UNIT 1
INTRODUCTION TO BIOLOGY
READING:
Chapter 1
Biology and You
OBJECTIVES:
At the end of this unit of study the student will be able to:
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Define Biology and identify its various branches.
Explain the steps of the scientific method.
Distinguish between pure and applied science.
Differentiate between magnification and resolution.
Compare and contrast light and electron microscopes.
List characteristics of living things.
Name the five stages of development of an organism.
Compare the theories of biogenesis and spontaneous generation (abiogenesis).
Describe the work that proved the theory of biogenesis.
ASSIGNMENTS:
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INTRODUCTION TO BIOLOGY
UNIT 1
I. Biology and Science
A. BIOLOGY
1. The study of life.
2. From the Greek a. Bios - "Life"
b. Logos (logy) - "word or reason" - study of
3. Branches of biology
a. BOTANY - study of plants
b. ZOOLOGY - study of animals
c. ANATOMY - study of the structure of living things.
d. TAXONOMY - study of the classification of living things.
e. GENETICS - study of heredity.
f. PHYSIOLOGY- study of the functions of living things.
g. MICROBIOLOGY - study of living things at the microscopic level
B. SCIENCE - Body of knowledge gained by observation and experiment.
1. PURE SCIENCE - Basic research which attempts to answer questions for the sake of knowledge itself.
2. APPLIED SCIENCE - Uses knowledge gained in basic research to solve practical problems;
3. Other sciences important to biology
a. Chemistry - study of matter, its structure and changes it undergoes.
b. Physics - science concerned with relationship between matter and energy.
II. Scientific Investigations
A. SCIENTIFIC METHOD
1. Logical, orderly way to solve a problem or answer a question.
2. Steps
a. State the Problem - define what you are trying to discover.
b. Gather Information on Problem
1) Collect and study previous information
2) Problem may already have been answered.
3) Usually library research
c. Form a Hypothesis
1) HYPOTHESIS - working explanation or trial answer to the problem; an "educated guess"
2) Based on the available information.
3) Attempts to explain the observed facts.
4) Can not be accepted until tested many times.
5) May have to be changed if test results don't support the hypothesis
d. Experimentation
1) EXPERIMENT - test that either proves or disproves the hypothesis.
2) Test only one factor at a time - EXPERIMENTAL FACTOR - what you are trying to answer.
3) CONTROL - tested the same as the experimental part except experimental factor is omitted.
e. Observe and Record Data from the Experiment.
1) The results.
2) Includes - notes, drawings, tables, graphs, or other forms of information.
f. State a Conclusion
1) Based on the facts observed in the experiment.
2) The answer to your problem.
3) THEORY - a hypothesis that has been supported by experimental evidence over and over; The
best explanation to the problem. May be strengthen or weakened by new data.
4) LAW - the way nature behaves.
g. Accurately Report Research Methods, Results, and Conclusions
1) Publish report.
2) Informs others of the new information - saves time, effort, money, and speeds progress.
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B. Tools of the Biologist
1. Microscopes
a. Middle Ages - single lens magnifying glasses
b. Around 1590 - Janssen brothers, Dutch eyeglass makers - first known compound microscope – two
lenses mounted at opposite ends of a tube.
c. Anton van Leeuwenhoek - used to his microscopes to observe many different things including
bacteria - considered to be the beginnings of microbiology.
d. Compound Light Microscope
1) Uses light to make specimen being studied, visible
2) Must consist of 2 lenses - modern microscopes have many.
a) Eyepiece lens - at top of microscope; magnifies the image from the objective.
b) Objective lenses - 3 or 4 lenses at bottom of tube; magnifies the specimen.
3) Magnification - increase in size of image of specimen
a) Each lens shows number of times it will magnify;
10x - 10 times, 43x - 43 times
b) Total magnification found by finding the product of eyepiece and objective magnifications
eyepiece lens
= 10x
objective lens
= 43x
Total Magnification = 430x (10 x 43)
c) Greatest magnification about 2000x with light microscope
4) Resolution (Resolving Power)
a) Measure of the clarity and sharpness of the image; ability to show close objects are really
separate.
b) More magnification usually mean poorer resolution.
e. Electron Microscopes
1) Use beam of high speed electrons to make specimen visible
2) Types
a) Transmission Electron Microscope (TEM) - electron beam passes through specimen - must
be thinly sliced; magnifies about 200,000x.
b) Scanning Electron Microscope (SEM) - electron beam bounces off surface - produces 3-D
images.
2. Ultracentrifuge - spins materials at very high speeds - separates solids from liquids using centrifugal force.
3. Chromatography - method of separating substances in a mixture based on their ability to dissolve at
different rates in a solvent.
4. Electrophoresis - separates substances due to electrical differences.
5. Computers
a. Make long, complex calculations; used in modeling.
b. Organize data.
II. Characteristics of Life
A. Living things organize protoplasm
1. PROTOPLASM - special system in which very complex compounds react with each other.
2. Protoplasm is nonliving; doesn't have a definite composition - varies from organism to organism.
3. Protoplasm organized into cells - common unit of life
4. When parts of protoplasm work together in cell to produce chemical activity then life exists
5. Levels of organization
a. CELL - lowest level; Ex. - nerve cell
b. TISSUE - groups of different cells working together to perform a similar function - nervous tissue
c. ORGAN - groups of tissues working together to perform a similar function - brain
d. ORGAN SYSTEM - groups of organs working together; Nervous system.
e. ORGANISM - combination of organ systems; human being
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B. Display Metabolism and Require Energy
1. All living things perform chemical activities - transform energy (ability to do work).
2. METABOLISM - all chemical reactions in an organism
a. ANABOLISM - simple substances combine to form more complex chemicals; stores energy;
production of new materials and growth.
b. CATABOLISM - breakdown of complex compounds into simpler substances; energy released,
material used.
3. Metabolic Functions
a. INGESTION - taking in food, water, oxygen, and carbon dioxide.
b. DIGESTION - breakdown of complex food materials.
c. ASSIMILATION - production of living materials from chemical substances; new material used for
growth, repair and maintenance.
d. RESPIRATION - release of energy stored in food substances
1) AEROBIC - uses oxygen
2) ANAEROBIC - breakdown food without using oxygen.
e. EXCRETION - process of waste material elimination.
4. Energy Relationships
a. All energy for life comes from sunlight.
b. AUTOTROPH - organism that converts light energy and makes their own food.
c. HETEROTROPH - organisms that gain energy by eating other organisms.
C. Respond to Environment
1. STIMULUS - change in the environment.
2. RESPONSE - action or movement of an organism caused by a stimulus.
3. IRRITABILITY - ability of organism to respond to a stimulus.
D. Adapt to the Environment
1. Some organisms have characteristics that enable them to survive a harsh environment.
2. VARIATIONS - differences in organisms.
3. ADAPTATION - characteristic of an organism that makes it able to live in its environment.
4. Organisms that are adapted to an environment are capable of surviving and reproducing.
5. Organisms don't instantly change to fit the environment.
E. Exhibit Growth and Development.
1. GROWTH - increase in size; either cell size increases or cell number increases.
2. DEVELOPMENT - series of orderly changes in form and function that occur in an organism from its
beginning to maturity and death.
a. Stages
1) Beginning
4) Decline
2) Growth
5) Death
3) Maturity
F. Capable of REPRODUCTION
1. Process by which organism makes more of its own kind.
2. Necessary for species survival not individual survival - prevents extinction of the species.
3. Forms of reproduction
a. SEXUAL - requires 2 parents
b. ASEXUAL - requires 1 parent
IV.Abiogenesis/Biogenesis
A. Spontaneous Generation - Abiogenesis
1. Before the mid 17th century, many believed living things developed from nonliving materials.
a. Frogs and eels - made from pond mud
b. Rotting meat - turned into maggots then flies.
c. Jean van Helmont, Belgian doctor, 1600's - recipe for mice: dirty shirt in container of wheat would
produce mice in 21 days.
2. ABIOGENESIS - idea that living organisms could develop from nonliving matter.
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B. PRINCIPLE OF BIOGENESIS - idea that living things could develop only from other living things.
C. Support for Biogenesis
1. Redi's Experiment - 17th century
a. Francesco Redi, Italian physician - believed flies came from eggs laid by other flies.
b. Place raw meat in jars - sealed some, left some open.
c. Maggots (fly larvae) appeared in open jars; none in closed - People argued that air was needed,
provided vital force.
d. Repeated experiment - didn't seal jars - covered some with fine netting - maggots appeared in open
jars but not in net covered jars; eggs found on the netting.
e. Proved flies came from other flies.
2. John Needham's Experiment - 18th century English scientist.
a. Heated meat broth - believed boiling would kill all living things in broth.
b. Allowed broth to cool then loosely sealed flasks.
c. Found microorganisms in broth several days later.
d. Conclude microorganisms appeared spontaneously.
3. Lazzaro Spallanzani's Experiment - 19th century Italian biologist.
a. Believed Needham hadn't boiled broth long enough
b. Boiled broth in sealed flasks for about 1 hour.
c. After several days no growth; opponents believe boiling had destroyed the "active principle" of the
broth and that air was necessary
d. Repeated experiment by boiling broth for different amounts of time; loosely covered them –
microorganisms found in all flasks.
4. Louis Pasteur's Experiment - 19th century French chemist
a. Earlier work with microorganisms was inconclusive as to how they formed.
b. Pasteur believed air contained inactive microorganisms called spores.
c. First experiment - boiled broth in sealed flasks - opened and placed them in places where the air was
likely to contain varying amounts of dust and spores; high/low altitudes; dusty/clean areas - greatest
number of microorganisms found in flasks with greatest amount of dust. Opponents questioned
amount of air
d. Second experiment - Pasteur prepared set of flasks with swan necks - air could get to broth
e. Boiled flasks of broth - allowed them to set; after a period of time he observed that dust had collected
in the s-trap of the flask's neck. When he tipped the flask so that the dust got into the broth,
microorganisms then appeared
f. Some of his flasks set for more that a year with no growth
g. Showed that boiling didn't destroy the broth's ability to grow microorganism; also showed that air
didn't contain any "active principle" or "vegetative force" that gave rise to life.
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