The Science of Biology
Chapter 1
Potatoes and Observations
1-1 What is the goal of Science?
• Investigate and understand the world around us
• Explain events in nature• Make predictions
The Scientific Method ObservationsState the Problem Conclusion
Hypothesis Data Collection and analysis
Experiment
Experimentation
• Controlled steps used to test the hypothesis
• Controlled Experiment-only 1 variable is changed and all others are kept the same.
• 2 Groups– Control Group: no IV tested; standard
for comparing with…– Experimental Group: IV tested
Observations*using the senses to gather/collect data
Quantitative-observations based
on numbers or quantities
Ex.Counting/measuring
7 birds, 14 miles, 200 people
Qualitative-observations based
on description
Ex. Color/textureblue neck, large
teeth, soft cushion
Hypothesis
• A possible answer to a scientific question
Ex. Use hypothesis to discover how infected disease was contracted:
-spread by human contact?-spread through insect bites?**All of these are then tested to find the correct
explanation.
Procedures
• Procedural Drawings
Variables
• IV = Independent: the one that is tested (only 1); on X axis. AKA Manipulated Variable
• DV = Dependent: the one that is measured; on Y axis. AKA Responding Variable
• Controls: those that remain constant/unchanged
I.V. is changed by me- D.V. is the result I see!!!!
Data Collection and Analysis
• Displayed in table/graph• What does the data tell us??
– What does it mean?– How can I APPLY this information?
Conclusion
• Analyzing data brings you to a final decision/conclusion
• Evidence found supports or refutes hypothesis will test correct or wrong
• Validity• Future investigations New Qs• Improvements
Scientific method practice
What is a Theory?
A well tested explanation that unites many observations (evidence builds up to make
hypothesis very well supported)
Can be proven wrong when new data arises to challenge it.
May be revised or replaced by a more useful explanation.
1-3 Studying Life
• What do all living things have in common?
List 5 things that all living things do:
martian
Prosecutor-
Defense-
Is a hurricane alive?
Are flowers alive?
Is a fire alive?
Is a dragon fly alive?
Is a river alive?
Is a crowd alive?
What is Life?
6 Major Characteristics of Living Things:
• Grow• Genetic Information• Reproduce• Adapt and respond to their
environment• Made of Cells• Use and make Energy
• Remember: GGRACE !
Growth and Development
Universal Genetic Code**Everything living is based on this
the molecule of inheritance
Asexual ReproductionNew organism has a single
parent(ex. Budding hydra)
Sexual Reproduction2 cells from different parents unite
to produce new organism(ex. Sperm and egg)
Adapting and Responding
• Organisms sense changes in their environment and make responses to them
• Receptors detect specific forms of energy
• The form of energy detected by a receptor is a stimulus
Living Things are Made of Cells
A Cell
• Collection of living matter enclosed by barrier separating the cell from its surroundings.
• Smallest units of an organism that can be considered alive.
• Small size, but highly organized and complex.
Nothing Lives Without Energy
Energy = Capacity to do work
Evolution - as a group all living things change over
time
Evolution
• Genetically based change in a line of descent over time
• Population changes, not individuals
Homeostasis
• Maintenance of stable internal environment within range suitable for cell activities
• Ex. pancreas maintains level of sugar in blood by secreting hormones
Required for Life…
Metabolism-chemical reactions
an organism uses to build up and break down materials
-how cells acquire and use energy to grow and survive
(ex. Digestion, making proteins)
Homeostasis-keeping the internal
conditions of an organism stable
(ex. Body temperature, breathing, heart rate)
Work together
Redi’s experiment
What differences do you notice about the two groups?
Spallanzani’s Experiment
Pasteur’s ExperimentWhat do all 3 experiments have in common?
What does this tell us about where life comes from?
Spontaneous Generation
Real-life Connection!
Pasteur’s experiment
Is this process used today? (Hint- look at the scientist’s name)
What are the different levels of organization in Biology?
Smallest to Largest
Atom
• Smallest unit that takes up space
Molecules - groups of atoms
Organelle
• Membrane-bound internal compartment for specialized reactions
• Not found in most prokaryotic cells
Cells - smallest functional unit of life
Tissues
Organs
Organ Systems
Organism - an individual living thing
Population - group of organisms of one type (species) living in the same area
Community - Populations that live together in a defined area
Ecosystem - community and its nonliving surroundings
Biosphere - Part of the Earth that contains all ecosystems
You and the Levels of Organization
••••••
You
Atom Molecul
e
Cell Tissue
BiomePopulation
Organ systemsOrgan
CommunityEcosystemBiosphere
OrganisM
• Organization of Life Poster
1-4 Tools and Procedures
Metric System-SI-International System of Units
• To collect data and perform experiments
• Decimal system of units scaled on multiples of 10
• Measures: length, mass, volume, and temperature
Metric Base Units
Mass- gram (g) Distance- meter (m)
Volume
Volume- liter (L)
Mnemonic
Kelly Had Dan’s Uncle
Drink Chocolate Milk
khdudcmKing Henry's Daughter Undercooks Delicious Chocolate Muffins
Units
Prefix SymbolFactor Number
Factor Word
Kilo k 1,000 Thousand
Hecto h 100 Hundred
Deca d 10 Ten
B A S E
Deci d 0.1 Tenth
Centi c 0.01 Hundredth
Milli m 0.001 Thousandth
Examples
• 1000 g = 1 kg
• 1000 m = 1 km
• 0.01 L = 1 cL
• 30 mL = ??? L
• 3.068 m = ??? mm
x1000 x1000
mg
mm
x10 x100 x1000
x1000
mL
x10 x100
x1000
Lab Materials per Group• Meter stick
• Metric ruler
• Test tube
• Rubber stopper
• Penny
• Triple beam balance
• 50 mL beaker
• 100 mL graduated cylinder
How can a graph help biologists to organize this
data?
Microscopes-produce magnified images of structures too small for
naked eye• Light Microscope-
produce magnified images by focusing visible light rays.
• Fig. 1-25 (compound light microscope)
• Up to 1000 times.• Live and dead
organisms
• Electron Microscopes- produce magnified images by focusing beams of electrons.
• Fig. 1-26 • Form images 1000
times smaller than those of light microscope.
• Only dead organisms.• Have no color. Why?
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