Observation Or Inference

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Transcript Observation Or Inference

Scientific Method
1.
2.
3.
4.
5.
Observation
Gather Information
Hypothesis
Experiment
Conclusion
What is an Observation?
Definition: Using senses to gather information
Observations lead to questions
“what is the effect of …on …?”
Two types of Observations
1. Qualitative:

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Using your senses to describe something
Ex: Mrs. Peddie has Brown Hair
2. Quantitative:
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Using tools to take a numerical measurement
Ex: Mrs. Peddie is 5 ft 2 in.
Hypothesis
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Predicts the answer to a question
Hypotheses are based on--
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
Past Experience
Observations
Research
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.
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
Types of Variables
1.
Dependent Variable:

Is the data collected through observation
and measurement

2.
heart rate
Independent Variable:

Variable that is manipulated (changed)
during the experiment.

rest, stand, walk, run
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?
Theory
Theory = hypothesis supported by
many experiments over time
Examples of theories:
Gravity or Evolution
Making Conversions
How to Create Bar
and Line Graphs
Draw the Axes
Identify the Axes
Y- Axis
X- Axis
Identify the Axes
Y- Axis
Dependent
Variable
(what is observed
and measured)
X- Axis
Independent
Variable
(what is changed by
the scientist)
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
R- Responding
Y- Y-axis
M-Manipulated
I- Independent
X- X-axis
Title
 Write
an appropriate title for the graph
at the top.
 The
title should contain both the
independent and dependent
variables.
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.

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
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
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 Procedure
1.
Label the RIM of Styrofoam cups
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2.
3.
4.
5.
6.
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
Data Collection
1.
Water daily (before school on off days)

2.
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
Six Criteria of Science :
Consistent,
Observable,
Natural,
Predictable,
Testable,
Tentative.
Consistency : The results of
observations and/or experiments are
reasonably the same when repeated.
1.
2.
Green plants will grow towards a light source.
Walking under a ladder will cause bad luck.
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.
1.
2.
Some plants eat meat.
Extraterrestrial beings have visited Earth.
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..
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.
2.
Without sunlight (or artificial light), green plants will
die.
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."
Testability : the event must be
testable through the processes of
science, and controlled
experimentation.
1.
2.
The Bermuda Triangle causes ships and
planes to sink and disappear.
Life comes from life and cannot come from
non-life.
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
1.
2.
Pluto was once a planet but due to it’s orbits, is
now considered a dwarf planet.
We know that the world began about 6000
years ago, and nothing will change that.
Experimental Design
Activity
The Scientists
Jean Baptist Lamarck
vs.
Charles Darwin
Jean Baptiste Lamarck
Evolution occurs as
structures develop
through use, or
disappear because of
disuse, and these
“acquired
EXAMPLE:
characteristics” Over a Giraffes Lifetime it
are passed to offspring
can stretch it’s neck and
it’s offspring will be born
with long necks….
Valid?
Darwin and The Monkey!
THIS IS NOT
WHAT HIS
THEORY
SAYS
Who was Charles Darwin
 Studied
 Hated
Medicine
the sight of blood
 Received
a BA in Theology
 Had 10 children
 Darwin was a Naturalist
on the HMS Beagle
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”
Darwin’s Finches
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?”

After his voyage, Darwin made the
following inferences:
1.
2.
3.
4.
5.
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.
Darwin called this process by which
populations change in response to
their environment
Natural Selection
Evolution happens because
of natural selection
Selection acts on individuals, populations evolve
Change creates advantages
for some species &
disadvantages for others
Fossils reveal changes in species over
millions of years
Adaptation
Adaptations are inherited traits that
increase a group’s chance of
survival & reproduction
This type of finch has a
thick beak  adaptation
for cracking open seeds
Variation
Within a species, there is variation
Variation = differences between members of
a population
Species = group that can breed & produce
healthy offspring
Evidence for Evolution
1. Fossils show change over time
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–
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
How Anatomy supports Evolution
2.
Homologous Structures
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Traits similar in different species
because they share a common ancestor
Ex: human arm, dog front limb, horse
leg, whale fin
“ Look the Same”
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”
How Anatomy supports Evolution
4. Vestigial structures
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Structures reduced in size & often
unused
Remains of functional structures
inherited from an ancestor
Ex: leg & hip bones in pythons & whales
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
So….. Where Do
New Species
Come From?
How do new species form?
1.
Geographic Isolation


When members of a population are
separated
Ex: polar, grizzly, & black bears
2. Reproductive Isolation
 When
members of a population can’t
breed even though they live nearby
 Ex: different mating seasons or different
mating calls
Different Types of Evolution
1.
2.
3.
4.
Divergent evolution
Convergent evolution
Coevolution
Adaptive radiation
Divergent Evolution
Isolated populations evolve
independently
Ex: polar & grizzly bears
changed independently due to
different habitats
Convergent Evolution
Unrelated species become more
alike because they live in similar
environments
Ex: shark & dolphin
Coevolution
Species that interact closely adapt to one
another
Ex: Flowers & Pollinators
(Birds, Bees and Butterflies too)
Adaptive Radiation
Evolution of many diverse species from
one common ancestor
Ex: famous Galapagos finches discovered
by Darwin
How fast does evolution
Gradualism
occur?
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