Study of Life
Chapter 1
Themes
AP Biology
2007-2008
 Biology is a subject of enormous
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scope
Studying the diverse forms of life
reveals common themes in Biology
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Themes in biology
 Science as a process of
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inquiry
 questioning & investigation
Evolution
Hierarchy and emergent properties
The cellular basis of life
Relationship of structure to function
Energy transfer
Continuity & Change
Regulation
Interdependence and interactions in nature
Science, technology & society
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Science as a process of inquiry
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Common theme of the scientific
process
 Hypothetico-deductive thinking
The first part refers to hypothesis which
is a tentative answer to some question
(an explanation on trial)
Ex. Maybe eating a big lunch just before
going to history every day makes Scott
sleepy
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 The deductive refers to the use of
deductive reasoning to test hypothesis,
Deduction contrasts with induction.
 Induction is reasoning from a set of
specific observations to reach a
general conclusion (as in all organisms
are composed of cells)
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 Deduction the reasoning flows reverse
from induction from the general to the
specific.
 In the scientific process deduction
usually takes the form of predictions
about the results of experiments or
observations we should expect if a
particular hypothesis (premise) is
correct.
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 This deductive testing takes the form of
“ If……..then logic
 EX. If Scott eats before History class,
then he will be sleepy in class.
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Hypotheses
 Are Possible explanations
 Should reflect past experience
 Multiple hypothesis should be
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proposed whenever possible
Should be written as if ….then (the if is
the independent variable and the then
is the dependent variable)
Should be testable via the hypotheticodeductive approach.
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 Can be eliminated but not confirmed
with absolute certainty.
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Science as a process of inquiry
 Built on repeatable observations &
testable, falsifiable hypotheses
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"Nothing in biology
makes sense except in
the light of evolution."
-- Theodosius Dobzhansky
March 1973
Geneticist, Columbia University
(1900-1975)
AP Biology
2007-2008
Natural selection
 Evolutionary change is a
product of the process of
natural selection –can produce
new species
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The origin of species
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Charles Darwin presented two ideas:
Current species arose from a succesion of ancestors
through “decent with modification “ (evolution)
 The mechanism of evolution is natural selection
He observed this by
1. Individuals in a population of any species vary in many
heritable traits
2. Any population can potentially produce far more
offspring than the environment can support
Result of these 2-> a struggle for existence among variant
members of a population
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Evolution explains unity & diversity (all
life is connected through evolution)
 Unity

what do organisms have in common & why do
similarities exist?
 common biochemistry & physiology
 evolutionary relationships
 connected through common ancestor
 Diversity
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but why are there
differences?
 natural selection
 adaptations allow different
individuals to survive
in different environments
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Organizing systems Taxonomy is
the study of classification
 Making sense out of the diversity
 Hierarchical
scheme
Eastern gray squirrel
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Sciurus
Biology
carolinensis
3 Domains of Life
Bacteria, Archaea, Eukarya
Bacteria
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Archaea
Eukarya
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Life’s Hierarchical Order
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(atoms), (organelles) Emergent properties
Cells
Tissues
Organs
Organism
Population *
Community *
Ecosystem *
Emergent Properties:
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Novel properties which
result from interactions
between components.
An organism is a living
whole, greater than the
sum of its parts.
Reductionism vs.
systems biology
Properties of life
 Order
 Reproduction
 Growth and development
 Energy utilization
 Response to environment
 Homeostasis
 Evolutionary adaptaions
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The Cellular Basis of Life
 Prokaryotes vs. Eukaryotes
 Prokaryotes do not have DNA enclosed
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in a nucleus or membrane-bound
structures.
Eukaryotes do have DNA enclosed in a
membrane bound nucleus and include
membrane bound organelles.
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Examples of Cells
Form follows function (cell is the
smallest unit of life)
 The alignment of structure & function is
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seen at all levels of biology
Form fits function
organism
cell
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organ
organelle
Energy transfer
 Life is an open system
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need input of energy
 energy flows through
 energy comes in,
energy goes out
 need a constant input
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need input of materials
 nutrients are recycled
around & around
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DECOMPOSERS
ENTROPY RULES!
RULE, too!
nutrients
Energy utilization
You think
they’re eating…
They’re harvesting
energy!
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Continuity & change
 Continuity of life is based on heritable
information in the form of DNA
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DNA – the genetic
material – carries
biological information
from one generation
to the next
T
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I
T
Regulation
 Organisms need to maintain a “steady state”
in the face of changing conditions
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maintain homeostasis
achieve this through feedback
 monitor the body like a thermostat
 turn on when it’s needed, off when its not
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Interdependence and Interactions
 No organism is an island standing alone
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communities, ecosystems
Science, technology & society
 Science & technology must function within
the rules of society
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ethics
4 Big Ideas (Themes) in AP Biology
Big Idea 1: The process of evolution drives the diversity
and unity of life.
Big Ideas in AP Biology
Big Idea 2: Biological systems utilize free energy and
molecular building blocks to grow, to
reproduce and to maintain dynamic
homeostasis.
Big Ideas in AP Biology
Big Idea 3: Living systems store, retrieve, transmit and
respond to information essential to life
processes.
Big Ideas in AP Biology
Big Idea 4: Biological systems interact, and these systems
and their interactions possess complex
properties.