1. Intro to Science Sept 2011 Biology 112

2. The Goals of Science 1. Deals only with the Natural World The supernatural is outside the realm of science

3. The Goals of Science 2. Collect & Organize Data

4. Goals of Science 3. Propose Explanations that can be tested

5. In Summary…..  SCIENCE is a BODY of KNOWLEDGE that EXPLAINS the NATURAL World.

6. Science Begins with Observation – How are your Skills?

7. OBSERVATION 1. Quantitative – a quantity/number or measure 2. Qualitative – a quality/characteristic; description

9. Inference  A logical interpretation based on prior knowledge  Examples of Inferences?  What can be the problem with inferences?  http://www.youtube.com/watch?v=tiy1M eXzhfA http://www.youtube.com/watch?v=tiy1M eXzhfA

10. Hypothesis  A proposed explanation; must be TESTABLE; written in an “If….then” format 1. If I give my dog Purina dog food for a month, then he will not shed as much. 2. If I use miracle grow then my plants will produce more tomatoes. 3. If I use the drug Avapro for a week then my blood pressure will be lower

11. Scientific Inquiry~ inquisitive thinker’s!!!  Scientists make observations, ask questions and then try to answer them through research and experimentation.  http://www.youtube.com/watch?v=VjE0K dfos4Y http://www.youtube.com/watch?v=VjE0K dfos4Y

12. Narrowing in on Science  BIOLOGY – One Branch of Science  Study of LIVING things

13. Copyright Pearson Prentice Hall A Few Branches of Biology:  Zoologists  Botanists  Paleontologists  Cell Biologists  Geneticists  Microbiologists  Ecologists

14. Biology is very broad (Remember it is the study of LIVING things…and there are LOTS of living things!!!!!) Terminology rich; very descriptive and has it’s own language~ – Handout #1 – Give it a try

15. Copyright Pearson Prentice Hall 1-2 How Scientists Work Scientists make educated guesses about how things work the way they do. These are called HYPOTHESIS. How do scientists test hypotheses ? A hypothesis should be tested by an experiment in which only one variable is changed at a time.

16. Scientific Method Summary 1) Ask questions, make observations 2) Gather information 3) Form a hypothesis (educated guess) 4) Set up a controlled experiment  Manipulated variable - the variable that is deliberately changed (aka independent variable ) Responding variable is variable that is observed (aka dependent variable ) 5)Record and analyze results 6)Draw a conclusion 7)Repeat & share findings

17. Scientific Method – Step 1: Ask Questions/Make Observations:  2300 years ago people thought that some “special force” brought some things into being from nonliving material Ex:  Beetles just “appeared” on cow dung  Mice were “found” on grain  Maggots “showed up” on meat Good thing we don’t’ just rely on observations!!!

18. Copyright Pearson Prentice Hall The idea that living things arise from non-living matter is called: spontaneous generation OR abiogenesis.  In Aristotle’s time, people hypothesized that maggots spontaneously appeared on meat. FRANCESCO REDI – BEGAN CHALLENGING ARISTOTLE BY ASKING QUESTIONS and Following the steps of the scientific method!!  In 1668, Redi proposed a different hypothesis: that maggots came from eggs that flies laid on meat.

19. Copyright Pearson Prentice Hall Redi’s Experiment Controlled Variables: jars, type of meat, Location, temperature, time Covered jars Uncovered jars What do you think are the manipulated and responding variables in this experiment??

20. John Needham – mid 1700’s – SG is BACK!???  English Scientist who tried to attack Redi’s work.  He heated a flask of gravy for a short time and corked the flask and microorganisms appeared.  He believed that the little “animalcules” must have come from the gravy!

21. Copyright Pearson Prentice Hall Repeating Investigations – TRIALS!!! Spallanzani's Test of Redi's Findings Gravy is boiled. Which variables are controlled??

22. Copyright Pearson Prentice Hall Spallanzani – Disproving SG! Flask is open. Flask is sealed. Is the flask the manipulated or responding variable??

23. Copyright Pearson Prentice HallH Gravy is teeming with microorganisms. Gravy is free of microorganisms. Helped prove the theory of BIOGENESIS!!!! Living things come from other living things!

24. Copyright Pearson Prentice Hall Pasteur's Test of Spontaneous Generation  Louis Pasteur conclusively disproved the hypothesis of spontaneous generation.  Pasteur showed that all living things come from other living things.

25. Copyright Pearson Prentice Hall Pasteur’s Experiment Broth is boiled Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

26. Copyright Pearson Prentice Hall The Impact of Pasteur’s Work  He began to uncover the nature of infectious diseases, showing that they were the result of microorganisms.  Pasteurization of dairy products

27. SCIENTIST SUMMARY: PRO SG: Aristotle, Needham ANTI SG: Redi, Spallanzani, Pasteur

28. Copyright Pearson Prentice Hall 1-3 Studying Life

29. Copyright Pearson Prentice Hall So…If Biology is the study of living things…. What makes something living?

30. Copyright Pearson Prentice Hall Living things share the following characteristics: * REFERENCE PAGE – pages 16/17 of student text!! 1. Made of cells

31. 2. Reproduction

32. 3. Universal genetic code

33. 4. Grow & Develop

34. 5. obtain and use materials and energy

35. 6. respond to stimuli

36. 7. Maintain a stable internal environment (called homeostasis/equilibrium)

37. 8. change over time

38. Martian & The Car Activity~

39. Microscopes  Anton van Leeuwenhoek (1632- 1723) was responsible for the first “microscope” as we know them today  Due to his knowledge of lenses he was able to construct a piece of equipment that made things appear closer and larger.

40. Microscopy and Measurement  Microscopes – produce an enlarged image of an object  Used to study organisms, cells, and cell parts magnification  Increase in apparent size is called magnification resolution  The ability to show details clearly is called resolution  Microscopes vary in both magnification and resolution 40

41. Compound Light Microscope (2 lens-microscope)  Uses light passing through a medium of liquid to view a specimen  Uses generally a 10X ocular lens in addition to a 4x, 10x, 40x objective lens  Magnification = ocular x objective  Limited in it’s magnification  Used to view living and dead specimens

42. Magnification Example:  Using the compound microscope in your classroom, you are asked to view a piece of hair under the medium power objective. What is the total Magnification of the hair being viewed?  What exactly does that mean?

43. Types of MICROSCOPES  Light vs. Electron  Smallest size seen with the Naked Eye is….  0.2mm = one ridge on your finger print (resolution OR resolving power)  Light Microscopes can view 0.0002 mm  Electron Microscopes can view 0.000000002 mm (0.2 nm)

44. Parts of the Compound Microscope – Fill in your sheet as we go!!  http://www.biologycorner.com/microquiz /# http://www.biologycorner.com/microquiz /#

45. Microscope Use http://www.youtube.com/watch?v=scEhgAiazzU

46. Focusing a Microscope  Always start with the low power objective (4X). Odds are, you will be able to see something on this setting. Use the Coarse Knob to focus.  Once you've focused on low power, switch to Med Power (10X). Use the Coarse Knob to refocus. Again, if you haven't focused on this level, you will not be able to move to the next level.  Now switch to High Power. (40X)  If the specimen is too light or too dark, try adjusting the diaphragm.

47. Making a Wet Mount 1. Gather a thin slice/piece of whatever your specimen is. your specimen is too thick, then the coverslip will wobble on top of the sample like a see- saw, and you will not be able to view it under High Power. 2. Place ONE drop of water/dye directly over the specimen. If you put too much water, then the coverslip will float on top of the water, making it hard to draw the specimen, because they might actually float away. (Plus too much water is messy) 3. Place the coverslip at a 45 degree angle (approximately) with one edge touching the water drop and then gently let go. Performed correctly the coverslip will perfectly fall over the specimen

48. Finished with your Microscope? 1. Store microscopes with the scanning objective (4X) in place. 2. Wrap cords and cover microscopes. 3. Wash slides/slips in the sinks and dry them, placing them back in the slide boxes to be used later. 4. Carry with 2 hands (arm/base) 5. Put back in the correct location

49. Transmission Electron Microscope Uses electrons instead of light Capable of over 200,000X magnification Specimens that contain many layers of cells, such as blood vessels, cannot be examined A thick specimen would absorb all the electrons and produce a blackened image Only view thin sections encased in plastic

50. TEM cont..

51. Scanning Electron Microscope (SEM)  Produces a 3-D image  View up to 100,000X  Takes “pictures” of surfaces  Specimens are usually preserved, coated in a metal, dehydrated…so specimen being viewed is non-living.

52. Scanning Electron Microscope

53. SEM cont…

54. Guess?

55. Guess??

58. Rules for Biological Diagrams  See handout (rules/practice assessment)

59. Figure 1 – Moss Cross-section

60. Biological Diagrams - Lab #1  Following all steps for biological diagrams complete the following:  (Do two drawings on one page of plain paper) 1. Obtain a sample from the front and draw the specimen in the container (do not draw the bottle)