Biology I NotesChapter 1—Characteristics of Life

Definition of BiologyBio = life

–ology = study of

Life is defined by 7 Characteristics:1. All living things are made of cells

-Cells are the smallest units of life capable of all functions

2. All living things can reproduce

3. All living things perform the chemical reactions necessary to obtain and use the energy that allows them to function—Metabolism

4. All living things must maintain a stable internal environment—Homeostasis

7 Characteristics of life continued

5. All living things are able to pass on characteristics to their offspring-Heredity

6. Species must be able to adapt and change as their environment changes—Evolution

7. All living things must live and interact with other organisms.

Salt on a pretzel

Human hair cut

• A strand of human hair is about 100 µm wide

Cricket leg

Red blood cell, platelet, T-lymphocyte

Red cells: nonnucleated/contain hemoglobin (contains iron and allows the cell to carry oxygen to other parts of the body)/carry carbon dioxide away from peripheral tissue to the lungs where it can be exhaled

infection-fighting white blood cells classified in two groups: granular and agranular. Granulocytes are formed in bone marrow; agranulocytes are produced by lymph nodes and spleen. Two types of agranulocytes: lymphocytes, which fight disease by producing antibodies and thus destroying foreign material, and monocytes.

Platelets: tiny cells formed in bone marrow/ necessary for blood clotting.

Red blood cells are 7 µm in diameter.

Types of Microscopes (p 52-54)Compound Light Microscope (CLM) -light microscopes that use two

lenses (ocular and objective)

Stereo Microscope

Electron Microscopes-more powerful than CLM-cannot be used on living specimen b/c it requires a vacuum chamber-up to 200,000x magnification

TEM (transmission electron microscope)-electron beam is directed at a thin slice of a specimen stained with metal ions-shows internal detail

SEM (Scanning electron microscope)-Shows surfaces in great detail

Scanning Tunneling Microscope-uses a probe attached to a computer-can be used on living specimen

SEM

For more samples go to:http://academic.udayton.edu/ShirleyWright/SEM/Samples.htm

TEM

The TEM can view objects that are 60,000 times smaller in diameter than a human hair $475,000 Portland State Univ.

Compound light->

TEM

SEM

The Scientific Process– Collecting Observations-using your senses– Asking Questions-What is the effect of _ on _?– Forming hypotheses and making predictions

• If _______ changes, then it will affect _______.

– Confirming predictions through experimentation• Writing a procedure

– Collecting/Analyzing data –tables and graphs– Drawing Conclusions– Publishing results in scientific journals

(magazines)

Observation/Question/Hypothesis

• Observing problems, or using senses

• Question– What is the effect of ____ on ____?

• Hypothesis– If /then or cause/effect statement.

Experiments need 2 groups:Control group —receives no experimental treatmentExperimental group —identical to the control group

except for one factor, or variable. (receives the experimental treatment)

>This variable that is being tested or changed by the experimenter is called the independent variable or manipulated variable

? What did I change about the control/experimental group?

>The variable that is measured is called the dependent variable or responding variable

? What data did I measure and collect ?ALL other variables must remain the same, or

constant. (also sometimes called controls)

WHY DO I NEED CONSTANTS?

• Other variables could affect the results, so we must control those by keeping them the same. We want to see the effect of the IV on the DV without other factors interfering.– TO MAKE SURE THAT WE ARE ONLY

TESTING ONE VARIABLE!!!

Procedure• 3 or more specific steps answering the

question.• Someone could repeat the experiment

exactly as you did.• How did you:

– change the IV?– Measure the DV?– Hold other variables constant?

• Be detailed!!!!!!!!

Tables

• Needs these items:– IV with units– DV with units– Place to record data– Periods of time shown if needed

*Choose the one that best displays the data.

IV DV IV DV DV

Time DV IV Time Time IV

GraphsLine Graphs

• Best for data that changes with time (continuous) • x-axis contains the independent variable• y-axis contains the dependent variable

Bar Graphs• Useful when comparing data for several individual items• Set-up is the same as a line graph

Rules for graphing• Always label the axes• Always include units of measure• Always include a title• Number scales must be consistent

TITLE: The effect of (the IV) on (the DV)

• DRY MIX• Dependent or

Responding variable – Y axis

• What is the:• IV?• DV?• Title?• Interval on the x axis?• Interval on the y axis?

Manipulated or Independent variable-

X axis

“When there’s a key, it’s the IV!”? What is the:

IV?

DV?

Variable on the x axis?

Variable on the y axis?

Title?

Unit on the x axis?

Unit on the y axis?

What group does the triangular data represent?

Conclusion (finally!)

• Analyze data (mean, median, mode) if needed

• Restate hypothesis and support or refute it using DATA

• Identify sources of error and explain effect on results

• Make proposals for future investigations