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Chapter 1 Biology: Exploring Life
THEMES IN THE STUDY
OF BIOLOGY
© 2012 Pearson Education, Inc.
1.1 All forms of life share common properties
 Biology is the scientific study of life.
 Properties of life include
1. Order—the highly ordered structure that typifies life,
2. Reproduction—the ability of organisms to reproduce
their own kind,
3. Growth and development—consistent growth and
development controlled by inherited DNA,
4. Energy processing—the use of chemical energy to
power an organism’s activities and chemical reactions,
© 2012 Pearson Education, Inc.
1.1 All forms of life share common properties
5. Response to the environment—an ability to respond
to environmental stimuli,
6. Regulation—an ability to control an organism’s
internal environment within limits that sustain life, and
7. Evolutionary adaptation—adaptations evolve over
many generations as individuals with traits best suited
to their environments have greater reproductive
success and pass their traits to offspring.
© 2012 Pearson Education, Inc.
Figure 1.1
(3) Growth and
development
(1) Order
(4) Energy
processing
(2) Reproduction
(6) Regulation
(5) Response to the
environment
(7) Evolutionary adaptation
Figure 1.2
Biosphere
Florida
Ecosystem
Florida
Everglades
Community
All organisms in this
wetland ecosystem
Population
All alligators living
in the wetlands
Organism
an American alligator
Nerve
Brain
Spinal
cord
Organ system
Nervous system
Organ
Brain
Tissue
Nervous tissue
Atom
Cell
Nerve cell
Nucleus
Organelle
Nucleus
Molecule
DNA
1.2 In life’s hierarchy of organization, new
properties emerge at each level
 Biological organization unfolds as follows:
– Biosphere—all of the environments on Earth that
support life,
– Ecosystem—all the organisms living in a particular
area and the physical components with which the
organisms interact,
– Community—the entire array of organisms living in a
particular ecosystem,
– Population—all the individuals of a species living in a
specific area,
© 2012 Pearson Education, Inc.
1.2 In life’s hierarchy of organization, new
properties emerge at each level
– Organism—an individual living thing,
– Organ system—several organs that cooperate in a
specific function,
– Organ—a structure that is composed of tissues and
that provides a specific function for the organism,
– Tissues—a group of similar cells that perform a
specific function,
– Cells—the fundamental unit of life,
© 2012 Pearson Education, Inc.
1.2 In life’s hierarchy of organization, new
properties emerge at each level
– Organelle—a membrane-bound structure that performs
a specific function in a cell, and
– Molecule—a cluster of small chemical units called
atoms held together by chemical bonds. Molecules that
make up organelles in cells include large
macromolecules like protein (made from 20 different
amino acids), lipids (made from 30 fatty acids),
disaccharides and polysaccharides (made from two to
many monosaccharides), and nucleic acids (made from
five nucleotides). Each of these are made of smaller
molecules that are the building blocks of the
macromolecules. DNA and RNA contain the blueprint
for assembling small molecules into macromolecules.
© 2012 Pearson Education, Inc.
1.3 Cells are the structural and functional units
of life
 Cells are the level at which the properties of life
emerge.
 A cell can
– regulate its internal environment,
– take in and use energy,
– respond to its environment,
– develop and maintain its complex organization, and
– give rise to new cells.
© 2012 Pearson Education, Inc.
1.3 Cells are the structural and functional units
of life
 All cells
– are enclosed by a membrane that regulates the
passage of materials between the cell and its
surroundings and
– use DNA as their genetic information, which serves as a
blueprint for making macromolecules.
© 2012 Pearson Education, Inc.
1.3 Cells are the structural and functional units
of life
 There are two basic types of cells.
1. Prokaryotic cells
– were the first to evolve,
– are simpler, and
– are usually smaller than eukaryotic cells.
2. Eukaryotic cells
– contain membrane-enclosed organelles, including a nucleus
containing DNA, and
– are found in plants, animals, and fungi.
© 2012 Pearson Education, Inc.
Figure 1.3
Eukaryotic cell
DNA
(no nucleus)
Prokaryotic
cell
Membrane
Organelles
Nucleus
(membraneenclosed)
DNA (throughout
nucleus)
1.4 Living organisms interact with their
environment, exchanging matter and energy
 Living organisms interact with their environments,
which include
– other organisms and
– physical factors.
 In most ecosystems
– plants are the producers that provide the food,
– consumers eat plants and other animals, and
– decomposers act as recyclers, changing complex
matter into simpler mineral nutrients.
© 2012 Pearson Education, Inc.
Figure 1.4
ENERGY FLOW
Sun
Inflow of
light energy
Outflow of
heat
Consumers
(animals)
Producers
(plants)
Leaves take up
CO2 from air; roots
absorb H2O and
minerals from soil
Chemical energy
in food
Decomposers such
as worms, fungi,
and bacteria return
chemicals to soil
EVOLUTION, THE CORE
THEME OF BIOLOGY
© 2012 Pearson Education, Inc.
1.5 The unity of life is based on DNA and a
common genetic code
 All cells have DNA, the chemical substance of
genes and the blueprint for making
macromolecules.
 Genes
– are the unit of inheritance that transmits information
from parents to offspring,
– are grouped into very long DNA molecules called
chromosomes, and
– control the activities of a cell.
© 2012 Pearson Education, Inc.
1.5 The unity of life is based on DNA and a
common genetic code
 A species’ genes are the sequences of the four
building blocks making up DNA’s double helix.
– All forms of life use essentially the same code to
transcribe the information stored in DNA into RNA that
is translated into proteins. Organelles are either made
of proteins or the proteins form enzymes that make the
three other macromolecules
– The diversity of life arises from differences in DNA
sequences.
– Evolution is the changes in DNA over time in a species
that can lead to adaptations in the species
© 2012 Pearson Education, Inc.
Figure 1.5
A
G
C
C
A
T
G
T
A
C
G
T
A
T
A
C
G
G
T
C
1.6 The diversity of life can be arranged into
three domains
 Diversity is the hallmark of life.
– Biologists have identified about 1.8 million species.
– Estimates of the actual number of species ranges from
10 to 100 million.
 Taxonomy names species and classifies them into
a system of broader groups.
© 2012 Pearson Education, Inc.
1.6 The diversity of life can be arranged into
three domains
 The diversity of life can be arranged into three
domains.
1. Bacteria are the most diverse and widespread
prokaryotes.
2. Archaea are prokaryotes that often live in Earth’s extreme
environments.
3. Eukarya have eukaryotic cells and include
– single-celled members of the protist and fungal kingdoms and
– multicellular members of kingdoms including protists, fungi,
animals, and plants.
© 2012 Pearson Education, Inc.
Figure 1.6
Domain Bacteria
Domain Eukarya
Bacteria
Domain Archaea
Protists
(multiple kingdoms)
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
Archaea
1.7 Evolution explains the unity and diversity of
life
 The history of life, as documented by fossil
species, is a saga of a changing Earth
– billions of years old and
– inhabited by an evolving cast of life forms.
 Evolution accounts for life’s dual nature of
– kinship and
– diversity.
© 2012 Pearson Education, Inc.
1.7 Evolution explains the unity and diversity of
life
 Natural selection was inferred by connecting two
observations.
1. Individuals in a population vary in their traits due to
differences in DNA, many of which are passed on from
parents to offspring.
2. A population can produce far more offspring than the
environment can support.
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Figure 1.7C
1 Population with varied inherited traits
2 Elimination of individuals with certain traits
3 Reproduction of survivors
1.7 Evolution explains the unity and diversity of
life
 From these observations, Charles Darwin first
inferred that
– those individuals with heritable traits best suited to the
environment are more likely to survive and reproduce
than less well-suited individuals,
– as a result of this unequal reproductive success over
many generations, an increasing proportion of
individuals will have the advantageous traits, and
– the result will be evolutionary adaptation, the
accumulation of favorable traits in a population over
time.
© 2012 Pearson Education, Inc.
Figure 1.7C List some adaptations for the snowy owl, flamingo, and penguin
THE PROCESS OF SCIENCE
© 2012 Pearson Education, Inc.
1.8 Scientific inquiry is used to ask and answer
questions about nature
 The word science is derived from a Latin verb
meaning “to know.” Science is a way of knowing.
 Scientists
– draw general conclusions from many observations and
– come up with ways to test a hypothesis, a proposed
explanation for a set of
© 2012 Pearson Education, Inc.
1.8 Scientific inquiry is used to ask and answer
questions about nature
 How is a theory different from a hypothesis? A
scientific theory is
– much broader in scope than a hypothesis,
– usually general enough to generate many new, specific
hypotheses, which can then be tested, and
– supported by a large and usually growing body of
evidence.
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1.9 Scientists form and test hypotheses and share
their results
 We solve everyday problems by using hypotheses.
– A common example would be the reasoning we use to
answer the question, “Why doesn’t a flashlight work?”
– Using reasoning we realize that the problem is either (1)
the bulb or (2) the batteries.
– Further, a hypothesis must be
– testable and
– falsifiable.
– In this example, two hypotheses are tested.
© 2012 Pearson Education, Inc.
Figure 1.9A_s1
Observation
Question
Hypothesis 1:
Dead batteries
Hypothesis 2:
Burned-out bulb
Figure 1.9A_s2
Observation
Question
Hypothesis 1:
Dead batteries
Hypothesis 2:
Burned-out bulb
Prediction:
Replacing batteries
will fix problem.
Prediction:
Replacing bulb
will fix problem.
Experiment:
Experiment:
Test prediction by
replacing batteries.
Test prediction by
replacing bulb.
Figure 1.9A_s3
Observation
Question
Hypothesis 1:
Dead batteries
Hypothesis 2:
Burned-out bulb
Prediction:
Replacing batteries
will fix problem.
Prediction:
Replacing bulb
will fix problem.
Experiment:
Experiment:
Test prediction by
replacing batteries.
Test prediction by
replacing bulb.
Test falsifies
hypothesis. Revise
hypothesis or
pose new one.
Test does not
falsify hypothesis.
Make additional
predictions and
test them.
1.9 Scientists form and test hypotheses and share
their results
 An actual research project demonstrates the
process of science.
 Scientists began with a set of observations and
generalizations that
 Camouflaged animals are protected from predation
 They then tested the hypothesis that Peromyscus
polionotus populations on the beach and inland
that had coat patterns that did not match the
environment would be more heavily predated
© 2012 Pearson Education, Inc.
1.9 Scientists form and test hypotheses and share
their results
 The scientists conducted a controlled
experiment, comparing
– an experimental group consisting of plastic models that
were not camouflaged like the environment
– control group consisting of models with coloration like
the environment
– The groups differed only by one factor, the coloration of
the mice models
– The data fit the key prediction of the camouflage
hypothesis.
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Beach mouse
Inland mouse
-the noncamouflaged models had a higher percentage of attacks
in the beach and inland habitats and these data fit the key
prediction of the camouflage hypothesis