Transcript Document

The Science of Biology
Chapter 1
What are some questions a biologist might
ask about the following pictures?
What do you think are the goals
of science?
• To investigate and understand the natural world
(Why things happen)
• To explain events in the natural world (How things
happen)
• To use those explanations to make useful
predictions. (What next?)
• Science is an organized way of using evidence to
learn about the natural world. It also refers to the
body of knowledge that scientists have built up.
The Scientific Method
•
1.
2.
3.
4.
5.
Do you know the steps? You should by now!
Make observations
Form a hypothesis
Design and conduct the experiment.
Interpret the data.
State you conclusion.
More info on the scientific
method
When do you use the scientific
method?
Creative problem solving…….
Making Observations
• What is the problem?
• Observe everything
you can including
color, shape, make-up,
texture, environment,
etc.
• Brainstorm possible
ways to prove or solve
your problem.
Observation vs. Inference
• Observation is the process
of gathering information
about events or processes
in a careful, orderly way.
Uses the senses,
particularly sight and
hearing.
• What are some examples?
• Inference is a logical
interpretation based on
prior knowledge or
experience. Scientists
use data to make
inferences.
Form a hypothesis
• A hypothesis is an
educational guess
(prediction) as to what
you think will happen
and why.
• When you write a
hypothesis it should
have reasoning behind
it and usually is an
“If…then” statement.
If Bounty paper towel is
the most durable then
it should hold the
most water.
Design and Conduct the Experiment:
testing your hypothesis
• In a controlled experiment, whenever
possible, a hypothesis should be tested by
an experiment in which only ONE variable
is changed at a time. All other variables
should be kept unchanged or controlled.
• There are two variables: manipulated and
responding.
Some experiments have a Control
and Experimental Group
• Control Group
– Something to test against
– Standard that is kept
constant
– All conditions are kept the
same.
– Ie. You want to see what
kind of light plants grow
the best in. Your control
group is regular sunlight.
• Experimental Group
– Test group that has one
condition varied to see
what effect it has.
– All other conditions are
kept the same just like the
control group.
– Ie. Same experiment, but
you put the plant under a
florescent bulb. You must
still water the plant the
same as the control group.
Data
• You must record all data as you • Data is the
continue the experiment. This
information gathered
includes tables, charts, physical
from the observations.
observations such as color
change, etc.
• You must be able to
graph data correctly.
• Remember to be consistent in
when you take measurements • Distinguish between a
bar, line, and pie
(you should do it the same way
and same time intervals) or how graph.
many places you round.
2 Kinds of Data
• Quantitative
(expressed in
numbers, obtained by
counting or
measuring.)
• Quantity
• Qualitative
(descriptive and
involve characteristics
that usually can’t be
counted.)
• Quality
• The plant has 4 buds.
• The leaves of the plant
are very green.
What kind of graph is this?
1. What was the minimum wage in January, 1978?
2. When did the minimum wage reach $3.35?
3. Between what time periods was the largest increase in minimum wage?
4. Based on your observations of the graph, make a prediction about what the wage
might be in the year 2000.
Stating your conclusion.
• If your results show
that your hypothesis
was wrong, you must
start over with a new
hypothesis.
• If your hypothesis is
correct you need to
state your conclusion
and your results.
Science experiments use…
Independent variables – the one factor
changed by the person doing the
experiment.
Dependent variables – the factor being
measured in an experiment.
Constants – all the factors that stay the
same in an experiment.
Variables
The manipulated
variable (independent
variable) is condition
that is changed. (Time,
or actual part of
testing.)
The responding variable
(dependent variable)
changes in response to
the manipulated
variable. (Growth,
amounts, etc.)
Time (years)
How is this graph different?
Do they have the same information?
1. What is the
manipulated variable?
Minimum wage is
dependent on (or
responds to) the year.
2. What is the responding
variable?
Spontaneous Generation or
Biogenesis?
• In the early 1600’s
scientists believed that
life came from nonliving things and
ethers (special forces).
• In the late 1800’s the
theory of biogenesis
replaced spontaneous
generation.
• Francesco Redi did an
experiment with
maggots and from
where they come.
• Biogenesis means that
life comes only from
other life.
• Bio-life
• Genesis- beginning
Applying scientific method
What were Redi’s observations?
What was his hypothesis?
What was his experiment?
Manipulated Variable?
Responding Variable?
What data did he collect?
What was his conclusion?
Testing Redi
• John Needham wanted to
prove that spontaneous
generation could occur.
• Boiled gravy. Sealed it..
• Flask had microorganisms.
He concluded they came
from the gravy (non-living)
because he boiled and
killed them all.
• Lazzaro Spallanzani
retested Needhams
work, thinking
Needham did not boil
the gravy enough.
• Boiled gravy. Flask
open, flask sealed.
• Open flask had
microorganisms,
sealed did not.
What did Needham conclude? Spallanzani?
What were controlled variables? Manipulated?
Pasteur
• Wanted to settle
argument that
Spallanzani’s experiment
was or wasn’t a fair test
because air had been
excluded from sealed jar.
• Boiled broth
• Broth free of
microorganisms for a year.
• Curved neck removed.
• Broth had microorganisms.
What was Pasteur’s
conclusion?
Impacts of Pasteur
1.
2.
3.
4.
Saved French wine industry, unexplained souring of
wine.
Saved silk industry, endangered by silkworm disease.
Uncovered nature of infectious diseases showing they
were result of microorganisms entering body.
Anthrax vaccine.
So, what is pasteurization?
Redi and Pasteur’s experiment: Active Art
Scientific Theories
• A scientific theory
applies to a well-tested
explanation that unifies a
broad range of
observations.
• Theories may sometimes
be modified as new
evidence is found.
– Atom theory
– Evolutionary theory
• Theories in science are
not like everyday
theories. Ie. I have a
theory the IU football
team will win today.
• That statement is not
back by any evidence.
It is just a belief.
Life and How It Came to Be
• We live in the
biosphere.
• What is the
biosphere?
• All living things are
called organisms.
• Bio-life
• -Sphere, circle
The Properties of Life
• 1. Living things are highly • Some cells are made
up on one cell –
organized.
unicellular.
– CellTissueOrgan
– Ie. Protists and
Bacteria
Organ System
• Others are
– Cell- basic unit of
multicellular.
organization.
– Plants and animals
Other characteristics of living things…
2. All organisms are able
to take in energy from
the environment and
use it for their life
processes.
(metabolism)
3.They grow and
develop.
4. They reproduce
(sexually or
asexually).
5. They respond to
environmental stimuli
and adapt to the
environment.
Living characteristics cont.
6. Maintain a stable
internal environmenthomeostasis.
7. Are based on a
universal genetic
code.
8. Taken as a group,
change over time
(evolution).
Adaptation to the Environment
• The ability to respond
and adapt to changes
in the environment is
one of the most
important
characteristics of
living things. Why?
• Who is Charles
Darwin?
• Darwin explained how only
those organisms that can
successfully compete for
Earth’s resources can
survive and reproduce.
The traits that allow the
organisms to survive are
passed onto offspring.
What is this called?
Energy in Life’s Processes
• Metabolism is the
combination of all the
chemical changes that
take place in an
organism.
• Do you have a high or
low metabolism?
• Organisms use
compounds that
contain energy in
chemical bonds as a
source of energy.
• Where do you get you
energy from and what
is it used for?
Homeostasis and Control
• Homeostasis is the
tendency of an
organism to maintain
stable internal
conditions.
• “Internal balance
System”
• Can you give any
examples of
homeostasis?
Living or Non-Living
• Using the
characteristics of
living things, tell
whether each thing is
living or non-living.
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Horse
Flower
Lichen
Cloud
Bacteria
Fire
Snowflake
The Organization of Life
Atoms are the smallest
units of organization.
They form molecules.
Cells are the
fundamental units that
exhibit all of the
characteristics of
living things.
What is someone called
who studies cells?
What’s Next?
• Tissues are made up
of cells working
together to perform a
specific function.
– Muscle tissue
• Organs are made up
of several types of
tissues that function
together for a specific
purpose.
– Heart is made up of
muscle tissue.
Keep Going..
• Organ Systems are made up of several organs
working together for a function.
• Individuals are made up by the organ
systems.
• Populations are a group of individuals that
live in one area.
• The different populations make up a
community.
• Communities and their non-living
surroundings make up ecosystems. and
• The part of the earth that contatins all
ecosystems is the biosphere.
The Metric System
• Scientists use the metric
system when collecting
data and performing
experiments.
• It is a decimal system of
measurements whose units
are based on certain
physical standards and are
scaled on multiples of 10.
(SI)
What is each measured in?
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Length
Volume
Mass
Time
Temperature
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Meter
Liter
Gram
Second
Celsius
Measuring
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Ones place 5
Tenth place .5
Hundredth place .05
Thousandth place .005
• Depending on what
you are measuring and
how precise you want
to be you will need to
be consistent in the
number of decimal
places you round to.
You should not
round the ones place
numbers up or down.
Conversions
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Kilo
Hecta
Deca
Unit
Deci
Centi
Milli
King
Herrold’s
Dad
Underestimated
Demetri’s
Cute
Muscles
Some things you should know..
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2.54 cm.=1 inch.
1 kg =1000 grams
10 mm= 1 cm.
1 m = 100 cm.
• Practice these
conversions.
• How many cm are
there in 5 inches?
• How many mm are
there in 3 cm.?
• How many feet in a
mile?
The Development of the
Microscope
Light Microscopes
– Compound- two or
more lenses, light
passes through
specimen.
– The first microscopes
were a single lens, like
a magnifying glass.
• Electron Microscopes
use electrons to create
an image of the
specimen.
– A monitor needed.
– Only dead material
and has to be used in a
vacuum.
Types of Electron Microscopes
• Scanning Electron
Microscope (SEM)– Bounces e- off
specimen
– Creates 3-D image
– Magnifies up to
60,000x
• Transmission Electron
Microscope (TEM)
– E- pass through
– Specimens must be
very thin
– Magnifies up to
2,000,000x
A New Microscope
• Scanning
Interferometric
Apertureless
microscope (SIAM)
– 500x better resolution
than light microscopes.
– Can image single
atoms.
– Can be used for DNA
sequencing.
Lab Techniques
• Cell cultures are groups of • Cell fractionation is used
cells made from one cell
to separate the different
dividing. They are grown in
cell parts.
a petri dish on a nutrient
1. Cells are broken into pieces
solution.
using a special blender.
2. Broken cells are added to
• They can be used to test cell
liquid and placed in tube.
responses under controlled
3. Centrifuge spins tube. Most
conditions to study
dense parts go to bottom
interactions between cells
and least dense to the top.
and to select specific cells
for further study.
Biotechnology
• Biotechnology is the
use of organisms to
produce things that
people need.
• Food
• Medicine
• Clothing- silk, wool,
leather
• Additional Resources
such as wood and
coal.
Lab Safety!
1. Wear goggles.
2. Tie hair back.
3. No loose clothes.
4. Don’t smell, eat, drink anything.
5. If you break something, don’t try to pick it up.
6. Don’t use anything not labeled.
7. Wash hands.
8. Ask teacher for any help.
9. No horseplay!
Ch. 1 Review
• Go to the following link click on your text
book. Check out the SciLinks and take the
Self-Test for Ch. 1
• Ch. 1 Review