1. Biology As A Science

2. The Scientific Method: Why have it?

3. Scientific Method 1.Define Problem 2.Formulate Hypothesis 3.Test Hypothesis -Write out the materials and methods needed Need Positive and Negative Controls

4. What is a Control Group?

5. Positive Control Group: Known fertilizer and water Experimental Group: Experimental fertilizer and water Negative Control Group: Water only Beginning of Experiment

6. 50 ft 90 ft 150 ft End of Experiment

7. What is a Variable? What was the variable in the example?

8. Independent vs. Dependent Variables

9. New Experiment Positive Control Group: 1 ounce known fertilizer and water Experimental Group 1: 1 ounce experimental fertilizer and water Experimental Group 2: 2 ounces of experimental fertilizer and water Negative Control Group: water

10. 150 ft 130 ft 100 ft

11. How many variables were in the experiment?

12. Independent Variables: –Number varies but you control it –Ex. Amount of fertilizer you added Dependent Variables: –Number varies but nature controls it –Ex. Height reached by the tree

13. More Scientific Method 4. Collect Data: –Display in form of graph or table or photo in a “Results” section of a scientific paper 5. Analyze data and make conclusions about data in a “Conclusions” section of a scientific paper

14. How do we decide in an objective way if measured differences are significant? Ex. Avg Control Group Plant Height=12in Avg Experimental Group Plant Height= 12.7in 0.7 inches: Was this because of my fertilizer or just by chance?

15. Statistics Step 1: Null Hypothesis=premise that no difference exists. Step 2: Collect Data Step 3: Use statistics to determine the probability that any differences are due to chance Step 4: If there is a probability of error or chance below 5% then Null Hypothesis correct

16. More Scientific Method 6. Report your paper to the world for examination and duplication

17. Theory vs. Law?

18. Theory “Sick people have Bacteria A” “Sick people have Virus X” “Sick People have Parasite Q” “Sick people have Fungus P” Germ Theory= Germs cause us to be sick

19. Theory= Established explanation given for many different observations seen by researchers = Explanation for many proven hypothesizes

20. Law Law of Gravity= Things always fall towards the center of Earth This event is always seen over and over Accepted at face value, no proof needed Law doesn’t go into How? and Why? Law based on 1000s of observations

21. The Metric System Length=Meter Volume=Liter Mass=Gram

22. Metric System 1 Meter= 1000000 micrometers or Microns 1 Meter= 1000 mm 1 Meter= 100 cm 1 Kilometer= 1000 meters

23. Question 2cm= ___ Microns? 50 micrometers= ____ mm?

24. Tools of a Biologist Light Microscopes: –Simple Microscope (Single Lens-Magnifying Glass (1600s) –“Inventor”: really improved on existing technology

25. Microscopes Really 1590 invented by: Hans and Zaccharias Janssen (father and son)

26. Tools of a Biologist –Compound Microscope (2 lenses) –Robert Hooke (1600s)

27. Modern Compound Light Microscope PARTS

29. Tissue Prep for Microscopy 1. Fixation 2. Embed in wax 3. Slice with Microtome, Mount on slide, Stain

30. Stains Help visualize details of specimen –Vital Stains=Don’t harm living specimens (ex. Methyl Blue) –Lethal Stains=Kills Specimen (ex. Iodine)

31. Tissue Prep Center Embedding Area Microtome Water bath with sliced wax/tissue

32. Tissue prep-Mount onto slides

33. Dissecting Scope/Zoom Scope 3D Image More working space Can view “large” objects

34. Cheek Cells using Phase-Contrast Microscope No Stains Needed Can view live specimens

35. Scanning Electron Microscope 100,000X Magnification Can’t view live organisms 3D Image Blast electrons at object

36. Red Blood Cells using a SEM

37. Transmission Electron Microscope 2D Image Can’t View live organisms 250,000X Mag Blast electrons at object

38. Blood Cells using a TEM

39. Confocal Laser Microscope

40. Ever been in a centrifuge?

41. Centrifuge Separate mixtures based on density Most dense at bottom of tube Least dense at top

42. Chromatography Solvent Sample Separation into components based on solubility in solvent

43. Spectrophotometry Use light absorbance to determine the concentration of substances Detect amount of light that made it through

44. Spectrophotometry Known Concentration Unknown Concentration Absorbance #

45. Spectrophotometry Spectrophotometry Demo

46. Electrophoresis Separate mixtures based upon size and charge

47. Electrophoresis

48. Tissue Culture

49. Microdissection

50. Recombinant DNA

51. Transgenic Organisms Fluorescent “Reporter” Genes