Scientific Method

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Scientific Method

• Observation
• Gather Information
• Hypothesis
• Experiment
• Conclusion

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What is an Observation?

• Definition Using senses to gather information
• Observations lead to questions
• what is the effect of on ?

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Two types of Observations

• 1. Qualitative
• Using your senses to describe something
• Ex Mrs. Peddie has Brown Hair
• 2. Quantitative
• Using tools to take a numerical measurement
• Ex Mrs. Peddie is 5 ft 2 in.

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Hypothesis

• Predicts the answer to a question
• Hypotheses are based on---
• Past Experience
• Observations
• Research

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The format for writing a hypothesis

• IF . . . THEN . . .because.
• Example IF I exercise, THEN my heart rate will
  increase BECAUSE heart rate is dependent upon
  activity levels.

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What is an Experiment

• Experiments test your Hypothesis
• The experiment tests ONE VARIABLE
• (factor that changes)
• EX increasing or decreasing your Exercise
  level
• Experiments need a CONTROL GROUP
• (to compare results to)
• EX your heart rate at rest.
• Constants the parts of the lab that must remain
  the same
• EX temperature, type of exercise, time

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Types of Variables

• Dependent Variable
• Is the data collected through observation and
  measurement
• heart rate
• Independent Variable
• Variable that is manipulated (changed) during the
  experiment.
• rest, stand, walk, run

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• Conclusion
• Did the experiment support the hypothesis?
• Analysis
• Paragraph explaining your results and discussing
  these questions.
• If you did the experiment again, what would you
  do differently?
• What did you learn?
• Possible Errors

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Theory

• Theory hypothesis supported by many experiments
  over time
• Examples of theories
• Gravity or Evolution

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Making Conversions
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How to Create Barand Line Graphs
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Draw the Axes
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Identify the Axes
Y- Axis
X- Axis
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Identify the Axes
Y- Axis
Dependent Variable (what is observed and measured)
X- Axis
Independent Variable (what is changed by the
scientist)
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DRY MIX

• One way to remember which data goes on which
  axis is the acronym DRY MIX.
• D.R.Y. M.I.X.
• D- Dependent M-Manipulated
• R- Responding I- Independent
• Y- Y-axis X- X-axis

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Title

• Write an appropriate title for the graph at the
  top.
• The title should contain both the independent and
  dependent variables.

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Scale

• Decide 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.

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Scale
The Y-axis scale is from 0-100. The largest
value though is only 35.
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Scale

• The Y-axis scale is now from 0-40.
• This does a better job emphasizing the
  comparisons between coins.

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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.

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Intervals
The interval for the Y-axis is 20.
The X-axis does not have numerical data and does
not need an interval.
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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).

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Labels
DV label
IV label
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TAILS

• Another handy acronym to help you remember
  everything you need to create your graphs..
• T.A.I.L.S.
• Title
• Axis
• Interval
• Labels
• Scale

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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.
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Bar Graphs vs Line Graphs
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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.

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Example

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Another example

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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

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Example
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Another example
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Planting Procedure

• Label the RIM of Styrofoam cups
• Group and Period, Date
• control or experimental
• Amount of Water
• Punch 3 holes in bottom of cup (already done)
• Place one beaker of soil in cup (60 ml)
• Plant sprinkle ¼ teaspoon of grass seeds evenly
  across the soil
• Place another beaker of soil (60 ml) over seeds
• Water (50ml/one beaker)
• More water is needed at planting to get the seeds
  to germinate

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Data Collection

• Water daily (before school on off days)
• Place watered amount and date on cups
• Measure on days that you have biology
• Place measurements and date on cup and in your
  data table

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CONPTT
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Six Criteria of Science Consistent,
Observable, Natural,Predictable, Testable,
Tentative.
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Consistency The results of observations and/or
experiments are reasonably the same when
repeated.

• Green plants will grow towards a light source.
• Walking under a ladder will cause bad luck.

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Observability The event or evidence of the
event, can be observed and explained. The
observations are limited to the basic human
senses or to extensions of the senses.

• Some plants eat meat.
• Extraterrestrial beings have visited Earth.

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Natural A natural cause (mechanism) must be
used to explain why or how the event happens.

• 1. Green plants convert sunlight into energy.
• 2. With a rod, Moses parted the sea so his people
  could cross to the other side..

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Predictability Specific predictions can be used
to foretell an event. Each prediction can be
tested to determine if the prediction is true or
false.

1. Without sunlight (or artificial light), green
   plants will die.
2. If you are a "Scorpio", your horoscope for today
   is "You'll be saying 'I feel rich !' Lunar
   position highlights back pay, refunds, correction
   of accounting error."

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Testability the event must be testable through
the processes of science, and controlled
experimentation.

1. The Bermuda Triangle causes ships and planes to
   sink and disappear.
2. Life comes from life and cannot come from
   non-life.

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Tentativeness Scientific theories are
changeable and correctable, even to the point of
the theory being proven wrong. Scientific
theories have been modified and will continue to
be modified

• Pluto was once a planet but due to its orbits,
  is now considered a dwarf planet.
• We know that the world began about 6000 years
  ago, and nothing will change that.

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What Factors effect Seed Germination?

• Experimental Design
• Activity

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EVOLUTIONARY THEORY
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The Scientists

• Jean Baptist Lamarck
• vs.
• Charles Darwin

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• Jean Baptiste Lamarck Evolution occurs as
  structures develop through use, or disappear
  because of disuse, and these
• acquired characteristics
• are passed to offspring

EXAMPLE Over a Giraffes Lifetime it can stretch
its neck and its offspring will be born with
long necks. Valid?
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Darwin and The Monkey!
THIS IS NOT WHAT HIS THEORY SAYS
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Who was Charles Darwin

• Studied Medicine
• Hated the sight of blood
• Received a BA in Theology
• Had 10 children
• Darwin was a Naturalist
• on the HMS Beagle

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Theory of Evolution

• In The Galapagos Islands, Darwin collected
  species of finches (13)
• Each had a specialized diet and beak structure
• These finches all closely resembled a South
  American finch ancestral species
• On the trip Darwin saw things he could only
  attribute to a process called
• Natural Selection

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Darwins Finches
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Theory of Evolution

• Hypothesized that the differences were do to
  gradual change
• Darwin referred to such change as descent with
  modification evolution
• Wrote Origin of Species
• He still wondered
• How does evolution occur?

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• After his voyage, Darwin made the following
  inferences
• There is variation within populations
• Some variations are favorable
• Not all young produced in each generation can
  survive
• Individuals that survive and reproduce are those
  with favorable variations
• Favorable traits will increase in future
  generations.

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• Darwin called this process by which populations
  change in response to their environment
• Natural Selection

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So....What is Evolution?
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Evolution happens because of natural selection
Selection acts on individuals, populations evolve
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Change creates advantages for some species
disadvantages for others

• Fossils reveal changes in species over millions
  of years

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Adaptation

• Adaptations are inherited traits that increase a
  groups chance of
• survival reproduction

This type of finch has a thick beak ? adaptation
for cracking open seeds
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Variation

• Within a species, there is variation
• Variation differences between members of a
  population
• Species group that can breed produce healthy
  offspring

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Evidence for Evolution

• 1. Fossils show change over time
• scientists can date fossils use them to support
  the theory of evolution
• common ancestors reveal whether species are
  related
• Anatomy of living species also
• shows relatedness

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How Anatomy supports Evolution

• Homologous Structures
• Traits similar in different species because they
  share a common ancestor
• Ex human arm, dog front limb, horse leg, whale
  fin

Look the Same
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How Anatomy supports Evolution

• 3. Analogous structures
• Distantly related species have structures that
  have the same function but are different in
  structure
• Ex wing of butterfly bird

Work the Same
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How Anatomy supports Evolution

• 4. Vestigial structures
• Structures reduced in size often unused
• Remains of functional structures inherited from
  an ancestor
• Ex leg hip bones in pythons whales

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How DNA Supports evolution

• 5. Molecular Evidence
• Also called biochemical evidence
• Compares biomolecules such as DNA or amino acid
  sequences between organisms
• Related organisms have more of the same molecules
  in common

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So.. Where Do New Species Come From?
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How do new species form?

• Geographic Isolation
• When members of a population are separated
• Ex polar, grizzly, black bears

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• 2. Reproductive Isolation
• When members of a population cant breed even
  though they live nearby
• Ex different mating seasons or different mating
  calls

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Different Types of Evolution

1. Divergent evolution
2. Convergent evolution
3. Coevolution
4. Adaptive radiation

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Divergent Evolution

• Isolated populations evolve independently
• Ex polar grizzly bears changed independently
  due to different habitats

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Convergent Evolution

• Unrelated species become more alike because they
  live in similar environments
• Ex shark dolphin

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Coevolution

• Species that interact closely adapt to one
  another
• Ex Flowers Pollinators
• (Birds, Bees and Butterflies too)

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Adaptive Radiation

• Evolution of many diverse species from one common
  ancestor
• Ex famous Galapagos finches discovered by Darwin

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How fast does evolution occur?

• Gradualism
• One species changes slowly eventually becomes
  two species
• (supported by fossil evidence)
• Punctuated Equilibrium
• Stable with short periods
• of change during which a new species forms