Attributes of Life (Chapter 19)
Introduction to life
 Themes/Characteristics of all living
organisms
 Cardinal structural and functional “nuts
and bolts” of all life
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Introduction
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What defines life?
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Some exceptions
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Irritability (particularly after a test!)
Grows spontaneously (as in first year of college and old age)
Reproduce
Ice grows
Mule (donkey x horse) but does not reproduce
Defining life
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Multiple definitions all with multiple perspectives
Best to focus on what are themes or general features
What is Life?
Chapter 23
Introduction to life
 Themes/Characteristics of all living
organisms
 Cardinal structural and functional “nuts
and bolts” of all life
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Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is the cell, stupid”
Continuity of life based on information: “it is your genes,
stupid” (not jeans)
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Take-Home Messages - Themes
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Hierarchical nature of the living world
Emergent properties of living systems
Cell as a basic unit of structure and function
Continuity of life based on information
Openness of biological systems
Regulatory capacity of living systems: homeostasis
Capacity to reproduce
Capacity to utilize energy
Two sides of the same coin: diversity and similarity of living
systems
Evolution as the cornerstone of biology and living systems
(explains diversity and similarity)
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is your cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Hierarchical Nature of Living
Systems
Community
Population
Organism
Organ
Tissue
Cell
Organelles
Macromolecules
Atoms
Emergent Properties of Living
Systems
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Consequence of hierarchy theory: emergent
properties
With each step up in the hierarchy, novel
properties emerge that were not present at lower
levels and were not predictable
Example: cell composed of trillions of
macromolecules arranged in very precise ways
that result in highly ordered and complex
machinery (sum far greater than the parts)
Infrastructure of A Cell
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Structure correlated with function
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Cell: Structure and Function
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Organism’s basic unit of structure and function
Lowest level of structure capable of performing life’s
activities
 Most common basic structure of all living organisms
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Robert Hooke (1665) and Anton van
Leewenhook
Cell Theory
Ubiquitous nature of cells
 All cells come from previous cells
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Hooke’s Cell (Cork)
General Cell Structures
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Continuity of Life and Information
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Order in any system originates from information and
instructions that serve as a template for organizing
“parts”
In living systems, instructions are encoded/inherited in
the DNA
Inheritance is based on the precise order of nucleotides
(ATCG)
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Example: RAT versus TAR versus ART
Continuity of life is based on information that is:
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Transferred from generation to generation over time
Preserved/stores at the molecular level in DNA
Infrastructure of A Cell
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your
genes, stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Diversity and similarity of living systems
Evolution of living systems
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your
genes, stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Diversity and similarity of living systems
Evolution of living systems
Open Systems
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All living organisms are open systems, allowing
organisms to interact with their environment
Processing stimuli from the environment
Responding to stimuli in the environment
Characterize an “open” versus a “closed” system
Examples
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Orientation of leaves to sun
Eyes
Ears
Microbes and single cell organisms (e.g., amoeba)
The structure of the eye
Figure 26.41
26-580
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Regulatory Systems
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Constant interplay of organisms with the
environment requires a well balanced regulatory
system
Consequence is homeostasis
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Set point, effectors, control centers and sensors
Analogy to thermostat for heat control
Examples
Enzymes in cells (lab exercise next week)
 Thermostatic control of body temperature
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Regulatory Systems: Cybernetics
Positive
Feedback
Set Point
Control
Center/
Sensor
Effector
Negative
Feedback
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Feedbacks (+ and -), homeostasis and cybernetics
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Universality of Reproduction
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Reproduction: regenerative process of making new
organisms from previously existing organisms (not
necessarily copies)
Methods
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Sexual
Asexual (microbes; cell division/mitosis)
Ancillary but important function: creating new variants
Example: siblings
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Energy Utilization
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Why is energy use an important theme?
Energy transduction
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Thermodynamics (1st and 2nd laws)
Energy source is ________
Energy capture
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Energy storage
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Autotrophs (energy from sun “directly” via phoptosynthesis)
Heterotrophs (energy from other organisms)
Chemical bonds (C-C bonds, which are _____ bonds)
ATP (adenosine triphosphate and ADP (adenosine diphosphate)
Energy dissipation
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2nd Law of Thermodynamicvs
Energy Flow
ADP
Catabolism
Biosynthesis
ATP
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution of living systems
Two Sides of a Coin:
Diversity and Similarity
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Diversity is a hallmark of living systems
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1.5 M known species of plants, animals and microbes
100 M+ thought to exist
Similarity is a hallmark of living systems
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Striking similarity at the molecular level (DNA) so you are
more akin to worms, squirrels, birds and pigs (~90%!) than
you think
Examples
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Biochemistry
Structure and morphology
DNA
Conclusion: two sides of the same coin
Themes/Characteristics
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Hierarchy theory and emergent properties
Structure and function: “it is cells, stupid”
Continuity of life based on information: “it is your genes,
stupid”
Openness of biological systems
Regulatory capacity of living systems
Capacity to reproduce
Capacity to utilize energy
Diversity and similarity of living systems
Evolution and adaptation of living systems
Evolution and Adaptation
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Define “evolution”
Define “adaptation”
Why is “evolution” and “adaptation” important in
living systems
Examples of evolution
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Macroscale: origin of species
Microscale:
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Microbes resistant to antibiotics
Moths resistant to air pollution
Examples of adaptation
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Articulation of the joints in animals
Planar structure of leaves
Evolution and Adaptation
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Cornerstone theory of biology (relate to hypothesis)
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Explains diversity of life
Explains similarity of life
Theories in biology are difficult to have stood the test of
time and even more difficult to address very divergent
features of living systems
Evolution is one of the long-standing theories that has
the fascinating and unusual feature of explaining not only
the diversity of life but at the same time the striking
similarity among all living organisms
Charles Darwin (1859): Origin of Species
Take-Home Messages - Themes
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Hierarchical nature of the living world
Emergent properties of living systems
Cell as a basic unit of structure and function
Continuity of life based on information
Openness of biological systems
Regulatory capacity of living systems: homeostasis
Capacity to reproduce
Capacity to utilize energy
Two sides of the same coin: diversity and similarity of living
systems
Evolution as the cornerstone of biology (explains diversity and
similarity)