Introduction to Biology
Biology and Science
Biology
The study of life.
From the Greek Bios - "Life"
Logos (logy) - "word or reason" - study of
Biology and Science
Branches of biology
Botany - study of plants
Zoology - study of animals
Anatomy - study of the structure of living things.
Taxonomy - study of the classification of living things.
Genetics - study of heredity.
Physiology - study of the functions of living things.
Microbiology - study of organisms at microscopic level
Biology and Science
Science
Body of knowledge gained by observation and experiment.
Pure Science
Basic research; Answers questions
Applied Science
Uses knowledge gained in basic research
Solve practical problems
Other sciences important to biology
Chemistry - study of matter, structure and its changes
Physics - relationship between matter and energy.
Scientific Investigations
Scientific Method
Logical, orderly way to solve a problem or answer a
question.
Steps
State the Problem
Gather Information on Problem
Form a Hypothesis
Experimentation
Observe and Record Data from the Experiment.
State a Conclusion
Accurately Report Research Methods, Results, and
Conclusions
Scientific Investigation
State the Problem
Define what you are trying to discover
Gather Information on Problem
Collect/study previous information
May already have been answered.
Usually library research/Internet Studies
Scientific Investigation
Form a Hypothesis
Hypothesis - working explanation or trial answer
an "educated guess"
Based on the available information.
Attempts to explain the observed facts.
Tested many times before acceptance
May have to be changed if test results don't
support the hypothesis
Scientific Investigation
Experimentation or Test the Hypothesis
Experiment
Test to prove or disprove the hypothesis.
Experimental Factor/Variable
What you are trying to answer
Test only one variable at a time
Independent Factor – changes by itself
Dependent Factor – changes because other factors
Control
Tested the same as the experimental part except
experimental factor is omitted
Scientific Investigation
Observe and Record Data from the Experiment.
The results.
Includes:
Notes, drawings, tables, graphs, or other
forms of information.
Scientific Investigation
State a Conclusion
Based on the facts observed in experiment.
Answer to your problem.
Theory - Best explanation to the problem
Hypothesis that has been supported by
experimental evidence over and over
Strengthen or weakened by new data.
Law - the way nature behaves.
Scientific Investigation
Accurately Report
Research Methods, Results, and Conclusions
Publish report.
Informs others of the new information
Saves time, effort, money, and
speeds progress.
Scientific Investigation
Microscopes
History of development
Middle Ages - single lens magnifying glasses
1590 ‘s - Janssen brothers, Dutch eyeglass makers
First known compound microscope
Two lenses at opposite ends of a tube.
Anton van Leeuwenhoek
Used to his microscopes to observe many
different things including bacteria
Considered beginning of microbiology.
Scientific Investigation
Types of Microscopes
Compound Light Microscope
Uses visible light to light specimen
Must consist of 2 lenses – most have many
Eyepiece lens
Objective lenses
Electron Microscopes
Use beam of high speed electrons to illuminate specimen
Types
Transmission Electron Microscope (TEM)
Electron beam passes through specimen
Magnifies about 200,000x.
Scanning Electron Microscope (SEM)
Electron beam bounces off surface
Produces 3-D images.
Scientific Investigation
Attributes of a Microscope
Magnification - increase in size of image of specimen
Each lens shows number of times it will magnify;
10x - 10 times; 40x - 40 times
Total magnification found by finding the product of eyepiece and
objective magnifications
eyepiece lens
= 10x
objective lens
= 40x
Total Magnification
= 400x (10 x 40)
Greatest magnification about 2000x with light microscope
Resolution (Resolving Power)
Measure of the clarity and sharpness of the image; ability to show
close objects are really separate.
More magnification usually mean poorer resolution.
Scientific Investigation
Other Major Equipment
Ultracentrifuge - spins materials at very high speeds
Separates solids from liquids using centrifugal
force.
Chromatography - Separating substances in a mixture
Uses differences in solubility of solids in a solvent
Electrophoresis - separates due to electrical charges.
Computers
Make long, complex calculations; modeling.
Organize data.
Characteristics of Life
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Living things organize protoplasm
Display Metabolism and Require Energy
Respond to Environment
Adapt to the Environment
Exhibit Growth and Development.
Capable of Reproduction
Characteristics of Life
Living things organize protoplasm
Protoplasm - special system of very complex compounds reacting
Protoplasm is nonliving
Doesn't have a definite composition
Protoplasm organized into cells - common unit of life
When parts of protoplasm work together producing chemical
activity then life exists.
Levels of organization
Cell
Tissue
Organ
Organ System
Organism
Characteristics of Life
Display Metabolism and Require Energy
All living things perform chemical activities
Transform energy (ability to do work).
Metabolism - all chemical reactions in an organism
Anabolism – assembly of compounds; stores energy;
Catabolism - breakdown compounds; energy released,
Energy Relationships
All energy for life comes from sunlight.
Autotroph - makes its own food.
Heterotroph - eats other organisms.
Characteristics of Life
Metabolic Functions
Ingestion - take in materials
Digestion - breakdown of complex food materials.
Assimilation – assembly of new materials
Respiration - release of energy from food
Aerobic - uses oxygen
Anaerobic - without using oxygen.
Excretion - waste material elimination.
Characteristics of Life
Respond to Environment
Stimulus
Change in the environment.
Response
Action of an organism caused by stimulus.
Irritability
Ability of organism to respond to stimulus.
Characteristics of Life
Adapt to the Environment
Some organisms have characteristics that enable
survival a harsh environment.
Variations - differences in organisms.
Adaptation - characteristic of an organism
that enables it to live in its environment.
Adapted organisms are capable of surviving and
reproducing.
Organisms don't instantly change.
Characteristics of Life
Exhibit Growth and Development.
Growth - increase in size
Either cell size or cell number increases.
Development - series of orderly changes in form and function.
Occur from beginning to maturity and death of organism.
Stages
Beginning
Growth
Maturity
Decline
Death
Characteristics of Life
Capable of Reproduction
Process where organism makes more of its
own kind.
Necessary for species survival not individual.
Prevents extinction of the species.
Forms of reproduction
Sexual - requires 2 parents
Asexual - requires 1 parent
Abiogenesis/Biogenesis
Spontaneous Generation - Abiogenesis
Before mid 17th century, many believed living things
developed from nonliving materials.
Frogs and eels - made from pond mud
Rotting meat - turned into maggots then flies.
Jean van Helmont, Belgian doctor, 1600's
Recipe for mice
Dirty shirt in container of wheat
would produce mice in 21 days.
Abiogenesis
Idea that living organisms could develop from nonliving
matter.
Abiogenesis/Biogenesis
Principle of Biogenesis
Idea that living things could develop only from
other living things.
Now part of Cell Theory
Support for Biogenesis
Francesco Redi's - 17th C Italian physician
John Needham's - 18th C English scientist.
Lazzaro Spallanzani's - 19th C Italian biologist.
Louis Pasteur's - 19th C French chemist
Abiogenesis/Biogenesis
Redi's Experiment - 17th century
Believed flies came from eggs laid by other flies.
Place raw meat in jars - sealed some, left some open.
Maggots (fly larvae) appeared in open jars; none in closed
People argued that air needed, provided vital force.
Repeated experiment - didn't seal jars
Covered some with fine netting
Maggots appeared in open jars; not in net covered jars
Eggs found on the netting.
Proved flies came from other flies.
Abiogenesis/Biogenesis
Needham's Experiment - 18th century
Heated meat broth
Believed boiling would kill all living things in broth.
Allowed broth to cool then loosely sealed flasks.
Found microorganisms in broth several days later.
Concluded microbes appeared spontaneously.
Abiogenesis/Biogenesis
Spallanzani's Experiment - 19th century
Believed Needham hadn't boiled broth long enough
Boiled broth in sealed flasks for about 1 hour.
After several days - no growth
Opponents believe boiling destroys "active principle"
Believed air was necessary
Repeated experiment by boiling broth for different
amounts of time
Loosely covered them
Microbes found in all flasks.
Abiogenesis/Biogenesis
Pasteur's Experiment - 19th century
Earlier work with microbes was inconclusive how they formed.
Pasteur believed air contained inactive microbes called spores.
First experiment
Boiled broth in sealed flasks
Opened/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 microbes found in flasks with greatest
amount of dust
Opponents questioned amount of air
Abiogenesis/Biogenesis
Second experiment
Pasteur prepared set of flasks with swan necks.
Air could get to broth
Boiled flasks of broth - allowed them to set
Observed that dust had collected in the s-trap of flask's neck
When flask tipped the so that the dust got into the
broth, microbes appeared
Some flasks sat for more that a year with no growth
Showed boiling didn't destroy the broth's ability to grow microbes
Showed that air didn't contain any "active principle" or
"vegetative force" that gave rise to life.