Chapter 1 The Study of Life

The Science of Biology Science – the process to understand the world around us. Biology – the study of life Bio means life Ology means study of

Biologists Study the Diversity of Life Why Study Biology? Lead to advances in medical treatment and disease prevention. Help preserve species in danger of disappearing Teach you how humans function

Characteristics of Living Things Living organisms must have all 7 characteristics of life to be considered living 7 Characteristics of Living Things: 1. All living things are made of cells A cell is the smallest unit of an organism that can be considered alive All living things contain DNA

3. All living things reproduce Reproduction is not essential for the survival of an individual organism, but it is essential for the survival of the species. 4. All living things grow and develop Growth – an increase in size and the formation of new structures. Development – all of the changes that take place during life.

5. All living things obtain and use energy Organisms need energy to grow, develop and reproduce Metabolism – chemical reactions through which an organism carries out its life processes 6. All living things adapt and evolve Adaptation – respond to stimuli for better survival Evolution – the gradual accumulation of adaptations over time.

All living things maintain a stable internal environment Homeostasis – regulation of an organisms internal environment to maintain conditions suitable for its survival

The Methods of Biology and Science  Scientific Method – common steps that scientists use to gather information and answer questions. Scientific Method has 5 steps: 1. Collect observations and state the problem. Scientists first observe something with one or more of their five senses What do you want to find out

2. Form a hypothesis – an explanation for a question or a problem that can be tested. 3. Plan and Perform MULTIPLE Experiments. Perform the experiment many times to reduce the chance of error. You must always have a control. Control - the group in which all conditions are kept the same and you can compare your results against.

4. Observe and Record Results. Make tables, charts, graphs Do you see any patterns or trends? 5. Draw Conclusions Does the data support your hypothesis? What errors occurred in your experiment? What would you do different next time?

Form a Theory Theory – a hypothesis that is supported by a large body of scientific evidence. No theory is considered absolute truth. As new evidence is uncovered a theory may be revised or replaced. It becomes a Law after many years of holding true.

Two Things Involved in Testing Independent Variable It is the variable you mess with or what you can change Value does not depend on change in the other value. Goes on the X axis Dependent Variable The variable you measure or what you can’t directly control. Value depends on change in the other value. Goes on the Y axis

Graphing The X axis is horizontal The Y axis is vertical What Makes a Good Graph? Make sure your graph has a title Make sure the axis is labeled with units of measurement Use all of graph paper. Key

LINE GRAPH Effect of Enzyme Concentration on Enzyme Activity H2O2 Depth Your Data Time Your Data Rate Class Data Avg. Rate 0 units/ml (0%) 100mm 0.0sec 0 mm/sec 0.0mm/sec 20 units/ml (20%) 98mm 31 sec 3.2 mm/sec 2.98mm/sec 50 units/ml (50%) 103mm 18 sec 5.7 mm/sec 5.48mm/sec 80 units/ml (80%) 14 sec 7.1 mm/sec 7.39mm/sec 100 units/ml (100%) 110mm 12 sec 9.2 mm/sec 8.42mm/sec

BAR GRAPH Effect of Enzyme Concentration on Enzyme Activity H2O2 Depth Your Data Time Your Data Rate Class Data Avg. Rate 0 units/ml (0%) 100mm 0.0sec 0 mm/sec 0.0mm/sec 20 units/ml (20%) 98mm 31 sec 3.2 mm/sec 2.98mm/sec 50 units/ml (50%) 103mm 18 sec 5.7 mm/sec 5.48mm/sec 80 units/ml (80%) 14 sec 7.1 mm/sec 7.39mm/sec 100 units/ml (100%) 110mm 12 sec 9.2 mm/sec 8.42mm/sec Effect of Enzyme Activity on Enzyme Concentration

PIE GRAPH

Kinds of Research Quantitative Research Experiments that result in counts, measurements, or numerical data Data may be used to make a graph or table. Qualitative (Descriptive) Research Observational data that is written descriptions of what scientists observe. Useful because some experiments aren’t appropriate for quantitative research.

Microscopes 2 important concepts of microscopes: Magnification – to make an image appear larger. Resolution - shows details clearly. Light Microscopes Use a beam of light passing through one or more lenses Compound microscopes use two sets of lenses Use compound microscopes to study living cells As magnification increases the resolution decreases.

Electron Microscope Use electrons instead of light Can magnify more than light microscopes Living cells cannot be viewed 2 Types of Electron Microscopes 1. Transmission Electron Microscope Reveals its internal structures.

2. Scanning Electron Microscope See 3-D images of cell surfaces Reveals surface structures.

Scanning Electron Microscope Image Comparison Compound Scanning Electron Microscope Transmission EM Cyclotella 1000X Cyclotella 1000X Viruses Bacteria 10,000X Bacteria 1000X

Eyepiece or Ocular Lens Rotating Nose Piece Arm Objectives Stage Clips Stage Diaphragm Coarse Adjustment Knob Light Fine Adjustment Knob Base

How to Get an Image in Focus Put on low power objective Turn the coarse adjustment knob to move stage all the way up Turn the coarse adjustment knob away until the image is in focus Turn the fine adjustment knob to get a clearer and sharper image Change to the medium objective Only use the fine adjustment knob to bring the image into focus. Do not use the coarse knob. Change to the high objective. Use the fine adjustment knob to bring the image into focus.

Parfocal – once the image is in focus on low power, the image will remain in focus.

Total Magnification The eyepiece has a lens in it that magnifies 10X The low power objective magnifies at 4X The medium objective magnifies at 10X The high objective magnifies at 40X To find the total magnification you must multiply the eyepiece and the objective you are on: Example: 10 X 4 = 40 10 X 10 = 100 10 X 40 = 400