Chapter One: Science as a Process

Ch. 1.1 Intro to Biology & Characteristics of Life

SCIENCE The continuous effort to discover and increase human knowledge through research The process of observing, explaining, and understanding our world Does NOT include “supernatural” explanations

Biology “Bio” = life “ology” = study of The study of life (organisms) Answers questions about the natural world: –How they work –How they interact with the environment –How they change over time

Branches of Biology 1.Anatomy: external & internal structures of organisms 2.Ecology: interactions between organisms and their environment 3.Cytology: structure & function of cells 4.Botany: plants

5. Genetics: heredity, how traits pass from parent to offspring 6. Microbiology: “micro” = small, organisms seen with a microscope 7. Taxonomy: classification 8. Zoology: animals

Characteristics of Life: 1.Organisms are made of cells. 2.Respond to stimuli. 3.All living things maintain homeostasis. 4.Organisms use energy (metabolism). 5. All living things grow and develop. 6.All living things reproduce. 7. Living things change through time.

Homeostasis Stable internal conditions Ex: –Temperature Ex: Thermostat –Water intake –Food intake –pH

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

Levels of Biological Organization Place the following terms in the appropriate places on the pyramid Biosphere Biome PopulationOrganism Community Ecosystem

Levels of Biological Organization Place the following terms in the appropriate places on the pyramid Organ SystemsCell AtomOrganTissue MoleculeOrganism

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 –Put it to the TestPut it to the Test

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 independent 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 after many hypotheses have been tested and supported by much experimental evidence. 7. Report research methods & findings. –Scientific journals –Lab reports

Mythbusters Example Identify the hypothesis, control, independent and dependent variables in the following experiment Mythbusters Plant Experiment part 1 Mythbusters Plant Experiment part 2

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 graphs should include dependent and independent variables  Y-axis has the dependent variable  X-axis has the independent variable

Scientific Method Review Tutorial Video Review

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

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