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 ScienceScience

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 changesPhysics - relationship between matter and energy.

Scientific InvestigationsScientific Method

Logical, orderly way to solve a problem or answer a question. Steps State the ProblemGather Information on Problem Form a HypothesisExperimentation Observe and Record Data from the Experiment. State a Conclusion Accurately Report Research Methods, Results, and Conclusions

Scientific Investigation

State the ProblemDefine what you are trying to discover

Gather Information on Problem Collect/study previous information May already have been answered. Usually library research/Internet Studies


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 InvestigationExperimentation or Test the Hypothesis

Experiment Test to prove or disprove the hypothesis. Experimental Factor/Variable What you are trying to answerTest only one variable at a time Independent Factor – changes by itself Dependent Factor – changes because other factors ControlTested the same as the experimental part except experimental factor is omitted


Observe and Record Data from the Experiment. The results. Includes:

Notes, drawings, tables, graphs, or other forms of information.


State a ConclusionBased 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 overStrengthen or weakened by new data.

Law - the way nature behaves.


Accurately Report Research Methods, Results, and Conclusions

Publish report. Informs others of the new information

Saves time, effort, money, and speeds progress.


MicroscopesHistory of developmentMiddle Ages - single lens magnifying glasses 1590 ‘s - Janssen brothers, Dutch eyeglass makers First known compound microscopeTwo 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 InvestigationTypes of Microscopes

Compound Light Microscope Uses visible light to light specimen Must consist of 2 lenses – most have many

Eyepiece lens Objective lenses

Electron MicroscopesUse beam of high speed electrons to illuminate specimenTypes

Transmission Electron Microscope (TEM) Electron beam passes through specimen

Magnifies about 200,000x.Scanning Electron Microscope (SEM)

Electron beam bounces off surfaceProduces 3-D images.

Scientific InvestigationAttributes of a Microscope

Magnification - increase in size of image of specimenEach lens shows number of times it will magnify;10x - 10 times; 40x - 40 timesTotal magnification found by finding the product of eyepiece and objective magnificationseyepiece lens = 10xobjective lens = 40xTotal Magnification = 400x (10 x 40)Greatest magnification about 2000x with light microscopeResolution (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.


Other Major EquipmentUltracentrifuge - 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

• 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 LifeLiving things organize protoplasm

Protoplasm - special system of very complex compounds reacting Protoplasm is nonlivingDoesn't have a definite compositionProtoplasm organized into cells - common unit of life When parts of protoplasm work together producing chemical activity then life exists. Levels of organization Cell Tissue OrganOrgan SystemOrganism


Display Metabolism and Require EnergyAll living things perform chemical activities Transform energy (ability to do work).Metabolism - all chemical reactions in an organismAnabolism – 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.


Metabolic FunctionsIngestion - take in materialsDigestion - 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.


Respond to Environment Stimulus Change in the environment. Response Action of an organism caused by stimulus. Irritability Ability of organism to respond to stimulus.


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 LifeExhibit Growth and Development.

Growth - increase in sizeEither 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 BeginningGrowthMaturity DeclineDeath


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/BiogenesisSpontaneous Generation - Abiogenesis

Before mid 17th century, many believed living things developed from nonliving materials.Frogs and eels - made from pond mudRotting meat - turned into maggots then flies.Jean van Helmont, Belgian doctor, 1600's Recipe for miceDirty 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 BiogenesisIdea that living things could develop only from other living things.Now part of Cell TheorySupport for BiogenesisFrancesco Redi's - 17th C Italian physicianJohn Needham's - 18th C English scientist.Lazzaro Spallanzani's - 19th C Italian biologist.Louis Pasteur's - 19th C French chemist


Redi's Experiment - 17th centuryBelieved 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 closedPeople 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 jarsEggs found on the netting. Proved flies came from other flies.


Needham's Experiment - 18th centuryHeated meat brothBelieved 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.


Spallanzani's Experiment - 19th centuryBelieved Needham hadn't boiled broth long enoughBoiled broth in sealed flasks for about 1 hour.After several days - no growthOpponents believe boiling destroys "active principle" Believed air was necessaryRepeated experiment by boiling broth for different amounts of timeLoosely covered themMicrobes found in all flasks.

Abiogenesis/BiogenesisPasteur's Experiment - 19th century

Earlier work with microbes was inconclusive how they formed.Pasteur believed air contained inactive microbes called spores.First experimentBoiled broth in sealed flasks Opened/placed them in places where the air was likely to contain varying amounts of dust and sporesHigh/low altitudesDusty/clean areas Greatest number of microbes found in flasks with greatest amount of dustOpponents questioned amount of air

Abiogenesis/BiogenesisSecond experiment

Pasteur prepared set of flasks with swan necks.Air could get to broth Boiled flasks of broth - allowed them to setObserved that dust had collected in the s-trap of flask's neckWhen flask tipped the so that the dust got into the broth, microbes appearedSome flasks sat for more that a year with no growthShowed boiling didn't destroy the broth's ability to grow microbesShowed that air didn't contain any "active principle" or "vegetative force" that gave rise to life.

Introduction to Biology

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