PART I INTRODUCTION TO LIVING ANIMALS
1 Life: Biological Principles and the Science of Zoology
2 The Origin and Chemistry of Life
3 Cells as Units of Life
4 Cellular Metabolism
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CHAPTER 1 LIFE: BIOLOGICAL PRINCIPLES
AND THE SCIENCE OF ZOOLOGY
CHAPTER OUTLINE
1.1. The Uses of Principles
A. Underlying Principles Central to Understanding Zoology
1. Laws of physics and chemistry underlie some zoology principles.
2. Principles of genetics and evolution guide much zoological study.
3. Principles learned from one animal group can be applied to others.
4. Some science methods specify how to conduct solid research.
B. Zoology, the Study of Animal Life (Figure 1.1)
1. Zoologists studying many dimensions base research upon a long history of work.
2. Two central principles are evolution and the chromosomal theory of inheritance.
1.2. Fundamental Properties of Life
A. Historical Continuity of Life
, 1. Properties exhibited by life today are different from those at its origin.
2. Change over time, or evolution, has generated many unique living properties.
3. Definitions based on complex replicative processes would exclude non-life, but also
early forms from which cellular life descended.
4. We do not force life into a simple definition, yet we can readily recognize life from a
nonliving world.
B. General Properties of Living Systems
1. Chemical Uniqueness (Figures 1.2, 2.15)
a. Macromolecules in organisms are far more complex than molecules in nonliving
matter.
b. They obey the same physical laws as nonliving molecules but are more complex.
c. Nucleic acids, proteins, carbohydrates and lipids are common molecules in life.
d. Their general structure evolved early; thus the common amino acid subunits of
proteins are found throughout life.
e. They provide both a unity based on living ancestry and a potential for diversity.
2. Complexity and Hierarchical Organization (Figures 1.3, 1.4; Table 1.1)
a. Life has an ascending order of complexity: macromolecules, cells, organisms,
populations and species.
b. Each of these levels has an internal structure: macromolecules form ribosomes
and membranes, etc. and cells form tissues.
c. However, each level has unique abilities and requirements; cells can replicate
but are not independent in an organism.
d. New characteristics that appear at the next level of organization are emergent
properties.
e. Because of the interactions of the components, we must study all levels directly
as well as together.
f. Diversity of emergent properties at higher levels is a result of evolution (i.e.,
lower levels without hearing cannot develop language).
,3. Reproduction (Figure 1.5)
a. Life comes from previous life but had to arise from nonliving matter at least
once.
b. Genes replicate genes, cells divide to produce new cells and organisms produce
new organisms sexually or asexually.
c. Reproduction is not necessary of individuals, but is necessary for a lineage to
survive.
d. Reproduction is a combination of contradictory processes of copying traits, but
with variation.
e. If heredity were perfect, life would never change; if it were wildly variable, life
would lack stability.
4. Possession of a Genetic Program (Figure 1.6)
a. Nucleic acids encode structures of protein molecules.
b. DNA stores genetic information in animals.
c. Sequences of nucleotide bases (A, C, G and T) code for the order of amino acids
in a protein.
d. The genetic code is correspondence between bases in DNA and sequence of
amino acids.
e. This genetic code was established early in evolution and has undergone little
change.
f. The genetic code in animal mitochondrial DNA is slightly different from nuclear
and bacterial DNA.
g. Changes in mitochondrial DNA (it contains fewer proteins) are less likely to
disrupt cell functions.
5. Metabolism (Figure 1.7)
a. Living organisms maintain themselves by acquiring nutrients from the
environment.
b. Breakdown of nutrients provides both energy and molecular components for
cells.
c. Metabolism is the range of essential chemical processes.
, d. Metabolism involves constructive (anabolic) and destructive (catabolic)
reactions.
e. Most metabolic pathways occur in specific cell organelles.
f. The study of the performance of complex metabolic functions is physiology.
6. Development (Figure 1.8)
a. Development describes characteristic changes an organism undergoes from
origin to adult.
b. It involves changes in size and shape, and differentiation within the organism.
c. Some animals have uniquely different embryonic, juvenile and adult forms.
d. The transformation from stage to stage is metamorphosis.
e. Among animals, early stages of related organisms are more similar.
7. Environmental Interaction (Figure 1.9)
a. Ecology is the study of an organism's interaction with the environment.
b. Organisms respond to stimuli in the environment, a property called irritability.
c. We cannot separate life and its evolutionary lineage from its environment.
8. Movement
a. Energy extracted from environment permits living systems to initiate controlled
movements that are essential for reproduction, growth, response to stimuli, and
development.
b. Animals are adapted for locomotion which has led to dispersal of entire
populations from one geographic location to another over time.
c. Movement of nonliving matter is controlled by external forces and thus is
dissimilar to purposeful movements exhibited by living systems.
C. Life Obeys Physical Laws
1. Vitalism is the belief that life requires more than basic laws of physics; biological
research has found no basis for vitalism.
2. All aspects of life require energy.
a. First Law of Thermodynamics (the law of conservation of energy): Energy
cannot be created or destroyed; it can be transformed from one form to another.
1 Life: Biological Principles and the Science of Zoology
2 The Origin and Chemistry of Life
3 Cells as Units of Life
4 Cellular Metabolism
__________________________________________________________________________________________________________________
CHAPTER 1 LIFE: BIOLOGICAL PRINCIPLES
AND THE SCIENCE OF ZOOLOGY
CHAPTER OUTLINE
1.1. The Uses of Principles
A. Underlying Principles Central to Understanding Zoology
1. Laws of physics and chemistry underlie some zoology principles.
2. Principles of genetics and evolution guide much zoological study.
3. Principles learned from one animal group can be applied to others.
4. Some science methods specify how to conduct solid research.
B. Zoology, the Study of Animal Life (Figure 1.1)
1. Zoologists studying many dimensions base research upon a long history of work.
2. Two central principles are evolution and the chromosomal theory of inheritance.
1.2. Fundamental Properties of Life
A. Historical Continuity of Life
, 1. Properties exhibited by life today are different from those at its origin.
2. Change over time, or evolution, has generated many unique living properties.
3. Definitions based on complex replicative processes would exclude non-life, but also
early forms from which cellular life descended.
4. We do not force life into a simple definition, yet we can readily recognize life from a
nonliving world.
B. General Properties of Living Systems
1. Chemical Uniqueness (Figures 1.2, 2.15)
a. Macromolecules in organisms are far more complex than molecules in nonliving
matter.
b. They obey the same physical laws as nonliving molecules but are more complex.
c. Nucleic acids, proteins, carbohydrates and lipids are common molecules in life.
d. Their general structure evolved early; thus the common amino acid subunits of
proteins are found throughout life.
e. They provide both a unity based on living ancestry and a potential for diversity.
2. Complexity and Hierarchical Organization (Figures 1.3, 1.4; Table 1.1)
a. Life has an ascending order of complexity: macromolecules, cells, organisms,
populations and species.
b. Each of these levels has an internal structure: macromolecules form ribosomes
and membranes, etc. and cells form tissues.
c. However, each level has unique abilities and requirements; cells can replicate
but are not independent in an organism.
d. New characteristics that appear at the next level of organization are emergent
properties.
e. Because of the interactions of the components, we must study all levels directly
as well as together.
f. Diversity of emergent properties at higher levels is a result of evolution (i.e.,
lower levels without hearing cannot develop language).
,3. Reproduction (Figure 1.5)
a. Life comes from previous life but had to arise from nonliving matter at least
once.
b. Genes replicate genes, cells divide to produce new cells and organisms produce
new organisms sexually or asexually.
c. Reproduction is not necessary of individuals, but is necessary for a lineage to
survive.
d. Reproduction is a combination of contradictory processes of copying traits, but
with variation.
e. If heredity were perfect, life would never change; if it were wildly variable, life
would lack stability.
4. Possession of a Genetic Program (Figure 1.6)
a. Nucleic acids encode structures of protein molecules.
b. DNA stores genetic information in animals.
c. Sequences of nucleotide bases (A, C, G and T) code for the order of amino acids
in a protein.
d. The genetic code is correspondence between bases in DNA and sequence of
amino acids.
e. This genetic code was established early in evolution and has undergone little
change.
f. The genetic code in animal mitochondrial DNA is slightly different from nuclear
and bacterial DNA.
g. Changes in mitochondrial DNA (it contains fewer proteins) are less likely to
disrupt cell functions.
5. Metabolism (Figure 1.7)
a. Living organisms maintain themselves by acquiring nutrients from the
environment.
b. Breakdown of nutrients provides both energy and molecular components for
cells.
c. Metabolism is the range of essential chemical processes.
, d. Metabolism involves constructive (anabolic) and destructive (catabolic)
reactions.
e. Most metabolic pathways occur in specific cell organelles.
f. The study of the performance of complex metabolic functions is physiology.
6. Development (Figure 1.8)
a. Development describes characteristic changes an organism undergoes from
origin to adult.
b. It involves changes in size and shape, and differentiation within the organism.
c. Some animals have uniquely different embryonic, juvenile and adult forms.
d. The transformation from stage to stage is metamorphosis.
e. Among animals, early stages of related organisms are more similar.
7. Environmental Interaction (Figure 1.9)
a. Ecology is the study of an organism's interaction with the environment.
b. Organisms respond to stimuli in the environment, a property called irritability.
c. We cannot separate life and its evolutionary lineage from its environment.
8. Movement
a. Energy extracted from environment permits living systems to initiate controlled
movements that are essential for reproduction, growth, response to stimuli, and
development.
b. Animals are adapted for locomotion which has led to dispersal of entire
populations from one geographic location to another over time.
c. Movement of nonliving matter is controlled by external forces and thus is
dissimilar to purposeful movements exhibited by living systems.
C. Life Obeys Physical Laws
1. Vitalism is the belief that life requires more than basic laws of physics; biological
research has found no basis for vitalism.
2. All aspects of life require energy.
a. First Law of Thermodynamics (the law of conservation of energy): Energy
cannot be created or destroyed; it can be transformed from one form to another.
