Introduction to Life The Science of Biology. Biology is… The study of life…

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