Transcript honors biology chapter 1

Chapter 1
Biology: Exploring Life
PowerPoint Lectures for
Biology: Concepts and Connections, Fifth Edition
– Campbell, Reece, Taylor, and Simon
Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
A Big-Billed Bird Rebounds
• Some core themes underlie all of biology:
evolution, cells as the fundamental unit of life,
a nearly universal genetic code, the relation of
structure and function
• The brown pelican is an example of the
connection between organisms and their
environment
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
THE SCOPE OF BIOLOGY
1.1 Life’s levels of organization define the scope
of biology
• These levels represent a hierarchy
• Starting with the biosphere, each level is less
inclusive than the one below it
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– Biosphere: all the environments of Earth
that support life
– Ecosystem: All the living and nonliving
components of a particular environment
– Community: All the living organisms in an
ecosystem
– Population: an interacting group of
individuals of one species
– Organism: An individual living entity
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• The hierarchy continues downward with
– Organ systems
– Organs
– Tissues
– Cells
– Organelles
– Molecules
– Atoms
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 1-1
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Spinal cord
Organ system
Nervous system
Nerve
Brain
Organ
Brain
Tissue
Nervous tissue
Cell
Nerve cell
Nucleus
Atom
Organelle
Nucleus
Molecule
DNA
1.2 Living organisms and their environments form
interconnecting webs
• Producers-photosynthetic organisms-use
energy from the sun to produce food
• Consumers are ultimately dependent on
producers for food
• Decomposers break down dead organic
material, which is recycled
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• The dynamics of an ecosystem include two
major processes:
– The cycling of chemical nutrients
– The one-way flow of energy, entering as
sunlight and leaving as heat
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LE 1-2
Sun
Air
Inflow
of
light
energy
O2
CO2
CO2
Chemical
energy
Producers
Cycling of
chemical
nutrients
Consumers
Decomposers
H2O
Soil
Ecosystem
Loss
of
heat
energy
1.3 Cells are the structural and functional units of
life
• Cells perform all functions necessary for life
– Regulate their internal environment
– Take in and use energy
– Respond to the local environment
– Develop and maintain their complex
organization
– Divide to form new cells
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• Theme of emergent property
– "The whole is greater than the sum of its
parts"
– The combination of the parts that form a
more complex organization is called a
system
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Two basic types of cells: prokaryotes and
eukaryotes
– Prokaryotes are smaller and less complex
than eukaryotes and lack a nucleus and
other organelles
– Eukaryotes are generally larger and more
complex and contain a nucleus and other
organelles
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 1-3
Eukaryotic cell
Prokaryotic cell
DNA
(no nucleus)
Organelles
25,000 
Nucleus
(contains
DNA)
EVOLUTION, UNITY, AND DIVERSITY
1.4 The unity of life: All forms of life have
common features
• Genetic information within all cells is coded in
DNA molecules
• Each DNA molecule is made up of chains of
four chemical "building blocks"
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LE 1-4a
A
C
T
A
T
A
C
C
G
T
A
G
T
A
• Other common properties of organisms:
– Order
– Regulation
– Growth and development
– Energy use
– Response to the environment
– Reproduction
– Evolution
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
1.5 The diversity of life can be arranged into
three domains
• Scientists have identified about 1.8 million
species-particular types of organisms
• Taxonomy classifies species into a hierarchy
of increasingly broad groups
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Three domains are the most overarching
groups:
– Domain Bacteria, unicellular prokaryotes
(cells that lack a nucleus)
– Domain Archaea, unicellular prokaryotes
– Domain Eukarya, unicellular and
multicellular eukaryotes (cells with a
nucleus), including protists, plants, animals,
and fungi
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LE 1-5c
275
Kingdom Fungi
Kingdom Animalia
Protists (multiple kingdoms)
Kingdom
Plantae
1.6 Evolution explains the unity and diversity of
life
• Charles Darwin proposed the theory of
evolution by natural selection
– Species evolved from ancestors through
"descent with modification"
– Natural selection occurs as heritable
variations are exposed to environmental
factors that favor the reproductive success
of some individuals over others
• The product of natural selection is adaptation
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LE 1-6b
Population with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors
Video: Seahorse Camouflage
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THE PROCESS OF SCIENCE
1.7 Scientists use two main approaches to learn
about nature
• Discovery science
– Primarily describes nature through verifiable
observations and measurements
• Hypothesis-driven science
– Attempts to explain nature by studying
questions drawn from observations made
during "discovery science"
– Hypothesis: a tentative answer to a problem
or question that is being asked
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1.8 With hypothesis-based science, we pose and
test hypotheses
•
Hypothesis-based science applies the five
steps of the scientific method:
(1) Observations from others or results of
earlier tests
(2) Questions about unclear aspects of the
observations: How? Why? When?
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(3) Hypotheses or tentative explanations of a
phenomenon
Must be testable
Must be falsifiable
(4) Predictions developed by the use of
deductive reasoning (if...then)
(5) Tests of predictions to determine if the
predictions are supported or falsified.
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A Case Study from Everyday Life
• Following the scientific method to discover why
a flashlight doesn't work
• Using deductive reasoning to test alternative
hypotheses
– If a hypothesis is correct, and we test it,
then we can expect a particular outcome
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LE 1-8a-1
Observations
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb
LE 1-8a-2
Observations
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Prediction:
Replacing bulb
will fix problem
LE 1-8a-3
Observations
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Prediction:
Replacing bulb
will fix problem
Test prediction
Test prediction
Test falsifies hypothesis
Test does not falsify hypothesis
A Case Study of Hypothesis-Based Science
• Following the scientific method to test an
hypothesis about the function of biological
mimicry
– Predict that mimicry should protect coral
snakes in the areas where king snakes live
– Develop a controlled experiment using
artificial snakes
– Summarize results confirming prediction in
a graph
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LE 1-8e
100
Artificial king snakes
84%
83%
Percent of total attacks
on artificial snakes
80
Artificial brown snakes
60
40
20
17%
16%
0
Coral snakes
absent
Coral snakes
present
BIOLOGY AND EVERYDAY LIFE CONNECTION
1.9 Biology is connected to our lives in many
ways
• Technology applies scientific knowledge for a
specific purpose
• Biology and technology affect our everyday
lives
– Environmental problems and solutions
– Genetic engineering
– Medicine
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings