CHAPTER 1 – THE SCIENCE OF BIOLOGY

I. What Is Science? (A) Organized way of using evidence to learn about the natural world.

(B) Collection of knowledge that scientists have built up after years of using this process.

II. Scientific Method – Method used in solving a problem.

NOTE: Used by more than scientists in solving problems. (coaches, mechanics, detectives etc).

III. Steps in the Scientific Method: (A) Step 1 – Observations – gathering data (information) This can be Quantitative – expressed in #’s.

Or Qualitative – expressed other than #’s.

1. Inference – logical interpretation based on prior knowledge or experience. (B) Step 2 – Hypothesis (Prediction; Educated guess).

1. Proposed explanation for a set of observations.

2. Based on prior knowledge or informed creative imagination.

3. Represents a possible solution to a problem.

4. Sometimes If…Then statements.

5. Some solved by gathering more data; some tested by doing controlled experiments.

(C) Step 3 – Test Hypothesis – with a controlled

experiment.

1. Important parts of an experiment a. Test one variable at a time …if possible.

(Variable – is something that causes the changes observed in an experiment) b. Controlled variable –the one(s) that you don’t change c. Experimental variable, independent variable) – contains the variable you are testing. (called the manipulated variable).

d. Dependent variable-the condition that is affected by the independent variable D. Step 4 - Recording & Organizing Data: 1. Tables; Graphs; Averages etc.

2. More data the better.

E. Step 5 – Drawing Conclusions: 1. Based on data and observations.

Example of Famous Experiments: Redi’s Experiment

on Spontaneous Generation Pg. 9 Observations: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

Hypothesis: Flies produce maggots.

Procedure

Uncovered jars Covered jars

Controlled Variables:

jars, type of meat, location, temperature, time.

Manipulated Variable:

lid Several days pass

Responding Variable:

Whether maggots appear Maggots appear Conclusion: Maggots form only when flies come in contact with meat.

Spontaneous Generation of maggots did not occur.

No maggots appear

Other Examples of Famous Experiments – Spallanzani’s

Experiment pg. 11 This experiment showed that microorganisms will not grow in boiled and sealed gravy that is left open to the air.

Questions:

1. What variable was controlled in this experiment?

2. What variable is the experimental (manipulated) variable?

Gravy is boiled Flask is open Gravy is teeming with organisms Flask is sealed Gravy is free of organisms.

Louis Pasteur’s Experiment on Spontaneous Generation Fig. 1-11 pg. 12

Broth is boiled Broth is free of organisms for a year.

Curved neck is removed Broth is teeming with microorganisms.

Questions: 1. Why did microorganisms not grow in the flask before the neck was removed?

2. Why did the microorganisms grow after the neck was removed?

F. Step 6 – Theories: well tested explanations that unifies a broad range of observations.

1. Example: Theory of Evolution.

1-3 Studying Life

(A) Biology – Study of living organisms; study of the living world.

(B) Biosphere – The part of the Earth that contains all ecosystems (C) Levels of environmental organization found on page 21

C. Characteristics of Living Things.

1. Made of units called cells.

a. Unicellular – one-celled.

b. Multicellular – many celled.

2. Reproduction.

3. Based on a universal genetic code. (DNA) 4. Growth & development.

5. Obtain & use materials and energy.

6. Respond to their environment. (Respond to a stimuli) 7. Maintain a stable internal environment.

8. Taken as a group, living things change over time.

(Evolution)

1-4 Tools and Procedures

A. Metric System – Also called the International System Of Units (SI).

1. Based on units of 10, or moving a decimal place one place.

2. Base Units: suffixes (end of words) a. Length/width (linear) = Meter (M) b. Volume = Liters (L) c. Weight = Grams (G) d. Temperature = Celsius (Centigrade) Boiling = 100 degrees Freezing = 0 degrees

How to Convert in the Metric System

Prefixes Kilo – (K) = 1000 M, L. G Hecto – (H) 100 M, L, G Deka – (dk) 10 M, L, G deci – (d) 1/10th of a M, L ,G centi – (c) 1/100 th of a M. L, G Milli – (m) 1/1000 th of a M, L, G

Table on Metric Conversions (found on the test)

Sample Problems:

0.05 mm = __________ cm 585 Kl = ___________ dl 0.005 cm 5,850,000 dl 6, 555 dg = __________ mg 655,500 mg 530 Km = ___________ dm 5,300,000 dm 65 mg = ____________ cg 6.5 cg 5.2 Kg = ____________ cg 520,000 cg 150 g = ____________mg 150,000 mg 6.18 L = ___________cl 618 cl 961 cg = ____________Kg.

0.00961 Kg 0.045 L = __________ ml. 45 ml

How to Read Tables & Graphs

NOTE: The graph has a title, & labeled X & Y axis.

1. At what time of day is the rate of water released by leaves equal to the rate of water absorbed by roots?

Answer: Approx. 5:00 PM 2. What pattern does this graph show about water given off and taken in by a tree? Answer: Water released by leaves peaks at 2 PM; the water absorbed by roots at 6 PM.

Microscopes

• • • Simple Microscopes – magnifying glass (use 1 lens) Compound Microscopes – use more than 1lens (ex. Light microscope that we use in class) Electron Microscopes (SEM and TEM)

Comparison of SEM and TEM See your graphic organizer for review Pg 26 SEM TEM