Chapter 1The Science of Life

1.1 The World of Biology• Biology- the study of life– Bio = life– ology = study of

1.1 The World of Biology

The Characteristics of Life•All living organisms share 7 characteristics1.Organization – having a set make-up of parts– unicellular – 1 cell– multicellular – many cells– Order of organizationorganelle cell tissue organ system

organism

1.1 The World of Biology

1.1 The World of Biology

2. Response to stimuli – having a reaction to a change in the environment– Ex: pupils dilate in a dark room

3. Homeostasis – being able to keep the inside conditions of the body the same (like body temperature)– homeo = similar stasis = a state of equilibrium

1.1 The World of Biology4. Metabolism – all of the chemical reaction that take place in the body to turn food into energy the body can use 5. Growth and development– increasing in size AND changing from an infant to an adult

1.1 The World of Biology

6. Reproduction – producing new organisms– Asexual - 1 organism reproduces– Sexual – 2 organisms reproduce

7. Change through time– also called evolution - populations change over a long period of time

1.3 The Study of Biology

• Scientific Method– model or guide used to solve problems or get information

1.3 The Study of BiologySteps of the Scientific Method•There are 7 common steps found in the scientific method1.Observation– This could be anything that causes you to wonder or

ask a question2.Hypothesis– Before you can go onto the next step you need a little

bit of information to help you form a prediction3.Make a prediction– A prediction about you think is going to happen in the

experiment

1.3 The Study of Biology

4. Experiment– See “Parts of an Experiment” next page

5. Analyze Data– Usually put into a chart format and then graphed

to see a visual relationship6. Draw a conclusion– Based on the data and analysis

7. Peer Review– To ensure that your results were not just by

chance

1.3 The Study of Biology

Parts of an Experiment•Variable– a factor that changes in an experiment– Independent variable– aka manipulated variable -

the factor the experimenter changes on purpose – Dependent variable– aka responding variable –

what you measure in response to the independent variable

– Constants – factors that are kept the same during the experiment

1.3 The Study of Biology

Components:

oTitleoX-axisoY-axisoDependent VariableoIndependent Variable

1.3 The Study of Biology

• Setups– Control group– the setup that stays at normal or

typical conditions– Experimental group– identical to the control

setup except for the independent variable

1.3 The Study of Biology

• Other important points…– Placebo effect– a fake treatment given to a

control group– Experimenter bias – occurs when a scientist’s

expectations change how the results of an experiment are viewed

1.4 Tools & TechniquesMicroscopes– tools that extend human vision by making enlarged images of objects•Magnification – power to increase the size of an object•Resolution – power to show details clearly

1.4 Tools & Techniques

2 Types of Microscopes1.Light microscope– shines a light through a specimen– Has 4 lenses• Objective lenses

– 4x - scanning– 10x – low power– 40x – high power

• Ocular lens (also called the eyepiece) = 10x

1.4 Tools & Techniques

– Total magnification = objective lens X ocular lens (10x)

– What is my total magnification if I am on high power?

– Compound Light microscope• Objects can be LIVING• Lower cost than other microscopes• Commonly used in science classes• Maximum magnification is 2,000x

1.4 Tools & Techniques

2. Electron microscope– a beam of electrons produces an enlarged image of the specimen

– Scanning Electron Microscope (SEM) – passes a beam of electrons over the specimen to produce a 3-D image (max magnification = 100,000 times)

1.4 Tools & Techniques

– Transmission Electron Microscope (TEM) – transmits a beam of electrons through a thin slice of the specimen (max magnification = 200,000 times)• Better magnification• $$$• Specimens have to be dead

1.4 Tools & Techniques

Base Quantity Name Abbreviation

Length meter m

Mass kilogram kg

Time second s

Temperature kelvin k

Basic Units of Measurement