Post on 26-Dec-2015
Scientific MethodScientific Method
1.1. Observation Observation
2.2. Gather Information Gather Information
3.3. HypothesisHypothesis
4.4. ExperimentExperiment
5.5. ConclusionConclusion
What is an Observation?What is an Observation?DefinitionDefinition: Using senses to gather information: Using senses to gather information
Observations lead to questionsObservations lead to questions
““what is the effect of …on …?”what is the effect of …on …?”
Two types of ObservationsTwo types of Observations
1. Qualitative:1. Qualitative: Using your senses to describe something Using your senses to describe something Ex: Mrs. Peddie has Brown HairEx: Mrs. Peddie has Brown Hair
2. Quantitative:2. Quantitative: Using tools to take a numerical measurementUsing tools to take a numerical measurement Ex: Mrs. Peddie is 5 ft 2 in.Ex: Mrs. Peddie is 5 ft 2 in.
HypothesisHypothesis Predicts the answer to a questionPredicts the answer to a question Hypotheses are based on---Hypotheses are based on---
Past ExperiencePast Experience ObservationsObservations ResearchResearch
The format for writing a hypothesisThe format for writing a hypothesis
““IF . . . THEN . . .because….”IF . . . THEN . . .because….”Example : Example : IFIF I exercise, I exercise, THEN THEN my heart my heart
rate will increase rate will increase BECAUSE BECAUSE heart rate heart rate is dependent upon activity levels.is dependent upon activity levels.
What is an ExperimentWhat is an Experiment ExperimentsExperiments test your test your HypothesisHypothesis The experiment tests ONE The experiment tests ONE VARIABLEVARIABLE
(factor that changes)(factor that changes)
EX:EX: = increasing or decreasing your Exercise level = increasing or decreasing your Exercise level Experiments need a Experiments need a CONTROLCONTROL GROUP GROUP
(to compare results to)(to compare results to)
EX: EX: = your heart rate at rest.= your heart rate at rest.
Constants: Constants: the parts of the lab that must remain the the parts of the lab that must remain the same same
EX: EX: = temperature, type of exercise, time= temperature, type of exercise, time
Types of VariablesTypes of Variables
1.1. Dependent Variable:Dependent Variable: Is the data collected through observation Is the data collected through observation
and measurement and measurement heart rateheart rate
2.2. Independent Variable: Independent Variable: Variable that is manipulated (changed) Variable that is manipulated (changed)
during the experiment. during the experiment. rest, stand, walk, runrest, stand, walk, run
ConclusionConclusion Did the experiment support the Did the experiment support the
hypothesis?hypothesis?
AnalysisAnalysis……Paragraph explaining your results and Paragraph explaining your results and
discussing these questions.discussing these questions. If you did the experiment again, what would If you did the experiment again, what would
you do differently?you do differently? What did you learn?What did you learn? Possible ErrorsPossible Errors
TheoryTheory
TheoryTheory = hypothesis supported by = hypothesis supported by many experiments over timemany experiments over time
Examples of theories:Examples of theories:
Gravity or EvolutionGravity or Evolution
Making ConversionsMaking Conversions
How to Create Barand Line Graphs
Draw the Axes
Identify the Axes
Y- Axis
X- Axis
Identify the Axes
Y- Axis
X- Axis
Dependent Variable
(what is observed and measured)
Independent Variable
(what is changed by the scientist)
One way to remember which data goes on which axis is the acronym DRY MIX.
D.R.Y. M.I.X.
D- Dependent M-ManipulatedR- Responding I- Independent
Y- Y-axis X- X-axis
DRY MIX
Title
Write an appropriate title for the graph at the top.
The title should contain both the independent and dependent variables.
ScaleDecide on an appropriate scale for each axis.The scale refers to the min and max numbers used
on each axis. They may or may not begin at zero.The min and max numbers used for the scale
should be a little lower than the lowest value and a little higher than the highest value.
This allows you to have a smaller range which emphasizes the comparisons/trends in the data.
Scale
The Y-axis scale is from 0-100.
The largest value though is only 35.
Scale
•The Y-axis scale is now from 0-40.
•This does a better job emphasizing the comparisons between coins.
Intervals Look at your minimum and maximum values you
set up for both the Y and X-axis. (For most bar graphs, the X-axis will not have numerical values.)
Decide on an appropriate interval for the scale you have chosen. The interval is the amount between one value and the next.
It is highly recommended to use a common number for an interval such as 2, 5, 10, 25, 100, etc.
Intervals
The interval for the Y-axis is 20.
The X-axis does not have numerical data and does not need an interval.
Labels
Both axes need to be labeled so the reader knows exactly what the independent and dependent variables are.
The dependent variable must be specific and include the units used to measure the data (such as “number of drops”).
Labels
DV label
IV label
Another handy acronym to help you remember everything you need to create your graphs…..
T.A.I.L.S.
Title
Axis
Interval
Labels
Scale
TAILS
TAILS
Title: Includes both variables
Axis: IV on X-axis and DV on Y-axis
Interval: The interval (4) is appropriate for this scale.
Label: Both axes are labeled. (UNIT)
Scale: Min and max values are appropriate.
Bar Graphs vs
Line Graphs
Bar Graphs
•Bar graphs are descriptive.
•They compare groups of data such as amounts and categories.
•They help us make generalizations and see differences in the data.
Example
Another example
Line Graphs
•Line graphs show a relationship between the two variables. They show how/if the IV affects the DV.
•Many times, the IV plotted on the X-axis is time.
•They are useful for showing trends in data and for making predictions.
•Can be used to compare multiple sets of data, using different lines within the same graph
Example
Another example
Planting ProcedurePlanting Procedure1. Label the RIM of Styrofoam cups
Group# and Period, Date control or experimental Amount of Water
2. Punch 3 holes in bottom of cup (already done)3. Place one beaker of soil in cup (60 ml)4. Plant sprinkle ¼ teaspoon of grass seeds evenly
across the soil5. Place another beaker of soil (60 ml) over seeds6. Water (50ml/one beaker)
More water is needed at planting to get the seeds to germinate
Data CollectionData Collection1. Water daily (before school on off days)
Place watered amount and date on cups
2. Measure on days that you have biology Place measurements and date on cup and
in your data table
Six Criteria of Science : Six Criteria of Science :
CConsistent, onsistent, OObservable, bservable, NNatural,atural,PPredictable, redictable, TTestable, estable, TTentative. entative.
CConsistency :onsistency : The results of The results of observations and/or experiments are observations and/or experiments are reasonably the same when repeatedreasonably the same when repeated..
1.1. Green plants will grow towards a light source.Green plants will grow towards a light source.
2.2. Walking under a ladder will cause bad luck.Walking under a ladder will cause bad luck.
OObservability :bservability : The event or evidence The event or evidence of the event, can be observed and of the event, can be observed and explained. The observations are limited explained. The observations are limited to the basic human senses or to to the basic human senses or to extensions of the senses.extensions of the senses.
1.1. Some plants eat meat.Some plants eat meat.
2.2. Extraterrestrial beings have visited Earth.Extraterrestrial beings have visited Earth.
NNatural :atural : A natural cause (mechanism) A natural cause (mechanism) must be used to explain why or how must be used to explain why or how the event happens.the event happens.
1. 1. Green plants convert sunlight into energy.Green plants convert sunlight into energy.
2. With a rod, Moses parted the sea so his 2. With a rod, Moses parted the sea so his people could cross to the other side..people could cross to the other side..
PredictabilityPredictability : : Specific predictions Specific predictions can be used to foretell an event. can be used to foretell an event. Each prediction can be tested to Each prediction can be tested to determine if the prediction is true or determine if the prediction is true or false.false.
1.1. Without sunlight (or artificial light), green plants will Without sunlight (or artificial light), green plants will die.die.
2.2. If you are a "Scorpio", your horoscope for today is If you are a "Scorpio", your horoscope for today is "You'll be saying 'I feel rich !' Lunar position "You'll be saying 'I feel rich !' Lunar position highlights back pay, refunds, correction of highlights back pay, refunds, correction of accounting error."accounting error."
TTestability :estability : the event must be the event must be testable through the processes of testable through the processes of science, and controlled science, and controlled experimentation.experimentation.
1.1. The Bermuda Triangle causes ships and The Bermuda Triangle causes ships and planes to sink and disappear.planes to sink and disappear.
2.2. Life comes from life and cannot come from Life comes from life and cannot come from non-life.non-life.
TTentativeness :entativeness : Scientific theories are Scientific theories are changeable and correctable, even to changeable and correctable, even to the point of the theory being proven the point of the theory being proven wrong. Scientific theories have been wrong. Scientific theories have been modified and will continue to be modified and will continue to be modifiedmodified1.1. Pluto was once a planet but due to it’s orbits, is Pluto was once a planet but due to it’s orbits, is
now considered a dwarf planet.now considered a dwarf planet.2.2. We know that the world began about 6000 We know that the world began about 6000
years ago, and nothing will change that.years ago, and nothing will change that.
Experimental Design
Activity
The ScientistsThe Scientists
Jean Baptist LamarckJean Baptist Lamarck
vs.vs.
Charles DarwinCharles Darwin
Jean Baptiste LamarckJean Baptiste Lamarck Evolution occurs as Evolution occurs as structures develop structures develop through use, or through use, or disappear because of disappear because of disuse, and these disuse, and these
““acquired acquired characteristics”characteristics”
are passed to offspringare passed to offspring
EXAMPLE: EXAMPLE:
Over a Giraffes Lifetime it Over a Giraffes Lifetime it can stretch it’s neck and can stretch it’s neck and it’s offspring will be born it’s offspring will be born with long necks….with long necks….
Valid?Valid?
Darwin and The Monkey!Darwin and The Monkey!
THIS IS NOT WHAT HIS THEORY SAYS
Who was Charles DarwinStudied MedicineStudied Medicine
Hated the sight of bloodHated the sight of bloodReceived a BA in TheologyReceived a BA in TheologyHad 10 children Had 10 children Darwin was a Naturalist Darwin was a Naturalist
on the HMS Beagle on the HMS Beagle
Theory of EvolutionTheory of Evolution In The In The Galapagos IslandsGalapagos Islands, Darwin , Darwin
collected species of finches (13)collected species of finches (13)Each had a specialized diet and beak Each had a specialized diet and beak
structurestructureThese finches all closely resembled a These finches all closely resembled a
South American finch ancestral South American finch ancestral speciesspecies
On the trip Darwin saw things he could On the trip Darwin saw things he could only attribute to a process calledonly attribute to a process called
““Natural Selection”Natural Selection”
Darwin’s FinchesDarwin’s Finches
Theory of EvolutionTheory of EvolutionHypothesized Hypothesized that the differences were do that the differences were do
to gradual changeto gradual changeDarwin referred to such change as “Darwin referred to such change as “descent descent
with modification” – evolution; with modification” – evolution; Wrote Origin of SpeciesHe still wondered He still wondered
““How does evolution occur?”How does evolution occur?”
After his voyage, Darwin made the After his voyage, Darwin made the following following inferencesinferences::
1.1. There is variation within populationsThere is variation within populations
2.2. Some variations are favorableSome variations are favorable
3.3. Not all young produced in each Not all young produced in each generation can survivegeneration can survive
4.4. Individuals that survive and reproduce Individuals that survive and reproduce are those with favorable variationsare those with favorable variations
5.5. Favorable traits will increase in future Favorable traits will increase in future generations. generations.
Darwin called this process by which Darwin called this process by which populations change in response to populations change in response to
their environmenttheir environment
Natural SelectionNatural Selection
Evolution happens because Evolution happens because of natural selectionof natural selection
Selection acts on individuals, populations evolve
Change creates advantages Change creates advantages for some species & for some species &
disadvantages for othersdisadvantages for othersFossils reveal changes in species over Fossils reveal changes in species over
millions of yearsmillions of years
AdaptationAdaptation
Adaptations are inherited traits that Adaptations are inherited traits that increase a group’s chance of increase a group’s chance of
survival & reproductionsurvival & reproduction
This type of finch has This type of finch has a thick beak a thick beak adaptation for adaptation for
cracking open seedscracking open seeds
VariationVariationWithin a species, there is variationWithin a species, there is variation
VariationVariation = differences between members = differences between members of a populationof a population
SpeciesSpecies = group that can breed & produce = group that can breed & produce healthy offspringhealthy offspring
Evidence for EvolutionEvidence for Evolution1. Fossils show change over time1. Fossils show change over time
scientists can date fossils & use them to scientists can date fossils & use them to support the theory of evolutionsupport the theory of evolution
common ancestors reveal whether common ancestors reveal whether species are relatedspecies are related
– Anatomy of living species also Anatomy of living species also
shows relatednessshows relatedness
How Anatomy supports EvolutionHow Anatomy supports Evolution
2.2. Homologous StructuresHomologous Structures Traits similar in different species Traits similar in different species
because they share a common ancestorbecause they share a common ancestor ExEx: human arm, dog front limb, horse : human arm, dog front limb, horse
leg, whale finleg, whale fin
“ “ Look the Same”Look the Same”
3. Analogous structures3. Analogous structuresDistantly related species have structures that Distantly related species have structures that
have the have the same functionsame function but are different in but are different in structurestructure
ExEx: wing of butterfly & bird: wing of butterfly & bird
“ “ Work the Same”Work the Same”
How Anatomy supports EvolutionHow Anatomy supports Evolution
4. Vestigial structures4. Vestigial structures Structures reduced in size & often Structures reduced in size & often
unusedunused Remains of functional structures Remains of functional structures
inherited from an ancestorinherited from an ancestor ExEx: leg & hip bones in pythons & whales: leg & hip bones in pythons & whales
How Anatomy supports EvolutionHow Anatomy supports Evolution
How DNA Supports evolutionHow DNA Supports evolution 5. Molecular EvidenceAlso called biochemical evidenceAlso called biochemical evidenceCompares biomolecules such as DNA or Compares biomolecules such as DNA or
amino acid sequences between organismsamino acid sequences between organismsRelated organisms have more of the same Related organisms have more of the same
molecules in commonmolecules in common
So….. Where Do So….. Where Do New Species New Species Come From?Come From?
How do new species form?How do new species form?1.1. Geographic IsolationGeographic Isolation
When members of a population are When members of a population are separated separated
ExEx: polar, grizzly, & black bears: polar, grizzly, & black bears
2. Reproductive Isolation2. Reproductive IsolationWhen members of a population can’t When members of a population can’t
breed even though they live nearbybreed even though they live nearbyExEx: different mating seasons or different : different mating seasons or different
mating callsmating calls
Different Types of EvolutionDifferent Types of Evolution
1.1. Divergent evolutionDivergent evolution
2.2. Convergent evolutionConvergent evolution
3.3. CoevolutionCoevolution
4.4. Adaptive radiationAdaptive radiation
Divergent EvolutionDivergent Evolution
Isolated populations evolve Isolated populations evolve independentlyindependently
ExEx: polar & grizzly bears : polar & grizzly bears changed independently due to changed independently due to different habitatsdifferent habitats
Convergent EvolutionConvergent EvolutionUnrelated species become more Unrelated species become more alike because they live in similar alike because they live in similar
environmentsenvironments
ExEx: shark & dolphin: shark & dolphin
CoevolutionCoevolution
Species that interact closely adapt to one Species that interact closely adapt to one anotheranother
ExEx:: Flowers & Pollinators Flowers & Pollinators
(Birds, Bees and Butterflies too)(Birds, Bees and Butterflies too)
Adaptive RadiationAdaptive Radiation
Evolution of many diverse species from Evolution of many diverse species from one common ancestorone common ancestor
ExEx: famous Galapagos finches discovered : famous Galapagos finches discovered by Darwinby Darwin
How fast does evolution occur?How fast does evolution occur?GradualismGradualism
One species changes slowly & One species changes slowly & eventually becomes two eventually becomes two species species
((supported by fossil evidence)supported by fossil evidence)
Punctuated EquilibriumPunctuated Equilibrium
Stable with short periods Stable with short periods
of change during which a new of change during which a new species formsspecies forms