EXPLORING LIFE
What is SCIENCE?
• Derived from the Latin verb meaning “to know”
• Science is…
…a process by which we know and understand
how the natural world works
– Based on EVIDENCE – limits scientific study to
processes that can be observed, measured
– Scientific knowledge is PROVISIONAL – evidence we
have in front of us whether developed in lab/
observations in nature
Is Science ABSOLUTE?
• Evidence CAN change!
– New tools
– New technology
– New information
• Evidence DOES NOT provide proof or truth (we
SUPPORT)
• Models approximate the truth and are
susceptible to modification
• BIAS cannot always be eliminated our “thinking”
colors our interpretation
How do we obtain our information?
Different TYPES of Science
• Discovery Science: Describing nature
• Hypothesis-based Science: Explaining nature
How are they DIFFERENT???
Discovery Science
Involves careful observation,
measurement
Hypothesis-based Science
Scientific Method provides…
Hypothesis
Prediction
Results in a body
of knowledge
Experiment
Observation
Law
(Summary)
Theory
(Explanation)
Theory vs. Law
• LAW: expresses a FUNDAMENTAL principle of science (“Rule”)
– Summarizes the results of repeated observation
– MUST be confirmed, agreed upon
– Only applies under defined conditions
– Does not explain a mechanism
Example: Newton's Law of Gravity
• THEORY: explains how nature works (“Explains Rules”)
– A scientific theory summarizes a hypothesis or group of
hypotheses that have been supported with repeated testing,
accumulation of extensive, varied evidence
– Valid as long as there is no evidence to dispute it. Therefore,
theories can be disproven.
• Regardless of which definitions one uses, scientists agree that a
theory is NOT a “ law in waiting". Theories DO NOT “grow up” to be
Laws!
The Culture of Science
• Scientists build on each other’s work by
always remaining skeptical and by seeking
reproducible evidence to confirm ideas
Science, Technology, & Society
• Scientific advances promote new
technologies, which in turn enable further
scientific advances and useful applications to
our lives.
The Cell Theory
“All life is composed of one or more cells.”
• BUT….
What is LIFE?
Properties of Life
Levels of biological organization
(1)
(8)
(6)
(2)
(9)
(3)
(4)
(7)
(10)
(5)
Energy flow in an ecosystem
DNA: The Genetic Material
In each cell, the genes along the
length of the DNA molecules
encode the information for
building the cell’s other molecules.
In this way, DNA controls the
development and maintenance of
the entire organism and, indirectly,
everything it does.
Prkaryotic vs Eukaryotic Cells
What is the
importance of
Emergent
Properties?
Characteristics that
can be attributed to
the arrangement
and interactions of
parts as complexity
increases.
Reductionism
• Breaking down complex systems to simpler
components that are more manageable to
study
How is this useful in science?
Systems Biology
Focuses on the parts
of the system
Focuses on how the
parts influence one
another; results of
their interactions
Form Fits Function
Analyzing a biological structure gives us clues
about what it does and how it works (FORM)
Knowing the function of something provides
insight into its construction (FUNCTION)
Feedback
mechanisms
regulate
biological
systems.
Unifying Theme: EVOLUTION
• The process
of evolution
(change over
time) is
responsible
for life’s dual
nature of
unity and
diversity
What does this statement mean?
Unity in Diversity
While a sea horse, a jackrabbit, hummingbird,
crocodile and penguin look very different, their
skeletons are basically similar.
This supports the idea that the organisms living
on Earth today are modified descendents of
common ancestors.