3. Selection & Speciation


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3. Selection & Speciation

  1. 1. Selection & Speciation Genetics & Adaptation SQA HIGHER BIOLOGY
  2. 2. Learning Content <ul><li>Natural selection </li></ul><ul><ul><li>Survival of those organisms best suited to their environment. </li></ul></ul><ul><ul><li>Concept of the species. </li></ul></ul><ul><ul><li>Importance of isolating mechanisms as barriers to gene exchange leading to evolution of new species. </li></ul></ul><ul><ul><li>Adaptive radiation. </li></ul></ul><ul><ul><li>High-speed evolution of organisms such as antibiotic resistant bacteria and the melanic peppered moth. </li></ul></ul><ul><ul><li>Conservation of species and the maintenance of genetic diversity. </li></ul></ul>
  3. 3. Natural Selection <ul><li>Summarise the process of natural selection as a flowchart. </li></ul><ul><li>E.g. </li></ul>Organisms produce large numbers of offspring.
  4. 4. Examples of Natural Selection <ul><li>Most mutations produce inferior versions of the gene. </li></ul><ul><li>Some mutations however give the organism a selective advantage in a changing environment. </li></ul><ul><li>Changes in the environment can be biotic or abiotic. </li></ul><ul><li>You need to be able to describe various examples of this process. </li></ul>
  5. 5. Examples of Natural Selection <ul><li>Produce summaries of the following examples of natural selection in action: </li></ul><ul><ul><li>Industrial melanism in the peppered moth </li></ul></ul><ul><ul><li>Sickle cell trait </li></ul></ul><ul><ul><li>Resistance to antibiotics </li></ul></ul><ul><ul><li>Resistance to insecticides </li></ul></ul><ul><ul><li>Heavy metal tolerance in grasses </li></ul></ul><ul><ul><li>Calcifuge & calcicole plants </li></ul></ul>
  6. 6. Speciation <ul><li>Define the following terms: </li></ul><ul><ul><li>gene pool </li></ul></ul><ul><ul><li>gene frequency </li></ul></ul><ul><ul><li>genetic equilibrium </li></ul></ul><ul><li>Evolution occurs due to changes in the gene pool. </li></ul><ul><ul><li>What causes these changes? </li></ul></ul>
  7. 7. Speciation <ul><li>Complete the diagram with notes on each factor. </li></ul>Gene Pool Mutation Natural Selection Gene Migration Non-random Mating Genetic Drift Chance Forms new alleles
  8. 8. Species <ul><li>Define the term ‘species’. </li></ul><ul><li>How many different species are thought to exist? </li></ul><ul><ul><li>Is this stable? </li></ul></ul><ul><li>What is speciation? </li></ul><ul><li>Produce a flowchart to demonstrate the process of speciation. </li></ul><ul><li>What different isolating mechanisms exist? </li></ul><ul><li>What is meant by the term ‘endemic’? </li></ul>
  9. 9. Examples <ul><li>Describe how the species Sorbus arranensis has arisen. </li></ul><ul><li>Why has St Kilda got its own subspecies of Troglodytes troglodytes ? </li></ul><ul><ul><li>Why is this not a separate species? </li></ul></ul><ul><li>Explain why two populations which can not interbreed can still be described as belonging to the same species? </li></ul><ul><ul><li>How can they become separate species? </li></ul></ul>
  10. 10. Continental Distribution <ul><li>Describe the continental distribution of mammals. </li></ul><ul><li>What is continental drift ? </li></ul><ul><ul><li>How has this affected the distribution of mammals? </li></ul></ul><ul><li>Why does Australia posses marsupials? </li></ul><ul><ul><li>What is an ecological niche? </li></ul></ul><ul><li>What provides much of the evidence for the theory of evolution? </li></ul><ul><li>Answer question 7 on page 137. </li></ul>
  11. 11. Adaptive Radiation <ul><li>What is adaptive radiation? </li></ul>
  12. 12. Adaptive Radiation <ul><li>How do the Galapagos finches demonstrate adaptive radiation? </li></ul><ul><li>Summarise another example of adaptive radiation. </li></ul><ul><li>Define the following terms: </li></ul><ul><ul><li>Homologous </li></ul></ul><ul><ul><li>Divergent evolution (include an example) </li></ul></ul><ul><ul><li>Convergent evolution (include an example) </li></ul></ul>
  13. 13. Extinction & Conservation <ul><li>What evidence exists for extinction? </li></ul><ul><li>What is mass extinction? </li></ul><ul><li>What causes mass extinctions? </li></ul><ul><li>What led to mammalian success? </li></ul><ul><li>What effects are human activities having on species? </li></ul><ul><li>What is biodiversity? </li></ul><ul><li>Why should we conserve species? </li></ul><ul><li>Describe how species can be conserved. </li></ul>
  14. 14. Conservation Task <ul><li>You are a team of marketing executives at Ross Advertising Ltd. </li></ul><ul><li>You have been commissioned by the National Trust for Scotland to raise the awareness of global and local conservation projects amongst the citizens of East Lothian. </li></ul><ul><li>Your work needs to be informative, persuasive and eye-catching. </li></ul><ul><ul><li>You will also be credited for including Higher Biology Learning Content. </li></ul></ul>
  15. 15. Discuss What is Natural Selection? What do you think is meant by Artificial Selection? What other techniques do humans have for changing species?
  16. 16. Learning Content <ul><li>Artificial selection. </li></ul><ul><ul><li>Evolution of a wide variety of crops and domesticated animals through selective breeding and hybridisation as undertaken by humans. </li></ul></ul><ul><ul><li>Contribution of genetic engineering to the development of new varieties. </li></ul></ul><ul><ul><li>Somatic fusion in plants to produce new species. </li></ul></ul>
  17. 17. Artificial Selection <ul><li>What is artificial selection? </li></ul><ul><li>Describe examples of artificial selection in plants & animals. </li></ul><ul><li>What role does inbreeding have in artificial selection? </li></ul><ul><li>What is a hybrid? </li></ul><ul><li>What is hybrid vigour? </li></ul><ul><ul><li>Outline examples of hybrid vigour in plants & animals. </li></ul></ul>
  18. 18. Genetic Engineering <ul><li>What is genetic engineering? </li></ul><ul><li>Revision: </li></ul><ul><ul><li>Complete the insulin cut and stick activity . </li></ul></ul>
  19. 19. Insulin Cut and Stick Human cells contain a gene for making insulin. Bacteria cells contain a ring of portable DNA called a plasmid. Extract the DNA from some human cells. Use an enzyme to cut the insulin gene out of the DNA. Use the same enzyme to cut bacteria DNA plasmid. Use a different enzyme to stick the human insulin gene into the bacteria plasmid. The plasmid holding the insulin gene is put into bacteria. The bacteria reproduce and start to make human insulin.
  20. 20. Genetic Engineering <ul><li>Finding The Gene </li></ul><ul><li>Makes notes on locating genes : </li></ul><ul><ul><li>Banding patterns </li></ul></ul><ul><ul><ul><li>In what ways can chromosomes be distinctive? </li></ul></ul></ul><ul><ul><ul><li>How can the gene for red/white eye colour in fruit flies be located? </li></ul></ul></ul><ul><ul><li>Gene probes </li></ul></ul><ul><ul><ul><li>What are gene probes used for? </li></ul></ul></ul><ul><ul><ul><li>What is a gene probe? </li></ul></ul></ul><ul><ul><ul><li>Summarise how a gene probe can be used. </li></ul></ul></ul>
  21. 21. Genetic Engineering <ul><li>Cutting up DNA </li></ul><ul><ul><li>What is the name of the group of enzymes used for cutting DNA? </li></ul></ul><ul><ul><li>Each restriction endonuclease is specific. Explain what this means? </li></ul></ul><ul><ul><li>Why do you need to cut open the vector plasmid with the same restriction endonuclease used to remove the desired gene from the chromosome? </li></ul></ul><ul><ul><li>What is ligase? </li></ul></ul>
  22. 22. Genetic Engineering <ul><li>What is used as a vector for genetic engineering? </li></ul><ul><li>Not all plasmids will take up the desired gene (insulin in this case). How can you isolate the plasmids which have taken up the insulin gene? </li></ul>
  23. 23. Transgenic Varieties <ul><li>How can Agrobacterium tumefaciens be used to genetically engineer crop plants? </li></ul>
  24. 25. Transgenic Varieties <ul><li>How can Agrobacterium tumefaciens be used to genetically engineer crop plants? </li></ul><ul><li>In what ways have crop plants been altered by genetic engineering? </li></ul><ul><li>What future benefits could there be from genetic engineering of crops and farm animals? </li></ul><ul><ul><li>What problems do these developments face? </li></ul></ul>
  25. 26. Somatic Fusion
  26. 27. Somatic Fusion <ul><li>What problem does somatic fusion address? </li></ul><ul><li>Define </li></ul><ul><ul><li>a protoplast. </li></ul></ul><ul><ul><li>a hybrid protoplast/somatic cell hybrid. </li></ul></ul><ul><ul><li>a callus </li></ul></ul><ul><li>What is somatic fusion? </li></ul><ul><li>How can a callus develop into a plant? </li></ul><ul><li>Outline an example of somatic fusion in potato plants. </li></ul>