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Variation, Inheritance & Evolution Learning Objectives

Science Knowledge : Science 2: Life Processes and living things K2.4 Variation, Inheritance & Evolution.

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Variation, Inheritance & Evolution Learning Objectives

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  1. Science Knowledge: Science 2: Life Processes and living things K2.4 Variation, Inheritance & Evolution • This document can be freely copied and amended if used for educational purposes. It must not be used for commercial gain. The author(s) and web source must be acknowledged whether used as it stands or whether adapted in any way. • Subject Knowledge – K2.4 Variation, Inheritance & Evolution (download 2). Authored by Liz Lakin and Keith Ross, University of Gloucestershire. accessed from http://www.ase.org.uk/scitutors/ • date created March 2006 K2.4 Download 2

  2. To explore the science behind the headlines To establish a timeline of events leading to our current scientific understanding To identify the ‘big ideas’ in this field of biology and recognise how they are interlinked To discuss modern applications & their associated issues Variation, Inheritance & Evolution Learning Objectives K2.4 Download 2

  3. http://www.ncseweb.org/evc/EvsC-cover_400.jpg K2.4 Download 2

  4. http://users.hol.gr/~dilos/prehis/Darwcar.jpg K2.4 Download 2

  5. Variation http://www.healthcastle.com/images/vegetables.jpg & : www.picture-newsletter.com/ vegetables/index.htm K2.4 Download 2

  6. Charles Darwin recognised the significance of variation in a range of organisms www.nmm.ac.uk/.../ outputRegister/lowhtml K2.4 Download 2

  7. The Story of the Peppered Moth K2.4 Download 2

  8. Human Evolution K2.4 Download 2

  9. Selection? • What we are is determined by our genes and our environment K2.4 Download 2

  10. Father of Modern Genetics • Gregor Mendel • Austrian Monk (1850s) • Identified the patterns of inheritance • Laws of Inheritance K2.4 Download 2

  11. Multiple choice questions The questions in the slides that follow are taken from a set of over 100 available from www.escalate.ac.uk/1141 Percentages quoted in the slides are for a group of 100 trainee primary teachers on entry to ITE, having obtained a ‘C’ or better at GCSE, usually two or three years previously. This gives secondary trainees an insight into the misconceptions that survive a GCSE course, and all trainees some comfort that they are not alone with their own misconceptions about how genetics and evolution works. K2.4 Download 2

  12. Recessive Genes If you and your partner both carry the disease for cystic fibrosis (but are not sufferers), what would be the probability that your children will then inherit the actual disease? a. 25% (1 in 4) 5% b. 33.3% (1 in 3) 19% c. 50% (1 in 2) 35% d. 100% (1 in 1 - certainty) 39% (% are for a survey of post GCSE students – see notes)

  13. Mendelian Cross Both parents carry the recessive gene for cystic fibrosis (c) they also carry the ordinary gene (C). The cross can be summarised as follows: CC c K2.4 Download 2

  14. Eye Colour In eye colour the allele for brown eyes is dominant (B) and the allele for blue eyes is recessive (b). Try some different crosses with homozygous parents (BB or bb) and heterozygous parents (Bb): K2.4 Download 2

  15. So what are Genetics? • Look at the person next to you and identify as many external similarities between the two of you, as you can. • Now identify as many differences as possible. Our common inheritance as humans The tiny amount of variation in our genes We share half our genes with bananas and 99% with the chimpanzee K2.4 Download 2

  16. One fertilised cell to an organism! K2.4 Download 2

  17. Development of an egg What will happen to the weight of a fertilised bird's egg from time of laying to just before the chick hatches? • It gets lighter  6% • It gets heavier  54% • It stays much the same  35% (% are for a survey of post GCSE students – see notes) K2.4 Download 2

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  19. Genes • What are your genes? • Do bacteria have genes? • Is the genetic information in the sex cells the same as in other cells? K2.4 Download 2

  20. Let’s look at cells … • Several types • 75 billion in a human being • Capable of carrying out many different functions e.g. … • Protection • Movement • Excretion K2.4 Download 2

  21. Importance of Proteins Click on the one statement you most agree with about why proteins are so important to living things. a. They are a nutritious food 8% b. They are the enzymes in our bodies which enable our cells to work. 37% c. When combined with oxygen, lots of energy is given off 6% d. Protein provides the structural material in all living things 45% (% are for a survey of post GCSE students – see notes) K2.4 Download 2

  22. Material of Inheritance … • What are the requirements of hereditary material? • Store information • Permanence • Ability to change (mutate) K2.4 Download 2

  23. Unique function of DNA • Stores information for protein synthesis • Makes copies of itself ~ self replication • Able to change/vary/mutate K2.4 Download 2

  24. DNA • Deoxyribonucleic Acid • Molecular language ~ 4 different letters • Codon – three letter word – most code for an amino acid • GENE ~ sentence of many words (amino acids) which enables it to build PROTEINS • Proteins are enzymes that enable reactions to take place in cells K2.4 Download 2

  25. … base, nucleotide, gene, chromosome The following terms all relate to the DNA molecule. List them in relation to their size, starting with the smallest a gene b nucleotide c chromosome d bases (4% of the BEd Students got it right) http://en.wikipedia.org/wiki/Nucleotide K2.4 Download 2

  26. DNA Click on the four sentences about human DNA that are true. a. It carries the code to make proteins. 50% b. It can pass from one generation to the next. 83% c. It can make copies of itself. 68% d. It is a single stranded molecule. 26% e. It is made of protein. 51% f. It is identical in almost every cell of our body. 66% (% are for a survey of post GCSE students – see notes)

  27. Protein Synthesis • A simulation … K2.4 Download 2

  28. Link to HOME Quiz K2.4 Download 2

  29. Variation from mutation Which two of the following processes leads to 'variation' in the offspring: a. Cell cloning. 4% b. Gamete formation. 34% c. Mitosis (normal cell division). 51% d. Meiosis (sex cell formation) 55% (% are for a survey of post GCSE students – see notes) K2.4 Download 2

  30. Tracing your ancestry A mutation of which of the following could be inherited from both your parents? a. Messenger RNA 20 b. Nuclear DNA 29 c. Ribosomal RNA 13 d. Mitochondrial DNA 35 (% are for a survey of post GCSE students – see notes) K2.4 Download 2

  31. Artificial Selection K2.4 Download 2

  32. Manipulation of genes … • Genotype • Phenotype & selective breeding • Manipulation of genes • Biotechnology K2.4 Download 2

  33. How genes work … • Inheritance • Mutations • Stem cells K2.4 Download 2

  34. Genetic Engineering K2.4 Download 2

  35. Location of genes Isolation of genes Removal of genes Transfer of genes Cultivation of genes What do we need to do to genetically engineer something? K2.4 Download 2

  36. Where do we go from here …? • Dolly ~ cloned from a mature cell by nuclear transfer • Polly ~ cloned from an embryo cell, but contains a human gene which produces the human protein in the sheep’s milk • Why are they scientifically significant? K2.4 Download 2

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  38. What are the issues … ? • Monsanto monopoly • 1998 Government moratorium on the growth of GM crops • Media hype and scare mongering • Human cloning & designer babies K2.4 Download 2

  39. So what do you think? K2.4 Download 2

  40. Should scientist be allowed to alter animal genes: For medical reasons? For healthier or more efficient food production? For commercial reasons? Should scientists be allowed to alter Human genes: For medical reasons? For commercial reasons? So what do you really think? K2.4 Download 2

  41. Recap … • What do genes do? • Where do we find genes? • What makes DNA so good as hereditary material? • What information does DNA store? • How does it store it? • What happens next … K2.4 Download 2

  42. Protein (enzyme) Synthesis • Key points: • Copy DNA • Messenger RNA copy to site of synthesis • Collect (Transfer RNA) selection of amino acids and arrange amino acids in correct sequence • Builds a polypeptide chain (= protein) • Several produced at one time • Allows chemical reactions to take place in cell. K2.4 Download 2

  43. Gene Expression • Switching genes on and off … • Stem cells and mature differentiated cells • Growth = cell division and cell differentiation K2.4 Download 2

  44. Gene Therapy • Treatment of diseases by the introduction of powders containing working copies of the defective gene ~ saturation approach • Cystic Fibrosis • Problems: • Disease is rare in the population • Expensive to treat • Research pressure into common ailments K2.4 Download 2

  45. Genetic Engineering • Transfer of genes from one species to another. • How is it done? • Gene Splicing • Limitations ~ can only add genes K2.4 Download 2

  46. http://www.food.gov.uk/gmdebate/aboutgm/?view=GM%20Microsite K2.4 Download 2 Countries which are already growing some GM crops

  47. Concept map • Compare building a house and cell? • DNA, genes and enzymes • Mitosis (cell division) and meiosis (sex) • Phenotype and genotype – recessive genes • Growth = cell division & differentiation • Mutation - natural and artificial • GM debate and other issues K2.4 Download 2

  48. Learning log • Look at the questions – where were your conceptual misunderstandings? K2.4 Download 2

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