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