Metabolism Sum of all chemical rxns that take in & transform E & materials from the environment Photosynthesis: converts light E into chemical E Cellular Respiration: converts organic cmpds into usable E (ATP)
Maple vs. robot toy
Themes in Biology & The Scientific Method
Ch. 1.2 Themes in Biology 1.Diversity and Unity of Life 2.Interdependence of Organisms 3.Evolution of Life
1. Diversity and Unity of Life Diversity = variety of life –Cell = basic unit of life –Highly organized –Unicellular vs. Multicellular –Cell differentiation- cells become specialized
Unity= all living things have features in common –The genetic code; the heredity info. in DNA –Contain organelles; cellular structures that carry out specific functions –“Tree of Life”; has 3 main branches called domains and 6 major categories called kingdoms
“Tree of Life”
2. Interdependence of Organisms Organisms interact with each other and the living world –Area of science known as Ecology –Ecosystems are communities of living species & their physical environment
1. Can you name some parts of an ecosystem? 2. How have humans affected the environment?
3. Evolution of Life Populations of living organisms change over time Descent with modification Occurs by natural selection; organisms with more favorable traits survive a changing environment and reproduce more successfully. Adaptations are traits that improve an organisms chance of survival.
Ch.1.3 The Scientific Method How problems are solved! –Scientists use controlled methods to collect observable evidence to answer questions about natural phenomena –YouTube - Scientific Method MTVYouTube - Scientific Method MTV
Steps of the Scientific Method 1. Define the problem. 2. Collect information. Qualitative vs. quantitative 3. Form a hypothesis. –a statement that can explain a scientists observations and data –Must be testable –Educated guess that can be proven FALSE –Written as an “if-than” statement
4. Test the hypothesis. –Controlled experiments test variables by comparing a control group with an experimental group. –The independent (manipulated) variable is the one that is changed by the scientist –The dependent (responding) variable changes in response to the change made to the ind. variable
Hypothesis Examples If skin cancer is related to ultraviolet light, then people with a high exposure to uv light will have a higher frequency of skin cancer. If leaf color change is related to temperature, then exposing plants to low temperatures will result in changes in leaf color. In the statements above the dependent variable is blue and the independent variable is red.
5. Observe & record data. 6. Draw conclusions. –Support or refute hypothesis –A theory may be formed- a collection of ideas, hypotheses, laws, and predictions which have been successfully tested, but are subject to modification when facts or experiments demand it. 7. Report research methods & findings. –Scientific journals –Lab reports
Setting Up a Controlled Experiment gKfkc&feature=related
Presenting Scientific Findings Tables- used to organize data
Graphs are used to visually represent data Bar graphs- illustrate comparisons Line graphs- recognize patterns or trends Pie graphs- represent percentages Title of graph should include dependent and independent variables Y-axis has the dependent variable X-axis has the independent variable
Microscopes Light Compound Microscope (LM): used to see small organisms and cells transparent specimen is mounted on glass slide Light passes through the specimen (pg. 21, parts of the microscope)
Electron Microscopes -Use a beam of electrons to produce an enlarged image of a specimen 1)Transmission electron microscope (TEM)- electrons sent through a thin specimen cannot view living specimens 200,000 x magnification
2)Scanning electron microscope (SEM) electrons pass over specimen producing a 3D image 100,000 x magnification cannot view living organisms
Units of Measurement Scientists use one system of measurement, the metric system ( SI system) Decimal system based on powers of 10 SI has 7 base units