1 / 24

Unit 1—Ch 2

Unit 1—Ch 2. Biology as a Science. Microscopes were 1 st introduced in the 1600’s by Galileo. Shown here is Robert Hooke’s simple microscope. Microscopy timeline. http://micro.magnet.fsu.edu/primer/anatomy/introduction.html.

rhea
Download Presentation

Unit 1—Ch 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 1—Ch 2 Biology as a Science

  2. Microscopes were 1st introduced in the 1600’s by Galileo. Shown here is Robert Hooke’s simple microscope. Microscopy timeline http://micro.magnet.fsu.edu/primer/anatomy/introduction.html http://www.moonmentum.com/blog/wp-content/uploads/2010/03/Robert-Hooke.jpg

  3. Microscopes • use to magnify & to increase resolving power • common lab microscopes uses light passing through an object & lens to produce a larger image • Simple light microscope • Compound light microscope

  4. Compound Light Microscopes • Uses light & 2 or more glass lenses to focus light • Total magnification • Eyepiece • Objectives • Total magnification up to 2000x • Lower resolving power • live & dead specimens • COLOR!!! • Many are portable

  5. stoma Light Microscopes • Shown here are an amoeba (left), stoma in leaf (center) & onion cells (right). Stains help us to see some specimens better…

  6. Microscope parts quiz Parts of a compound light microscope Interactive microscope guide

  7. Virtual Microscope Microscope parts http://www.science.smith.edu/departments/Biology/Bio111/Labmanual/scope.jpg

  8. Making a Wet Mount Slide

  9. Electron Microscopes • developed in 1960’s • beam of electrons & magnetic lenses  produce enlarged image • only dead specimens • greater resolving power & magnification than light microscope • 10,000-200,000x

  10. Transmission Electron Microscope (TEM) • Electrons pass through very thin non-living specimen • Black & white, 2-D, image of inside • Specimen frozen or embedded in plastic first • resolution: 0.5 - 10 nm • magnification: > 1,000,000x TEM simulator Preparation of a specimen http://nobelprize.org/educational/physics/microscopes/tem/index.html

  11. Scanning Electron Microscope (SEM) • electrons bounce off surface of non-living specimen • Black & white, 3-D, image of surface • Micrographs can be color enhanced using computer • Magnification < TEM • 100,000x plus • Resolving power < TEM SEM Interactive Virtual SEM

  12. SEM Micrographs

  13. The samples shown above are (clockwise from top left) an ant (Lasius flavus), passion fruit (Passiflora caerulea) pollen, a  freshwater shrimp parasite (Epistillis sp.), sunflower (Helianthus anuus) pollen and central, agreenbottle (Lucilia sericata) foot.

  14. Comparison of Microscopes http://universe-review.ca/R11-13-microscopes.htm

  15. Science & Technology • Science- is an organized process that produces a body of knowledge about nature. • Based on observation of phenomenon or their effects & experimentation in order to attempt to explain the cause of those effects • Goal is to produce useful models of reality • Technology-Applying knowledge to real problems

  16. The Scientific Method http://www.sciencebuddies.org/science-fair-projects/overview_scientific_method2.gif

  17. The Scientific Method • Observations • question or problem to investigate • background information • hypothesis is formed • “If _(IV)_, then _(DV)_, because __.” • Test hypothesis  controlled experiment

  18. Controlled experiment • to be valid has to have these two parts!!!!! • 1. Tests one variable, all others kept same • Independent Variable (IV) • Dependent Variable (DV) • Controlled Variables or Constants (Cv) • 2. Two groups must be tested. • control group (set-up) • experimental group (set-up) • Multiple Trials (replicates) • Ensure results are accurate

  19. The Scientific Method • Make observations & collect data • data tables • Interpret data & analyze results • graphs • Draw conclusions • Support/reject hypothesis (NOT prove/disprove) • Conduct additional experiments (revise or discard hypothesis if rejected) • Communicate results • Report & publish

  20. Which brand of mouthwash gets rid of stinky breath the best? • Independent Variable- • Dependent Variable- • Controlled Variables- • Experimental Group(s)- • Control Group-

  21. Theories & Laws • Can you prove anything in science? • Theory • hypothesis becomes theory when it has been supported repeatedly by experimental evidence • ex. evolution, natural selection, relativity • used to explain laws • as close to complete explanation as science can offer • can change/be refuted based on new evidence.

  22. Examples of Theories • Darwin’s finches  ex. of his theory of evolution through natural selection • Lack of proper experimentation led to belief in abiogenesis (spontaneous generation) • Controlled experiments like F. Redi’s “maggots from meat” experiment refuted this theory.

  23. Theories & Laws • Laws • Statements about events that always occur in nature • Does not give mechanism or explanation of phenomenon • often expressed as a numerical equation

  24. Examples of Laws • Newton • Nicolas Steno’s Law of Superposition • Fossils in lowest layer are oldest, in uppermost layer are youngest

More Related