What makes something living, living? Does it have to consume oxygen?? Does it have to be able to move?? Does it have to be able to think?? Does it have to grow?? Does it have to consume food?? Does it have to have a heart?? Does it have to reproduce?? Does it have to be able to die?? Hmmm????? Use these questions and work with your neighbor to compile a list of the Characteristics of Life (Hint: There are six total!) 1. Contain Cells All living things are composed of cells that contain hereditary information (DNA) In multicellular organisms, cells are specialized for the job that they perform Cells are the smallest unit of lifeso each cell contains the characteristics of life Nerve Cell Skin Cell 2. Organization All living things are highly organized. Cell structures carry out particular functions. **Structure equals function!** Multicellular Organisms: cells are grouped by their function Cells Tissues Organs Organ systems Click here for how it works! 3. Energy Use All living things use energy in order to: Maintain their organization Grow Reproduce Metabolism: chemical process of breaking down materials for energy 4. Maintain Internal Conditions All living things, even single cells, work to maintain a steady internal environment Homeostasis: process of maintaining these conditions Water level in cells Temperature Click to see how! 5. Growth and Development All living things grow as a result of cell division and cell enlargement. Unicellular (single-celled organisms): Simply an increase in size Multicellular (many-celled organisms): Develop from one cell into many through cell division (differentiation and different functions) 6. Reproduction Reproduction (transmitting hereditary information to offspring) is not essential to the survival of an individual organism-it is essential for the continuation of the species. Two types: Sexual: cells from two different parents unite to form a new cell Asexual: new cell formed from a single cell Scientific Method 1.Observe 2.Ask a Question 3.Collect Data (background information) 4.Form a Hypothesis 5.Experiment 6.Draw Conclusion 7.Communicate THERE IS NO NEED TO MEMORIZE THESE STEPS!! YOU KNOW HOW TO SOLVE A PROBLEM- THINK BACK TO SAVING SAM Variables Independent Variable- manipulated, the variable that is changed Dependent Variable- responding, the variable that changes in response to the independent variable Microscope and Measurement Compound Light Microscope Magnification: Increase of the images apparent size Resolution: The power to show details clearly Parts of Microscope Objective lenses Diaphragm/Condenser Lamp Base Fine Adjustment Coarse Adjustment Stage/Stage Clips Revolving Nosepiece Eyepiece Arm Ocular Lens High=40X; Low=10X; Scanning=4X Changes objective lenses Directs light into microscope Focuses the light Amount of light entering the microscope Look through; lens inside is 10X Brings objective into slow focus Carry and support (2 items) Supports the slide; positions the slide Brings object into rapid focus So How Do We Use It?? Click on the scientist to see Now lets do the lab! Working Space on a Light Microscope Depth of Field: Area between lens and stage Field of View: Area seen through the microscope Calculated by the equation: Total Mag AX Diameter A = Diameter B Total Mag B Practice Problems Calculate Total magnification at: -High Power -Low Power -Scanning Ocular x Objective High = 10x40 = 400 Low = 10x10 = 100 Scanning = 10x4 = 40 Practice Problems Calculate.. If a cell measures 20 um at 100X, what is the length of the cell at 200X? 100 X 20 um = um Practice Problems Calculate If the field diameter at scanning power measures 5 um, what is the field diameter at low and high power? Low 40 X 5 um = 2 um 100 High 40 X 5 um = 1/2 um 400 Electron Microscope A beam of electrons produces an enlarged image of the specimen. Types: TEM: Transmission Electron Microscope SEM: Scanning Electron Microscope Disadvantages of an electron miscroscope: Very expensive Cannot be used to view to a living specimen Can be large in size