things needed for class covered shoes dropbox account with shared folder noteability/pdf reader app...
Post on 12-Jan-2016
216 Views
Preview:
TRANSCRIPT
Things Needed for Class
Covered Shoes Dropbox account with shared
folder Noteability/PDF Reader App Charged, updated ipad Textbook Explaineverything App
The Biology website is at http://www.midpac.edu/~biology/Intro%20Biology/
.
The Science of
Biology
3 Goals of Science
Provide natural explanations for events in the natural world
Use these explanations to: Understand patterns in nature Make useful predictions about
natural events
What is Science?
An organized way of gathering and analyzing evidence about the natural world
A way of observing, thinking, and “knowing” about the world
A process - not a “thing” A body of knowledge scientists have
gathered over many years
Scientific Methodology
• The common steps that biologists and other scientists use to gather information and
answer questions are collectively known as scientific method.
The Steps
Making observations and asking questions Making inferences and forming hypotheses Conducting controlled experiments Collecting and analyzing data Drawing conclusions (Stating Sources of Error)
Observation
Scientific methodology usually begins with scientists identifying a problem to solve by observing the world around them.
Observation: Marsh grass grows to different heights in different locations
Question: Why does marsh grass grow different heights in different locations?
Making Inferences
Inference is a logical interpretation based on what you know or have observed – a guess at how things work
Inferences lead to a hypothesis - a TESTABLE logical explanation for the observations.
Hypotheses are SUPPORTED or REJECTED (not proved or disproved)
Formulating a Hypothesis
Always use an If… then… statement
Inference: something is limiting the growth of the marsh grass - like available nitrogen
Hypothesis: IF available nitrogen is related to the growth of marsh grass THEN locations with more nitrogen will grow taller marsh grass
Conducting an Experiment
Hypotheses are tested by conducting experiments
An experiment is an investigation that collects information under controlled conditions
The results of the experiment will either support or refute the hypothesis
Identifying Variables
In a controlled experiment only ONE condition is changed at a time. All other variables must be kept the same!
The condition in an experiment that is deliberately changed is the independent or manipulated variable. (Nitrogen level)
The variable that you observe changing in response to the independent variable is called the dependent or responding variable. (Grass height)
Controlled variables = variables that stay the same between control group and experimental group
Controlled Experiment
Many experiments involve at least two groups: the control group and the experimental group
The experimental group is the test group, in which all conditions are kept the same except for the single condition being tested (the experimental variable - added nitrogen)
The control group is the group in which all other conditions are kept the same, but there is no experimental variable (no added nitrogen)
Recording Data
Information collected during experiments is called data
There are 2 types of data Quantitative Qualitative
Quantitative – numerical data like length, mass, temperature and time.
Qualitative – verbal data or written observations like color or smell.
Data should be organized into tables
Qualitative or Quantitative?
Data Table
Table to show Marsh Grass growth in response to added Nitrogen
Time (weeks) Control GroupGrass Height (cm)
Expt GroupGrass Height (cm)
0 2 2
1 3 4
2 4 6
3 5 8
Analyzing Results
Analysis of results can include graphing data or applying statistical formula.
It makes any patterns in the data easy to see
Sources of Error
It is important to avoid errors in experimental procedure, data collection and analysis.
All measuring tools have limited accuracy
Sample size should be large enough to be representative of the general population
Repeating Investigations
After results of an investigation have been published, other scientists can try to verify the results by repeating the procedure
When a hypothesis is supported by data from additional investigations, it is considered valid and is generally accepted by the scientific community
Drawing a Conclusion
After careful review of the results a conclusion must be reached Is the hypothesis supported by the
data? Is the hypothesis refuted by the data? Is more data needed? Should changes be made to the
experiment?
Revisions to Hypothesis
During investigations hypotheses often need to be revised and experiments redone several timesPython video
Field Studies
Sometimes lab experiments are not possible
For animal behavior in the wild - Field observations are made – disturbing nature as little as possible
For cancer causing chemicals in humans – need to study people who have already been exposed vs. those who haven’t
Scientific Attitudes that help generate New Ideas
Curiosity Skepticism Open-mindedness Creativity
Scientists share ideas and review each others’ work, which often triggers new
questions and ideas
Why is Peer Review important
Scientific papers are reviewed by anonymous, independent experts
Ensures published work meets the standards of the scientific community
Publishing work in scientific journals allows scientists to share ideas and test and evaluate each other’s work.
Wikipedia is NOT peer reviewed!!
Developing a Theory
Once scientists have gathered a large body of evidence that supports a hypothesis it becomes a theory - a well tested explanation that unifies a broad range of observations and hypotheses and that enables scientist to make accurate predictions about new situations.
A theory is NOT an absolute truth A theory can be revised or replaced if
new evidence supports a different explanation
Spontaneous Generation
Life comes from nonliving material
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.PROCEDURE
Controlled Variables (keptthe same between exp):jars, type of meat,location, temperature,timeManipulated Variables:gauze covering thatkeeps flies away from meat
Uncovered jars Covered jars
Several days pass
Maggots appear No maggots appearResponding Variable: whether maggots appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.
Section 1-2
Figure 1-8 Redi’s Experiment on Spontaneous Generation
Leuwenhoek developed the first simple microscope in the 17th century and was the first to see microorganisms.
Gravy is boiled. Flask isopen.
Gravy is teeming with microorganisms.
Gravy is boiled. Flask issealed.
Gravy is free of microorganisms.
Section 1-2
Figure 1-10 Spallanzani’s Experiment
Needham believed that Spallanzani did not disprove spontaneous generation What problem did he point out?
Needham showed microorganisms growing from boiled gravy
Spallanzani showed sealing the flask prevented growth
Broth is boiled. Broth is free ofmicroorganismsfor a year.
Curved neckis removed.
Broth is teeming with microorganisms.
Section 1-2
Figure 1-11 Pasteur’s Experiment
Broth is boiled. Broth is free ofmicroorganismsfor a year.
Curved neckis removed.
Broth is teeming with microorganisms.
Section 1-2
Figure 1-11 Pasteur’s Experiment
In Pastuer’s experiment what was the dependent (responding) variable?
What was the independent (manipulated) variable?
What variables were controlled?
Variables
Link to Lab
Studying Life
Chapter 1-3
Biology
Bios means life and -logy means study of
So Biology is the study of living things.
Characteristics of Living Things
Biologists have made a list of characteristics that living things share
Organisms must have ALL the characteristics to be considered living.
8 Characteristics
Based on a genetic code
Grow and develop Respond to their
environment Reproduce Maintain internal
balance Use materials and
energy Made up of cells Evolve
1.Based on the Universal Genetic Code
DNA carry the directions for inheritance
Asexual same as parent
Sexual mix of both parents
2. Grow and Develop Grow = get bigger Develop =
change and mature
Cells become specialized – have specific jobs
3. Respond to their Environment
React to a change in the environment
Stimulus = signal Blink in bright sun Flinch if you are
hurt Plants
roots/shoots respond to gravity
4. Reproduce
One of the most obvious of all the characteristics of life is reproduction, the production of offspring.
• Sexual reproduction• Asexual reproduction• EX: budding, vegetative
reproduction, mitosis
5. Maintain Internal Balance
Homeostasis Keep conditions
constant Body Temperature
control Shiver warmer Sweat cooler 98.6oF or 37oC
6. Use Materials and Energy
Organisms need materials and energy to grow and develop
Metabolism = building up or breaking down materials
Plants need solar energy
We need food
7. Made up of Cells Cells are the basic unit
of life. Whether an organism
is made up of one cell (unicellular) or billions of cells (multicellular), all of its parts function together in an orderly, living system.
8. Evolve As a group organisms change over
time
Additional Themes of Biology
Structure and Function
Each major group of organisms have their own particular traits that allowed them to evolve in particular ways
Unity and Diversity of Life
Although life is diverse, at a basic level they have many things in common. DNA code, carbon based, etc. Share many traits
Interdependence of Nature
All organisms depend on each other in the biosphere
Science as a way of Knowing
Science helps to explain and predict the natural world so that we can take action. We must understand its strengths and limitations.
Big Ideas in Biology Cellular Basis of Life Information and Heredity Matter and Energy Growth, Development Reproduction Homeostasis Evolution Structure and Function Unity and the Diversity of Life Interdependence of Nature Science as a way of Knowing
A Common Measurement System
In science we always use the Metric System or SI (Systeme International)
Easy to use multiples of 10
The whole world uses the same units
SI Base UnitsMeasurement Unit SymbolLength meter mMass kilogram kg
Time second sElectric current ampere ATemperature kelvin KAmount of substance mole molIntensity of light candela cd
Common Biology Units of Measure
Meters and centimeters (length) Celsius (temperature) Grams and kilograms (mass) Milliliters and liters and
cm3(volume) Seconds and minutes (time)
top related