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Chapter One

Introduction: Themes inthe Study of Life

I nstructor : Beverly Cochran

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What is Biology?

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Biologyisthescienceoflife

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Traditionally divided into three divisions:

- Botany- Zoology (NOT Zoo-ology!)

- Microbiology

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Modern Biology

Many diversesubdivisions, such as:

- Wildlife Biology

- Cellular Biology

- Anatomy & Physiology

- Ecology- Genetics

- Evolutionary Biology

- Molecular Biology

- Developmental Biology- Immunology

- Behavioral Ecology

- Marine Biology

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There are two main types

of biologists . . .

- Laboratory

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- Field

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- asking questions and seeking science-based answers

The central activity of biology: scientific inquiry

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Biologists ask questions suchas:

- how a single cell develops intoan organism

- how the human mind works

- how living things interact incommunities

Biology is therefore a quest an ongoing inquiry about the

nature of life

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How do we define life?

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Order

Evolutionaryadaptation

Responseto theenvironment

Reproduction

Growth anddevelopment

Energyprocessing

Regulation

Character istics of l ife

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1) Order

living things arehighly organizedstructures made up

of cells

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2) Evolutionaryadaptation

adaptations that evolve

over many generations bythe reproductive success ofthose individuals with

heritable traits that arebest suited for theirenvironment

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3) Response to theenvironment

all living things cansense theirenvironment and

react to it

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4) Reproduction

all living thingsreproduce

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5) Growth and development

all living things inherit information (carried bygenes) that control the pattern of growth and

development

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6) Energy processing

all organismsneed energy forall life activities;plants get energythroughphotosynthesis,and animals getenergy fromcellularrespiration

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7) Regulation

all living thingscarry outhomeostatsis(maintaining astable, constantinternaltemperature)

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There are seven themes that connect theconcepts of Biology:

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Theme 1 : New properties emerge at each level in thebiological hierarchy

Life can be studied at different levelsfrom molecules to the entire livingplanet

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1) THE BIOSPHERE

10) molecules

The study of life can therefore be divided into different levels ofbiological organization, from largest (biosphere) to smallest(molecules)

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1) The Biosphere consists of all of the environmentson Earth that are inhabited with life

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2) Ecosystems consists ofall living things andnonliving components in aparticular area

- soil, water, light,atmospheric gases

http://www.marietta.edu/~biol/biomes/Prickly%20Pear%20(Opuntia%20sp.)

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3) Communities

All of the organisms

that live in a particularecosystem; plants,animals, fungi,microorganisms, etc.

http://www.marietta.edu/~biol/biomes/Prickly%20Pear%20(Opuntia%20sp.)

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4) Populations

consists of all of theindividuals of aspecies living withinan area

- e.g., all of the white-taileddeer ( Odocoileus virginianus )

in a certain forest in East Texas- e.g., all of the striped skunks(M ephitis mephitis ) in

Commerce, TX

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5) Organisms every individualliving thing

- each tree in a forest

- each squirrel

- each microbeActinomyces

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6) Organs and Organ Systems

Organs : body parts consisting oftwo or more tissues that carry out aparticular function in the body

Ex: heart, kidneys, brain

Organ System : team of organs

that work together for a specificfunction

Ex: tongue, stomach, intestines,

etc. = Digestive System

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7) Tissues integrated groups ofcells with a common

function, structure, orboth

e.g., different types of

muscle cells make updifferent muscle tissue

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9) Organelles

any of several membrane-enclosed structures withspecialized functions,

suspended in the cytosol ofeukaryotic cells

e.g., mitochondria, nucleus,

etc.

Nucl eus

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10) Molecules

Chemical structure consisting of two or more smallchemical units called atoms

e.g., H 2O the water molecule

Biologists can use reductionism

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Biologists can use reductionismto understand complexsystems

Reductionism is the reduction ofcomplex systems to simplercomponents that are moremanageable to study

e.g., studying just themolecular structure ofDNA

Reductionism is useful however!

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Reductionism is useful however!

Biologists must balance the reductionist strategy with the larger-scale understanding

- how parts of cells, organisms, ecosystems, etc. work together

This is called Systems Biology

A system is a combination of components that function together

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A system is a combination of components that function together

Systems biology constructs models for the dynamic behavior ofwhole biological systems

The systems approach poses questions such as:

- How does a drug for blood pressure affect other organs?

- How does increasing CO 2 alter the biosphere?

Theme2 : Organisms interact with other organisms and their

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Theme 2 : Organisms interact with other organisms and theirenvironments

Every organism interacts with the living and the nonliving parts

of their environment

- both organisms and their environments are affected by theseinteractions

e.g., a tree takes up water and minerals from the soil and carbondioxide from the air; the tree releases oxygen to the air androots help form soil

#1

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The in teraction betweenorgani sms and theirenvir onment is cal ledEcosystem Dynamics

The dynamics of anecosystem include twomajor processes:

1) The flow of energy fromsunlight to producers toconsumers

2) Cycling of nutrients, in

which materialsacquired by plantseventually return to thesoil

Sunlight

Ecosystem

Heat

Heat

Cyclingof

chemicalnutrients

Producers(plants and other

photosyntheticorganisms)

Chemical energy

Consumers(such as animals)

#1

#2

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Theme 3 : All of the activities of life require energy transfer andtransformation

e.g., light, chemical, kinetic, or thermal

Energy flows through an ecosystem, usually entering as light andexiting as heat

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Theme 4 : Structure and functionare correlated at all levels ofbiological organization

Structure and function of living organisms are closelyrelated

e.g., a leaf is thin and flat, maximizing the capture of

light by chloroplasts

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Example: The structures of birds function to enablethem to f ly

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Structures that function for flight:

1) Shape of the bird and its wings extremelyaerodynamic!

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2) Skeleton and hollow bones makes the bird very light, strutsmake bones strong

3) Feathers flight feathers

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3) Feathers flight feathers

Primaries: long and stiff, allow forthrust (flapping flight)

Secondaries: tightly overlapping, allowfor lift

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Theme 5 : Cells are an organisms

basic unit of structure andfunction

The cell is the lowest level of organization that can

perform all activities required for life

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All cells:

- are enclosed by a membrane

- use DNA as their genetic information

The ability of cells to divide is the basis of all reproduction, growth,

and repair of multicellular organisms

A eukaryotic cell has membrane-enclosed organelles

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y g

- largest is usually the nucleus

e.g., plants, animals, fungi, etc.

A prokaryotic cell is simpler and usually smaller

- no nucleus or other membrane-enclosed organelles

e.g., bacteria and Archaea

Theme 6 : The continuity of life is based on heritable information

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yin the form of DNA

Chromosomes contain most of acells genetic material in theform of DNA(deoxyribonucleic acid)

Chromosomes contain genes madeof DNA

- genes are the units of inheritancethat transmit information fromparents to offspring

Chr omosome

http://upload.wikimedia.org/wikipedia/commons/0/07/Gene.pnghttp://upload.wikimedia.org/wikipedia/commons/0/07/Gene.png

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Each chromosome has one long DNAmolecule with hundreds or thousandsof genes

Inherited DNA directs the development of an organism

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NucleicontainingDNA

Sperm cell

Egg cell

Fertilized eggwith DNA fromboth parents

Embryos cells with copies of inherited DNA

Offspring with traitsinherited fromboth parents

DNA

Inherited DNA directs the development of an organism

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Each link of a chain is one offour kinds of chemicalbuilding blocks callednucleotides

Each DNA molecule is made upof two long chains arranged in

a double helix

Nucleus

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Nucleus DNA

Cell

Nucleotide

(a) DNA double helix (b) Single strand of DNA

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DNA in genes also control protein

productionWhy are proteins important?

Proteins are essential parts of organisms and participate in everyprocess within cells

Many proteins are enzymes that catalyze (speed up) biochemicalreactions and are vital to metabolism

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Theme 7 : Feedback mechanismsregulate biological systems

Feedback mechanisms allow biological processes to self-regulate

1) Negative feedback a change in a physiological variable triggers aresponse that counteracts the initial fluctuation

2) Positive feedback a change in a physiological variable triggers

mechanisms that amplify the change

Negative feedback:

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Like a thermostat in the home: as the temperature rises (above theideal normal temperature), the thermostat detects the change andtriggers the air-conditioning to turn on and cool the house.

Once the temperature reaches its thermostat setting, the airconditioning turns off.

P iti f db k

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Positive feedback:

The onset of contractions in childbirth: when a contraction occurs,the hormone oxytocin is released into the body, which stimulatesfurther contractions.

This results in contractions increasing in amplitude and frequency.

The Core Theme in Biology: Evolution is the fundamental

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organizing principle of biology

Biological evolution is the scientific explanation for all unity and

diversity on Earth- organisms on Earth today are the modified descendants of

common ancestors

TheCoreTheme : Evolution accounts for the unity

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The Core Theme : Evolution accounts for the unityand diversity of life

Biologists agree the most importanttheme of all

Nothing in biology makes sense exceptin the light of evolution

Evolution unifies all of biologythroughout the history of life on Earth

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Grouping Species: The Basic Idea

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Taxonomy is the branch of biology that names and classifies

species into groups of increasing sizeDomains, followed by kingdoms, are the broadest units of

classification

Species Genus Family Order Class Phylum Kingdom Domain

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Ur sus americanus (American black bear)

Ursus

Ursidae

Carnivora

Mammalia

Chordata

Animalia

Eukarya

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( ) DOMAIN BACTERIA h di d id d f h

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(a) DOMAIN BACTERIA the most diverse and widespread of theprokaryotes

- there are approximately ten times as many bacterial cells in thehuman body as there are human cells in the body

e.g., Staphylococcus spp., Lactobacillus spp., Streptomyces spp.

E. coli

http://upload.wikimedia.org/wikipedia/commons/6/69/Bacterial_morphology_diagram.svg

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(b) DOMAIN ARCHAEA - prokaryotes that live in extremeenvironments, such as salt lakes and boiling hot springs (sometimescalled extremophiles); believed to be the oldest organisms on Earth

http://www.ucmp.berkeley.edu/archaea/KOSmethanococcus.jpghttp://www.ucmp.berkeley.edu/archaea/NIJmethanosarcina.gifhttp://www.ucmp.berkeley.edu/archaea/NIJmethanobac.gif

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Protists are in multiple kingdoms; unicellular eukaryotes and theirl i l i l l i ll l l i

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relatively simple multicellular relatives

e.g., Amoebas, Euglena (unicellular animal-like protists); Algae(multicellular plant-like protists)

d b b f d

http://en.wikipedia.org/wiki/Image:Laurencia.jpghttp://upload.wikimedia.org/wikipedia/commons/8/88/Euglena_EPA.jpghttp://en.wikipedia.org/wiki/Image:Chaos_diffluens.jpg

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Kindom Fungi absorb nutrients after decomposing organic matter(leaf litter, animal feces)

Kingdom Plantae consists of multicellular eukaryotes

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that carry out photosynthesis

convert light energy into the chemical energy in food

Kingdom Animalia consists of multicellular

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Kingdom Animalia consists of multicellulareukaryotes that ingest other organisms

I n all of thi s diversity there is unity!

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For example:

- DNA is the universal genetic language common to all organisms- unity is evident in many features of cell structure

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Cilia ofParamecium

Cross section of a cilium, as viewedwith an electron microscope

Cilia of tracheacells

CharlesDar inandtheTheor of

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Charles Darwin and the Theory ofNatur al Selection explain diversity anduni ty in li fe

Fossils and other evidence document theevolution of life on Earth over billions ofyears

Charles Darwin published On the Origin of Species by M eans ofN t lS l ti i 1859

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Natural Selection in 1859

Darwin made two main points:

Species showed evidence of descent with modificationfrom common ancestors

Natural selection is the mechanism behind descent with

modification

Darwins theory explained the duality of unity anddiversity

Darwin observed that:

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Individuals in a population have traits that vary

Many of these traits are heritable (passed from parentsto offspring)

More offspring are produced than survive

Competition is inevitable

Species generally suit their environment

Darwin inferred that:

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Individuals that are best suited to their environment aremore likely to survive and reproduce

Because of this, over time, more individuals in a populationwill have the advantageous traits

In other words, the natural environment selects for beneficialtraits

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Natural selection is often evident in adaptations of organisms to theirway of life and environment

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Scientists make observations andthen form and test hypotheses:

Science is a way of knowing

- use inquiry: search forinformation and explanation,focusing on specific questions

Science describes natural structures and processes

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Science describes natural structures and processes

- based on observation and the analysis of data

European black caps

Types of Data

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Data are recorded observations or items of information

Data fall into two categories:

1) Qualitative : descriptions rather than measurements

2) Quanti tative : recorded measurements, sometimes

organized into tables and graphs

FYI the word data is plural, datum is singular!

e.g., The data were collected from 120 nests.

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Qualitative data:

GTGrackle Nestling Data2009 Percentage Male 33.33 Female 66.17

Gender Outcome Mites?

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Date Time Nest Est. Age M=1 F=2MassBird Mass Bag

MassTotal ROP Rtarsus

Dead=1Unknown=2

Yes=1No=2

161 1209 937021 11 2 94.0 16.0 78.0 29.07 33.89

161 1209 937023 10 2 68.0 16.0 52.0 25.34 30.72 1

161 1209 937023 10 2 83.0 16.0 67.0 34.25 33.73

161 1315 938005 10 2 75.0 16.0 59.0 28.42 33.32

161 1315 938005 10 2 101.0 16.0 85.0 25.04 34.84

161 1315 938009 9 2 83.0 17.0 66.0 19.93 29.33161 1315 938009 9 2 73.0 17.0 56.0 27.40 32.12

161 1315 938014 12 2 50.0 18.0 32.0 22.89 26.87 1 1

161 1315 938014 12 2 96.0 18.0 78.0 46.98 37.74 1

161 1315 938014 12 2 91.0 18.0 73.0 41.88 38.92 1

161 1315 938019 12 1 120.0 17.0 103.0 35.66 38.97

161 1315 938019 12 2 59.0 17.0 42.0 26.33 26.46

163 0845 927038 9 1 102.0 17.0 85.0 25.27 35.82

163 0845 927038 9 2 57.0 17.0 40.0 20.77 25.94 1

163 0845 927022 10 1 110.0 17.0 93.0 28.96 37.74

163 0845 927022 10 2 78.0 17.0 61.0 26.32 31.86

163 0845 927044 10 2 66.0 18.0 48.0 19.37 29.21163 0845 927044 10 2 71.0 18.0 53.0 16.18 28.87

163 0845 933049 10 2 76.0 18.0 58.0 24.49 29.90

163 0845 933049 10 2 82.0 17.0 65.0 29.91 32.92

163 0845 937026 9 1 102.0 18.0 84.0 21.56 33.70

163 0845 937026 9 2 63.0 18.0 45.0 18.56 26.40

163 0845 937017 10 2 79.0 17.0 62.0 9.24 27.37

163 0845 937016 9 2 50.0 17.0 33.0 14.19 22.06

163 0845 938026 9 2 40.0 17.0 23.0 9.26 20.64

163 0845 938026 9 1 96.0 17.0 79.0 22.24 32.66

163 0845 938026 9 2 71.0 17.0 54.0 28.41 18.39

166 0900 938012 11 2 103.0 30.0 73.0 39.09 36.33

166 0935 937001 11 2 87.0 30.0 57.0 19.79 30.01

166 0935 937001 11 2 92.0 32.0 60.0 23.27 30.84

166 0935 937008 11 1 94.0 17.0 77.0 25.20 35.32

166 0935 937002 9 2 64.0 30.0 34.0 16.49 26.81 1

166 0935 937002 9 2 53.0 17.0 36.0 16.89 26.00 1

166 0935 937024 10 1 142.0 34.0 108.0 41.99 42.43

166 0935 933055 10 2 81.0 17.0 64.0 26.02 33.05 1

166 0935 933055 10 1 119.0 17.0 102.0 33.34 39.11 1

166 0935 933048 11 1 87.0 17.0 70.0 26.79 34.66

166 0935 933050 10 2 73.0 17.0 56.0 26.73 30.49

166 1430 927030 9 2 62.0 18.0 44.0 25.60 29.62 1

166 1430 927030 9 2 60.0 18.0 42.0 23.53 29.67 1

Quanti tative data:

Forming and testing hypotheses involves explainingnature

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nature

Observations can lead to questions

- questions can lead to hypothetical explanationscalled hypotheses

What is a hypothesis?

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A hypothesis is a tentative answer to a well-framedquestion

A scientific hypothesis leads topredictions

- predictions are tested byobservation or experimentation

For example:

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Observation: Your flashlight doesnt work

Question: Why doesnt your flashlight work?

Hypothesis 1: The batteries are deadHypothesis 2: The bulb is burned out

Both of these hypotheses are testable

The Scientific Method

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The scienti f ic method is an process ofinquiry

Science is based on the textbookscientific method but rarelyfollows all the ordered steps

1) D fi th ti

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1) Define the question

2) Gather information and resources

(observe)

3) Form hypothesis

4) Perform experiment and collect data

5) Analyze data

6) Interpret data and drawconclusions that serve as a starting

point for new hypothesis

7) Publish results

8) Retest (frequently done by otherscientists)

H ow Scienti sts Do I t!

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Limitations of Science

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In science, observations and experimental

results must be repeatableScience cannot support or falsify

supernatural explanations

- outside the bounds of science

Theories in Science

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In the context of science, a theory is different than a hypothesis:

1) Broader in scope than a hypothesis

2) General, and can lead to new testable hypotheses

3) Supported by a large body of evidence in comparison to ahypothesis

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In ordinary speech, "theory" isoften used to mean "guess" or

"hunch"

- in scientific terminology, a theoryis a set of universal statements thatexplain some aspect of the naturalworld

- held with a high degree ofconfidence

- supported by enough physicalevidence and research to make itsabandonment unlikely

Examples of a theories in Biology:

Th C ll Th (1838) ll k li i hi d f

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- The Cell Theory (1838) - all known living things are made up ofcells

- Darwins Theory of Evolution (1859)- Mendels Laws of Inheritance (1865) - transmission of hereditary

characteristics from parent organisms to their children

Robert Hookes cork

cells

Theories are not easily discarded

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New discoveries are first assumedto fit into the existing theory

It is only when, after repeatedexperimental tests, the newphenomenon cannot beaccommodated that scientistsseriously question the theory andattempt to modify it

Scientific theories represent the reality of the physical world

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To say It's only a theory is nave and exhibits a lack ofbasic understanding of science, research, and the scientificmethod

Example :

It is unlikely that a personwill step off a tall building onthe assumption that they willnot fall, because "Gravity isonly a theory."

Science benefits from cooperation

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Most scientists work in teams, which often include graduate and

undergraduate studentsMust share results

- seminars, publications, and websites

Results are subject to peer-review:other biologists review experiment; canonly publish if passes peer-review

Science, Technology, and Society

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The goal of science is to understand natural phenomena

The goal of technology is to apply scientific knowledge for somespecific purpose

Science and technology are interdependent

Biology is marked by discoveries, while technology is markedby inventions

The combination of science and technologyhas dramatic effects on society

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Ethical issues often have as much to do with politics, economics, and culturalvalues as with science and technology

Example : the discovery of DNA by James Watson and FrancisCrick allowed for advances in DNA technology

However, ethical issues can arise:

- Who should have access to personal genetic information, andhow will it be used?

- Should parents have the right to have their minor childrentested for adult-onset diseases?

- What are the larger societal issues raised by newreproductive technologies?

- How does genomic information affect members of minoritycommunities?

Theend

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The end