Chapter 1 The Science of Biology. What were your first questions? WHY? What? How?
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Transcript of Chapter 1 The Science of Biology. What were your first questions? WHY? What? How?
Chapter 1
The Science of Biology
What were your first questions?
WHY?What?How?
What is Science?Science asks the same questions you did as
a young child.What is that?Why does it do what it does?How does that happen?What happens if …?
Science (Science (knowledge) is a ) is a process that investigates and process that investigates and attempts to understand and attempts to understand and
explain events in natureexplain events in nature.
Goal of ScienceGoal of ScienceProvide natural explanations for events
in the natural world.
Give examples of this
Use explanations to understand patterns in nature and to make useful predictions about natural events
Give examples of this
Since Science is a process, how do we go about doing “Science”?
The Scientific Method of course!!1. Ask a question based on an
observation
2. Do some research or infer
3. Propose a hypothesis
4. Conduct a controlled experiment
5. Collect data and make observations
6. Analyze data
7. Draw a conclusion
ObservingObserving and Asking QuestionsQuestions – Scientific investigations begin with observationobservation,
the act of noticing and describing events or processes in a careful, orderly way.
– Researchers observed that marsh grass grows taller in some places than others.
– A question is formed: Why do marsh grasses grow to different heights in different places?
Inferring & Forming a HypothesisHypothesis – Through observations and research, scientists
form inferencesinferences, or logical interpretations based on what is already known.
– These lead to a hypothesishypothesis, or a scientific explanation for a set of observations that can be tested in ways that support or reject it.
–
What kind of hypothesis could be made concerning the marsh grass growth?
– Researchers inferred that something limits grass growth in some places. Based on their knowledge of salt marshes, they hypothesizedhypothesized that marsh grass growth is limited by available nitrogen.
Design a Controlled ExperimentControlled Experiment• Design an experiment that keeps track of various
factors that can change, or variables– Only one variable is changed at a time
• Manipulative or Independent variableManipulative or Independent variable
– The variable that is observed and that changes in response to the independent variable is called the dependent variable dependent variable (also called the respondingresponding variable).
– All other variables should be kept unchanged, or controlled
• Controlled variableControlled variable
For the marsh grass experiment, identify each of the following variables:
• Manipulative or independent variable– Nitrogen fertilizer is added to the soil
• Control variables– Similar plant density, soil, plant type, sunlight,
amount of water, temperature…
• Dependent or responding variable– The rate at which the grass grows or its height.
Control and ExperimentalExperimental Groups An experiment typically has two groups:
1.An experimental group experimental group contains the independent variable
2.A control group control group is exposed to the same conditions as the experimental group except for one independent variable.
How will scientists keep track of experimental observationsand then analyze the results?
• Collecting DataData– Quantitative dataQuantitative data
• NumbersNumbers– How many blades of grass were found per meter?– How high, wide, long…was the grass?– How much nitrogen was found in the blades of grass?
– QualitativeQualitative• DescribeDescribe
– Which way did the grass grow?– What color was the grass?– Where there any other plants growing around it?
Recording the dataHow is data recorded?
Use charts, photos, drawings or graphs
This graph shows how grass height changed over time.
What might have been a source of error in this experiment?
The larger the sample size, the more reliably researchers can analyze variation and evaluate differences between experimental and control groups.
What conclusion could be drawn from the data collected?
Use experimental data as evidence to support, refute, or revise the hypothesis being tested, and to draw a valid conclusion.
Marsh grasses grew taller than controls by adding nitrogen.Marsh grasses grew taller than controls by adding nitrogen.
What if our hypothesis is not supported in our experiment?
– Close but no cigar. • Reevaluated and
revised the original hypothesis
• Make new predictions
• Redesign the experiment
Do you know where bees come from?
Recipe for Bees
1. Kill a bull during the first thaw of winter
2. Build a shed
3. Place the dead bull on branches and herbs inside the shed
4. Wait for summer. The decaying body of the bull produces bees
Words from a Roman poet about 2000 years ago
Spontaneous Generation Life arises from non-living matter or just suddenly
appear.Abiogenisis
Meat grows maggots Corn produces rats Bread breeds mold
So what do you think of this theory?
How are new living organisms produced?1. Question is stated Where do flies come from?2. Now we need to form a hypothesis
1. Francesco Redi (1668)Hypothesis: Flies lay small eggs on meat
that become maggotsSet up a controlled experiment to test his
hypothesisAnalysis: Found that by
keeping flies away from meat, no maggots appear
Conclusion: Maggots are the result of flies laying tiny eggs on meat that develop into
maggots
Variables
1. Controlled variable:
Jar, meat, location, temperature, time
2. Independent or Manipulative variable:
Gauze covering the meat jars
3. Dependant (responding) variable:
Whether maggots appear
Lazzaro Spallanzani 1776 • Designed experiment to show that life did not
arise spontaneously from food– Inferred that food spoils due to microbes in the food.
• Took 2 flasks with broth in them– Boils on but leaves it open– Boils the other but has it closed
Results – Only the closed one
prevented growth
What was wrong with what Spallanzani assumed?
No airEveryone knows that every living thing needs air to
liveWhose experiment solved Spallanzi’s air problem?
Louis Pasteur - 1859
Tested Spallanzani’s work by using a curved neck flask curved neck flask to prevent microbes from
entering flask but would let air in
Boiled broth in control and experimental flasks.
Result: No growth in curved neck flask.
Microbes collecting in bend
Pasteur’s broth in the curved necked flask stayed sterile for years until he tilted it and the airflow carried the microbes into the broth
ConclusionContamination is due to microbes in the air.
Spontaneous generation theory died here!!
Biogenesis is born!! All living things come from other living things.
Identify some scientific theories you have knowledge of.
1. Big Bang
2. Evolution
3. Relativity
A theorytheory is a well-tested explanation for a range of phenomena.
A lawlaw is a concise, specific description of how some aspect of the natural world is expected to behave in a certain situation such as the Gas laws
What is Biology?
Biology is the study of living things and how they interact with each other.
What are the characteristics of living things?
You and your partner are to brainstorm and ask yourselves the following.
• All living things have…
• All living things need…
• All living things can…
• All living things must…
What makes a living thing different from the desk you are sitting in?
• After you have brainstormed and edited your list, write them down on the chart on the next slide.
• When told to do so, go to each station in the back of the room, observe the specimen and check off if it has the characteristics you wrote down.
Specimen
Trait
1 2 3 4 5 6 7 8 9 10
1
2
3
4
5
6
7
8
9
10
What makes something living?Characteristics of LifeCharacteristics of Life
All living things…
1. …are made up of cells.
Unicellular or Multicellular.
2…need a constant flow of energy. Necessary for Metabolism Metabolism
All the chemical processes taking place in the organism including those that are needed for growthgrowth and those that are needed to break down break down molecules (such as digestion)
Some such as plants and some bacteria, make their own food from raw materials (Autotrophic)
Others such as animals, need to
process organic matter to obtain energy. (Heterotrophic)
3… maintain a stable, internal environment by responding to stimuli.
Maintain an internal steady state – Homeostasis.
Stimulus – anything that causes an organism to react/respond
Examples:• Increased heart rate when stressed• Goosebumps and shivering.• Pupillary response to light and darkness
– Let’s give this one a try
4. …Evolve
…as a group
• Evolution is a Evolution is a change in a species change in a species over timeover time
• Results from an species ability to adapt to changing conditions and reproduce.
5…grow and develop.
Your very first baby pictureProcess occurs by adding on more cells by cell
division (making more cells of the same kind) and cell differentiation (cells becoming different to
suit their various functions).
Red blood cell White blood cell Nerve cellsEasily flow through Change shape to Like a wire to capillaries squeeze through conduct electrical intracellular spaces impulses
6...can reproduce.
Adding on more cells or reproducing another organism
Passing on of genetic information (DNA and genes)
Not a necessary life process but needed for the continuation of the
species. Sexual (involves the fusion of two cells)
Asexual (involves only 1 cell dividing) reproduction.
7. …all living things are based on a universal genetic code
• DNAIt doesn’t matter if the
DNA of a bacterium or a human is analyzed, we all have the same 4 bases (ATCG) making up our DNA.
Measurements in Science
SI Measurements (Standard Increments)
aka: The Metric SystemUnit Abbreviation
Length Meters m Mass Gram gVolume Liter lTime Second sTemperature Celsius `C
Kelvin `KDensity Mass/Volume g/l or g/cm3
Prefixes Abbrevation Factor of base unitkilo k 1,000deci d .1 or 1/10centi c .01 or 1/100milli m .001 or 1/1000micro u .000001 or 1/1,000,000
Symbols of measurement
Metric Conversions
Convert: 5L = ______ml 1.025cm = _______ m .035um = ______ mm 2.5mm = ______um 7.2g = _____kg .017g = ______mg
Kilo Hecto Deka Meter Deci Centi Milli Micro
Liter
Gram
1. A recipe calls for 300ml of water. You add 0.25 L. Have you put in too much, too little or the right amount?
2. You are told that you need a jar with a volume of at least 150cm3. The label on the jar you find says 0.16L. Can you use it? Remember that 1cm3 = 1ml.
Lab Safety
• Contracts must be signed and returned to me immediately.
• All Science students must complete the Safety contract before entering into the lab
• Any student who does not have a lab safety contract signed will not be allowed to conduct labs.
The right tool is what is important
Where babies really come from
Our methodThe Way we do
things hereMeasure this
Watch it or the Safety Police will
get youThey're a What?
Life is a Wonderful Thing
Used to measure out a volume of a
liquid
Theory that life came from non-
living things
Method used to solve problems
Where the heating test tube should
be pointed
Basic units of measure for
Volume
If on fire, what should be done
Studies animalsNon-essential to the
individual's life characteristic
Vessel to hold and heat a liquid
Disproved the above using the
gauze covered jar
An educated guess
What shouldn't be on top of a
heating test tube
Basic units of measure for mass
Where to go if you get chemicals
in your eyesStudies plants
Type of reproduction found
in amoeba and hydra
Instrument used to pick up small
specimens
Also disproved it using the sealed boiled flasks of
gravy
What the above is based on
What should be on your eyes if
you are heating a test tube
How tall are you in meters
Three conditions when goggles would be worn
Studies bacteria and viruses
Keeping the body in a balanced state
Device used to observe small
specimens (not microscopic ones)
Father of Microbiology who
disproves this theory
Your 5 senses allows you to do
this
Where all the lab safety equipment are in the room
How many milliliters are in a
liter
What to do if you break a piece of
glassware
Looks at how living things
interact with their environment
Building up process
Measures the mass of an object
Special type of flask used by the
above
Keep these out of the above
How you should be dressed when doing a lab with an open flame
What part of a meter is a cm?
Where all glassware should
be on your lab tables
Studies how traits are passed from
one generation to the next
Breaking down process
Used on top of a glass slide with a
wet mount
What was the big difference between
Spallanzani's work and Pasteur's
The final answer to your problem
Caution should always be
exercised when working with this
What does um stand for?
How to pull out an electrical cord
from the socket
Studies the form of the human
body
The fact that you are getting scared about
taking this test means that you are
…
What units a graduated cylinder
measures in
Life comes from life
That which changes in an
experiment
The last thing you should always do after performing a
lab
1cm3 = ______What to use when
handling something hot
Studies how living things are
classified
All the chemical reactions in an
organism
The right tool is what is important
Where babies really come from
Our methodThe Way we do
things hereMeasure this
Watch it or the Safety Police will
get youThey're a What?
Life is a Wonderful Thing
Graduated cylinder
Spontaneous generation
Scientific methodAway from all people in lab
ml
Screamed that you are on fire, stop, drop and
roll and someone will bring a fire
blanket
Zoology Reproduction
Beaker or flask Redi Hypothesis A stopper g eye wash station Botony Asexual
Forceps SpallanzaniBasic research
and prior knowledge
Goggles </= 2m
Chemicals, heating
something, glassware
Microbiology Homeostasis
Hand lens Pasteur ObservationsOn the side of the
room1000ml in a m
Let the teacher know. Do not
touch itEcology Anabolism
BalanceSwan necked
flaskOpinions and
inferencesHair tied back and sleeves rolled up
1/100 or 100thAway from the
edge of your tableGenetics Catabolism
Cover slipPasteur allowed oxygen to get in
Conclusion Chemicals micrometerGently unplug by the plug, not the
cordAnatomy Irritability
ml Biogenesis VariablesClean up
everything and put all away
1mlTest tube holders,
tongs or mittsTaxonomy Metabolism