Chapter 1: The Science of Biology
Pages 2-33
Chapter 1-1: What is Science?
Pages 2-7
Vocabulary 1-1
observationdatainferencehypothesistheory
Question: Why do we study science?
Three Main Goals of Science: 1. To investigate and understand
nature2. To explain events in nature3. To use explanations to make
useful predictions
Science starts with observation – using our senses to gather
information!• Info gathered is called data • Two types of observations:
1)Quantitative: involves #’s (ex. counting, measuring)
2)Qualitative: involves things that cannot be counted (ex. color, texture)
What are some quantitative observations from this photo?
What about qualitative?
Processing the Data• Observations are interpreted – called
inferences (a logical interpretation based on prior knowledge or experience)
• Inferences lead to a hypothesis (a possible explanation for a set of observations or an answer to a problem)
Hypotheses must be testable! They are only supported or refuted, NEVER PROVEN!
Processing the Data
• When numerous tests and evidence support a hypothesis, it becomes a theory (a well-tested explanation that unifies many observations)
What makes a good scientist?
• Curiosity• Honesty• Openness• Skepticism• Recognition that science has limits
Remember…achieving the goals of science does not depend on science alone – very often our society, laws, morals all play a part in making final
decisions regarding science.
Chapter 1-2: How Scientists Work
Pages 8-15
Chapter 1-4: Tools and ProceduresPages 24-28
Vocabulary 1-2 and 1-4
scientific methodcontrolvariableelectron microscopemetric systemmicroscopelight microscope
Question: What steps do scientists take to solve
problems?
Answer: They use the Scientific Method.Definition: an organized way to solve a
scientific problem
Scientific Method
1) Stating the problem•Use observations to define a problem
2) Forming an hypothesis
•Use prior knowledge and experience to make a prediction
3) Setting up a controlled experiment• Test your hypothesis with a
controlled experiment
• In a controlled experiment, only one variable in the experiment is tested at a time – all other variables must be kept the same (or controlled)
• control: factor that is not changed
• variable: factor in an experiment that can change
A little more on variables…
• independent variable – the variable that is deliberately changed (point of comparison)
• dependent variable – changes in response to the independent variable (support or refute hypothesis)
***All other variables must be controlled, or kept constant.***
4) Recording and analyzing results•Keep accurate records of all data•Data is only useful after it is analyzed
5) Drawing a conclusion
•Review hypothesis and draw a conclusion – either the hypothesis was supported or refuted
•An hypothesis is never proven…only supported or refuted!!
Example: Controlled Experiment –
Growth of Bread Mold
Let’s go through the scientific method to create a controlled
experiment…
Famous series of experiments using the
Scientific Method: • Redi (1600’s) – Spontaneous
Generation
Question: How do scientists collect data?
• Scientific measurements must always have a NUMBER and a UNIT
• Metric system: a decimal system based on certain standards and scaled on multiples of 10
• Also known as the International System of Units, or SI
• Base unit tells the type of measurement
• Prefix indicates the size of each unit in relation to base unit
Common Prefixes
•kilo - (k) - 1000x
•hecto - (h) - 100x
•deka (da) or (dk) - 10x
•deci - (d) - .1x
•centi - (c) - .01x
•milli - (m) - .001x
Common Metric UnitsLength = Meter (m) Mass = Gram (g)
1 meter (m) = 100 centimeters (cm)
1 gram (g) = 1000 milligrams (mg)
1 meter (m) = 1000 millimeters (mm)
1 kilogram (kg) = 1000 grams (g)
1000 meters (m) = 1 kilometer (km)
1000 kilograms (kg) = 1 metric ton (t)
Volume = Liter (L) Temperature = Celsius (°C)
1 liter (L) = 1000 milliliters (mL)
0°C = freezing point of water
1 liter (L) = 1000 cubic centimeters (cm3)
100°C = boiling point of water
Common Measurements
•Length = distance from one point to another (meter)
Measurement Tools: Length
Tools: Meter stick or ruler
Common Measurements
•Volume = the measure of the amount of space an object takes up (liter)
Measurement Tools: Volume
Tools: Graduated Cylinder or Beaker
Using the Graduated Cylinder
• A graduated cylinder is a glass tube that is marked with divisions to show the amount of liquid in it.
• The surface of the liquid will have a “belly-down” curve called a meniscus.
• Place the cylinder on a flat surface.
• Read the mark that lines up with the bottom of the curve.
Using the Graduated Cylinder
Common Measurements
•Mass = a measure of the amount of matter in an object (gram)
Measurement Tools: Mass
Tool: Balance
Organizing Data
• After collecting data from an experiment, it is important to present it in an organized manner, either with graphs or tables
• Graphs provide a visual representation of the collection of data or results of the experiment
Graphs
Complete graphs contain:1) A title2) Labels for the X and Y axes
• X axis typically shows the constant (ex. time)
• Y axis typically shows the factor that is changing (ex. number of offspring)
• Both labels must contain units
3) Key
Microscopes• Devices that produce images of
structures that are too small to see withthe unaided eye
Two types important in biology:1) Light microscope2) Electron microscope
Light Microscope
•Most commonly used microscope•Magnify objects up to about
1000 times•Can be used to see tiny
organisms and cells while still alive
•Special dyes can be used to show different structures
Electron Microscope
• Uses electrons as its source of illumination or vision
• Can form images of objects 1000 times smaller than those visible using a light microscope
• Two types:1) Scanning (SEM) – electrons go across image and make 3-D
image of surface2) Transmission (TEM) – electrons go through object – must be
thin
• Cannot be used to study live specimens (processes used would kill them)
SEM (very large, very expensive)
Mosquito Head (SEM Image)
X 200X 200 X 1,000X 1,000
Cell Parts (TEM Image)
endoplasmic reticulum/mitochondria/ribosomesendoplasmic reticulum/mitochondria/ribosomes
Chapter 1-3: Studying Life
Pages 16-22
Vocabulary 1-3
biospheretissueecosystemcommunitypopulationhomeostasisspecies
evolutionorganismDNAcellbiologysexual
reproductionasexual
reproductionmetabolism
BIOLOGY IS THE STUDY OF LIFE.
Living things have 8 common characteristics:
1) Made up of cells2) Reproduce3) Based on a universal genetic code4) Grow and develop5) Obtain and use materials and energy6) Respond to their environment7) Maintain a stable internal environment8) Change over time
1) Made up of units called cells
Cell: a collection of living matter enclosed by a barrier that separates the cell from its surroundings
• cells are the smallest unit of an organism that is considered alive
• some living things are composed of 1 cell (unicellular); others are composed of several cells (multicellular)
2) Reproduce
Two kinds of reproduction:1) Sexual - 2 cells from different parents unite to produce the first cell of the new organism
2) Asexual - a single parent reproduces by itself (ex. budding)
3) Based on a universal genetic code
• Genetic code of DNA determines the inherited traits of every living thing on Earth
What does this mean?• DNA is a molecule that
contains the directions for inheritance
4) Grow and develop• Each type of organism has a
distinctive life cycle – they grow in size and number of cells
• The cells also differentiate for specialized tasks (ex. heart cells vs. brain cells)
5) Obtain and use materials and energy
• metabolism – combination of chemical changes in which an organism builds and breaks down materials as it carries out its life functions
6) Respond to their environment
7) Maintain an internal balance• homeostasis – the process by which
organisms keep their internal conditions relatively stable, despite changes to external environment; it is necessary for survival
8) Change over time as a group, or evolve• a single individual does not evolve
but a group of individuals can evolve or adapt over a long period of time
Living things can be studied on many levels…from very large to
very small.• Biosphere – sum total of all the
ecosystems on Earth• Ecosystem – communities and
their non-living environment• Community – populations living
together in the same area• Population – members of the
same species living together in the same area
Levels of Organization
• Species – organisms that: 1) can mate
2) produce fertile offspring3) in nature (the wild vs. the lab)
• Organism – individual living thing
Levels of Organization
•Tissue – group of cells working together to do a job
•Cell – smallest functional unit of life
Levels of OrganizationBiosphere
Ecosystem
Community
Population
The part of Earththat contains allecosystems
Community and its nonliving surroundings
Populations thatlive together in a defined area
Group of organisms of onetype that live in the same area
Biosphere
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
Hawk, snake, bison, prairie dog, grass
Bison herd
Levels of OrganizationOrganism
Groups ofCells
Cells
Molecules
Individual livingthing
Tissues, organs,and organ systems
Smallest functionalunit of life
Groups of atoms;smallest unit of most chemicalcompounds
Bison
Nervous tissue Nervous systemBrain
Nerve cell
Water DNA
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Have you ever heard of“nesting dolls?”