chapter one: science as a process. ch. 1.1 intro to biology & characteristics of life
TRANSCRIPT
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 Biology1. 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. Made of cells2. Respond to stimuli (change in enviro.)3. Maintain homeostasis4. Use energy (metabolism)5. Grow and develop6. Reproduce 7. Change through time (evolution)
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- cells become
specialized
Solution #2cell specializationand division of labor
cell specializationelaboration of one function and reduction of others
division of labordifferent cell types specialize on different tasks
• 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 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
http://www.youtube.com/watch?v=GKGtkzgKfkc&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