Transcript Document

Invitation to Biology
Chapter 1
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.
Consider what can fit across the
head of a pin:
• 375 RBC
• 1,200,000 fat molecules
• 53,908,355 H atoms
• Imagine number in your body.
• Cells counted in trillions.
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 contains all
ecosystems is the biosphere.
DNA: Basis of Inheritance
Deoxyribonucleic acid
Makes proteins:
DNA RNA Protein
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)
Energy flow in
environment:
producers 
consumers
decomposers
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. DNA
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: flows
from producers to consumers
• 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?
Kingdoms
• Monera- bacteria (can be
separated into 2 separate
kingdoms- Eubacteria (eu-true)
and Archaebacteria (archaeancient).
• Protista- protists
• Fungi
• Plantae
• Animalia
• Archaebacteria are evolutionarily
closer to eukaryotes than to
bacteria.
Plants Animals
Protists
Fungi
Eukarya
Archaea
Bacteria
Origin of Life
Other ways to Classify
• 6 Kingdoms * Most commonly used.
– Eubacteria, Archeabacteria, Protista, Plantae, Fungi,
Animalia
• 3 Domains
– Eubacteria, Archaebacteria, Eukarya
What would be an advantage to classifying organisms into 3
domains instead of 5 or 6 kingdoms? What would be a
disadvantage?
8 Kingdoms
- Eubacteria, Archaebacteria, 3 protists (fungus-like, plantlike, animal-like), Fungi, Plantae, Animalia
Variation among organisms
Inherited variation:
1. Mutation
2. Recombination
• Most mutations are either
neutral or harmful,
sometimes they may
increase the chance for
survival, esp. when the
environment is changing.
• Ie. Silver colored red fox
in a snowy environment.
1.23b Altered genes may be passed on to every cell that
develops from it. This may help, harm, or have little or no
effect on the offspring’s success in the environment.
Natural Selection Tutorial
•
Natural Selection
4 Main Points.
1. There is variation with a
population.
2. Some variations are
favorable.
3. Not all young produced in
each generation survive.
4. Individuals that survive and
reproduce are those with
favorable variations.
5. Descent with Modification
Ostriches are the fasted birds on land due to
favorable traits such as long, powerful legs.
1.31
Selective Breeding
• He found that any domesticated
plant or animal bred to
accentuate desirable
characteristics is the result of
artificial selection. (Natural
provides variation and humans
select the variations useful)
• Many veggies we eat today
came from the wild mustard
plant through artificial
selection.
What are some things
that we selectively
breed?
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
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.
Deductive Reasoning
Writing your hypothesis:
1. 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.
Variables
The independent
variable is condition
that is changed. (Time,
or actual part of
testing.)
The dependent variable
changes in response to
the manipulated
variable. (Growth,
amounts, etc.)
Time (years)
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.
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.
Which do you think scientists prefer? Why?
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.
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.
• It hasn’t been
disproven.
Example of Experimental Design
• Chicago suburban theater chosen as “lab” to
determine if Olestra, synthetic fat caused
gastrointestinal cramps.
• Both control and experimental groups were
random samples of moviegoers with no idea what
they were eating.
• Moviegoers later called to determine extent of
distress: 15.8% for Olestra, 17.6% reg. chips
• Was there a correlation?
Limits of Science
• Limited to questions that can be tested.
– Subjective (mentally, particular to an individual)
questions cannot be addressed.
– All of human society must participate in moral,
aesthetic, and other such judgements.
– Science can be considered controversial when it offers
explanations for an aspect of nature previously
considered supernatural. Copernicus.
External world, not internal conviction, must be ground
for testing science.
Field Experiment
• Durrell Kapan confirmed Mullerian
mimicry with experiment in Ecuador.
• He was able to show that birds “learned” to
associate yellow markings with
unpalatability of one species of butterfly
would also avoid butterflies of another
species with similar markings.
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.
First anthrax vaccine.
So, what is pasteurization?
Redi and Pasteur’s experiment: Active Art
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 ft. = .3048 m
1 mile = 1.609 km
1 gal = 3.78 l
1 lb. = 453.6 g
1 lb. = 16 oz
1 oz = 28.3g
1 l = 33.8 oz
• 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?
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