Introduction: Themes in the Study of Life

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Chapter 1
Introduction Themes in the Study of Life
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The College Board

• Same people that produce the SAT
• Provides students with the opportunity to take
  college level course work and exams while still
  in high school
• This course is meant to be the equivalent of a
  college introductory biology course usually taken
  by freshman biology majors

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Course Content Big Ideas

• The process of evolution drives the diversity
  unity of life
• Biological systems utilize free energy
  molecular building blocks to grow, reproduce, and
  maintain dynamic homeostasis
• Living systems store, retrieve, transmit, and
  respond to essential life processes
• Biological systems interact, and these systems
  and their interactions possess complex properties

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AP Biology Content Areas

• Evolution
• Ecology
• Biomolecules
• Cells
• Membranes Transport
• Energy Metabolism
• Genetics
• Reproduction

• DNA Structure Function
• Signal Transduction Gene Expression
• Genes Development
• Homeostasis Physiology
• Behavior

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Recommended Inquiry Labs

• Artificial selection
• Mathematical Modeling
• Comparisons of DNA sequences using BLAST
• Diffusion Osmosis
• Photosynthesis
• Cellular Respiration
• Transpiration
• Animal Behavior

• Cell Division Mitosis Meiosis
• Biotechnology Bacterial Transformation
• Biotechnology Restriction Enzyme Analysis of DNA
• Energy Dynamics in Ecosystems
• Enzyme Catalysis

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The AP Biology Exam
To provide the maximum information about
differences in students achievements in biology,
the exams are intended to have average scores of
about 50 percent of the maximum possible score
for the multiple choice section and for the free
response section. Thus students should be aware
that they may find these exams

• Exam Monday May 12th 8am
• 3 Hours long
• more difficult than classroom exams.
• 2 Parts
• Multiple Choice 50 final grade
• Free Response 50final grade

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AP Biology Exam

• MPC

• Free Response

• Part A 63 MPC questions on content knowledge
  process skills
• Part B 6 Grid in mathematics application
  questions
• No penalty for guessing

• 10 min reading time followed by 80min writing
  period
• 2 Long essay questions
• 6 short essay questions

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Scores
AP Grade Qualification
5 Extremely Well Qualified
4 Well Qualified
3 Qualified
2 Possibly Qualified
1 No Recommendation
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AP Biology Curriculum Framework

• We are faced with the challenge of balancing
  breadth of content coverage with depth of
  understanding
• AP Biology has shifted from a traditional
  content coverage model to one that focuses on
  enduring, conceptual understandings and the
  content that supports them

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Overview of the Concept Outline

• Big Ideas encompass
• core scientific principles
• theories
• and processes governing living organisms and
  biological systems
• For each Big Idea I will identify enduring
  understandings which incorporate the core
  concepts that you should retain from the learning
  experience

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How we have to organize content

• Underlying Content stuff you have to memorize
• Illustrative Examples the context in which you
  have to understand the content
• You DONT have to memorize this
• You do have to be able to understand these
• Exclusion Statements stuff you definitely dont
  have to know
• Concept Content Connections where 2 seemingly
  different topics intersect
• Learning Objectives what you should know and be
  able to do with the knowledge

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• Biology is the scientific study of life
• Biologists ask questions such as
• How does a single cell develop into an organism?
• How does the human mind work?
• How do living things interact in communities?
• Life defies a simple, one-sentence definition
• Life is recognized by what living things do

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Figure 1.3a
Evolutionary adaptation
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Figure 1.3b
Response to the environment
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Figure 1.3c
Reproduction
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Figure 1.3d
Growth and development
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Figure 1.3e
Energy processing
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Figure 1.3f
Regulation
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Figure 1.3g
Order
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Figure 1.3
Order
Response to the environment
Evolutionary adaptation
Reproduction
Regulation
Energy processing
Growth and development
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Concept 1.1 The themes of this book make
connections across different areas of biology

• Biology consists of more than memorizing factual
  details
• Themes help to organize biological information

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Theme New Properties Emerge at Each Level in the
Biological Hierarchy

• Life can be studied at different levels, from
  molecules to the entire living planet
• The study of life can be divided into different
  levels of biological organization

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Emergent Properties

• Emergent properties result from the arrangement
  and interaction of parts within a system
• Emergent properties are properties of a group
  that are not possible when any of the individual
  elements of that group act alone.
• Cities, the brain, ant colonies and complex
  chemical systems, for instance, all exhibit
  emergent properties that serve to illustrate the
  concept.

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The Power and Limitations of Reductionism

• Reductionism is the reduction of complex systems
  to simpler components that are more manageable to
  study
• For example, studying the molecular structure of
  DNA helps us to understand the chemical basis of
  inheritance

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• An understanding of biology balances reductionism
  with the study of emergent properties
• For example, new understanding comes from
  studying the interactions of DNA with other
  molecules

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Theme Organisms Interact with Other Organisms
and the Physical Environment

• Every organism interacts with its environment,
  including nonliving factors and other organisms
• Both organisms and their environments are
  affected by the interactions between them
• For example, a tree takes up water and minerals
  from the soil and carbon dioxide from the air
  the tree releases oxygen to the air and roots
  help form soil

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Figure 1.4
The biosphere
Tissues
Ecosystems
Organs and organ systems
Communities
Cells
Organelles
Organisms
Atoms
Molecules
Populations
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Figure 1.4a
The biosphere
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Figure 1.4b
Ecosystems
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Figure 1.4c
Communities
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Figure 1.4d
Populations
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Figure 1.4e
Organisms
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Figure 1.4f
Organs and organ systems
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Figure 1.4g
Tissues
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Figure 1.4h
Cell
Cells
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Figure 1.4i
Chloroplast
1 ?m
Organelles
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Figure 1.4j
Atoms
Chlorophyll molecule
Molecules
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Theme Life Requires Energy Transfer and
Transformation

• A fundamental characteristic of living organisms
  is their use of energy to carry out lifes
  activities
• Work, including moving, growing, and reproducing,
  requires a source of energy
• Living organisms transform energy from one form
  to another
• For example, light energy is converted to
  chemical energy, then kinetic energy
• Energy flows through an ecosystem, usually
  entering as light and exiting as heat

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Figure 1.6
Sunlight
Heat
When energy is usedto do work, someenergy is
converted tothermal energy, whichis lost as
heat.
Producers absorb lightenergy and transform it
intochemical energy.
An animals musclecells convertchemical
energyfrom food to kineticenergy, the energyof
motion.
Chemical energy
A plants cells usechemical energy to dowork
such as growingnew leaves.
Chemical energy infood is transferredfrom
plants toconsumers.
(b) Using energy to do work
(a) Energy flow from sunlight to producers to
consumers
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Figure 1.6d
PARKOUR!!!
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Theme Structure and Function Are Correlated at
All Levels of Biological Organization

• Structure and function of living organisms are
  closely related
• For example, a leaf is thin and flat, maximizing
  the capture of light by chloroplasts
• For example, the structure of a birds wing is
  adapted to flight

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Figure 1.7
(a) Wings
(b) Wing bones
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Theme The Cell Is an Organisms Basic Unit of
Structure and Function

• The cell is the lowest level of organization that
  can perform all activities required for life
• All cells
• Are enclosed by a membrane
• Use DNA as their genetic information

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• A eukaryotic cell has membrane-enclosed
  organelles, the largest of which is usually the
  nucleus
• By comparison, a prokaryotic cell is simpler and
  usually smaller, and does not contain a nucleus
  or other membrane-enclosed organelles

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Figure 1.8
Prokaryotic cell
Eukaryotic cell
DNA
(no nucleus)
Membrane
Membrane
Cytoplasm
Nucleus(membrane-enclosed)
DNA (throughoutnucleus)
Membrane-enclosed organelles
1 ?m
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Figure 1.8b
Prokaryotic cell
DNA
(no nucleus)
Membrane
1 ?m
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Theme The Continuity of Life Is Based on
Heritable Information in the Form of DNA

• Chromosomes contain most of a cells genetic
  material in the form of DNA (deoxyribonucleic
  acid)
• DNA is the substance of genes
• Genes are the units of inheritance that transmit
  information from parents to offspring
• The ability of cells to divide is the basis of
  all reproduction, growth, and repair of
  multicellular organisms

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Figure 1.9
25 ?m
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DNA Structure and Function

• Each chromosome has one long DNA molecule with
  hundreds or thousands of genes
• Genes encode information for building proteins
• DNA is inherited by offspring from their parents
• DNA controls the development and maintenance of
  organisms

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Figure 1.10
Sperm cell
Nucleicontaining DNA
Fertilized eggwith DNA fromboth parents
Embryos cells withcopies of inherited DNA
Egg cell
Offspring with traitsinherited fromboth parents
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• Genes control protein production indirectly
• DNA is transcribed into RNA then translated into
  a protein
• Gene expression is the process of converting
  information from gene to cellular product

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Genomics Large-Scale Analysis of DNA Sequences

• An organisms genome is its entire set of genetic
  instructions
• The human genome and those of many other
  organisms have been sequenced using
  DNA-sequencing machines
• Genomics is the study of sets of genes within and
  between species

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Theme Feedback Mechanisms Regulate Biological
Systems

• Feedback mechanisms allow biological processes to
  self-regulate
• Negative feedback means that as more of a product
  accumulates, the process that creates it slows
  and less of the product is produced
• Positive feedback means that as more of a product
  accumulates, the process that creates it speeds
  up and more of the product is produced

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Figure 1.13a
A
Negativefeedback
Enzyme 1
B
D
Enzyme 2
Excess Dblocks a step.
D
D
C
Enzyme 3
D
(a) Negative feedback
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Figure 1.13b
W
Positive Negative Feedback Animation
Enzyme 4
X
Positive feedback
?
Enzyme 5
Excess Zstimulates a step.
Z
Y
Z
Z
Enzyme 6
Z
(b) Positive feedback
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Evolution, the Overarching Theme of Biology

• Evolution makes sense of everything we know about
  biology
• Organisms are modified descendants of common
  ancestors

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Classifying the Diversity of Life

• Approximately 1.8 million species have been
  identified and named to date, and thousands more
  are identified each year
• Estimates of the total number of species that
  actually exist range from 10 million to over 100
  million

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Grouping Species The Basic Idea

• Taxonomy is the branch of biology that names and
  classifies species into groups of increasing
  breadth
• Domains, followed by kingdoms, are the broadest
  units of classification

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Figure 1.14
Species
Genus
Family
Order
Class
Phylum
Kingdom
Domain
Ursus americanus(American black bear)
Ursus
Ursidae
Carnivora
Mammalia
Chordata
Animalia
Eukarya
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The Three Domains of Life

• Organisms are divided into three domains
• Domain Bacteria and domain Archaea compose the
  prokaryotes
• Most prokaryotes are single-celled and
  microscopic

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• Domain Eukarya includes all eukaryotic organisms
• Domain Eukarya includes three multicellular
  kingdoms
• Plants, which produce their own food by
  photosynthesis
• Fungi, which absorb nutrients
• Animals, which ingest their food
• Other eukaryotic organisms were formerly grouped
  into the Protist kingdom, though these are now
  often grouped into many separate groups

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Figure 1.15c
(c) Domain Eukarya
Kingdom Animalia
100 ?m
Kingdom Plantae
Protists
Kingdom Fungi
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Unity in the Diversity of Life

• A striking unity underlies the diversity of life
  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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Figure 1.16
15 ?m
5 ?m
Cilia ofParamecium
Cilia ofwindpipecells
0.1 ?m
Cross section of a cilium, as viewedwith an
electron microscope
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• Charles Darwin published On the Origin of Species
  by Means of Natural Selection in 1859
• Darwin made two main points
• Species showed evidence of descent with
  modification from common ancestors
• Natural selection is the mechanism behind
  descent with modification
• Darwins theory explained the duality of unity
  and diversity

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• Darwin observed that
• Individuals in a population vary in their traits,
  many of which are heritable
• More offspring are produced than survive, and
  competition is inevitable
• Species generally suit their environment

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• Darwin inferred that
• Individuals that are best suited to their
  environment are more likely to survive and
  reproduce
• Over time, more individuals in a population will
  have the advantageous traits
• Evolution occurs as the unequal reproductive
  success of individuals

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• In other words, the environment selects for the
  propagation of beneficial traits
• Darwin called this process natural selection

Video Soaring Hawk
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Figure 1.20
Population withvaried inheritedtraits
Elimination ofindividuals withcertain traits
Reproduction ofsurvivors
4
Increasing frequency oftraits
thatenhancesurvival andreproductivesuccess
1
2
3
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• Darwin proposed that natural selection could
  cause an ancestral species to give rise to two or
  more descendent species
• For example, the finch species of the Galápagos
  Islands are descended from a common ancestor
• Evolutionary relationships are often illustrated
  with treelike diagrams that show ancestors and
  their descendents

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Figure 1.22
Green warbler finchCerthidea olivacea
Warbler finches
Insect-eaters
Gray warbler finchCerthidea fusca
COMMONANCESTOR
Sharp-beakedground finchGeospiza difficilis
Seed-eater
Vegetarian finchPlatyspiza crassirostris
Bud-eater
Mangrove finchCactospiza heliobates
Woodpecker finchCactospiza pallida
Insect-eaters
Tree finches
Medium tree finchCamarhynchus pauper
Large tree finchCamarhynchus psittacula
Small tree finchCamarhynchus parvulus
Large cactusground finchGeospiza conirostris
Cactus-flower-eaters
Cactus ground finchGeospiza scandens
Ground finches
Small ground finchGeospiza fuliginosa
Seed-eaters
Medium ground finchGeospiza fortis
Large ground finchGeospiza magnirostris
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Concept 1.3 In studying nature, scientists make
observations and then form and test hypotheses

• The word science is derived from Latin and means
  to know
• Inquiry is the search for information and
  explanation
• Scientific process includes making observations,
  forming logical hypotheses, and testing them

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Types of Data

• Data are recorded observations or items of
  information these fall into two categories
• Qualitative data, or descriptions rather than
  measurements
• For example, Jane Goodalls observations of
  chimpanzee behavior
• Quantitative data, or recorded measurements,
  which are sometimes organized into tables and
  graphs

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Quantative Data is Measured in SI Base Units
Quantity Measured Unit Symbol
Length Meter m
Mass Gram g
Time Second s
Electric Current Ampere A
Temperature Kelvin K
Intensity of Light Candela cd
Amount of Substance Mole mol
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SI Prefixes

• The SI system is based on multiples of 10
• Prefixes are used with the names of the units to
  indicate what multiple of 10 should be used with
  the units
• For Example
• Kilo 1000
• So if you have 1 kilogram, you have 1000g

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Common SI Prefixes
Prefix Symbol Multiplying Factor
Kilo- K 1,000
Deci- d 0.1
Centi- c 0.01
Milli- m 0.001
Micro- µ 0.000 001
Nano- n 0.000 000 001
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Forming and Testing Hypotheses

• Observations and inductive reasoning can lead us
  to ask questions and propose hypothetical
  explanations called hypotheses

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The Role of Hypotheses in Inquiry

• A hypothesis is a tentative answer to a
  well-framed question
• A scientific hypothesis leads to predictions that
  can be tested by observation or experimentation

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• For example,
• Observation Your flashlight doesnt work
• Question Why doesnt your flashlight work?
• Hypothesis 1 The batteries are dead
• Hypothesis 2 The bulb is burnt out
• Both these hypotheses are testable

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Figure 1.24
Observations
Question
Hypothesis 1 Dead batteries
Hypothesis 2 Burnt-out bulb
Prediction Replacing bulbwill fix problem
Prediction Replacing batterieswill fix problem
Test of prediction
Test of prediction
Test falsifies hypothesis
Test does not falsify hypothesis
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• Hypothesis-based science often makes use of two
  or more alternative hypotheses
• Failure to falsify a hypothesis does not prove
  that hypothesis
• For example, you replace your flashlight bulb,
  and it now works this supports the hypothesis
  that your bulb was burnt out, but does not prove
  it (perhaps the first bulb was inserted
  incorrectly)

82
Questions That Can and Cannot Be Addressed by
Science

• A hypothesis must be testable and falsifiable
• For example, a hypothesis that ghosts fooled with
  the flashlight cannot be tested
• Supernatural and religious explanations are
  outside the bounds of science

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The Flexibility of the Scientific Method

• The scientific method is an idealized process of
  inquiry
• Hypothesis-based science is based on the
  textbook scientific method but rarely follows
  all the ordered steps

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Variables

• In a controlled experiment, only one variable is
  changed at a time.
• Dependant Variable the condition that results
  from changes to the independent variable
• Independent Variable in an experiment, the only
  condition that is tested

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Constants Controls

• To be certain that you are really testing weather
  butter or oil make a better cake, you must keep
  other possible factors the same for each test or
  trial
• Constant a factor that does not change when
  other variables do
• Control a standard by which the test results can
  be compared

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Experimental Controls and Repeatability

• A controlled experiment compares an experimental
  group with a control group
• Ideally, only the variable of interest differs
  between the control and experimental groups
• A controlled experiment means that control groups
  are used to cancel the effects of unwanted
  variables
• A controlled experiment does not mean that all
  unwanted variables are kept constant

87
Theories in Science

• In the context of science, a theory is
• Broader in scope than a hypothesis
• General, and can lead to new testable hypotheses
• Supported by a large body of evidence in
  comparison to a hypothesis

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Summary

• Themes can provide a common framework for
  learning Biology
• What are the characteristics of Life?
• What is Science and how does it work?
• Evolutions role in the study of Biology