Honors Biology Chapter 2

The Science of Biology

Concept 2.1: Discovery Science Emphasizes Inquiry

and Observation

• I. Science as Inquiry

• A. Science = “to know”, to answer ?’s about the natural world

• 1. 2 main forms of science investigation:

• a. Discovery Science = Describes Nature

• b. Hypothesis Based Science = Explains Nature

• B. In Inquiry based Biology – ask

thoughtful ?’s, and then search for

answers

• C. Takes talent to know “what to ask!”

II. Observations and Data

• A. Observation = use of senses to gather and record info

• B. Data = recorded observations

• C. Scientific instruments – increase range of possible observations (telescopes, microscopes)

D. Two types of Data:

• 1. Quantitative Data = measurements,

amounts (involves numbers)

• a. Ex. Height, length, temperature,

how many, degrees, etc.

• 2. Qualitative Data = descriptions,

sensory impressions

• a. Ex. Color, smell, taste, sound,

behavioral observations

• Data should be: clearly organized (tables,

charts, graphs), consistently recorded,

reliable

III. What is Discovery Science?

• A. It is Descriptive Science!

• 1.Ex. Jane Goodall and Chimpanzees,

collecting and id’ing orgs in river,

describing cells seen under a microscope,

etc.

• 2. Can occur entirely by accident, too!

• - Ex. Alexander Fleming’s

discover of penicillin (Read p. 26)

• B. Inference = logical conclusion based on observations

• 1. Help refine general ?’s into specific ?’s to explore further

• a. Ex. Something in the mold prevented the bacterial growth in Fleming’s culture

• 2. Good inference – does not stretch too far beyond the data

• 3. Ex. Inference exercise: photo p. 27

• C. Generalization = broad conclusion

based on many specific observation put

together

• 1. Ex. All living things made of cells –

generalized from observing cells in all type

of samples from many types of orgs.

• 2. Can also be made from quantitative

data (graph of boy vs. girl height p. 28)

• D. Discovery science often leads to

Hypothesis based Science! – to test if

generalizations and inferences are true,

and to determine causes of some

discoveries!

Concept 2.2: Hypothesis Based Science is a Search

for Explanations

• I. Methods of Hypothesis Based Science

• A. Scientific Method: a plan of attack,

not always completely followed! (Read

p.30)

• 1. Diagram – p. 30: Observation,

Question, Hypothesis, Prediction, Test

(Replicate, Report)

• a. “PHEAC, R2”

• B. Hypothesis = suggested answer to a

well-defined scientific ? (Or: an

explanation on trial)

• 1. Should allow you to make

predictions in an

“If…………then……..”format

2. Ex. Dead flashlight p. 31

• C. Case Study of Hypothesis Based Science –Read p. 32-35

• 1. Controlled Experiment = tests the effects of a single variable only

• a. Variable = condition that can vary within an experiment

• b. Eliminating unwanted variables done by: dividing test subjects into 2 groups

• 1.) Experimental group

• 2.) Control group

• 3.) Constant = all variables that are kept the same for all groups in the experiment

• 2. Organizing Data and Interpreting

Results

• a. Quantitative Data – more easily

interpreted in chart and/or graph form

• 1.) Graphs – useful in seeing

trends at a glance

• 2.) Ex. Graph p. 35

Concept 2.3: Understanding Science will help You

Evaluate many Issues

• I. Evidence = (in science) collected body

of data from observations and experiments

• A. Must be repeated multiple times

with similar results for scientists to accept

it as valid.

• B. Useful to evaluate everything from

ads for food supplements, to “miracle”

cures

II. What makes a hypothesis

“scientific”?

A. Must be testable, otherwise worthless!

B. Can either be supported or contradicted by an experiment (Is it “falsifiable”)

C. Scientific hypotheses may be rejected later, esp. with new equipment advances.

1. Ex. Fungi once thought closely related to plants, but DNA technology refutes that idea now.

III. Limitations of Science

• A. Restricted to natural causes for natural

phenomena

• 1. Many things cannot be “tested”

scientifically

• a. Ex. Cannot prove/disprove with

science that rainbows, storms, etc. caused

by unobservable or supernatural forces

• 2. Not everything you “know” is based on

science, either

• a. Ex. You “know” what type of music

you like, what your favorite color is, etc.

• b. Ex. You “know” right from wrong –

ethical value

IV. Theories

• A. Theory = well-tested explanation that makes sense of a great variety of scientific observations

• (ties together many different sets of observations and data)

• 1. Can result in many different hypotheses that can be tested

• a. Ex. Theory of Natural Selection –explains many different adaptations of orgs. to envir.

• 2. Can be modified or replaced with new evidence

V. Models

• A. Model = physical, mental or mathematical representation of how people understand a process or idea

– 1. Ex. Drawing, graph, 3-D object, computer program, math equation, or verbal description or analogy of how process works

– 2. Judge value of models on: does it explain, can it help predict, does it match new observations?

• - 3. Poor models don’t last

VI. Communication in Science

• A. Scientists rarely work alone (unlike

movie sci.)

• B. Communicate by: journal articles,

giving talks at meetings, internet

communication, etc.

C. Competition/Cooperation driving forces

• 1. Ex. Race to map the human

genome (not in text)

VII. Science, Technology and

Society

• A. Technology’s Goal = to apply science

to a specific purpose

• 1. Scientists (biologists, ex.) make

“discoveries”

• 2. Technologists (engineers, ex.)

create “inventions”

Examples of Technology

• 3. Ex. Watson and Crick – discovered structure of DNA molecule

• Medical Technologists – working to cure diseases with recombinant DNA technology

• 4. *Technology often driven by current human needs and values.– Ex. Should people be tested for genes for diseases?

Should we perform stem cell research to cure disease?

• Notice: not “can it be done” but, “should” it be done?