Chapter 1 Notes (from Powerpoint)
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•The world of science
•Asking About Life
•A. Questions:
•Life science = the study of living things.
•Science is observing the environment around you & asking questions about it.
•Example questions:
•How do tiny bacteria feed inside my intestines?
•How do giant redwood trees seem to touch the sky?
•Look around you; what questions about your surroundings do you have?
•Asking About Life
•B. Looking for answers:
•Who? Any person can be a scientist!
•Irene Duhart asks: “How does the human body respond to space travel?”
•GeeratVermeiji (who is blind) asks: “How have shells changed over time?”
•Irene Pepperberg asks: “Are parrots smart enough to learn a language?”
•Where?
•In labs, forests, ocean floor, space.
•These scientists work for: businesses, hospitals, government agencies & universities. Many are teachers!
•Asking About Life
•What?
•Studies of a scientist are determined by curiosity.
•How organisms function & behave?
•How organisms interact with each other & with their environment?
•How organisms reproduce & how organisms pass traits from 1 generation to the next.
•Investigate the origins of organisms & how they change over time.
•Asking About Life
•C. Why Ask Why?
•Life science affects YOU & all living things around you!
•1. Combating Disease:
•Scientists find ways to fight diseases that have been around for a long time (ie: TB) & recent (ie: AIDS).
•Example: polio is a disease (virus) that affects the brain & nerves, causing paralysis.
•In 1950s, affected 1 in 3,000 Americans.
•Now, rare to get it, vaccine was made by a scientist.
•Example: Cystic Fibrosis (inherited disease) – scientists study human genome in order to find cure for this & other inherited diseases.
•Asking About Life
•2. Protecting the Environment:
•Solve problems such as: pollution, deforestation, & the extinction of wildlife.
•Decrease air & water pollution to help keep us & many other species healthy.
•Cutting down trees for lumber or growing crops destroys habitats for species & could cause extinction of some species.
•Thinking Like A Scientist
•All scientists have 2 things in common:
•1. They are curious about the natural world.
•2. They use similar methods to investigate it.
•One way = the Scientific Method
•Thinking Like A Scientist
•The Scientific Method:
•1. Ask a question- based on observations.
•2. Form a hypothesis - which is a possible explanation for what you have observed.
•3. Test a hypothesis - by conducting experiments.
•4. Analyze the results – collected from experiments.
•5. Draw conclusions – from the results of your experiment.
•6. communicate results – to other scientists.
•* Maybe, these steps are not always conducted in this order. Some experiments will test negative to what you thought (hypothesis) & you will test again with another question.
•Thinking Like A Scientist
•1. Ask a Question:
•Observe an environment around you & even make a few measurements, observe color/shape/texture/patterns…etc.
•Ask a question from the information that you gather.
•Ie: in a local area, there were deformed frogs that were observed & looked at.
•Thinking Like A Scientist
•2. Form a Hypothesis:
•Hypothesis = a possible explanation or answer to the question.
•Hypothesis must be testable by experimentation.
•Could have different hypothesis for the same problem- each hypothesis would have to be tested.
•Examples:
•Hypothesis 1: Deformities were caused by 1 or more chemical pollutants in the water.
•Hypothesis 2: Deformities were caused by attacks from parasites or other frogs.
•Hypothesis 3: Deformities were caused by an increase in the exposure to UV light from the sun.
•Thinking Like A Scientist
•2. Form a hypothesis:
•Predictions: before a scientist can test a hypothesis, he/she must first make a prediction.
•Prediction = a statement of cause/ effect that can be used to set up a test for hypothesis.
•Always written in a “If…Then...” statement.
•Ie: If an increase in exposure to UV light is causing deformities, then some frog eggs exposed to UV light in a lab will develop into deformed frogs.
•Thinking Like A Scientist
•3. Test the hypothesis:
•After a scientist makes a prediction, then they test the hypothesis.
•Scientists will design experiments that will clearly show if a particular factor was the cause of the observed outcome.
•Factor = anything in the experiment that can influence the experimental outcome.
•(ie: temperature, type of organism, etc.).
•Scientists try to have a controlled experiment =
•Tests 1 factor at a time.
•Has 1 control group & 1 or more experimental groups.
•All factors will be the same for control & experimental groups except 1.
•The factor that differs is called the variable.
•Experimental Setup:
•Thinking Like A Scientist
•3. Test the Hypothesis:
•Ie: variable: the amount of UV exposure.
•Other factors are the same: type of frog, # of frog eggs in each aquarium, temperature of water – for experimental & control groups.
•Making good experiments:
•Repeating the experiment to see if the same results are achieved.
•Have larger number of test subjects.
•Thinking Like A Scientist
•4. Analyze the Results:
•Organize the data into a table, graph, or chart.
•Interpret the data.
•Ie: charts & graphs made for results of the frog experiment.
•Results:
•Thinking Like A Scientist
•5. Draw Conclusions:
•Scientists decide whether the results of the experiment have shown that a prediction was correct or incorrect.
•Ie: UV light did cause deformities in frogs (from data).
•Sometimes, you can notice new patterns from the data: higher number of days in UV light confirmed deformities.
•When scientists find a hypothesis that is supported by the tests, they must try to find another explanation for what they observed.
•If old hypothesis was wrong, then scientists does a new experiment with a new hypothesis.
•Ie: the only ting it proved was how UV light may cause deformities.
•It did not proves that parasite/substances in pond water contributed to deformities: this would have to be proved by conducting 2 other experiments.
•Thinking Like A Scientist
•6. Communicate results:
•After a scientist completes his/her investigations, then a report is made to communicate results to other scientists.
•Information in the report can help other scientists discover new questions & answers.
•New answers may strengthen scientific theories or show that theories need to be altered.
•Thinking Like A Scientist
•Scientific Knowledge Changes:
•There can be more than 1 prediction for a hypothesis.
•Each time a prediction is proved, the hypothesis gains more support.
•A unifying explanation for a broad range of hypothesis’ & observations that have been supported by testing = theory.
•Development of new technologies also leads to answers.
•Technology = the use of knowledge, tools, & materials to solve problems & accomplish tasks.
•Tools of Life Scientists
•Scientists use various tools to aid them in their work.
•These tools are used to make observations & to gather, store, & analyze information.
•A. Tools for Seeing = magnifying tools help a scientist see many more organisms that cannot be seen with the naked eye.
•Compound Light Microscope:
•Made up of 3 parts: a tube with lenses, a stage, & a light.
•Some specimens viewed through a compound microscope are stained with special dyes, which enable the specimen to been seen more clearly.
•Specimens are placed on the stage so that light passes through them.
•The lenses, which are on each end of the tube, magnify the image of the specimen, making it appear larger than it is.
•X 1000 magnifcation
•Tools of Life Scientists
•A. Tools for Seeing:
•Electron Microscope = use tiny particles of matter called electrons to produce magnified images.
•Species have to be dead to use this microscope.
•2 types of electron microscopes:
•Transmission Electron Microscope:
•X 200,000 magnification.
•Electrons pass through specimen.
•A flat image is produced.
•Scanning Electron Microscope:
•X 100,000 magnification.
•Electrons bounce off surface of the specimen.
•Electron microscope images are more clear & more detailed than the compound microscope.
•Tools of Life Scientists
•A. Tools for Seeing – Seeing Internal Structures:
•Scientists use several tools to help them see inside organisms & to understand chemical composition of materials.
•X-Rays = pictures of internal body structures (ie: bones, heart, & lungs) & structures of proteins.
•CT Scans = “Computed Tomography” :low dosage x ray beams are passed through the body at different angles.
•Often, dye is injected to highlight tissues.
•Have more detailed & clear images.
•MRI scans = “Magnetic Resonance Imaging” : use short bursts of magnetic field & produces images.
•Tools of Life Scientists
•B. Computers:
•Computer technology improving.
•Used to create graphs & solve complex mathematical problems.
•Determine if there are differences in experimental data & ideas about data & prepare reports & articles about the research.
•C. Much more Instruments used in labs that you will learn from your teacher!
•Tools of Life Scientists
•D. Systems of Measurement:
•People used to compare base units to parts of the body.
•Problem with that: not all bodies are the same size.
•International System of Units (SI):
•All scientists & almost all countries use this system.
•Using SI measurements, help scientists to share & compare their observations & results.
•Units are based on 10.
•Prefixes are used with units to make it a smaller or larger number.
•Units commonly used for length, volume, mass, & temperature.
•* there are specific units used for certain sizes of species & objects.
•Tools of Life Scientists
•Area:
•Ie: how much carpet would it take to cover the floor of your classroom?
•Answering that question involves finding the area of the floor.
•Area = Length X Width
•Units: squared units (m^2, cm^2, km^2)
•Tools of Life Scientists
•Volume:
•Is the glass ½ full or ½ empty?
•Ie: suppose that some hippos born in a zoo are being relocated to their native habitat in Africa.
•How many hippos will fit into a moving crate?
•That depends on the volume of the crate & the volume of the hippos.
•Volume = the amount of space that something occupies or as in the case of the crate, the amount of space that something contains.
•Single units: liters (L), milliliters (mL), or microliters (uL).
•Volume units: cubic meters, cubic centimeters, or cubic millimeters.
•Tools of Life Scientists
•Volume:
•One way to figure out volume of an irregularly shaped object is to measure how much fluid the object displaces:
•Volume before- put object in liquid – measure volume after.
•Subtract the last final volume from the initial volume = volume of irregular shaped object.
•Tools of Life Scientists
•Mass =
•The amount of matter that makes up an object.
•Kg = basic unit for mass.
•Mass can be measured with a balance.
•Tools of Life Scientists
•Temperature =
•A measure of how hot or cold something is.
•Degrees C, degrees F and Kelvin (K).
•Kelvin (K) = official standard unit.
•Tools of Life Scientists
•Safety Rules:
•Follow teacher’s rules.
•Before setting up an experiment or doing an experiment, get the teacher’s permission first.
•Once you begin your experiment, read lab procedures carefully.
•Know common safety symbols.
•Classroom safety rules will be reviewed in more detail.