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Introduction to Life
The Science of Biology
Biology is…
• The study of life…
…at all levelsFigure 1.6
Life is…
• a phenomenon observed in organized genetic units and expressed as
Life is…
• a phenomenon observed in organized genetic units and expressed as
– metabolism by individuals
Life is…
• a phenomenon observed in organized genetic units and expressed as
– metabolism by individuals
– reproduction among individuals
Life is…
• a phenomenon observed in organized genetic units and expressed as
– metabolism by individuals
– reproduction among individuals
– evolution of populations through time
Paradigm
Paradigm
• a pattern or an example of something
Paradigm
• a pattern or an example of something
• a mental picture or pattern of thought
Paradigm
• a pattern or an example of something
• a mental picture or pattern of thought
• the model that scientists hold about a particular area of knowledge
• [Thomas Kuhn in The Structure of Scientific Revolutions]
Organic Evolution is the Principle Paradigm in the Biological Sciences
Organic Evolution is the Principle Paradigm in the Biological Sciences
• the model that scientists hold about a particular area of knowledge
Organic Evolution is the Principle Paradigm in the Biological Sciences
• the model that scientists hold about a particular area of knowledge
– an organizing concept
Organic Evolution is the Principle Paradigm in the Biological Sciences
• the model that scientists hold about a particular area of knowledge
– an organizing concept
– a principle
Organic Evolution is the Principle Paradigm in the Biological Sciences
• the model that scientists hold about a particular area of knowledge
– an organizing concept
– a principle
– an assumption
Organic Evolution is the Principle Paradigm in the Biological Sciences
• the model that scientists hold about a particular area of knowledge
– an organizing concept
– a principle
– an assumption
– a presupposition
Dueling Paradigms
Dueling Paradigms
Static Creation in
the Modern State
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Young Earth
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Young Earth Ancient Earth
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Young Earth Ancient Earth
Recent Origin of Life
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Young Earth Ancient Earth
Recent Origin of Life Ancient Origin of Life
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Young Earth Ancient Earth
Recent Origin of Life Ancient Origin of Life
Discrete Species
Dueling Paradigms
Static Creation in vs. Evolution from a
the Modern State Less-complex State
Young Earth Ancient Earth
Recent Origin of Life Ancient Origin of Life
Discrete Species Intergrading Species
The Puzzle of Nature
The Puzzle of Nature
Similarities Differences
The Puzzle of Nature
Similarities Differences
DNA is universal
All Organisms Share DNA LandmarksFigure 1.8
The Puzzle of Nature
Similarities Differences
DNA is universal Genomes Differ
The Puzzle of Nature
Similarities Differences
DNA is universal Genomes Differ
Eukaryotic
metabolism
The Puzzle of Nature
Similarities Differences
DNA is universal Genomes Differ
Eukaryotic Prokaryotic
metabolism metabolism
The Puzzle of Nature
Similarities Differences
DNA is universal Genomes Differ
Eukaryotic Prokaryotic
metabolism metabolism
Structural
homologies
Vertebrate Forelimb HomologiesFigure 1.2
The Puzzle of Nature
Similarities Differences
DNA is universal Genomes differ
Eukaryotic Prokaryotic
metabolism metabolism
Structural Functional
Homologies adaptations
Functional Adaptations Figure 1.7
The “Evolution” of Evolution
The “Evolution” of Evolution“Organic life beneath the shoreless waves Was born and nurs'd in ocean's pearly caves; First forms minute, unseen by spheric glass, Move on the mud, or pierce the watery mass; These, as successive generations bloom, New powers acquire and larger limbs assume; Whence countless groups of vegetation spring, And breathing realms of fin and feet and wing.”
The “Evolution” of Evolution“Organic life beneath the shoreless waves Was born and nurs'd in ocean's pearly caves; First forms minute, unseen by spheric glass, Move on the mud, or pierce the watery mass; These, as successive generations bloom, New powers acquire and larger limbs assume; Whence countless groups of vegetation spring, And breathing realms of fin and feet and wing.”
The “Evolution” of Evolution“Organic life beneath the shoreless waves Was born and nurs'd in ocean's pearly caves; First forms minute, unseen by spheric glass, Move on the mud, or pierce the watery mass; These, as successive generations bloom, New powers acquire and larger limbs assume; Whence countless groups of vegetation spring, And breathing realms of fin and feet and wing.”Darwin
The “Evolution” of Evolution“Organic life beneath the shoreless waves Was born and nurs'd in ocean's pearly caves; First forms minute, unseen by spheric glass, Move on the mud, or pierce the watery mass; These, as successive generations bloom, New powers acquire and larger limbs assume; Whence countless groups of vegetation spring, And breathing realms of fin and feet and wing.”Darwin,Erasmus (1731-1802) The Temple of Nature
The “Evolution” of Evolution• Count George-Louis Leclerc de Buffon (1707-
1788)Perhaps structural similarities are due to
descent from a common ancestor with similar characteristics
The “Evolution” of Evolution• Count George-Louis Leclerc de Buffon (1707-
1788)Perhaps structural similarities are due to
descent from a common ancestor with similar characteristics
• Jean-Baptiste de Lamarck (1744-1829)Organisms change from generation to
generation as they inherit characteristics that their parents acquired during their lives
The “Evolution” of Evolution• Charles Darwin
The “Evolution” of Evolution• Charles Darwin
Organisms reproduce more offspring than can survive on available resources
The “Evolution” of Evolution• Charles Darwin
Organisms reproduce more offspring than can survive on available resources
Populations of organism exhibit heritable variations in their characteristics
The “Evolution” of Evolution• Charles Darwin
Organisms reproduce more offspring than can survive on available resources
Populations of organism exhibit heritable variations in their characteristics
Some characteristics make certain individuals more likely to survive than others
The “Evolution” of Evolution• Charles Darwin
Given overpopulation/limited resources, biological variation & differential survival:
The “Evolution” of Evolution• Charles Darwin
Given overpopulation/limited resources, biological variation & differential survival: The characteristics of a population change over time
The “Evolution” of Evolution• Charles Darwin
Given overpopulation/limited resources, biological variation & differential survival: The characteristics of a population change over time
This pattern of “natural selection” is superimposed on the random processes of survival and death
The “Evolution” of Evolution
• Mid 18th century - evolution was “in the air”
The “Evolution” of Evolution
• Mid 18th century - evolution was “in the air”
• Mid 19th century - natural selection
The “Evolution” of Evolution
• Mid 18th century - evolution was “in the air”
• Mid 19th century - natural selection
• Mid 20th century - The Modern Synthesis
The “Evolution” of Evolution
• Mid 18th century - evolution was “in the air”
• Mid 19th century - natural selection
• Mid 20th century - The Modern Synthesis
– genetics, biochemistry, embryology, comparative anatomy, physiology, etc.
The “Evolution” of Evolution
• Mid 18th century - evolution was “in the air”
• Mid 19th century - natural selection
• Mid 20th century - The Modern Synthesis
– genetics, biochemistry, embryology, comparative anatomy, physiology, etc.
– mutation, neutral genetic change, genetic drift, gene flow, catastrophe
Scientific Methods
• Science is objective and naturalistic
Scientific Methods
• Science is objective and naturalistic
– scientific explanations are based on observations of nature that are available to anyone
Scientific Methods
• Science is objective and naturalistic
– scientific explanations are based on observations of nature that are available to anyone
– scientific explanations assume that events in nature occur without external intervention
Scientific Methods
• Scientific endeavors may be
– exploratory
Scientific Methods
• Scientific endeavors may be
– exploratory
– historical/“forensic”
Scientific Methods
• Scientific endeavors may be
– exploratory
– historical/“forensic”
– experimental
Scientific Methods
• Scientific investigation is hypothesis-driven
Scientific Methods
• Scientific investigation is hypothesis-driven
– Observations lead to questions
Scientific Methods
• Scientific investigation is hypothesis-driven
– Observations lead to questions
– Questions lead to hypotheses (+/- educated guesses)
Scientific Methods
• Scientific investigation is hypothesis-driven
– Observations lead to questions
– Questions lead to hypotheses (+/- educated guesses)
– Hypotheses lead to predictions
Scientific Methods
• Scientific investigation is hypothesis-driven
– Observations lead to questions
– Questions lead to hypotheses (+/- educated guesses)
– Hypotheses lead to predictions
– Predictions are tested by collection and analysis of data (natural, historical, experimental)
Landmarks in the Evolution of Life
Landmarks in the Evolution of Life• Life from non-life
Life Began Early
in Earth’s History
Figure 1.3
Landmarks in the Evolution of Life• Life from non-life• First cells
Landmarks in the Evolution of Life• Life from non-life• First cells• Oxygenic photosynthesis
An oxygenic cyanobacteriumFigure 1.4
Life Occurred Without Oxygen
for 13 Days
Figure 1.3
Landmarks in the Evolution of Life• Life from non-life• First cells• Oxygenic photosynthesis• Increased variability
Landmarks in the Evolution of Life• Life from non-life• First cells• Oxygenic photosynthesis• Increased variability• Eukaryotic cells
A compartmentalized eukaryotic cellFigure 1.5
All Organisms were
Prokaryotic for
19 DaysFigure 1.3
Landmarks in the Evolution of Life• Life from non-life• First cells• Oxygenic photosynthesis• Increased variability• Eukaryotic cells• Multicellularity
All Life was
Unicellular for
23 DaysFigure 1.3
Landmarks in the Evolution of Life• Life from non-life• First cells• Oxygenic photosynthesis• Increased variability• Eukaryotic cells• Multicellularity• Invasion of Land
All Life was
Aquatic for
27 DaysFigure 1.3
Landmarks in the Evolution of Life• Life from non-life• First cells• Oxygenic photosynthesis• Increased variability• Eukaryotic cells• Multicellularity• Invasion of Land• Human Influence
Recorded Human
History Began a Few Seconds
AgoFigure 1.3
