what is life and scientific method (talk1)
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what is life and scientific method (talk1) Presentation Transcript

  • 1. Biology Today (BIOL 109) Biology with an Issues approach
  • 2. What is Life?
      • Building LEGOs and playing “ soccer ” with Mazz
      • Quinn DelVal (age 11)
      • “ Life is a multi-faceted concept with no simple definition ……”
      • Life is a live album by Irish band Thin Lizzy
  • 3. Scientists at work
    • Biologists are NOT geeks !
    • Some work in a lab, others collect data in the field.
    • There are many “branches” of biology
      • Plant Biology
      • Ecology
      • Human Biology
      • Biochemistry
      • Genetics
      • Molecular Biology
  • 4. The Scientific method
    • Animals, Plants, and Bacteria are complex and variable
    • At any moment living systems may differ in external conditions, internal conditions, or in the way in which these conditions interact
    • The same individual is not the same from one day to the next.
    • Need to study more than one individual (say 100) and collect average data
    • Look out for variation!!!!!!
  • 5. The Scientific method
  • 6. The Scientific method
    • Scientists use the Scientific Method to test Theories.
      • Generate an Observation
      • Pose a Hypothesis
      • Perform Experiments
      • Analyze Results
      • Reach a Conclusion--does the date support or refute our Theory?
  • 7. Why do Experiments in Labs?
    • Controls! Controls! Controls!
    • Lab Experiments can prevent “variables”
      • Variable : Factor that can cause observable change and through results off.
        • Independent – what you vary during the experiment. Usually this will be time.
        • Dependant – what you measure – what will change during the experiment
      • Control : Subject to all experimental steps EXCEPT the experimental Factor.
  • 8.  
  • 9. The Experimental Approach!
    • Lederbergs experiments on bacterial genetics
    • Most bacteria are killed by streptomycin
    • The Lederbergs exposed E. coli to streptomycin and were able to isolate streptomycin-resistant E. coli strains.
    • They allowed these bacteria to reproduce and showed that resistance to streptomycin was inherited by their offspring
  • 10. The Experimental Approach!
    • This gave the Lederbergs two hypothesis to test
      • The mutation was caused by exposure to streptomycin
      • Bacteria mutated before exposure to streptomycin
    • So they conducted an experiment to test both of these hypotheses.
  • 11. Figure 1.3 (1)
  • 12. Figure 1.3 (2)
  • 13. Figure 1.3 (3)
  • 14. Figure 1.3 (4)
  • 15. Scientific theories
    • Animals, plants, and bacteria are examples of living systems that share many properties distinguishing them from nonliving things. These properties are branched into theories.
    Cellular organization Fundamental unit of life is the cell – all living things are made up of cells. Metabolism Living things take up energy-rich materials and give out waste to environment. Some energy fuels life processes some accumulates and is released after death. Selective response Living things respond selectively to stimulation in the environment. Organisms recognize certain chemicals as nutrients while ignoring others.
  • 16. Scientific theories Homeostasis Living systems have some capacity to change harmful conditions into conditions more favorable to their continuing existence – the conversion of chemical compounds. Growth and biosynthesis Living systems go through phases during which they make more of their own material. Genetic material Living systems contain genetic material (DNA and RNA) to allow inherited traits. Reproduction Living systems can reproduce & pass on genetic material. Population structure Organism form populations. Of these organism capable of sexual processes, a population is all those organisms that can interbreed with one another.
  • 17. Paradigms
    • A paradigm is much more than a theory
      • It includes a strong belief in the truth of one or more theories and shared opinions as to what problems are important and unimportant
      • What techniques and research methods are useful
    • Over time a paradigm shift occurs
      • Better technologies and scientific instruments lead scientists to look and old data in a different way
      • Younger scientists look at old data in a new way
      • In this way ideas and definitions of theories alter over time an new data is collected and explained.
  • 18. Paradigm Shifts
    • OLD PARADIGM
    • Natural Theology, Lamarckism, and several other competing paradigms
    • Blending inheritance and various folk ideas
    • Various beliefs: bad humors, bad air or water, evil spirits, and many others
    • Competing paradigms, including Darwinism, mutationism, population
    • genetics, neo-Lamarckism
    • Classical Mendelian genetics
    • Various theories of territorial behavior, sexual behavior, etc.; also
    • psychological theories (gestalt, behaviorism, ethology)
    • Descartes’ mechanistic theories and dualism
    • Classic germ theory: pathogenicity as a characteristic of pathogen only
    NEW PARADIGM Darwinism (since 1859) Classical Mendelian genetics (since 1865 or 1900) Germ theory of disease (Pasteur, Koch, since 1880) Modern evolutionary theory (since 1940) Molecular genetics (since 1950s) Sociobiology (since 1975) Mind–body connections (since 1980s) Pathogenicity as an interaction of pathogen and host (since 1990s)
  • 19. Science has Improved our Lives!
    • Antibiotics --Penicillin, others?
    • Vaccines --Polio, Measles, Smallpox, others?
    • Cell Biology- -Cancer Research, others?
    • Genetics --Basis for Disease, others?
    • Physics --Electricity!, others?
    • Engineering --Roads, Bridges, Buildings, Planes, Trains, Bikes, others?
    • Fermentation --Civilization!
  • 20. Science has also opened up “Pandora’s Box”
    • Bio-warfare -, Anthrax letters, Current worries?
    • Nuclear Weapons- -Does North Korea really have them?
    • Genome --Insurance issues, Selecting offspring?
    • Others ?
  • 21. Ethics and Information
    • One of your roles in our society is to help determine how future technologies should be used and regulated.
    • To make the best decision possible, you need to be informed!
    • My Goal is to help you to become informed!
  • 22. Ethical thinking
    • Ethics is a discipline dealing with the analysis of moral rule and the ways in which moral judgments are made and justified.
    • Would you park your car in this space?
    • Why?
  • 23. Ethical thinking
    • What benefits could come from nuclear power?
    • At what cost?
    • At what risk?
    • Remember Chernobyl ?
  • 24. Chernobyl Nuclear Disaster
    • April 26 , 1986 in the Ukraine ,
    • It is regarded as the worst accident in the history of nuclear power.
    • A plume of radioactive fallout drifted over parts of the western Soviet Union, Eastern and Western Europe, Scandinavia, the British Isles, and eastern North America. Large areas of Ukraine, Belarus, and Russia were badly contaminated
    • Resulted in the evacuation and resettlement of over 336,000 people. About 60% of the radioactive fallout landed in Belarus, according to official post-Soviet data
  • 25. Chernobyl Nuclear Disaster
    • Two hundred people were hospitalized immediately, of whom 31 died (28 of them died from acute radiation exposure).
    • Most of these were fire and rescue workers trying to bring the accident under control
    • At least 8,000 people have died, most from radiation-related diseases.
    • About 2,000 people have been diagnosed with thyroid cancer and between 8,000 and 10,000 cases are expected to develop over the next 10 years.
  • 26. Ethical thinking
    • Do animals have rights?
    • Nearly all new drugs, cosmetics, food additives, new forms of surgery are tested on animals first
    • Many societies have historically denied even the most basic of rights to classes of persons on the basis of economics, gender, race, ethnicity, or religious beliefs
  • 27. Ethical thinking
    • Humans as experimental subjects
    • 1932 The Tuskegee Syphilis Study begins. 200 African-American men infected with syphilis are never told of their illness, are denied treatment, and instead are used as human guinea pigs in order to follow the progression and symptoms of the disease. They all subsequently die from syphilis, their families never told that they could have been treated.
    • Voluntary informed consent
      • Both a moral and legal issue
        • As there are lawyers under every rock!
  • 28. Ethical thinking
    • Gender bias
      • What happens if this is not considered
      • It was only in 1992 that women were included in medical trials of new drugs by law!
    • Thalidomide (Kevadon® )
      • Developed as a morning sickness drug in the 1950s
      • BUT – never tested on women
    • Led to a generation of deformities
  • 29. Ethical thinking
    • In UK alone there were 12,000 victims.
    • Sometimes functional feet and hands were amputated to allow the fitting of lower- and upper-limb Prosthesis in order for the children to appear “ normal ”.
    • Special school were set up too, in an attempt to keep the children out of sight and out of the minds of the public.
  • 30. Ethical thinking
    • Victims of the 1970s Thalidomide scandal have passed their deformities on to their children.
    • Turns out that Thalidomide altered the DNA of the victims – so arms and legs are not developed!
  • 31. Ethical thinking
    • Still in use today
    • Cancer treatments
      • by cutting off the flow of blood to tumors
    • Leprosy
      • is an infectious disease caused by a DNA plasmid
      • invades human nerves.
      • If untreated can eventually cause a variety of skin problems, loss of feeling, and paralysis of the hands and feet .