  114. 115. Test? 8C& 8A: Monday Feb 20th
  115. 116. Hominids The human-like family of primates are called hominids. All hominids walk upright. Even though our skeletons are similar to Chimpanzees, hominids are unique in that their skeletons are built for walking upright.
  116. 117. Lucy Lucy is a skeleton of Australopithicus Afarensis, found in Ethiopia (where?) in 1974. Several hundred bones were found, and they are estimated to make up about 40% of her whole skeleton. She walked like a human, but was only 1.1m tall. She is estimated to have lived 3.2 million years ago.
  117. 119. Neanderthal Neanderthals lived in Europe and Asia from about 230 000 until as recently as 30 000 years ago. Please don't learn these figures! They had clothing, tools, art and culture. No one knows what caused them to die out.,_modelo_en_Neand-muzeo.JPG
  118. 120. Homo Sapiens We are Homo Sapiens. We left Africa between 40 000 and 100 000 years ago. Early homo sapiens had an organised and complicated society, with a lot of art, sculpture, paintings etc.
  119. 121. The End Next Unit: Chemicals and Their Reactivity