Transcript Slide 1

BIO55: Population Genetics and Evolution
I. What is Evolution?
I. What is Evolution?
A. Definitions
"descent with modification"
I. What is Evolution?
A. Definitions
1. Darwin - "descent with modification"
2. Ridley - "change in a lineage of populations between
generations"
3. Futuyma - "a change in the properties of populations
of organisms, or groups of such populations, over
generations"
4. Freeman and Herron - “changes in allele frequencies
over time"
I. What is Evolution?
A. Definitions
B. Key Elements
1. Populations evolve – individuals develop.
I. What is Evolution?
A. Definitions
B. Key Elements
1. Populations evolve – individuals develop.
2. - Evolution is an observable phenomenon:
heritable change in a population over generations. This
may be observed at the genetic level, in the genetic
structure of the population, or may also be reflected in
the physiological, morphological, or behavioral traits
affected by this genetic change. We might term this
"Lineage Evolution".
I. What is Evolution?
A. Definitions
B. Key Elements
1. Populations evolve – individuals develop.
2. - Evolution is an observable phenomenon:
heritable change in a population over generations. This
may be observed at the genetic level, in the genetic
structure of the population, or may also be reflected in
the physiological, morphological, or behavioral traits
affected by this genetic change. We might term this
"Lineage Evolution".
3. - with known, observable causes:
the genetic structure of a population changes as a
function of selection, drift, mutation, migration, and nonrandom mating.
I. What is Evolution?
A. Definitions
B. Key Elements
4. - and known, observable results:
As the genetic structure of a population changes over
generations, it can become different (diverge) from
other populations. These differences may mean that the
populations can no longer breed, and they become
biologically distinct entities - different species. We term
this "Radiational Evolution".
II. The History of Evolutionary Thought
(Mayr, E. 1982. The Growth of Biological Thought)
At one time, there were no scientists, theologians, or
historians. There were just philosophers that studied
everything, using one way of thinking. That has changed,
as we will see....
II. The History of Evolutionary Thought
A. Early Greeks
Pantheon of meddlesome gods that controlled
every aspect of nature and human experience; even
took humans for mating (produced the heroes).
Prometheus fashions humans out of earth and water,
and Athena gives humankind a soul
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
“I swear by Apollo
Physician and Asclepius
and Hygieia and Panaceia
and all the gods and
goddesses, making them
my witnesses, that I will
fulfill according to my
ability and judgment this
oath and this covenant…”
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
- Valued an empirical
approach… “look and
see” rather than a
purely philosophical
approach to knowledge.
- Believed in use and
disuse and inheritance
of acquired traits; so
accepted change within
a "family".
- Close to an
evolutionary approach
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
2. Plato (427-347 bc)
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
2. Plato (427-347 bc)
- trained in Pythagorean School; pure philosopher
- UNIVERSAL PHILOSOPHY (four dogmas)
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
2. Plato (427-347 bc)
- trained in Pythagorean School; pure philosopher
- UNIVERSAL PHILOSOPHY (four dogmas)
Essentialism (unchanging eidos)
Plenitude (harmony)
Demi-Urge (creative force)
Soul (spark of life; most in humans)
The cave
-
trained in Pythagorean School; pure philosopher
UNIVERSAL PHILOSOPHY (four dogmas)
Essentialism (unchanging eidos)
Plenitude (harmony)
Demi-Urge (creative force)
Soul (spark of life; most in humans)
Mayr states: "It took more than 2000
years for biology, under the influence of
Darwin, to escape the paralyzing grip
of essentialism...the rise of modern
biology is, in part, the emancipation
from Platonic thinking".
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
2. Plato (427-347 bc)
3. Aristotle (384-322 bc)
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
2. Plato (427-347 bc)
3. Aristotle (384-322 bc)
- Interested in nature
- Described 100’s of species
- Scala Naturae
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
1. Hippocrates (450-377 bc)
2. Plato (427-347 bc)
3. Aristotle (384-322 bc)
- Interested in nature
- Described 100’s of species
- Scala Naturae
- Formalized logic, and
accepted empirical observations
as premises in arguments. But
conclusions were drawn from the
internal consistency of the argument; they were not
tested by observation.
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
1. Constantine the Great
(reign 306-337 ad - First Holy Roman Emporor)
- conversion to Christianity signaled change from to
monotheism in west (middle east monotheistic for
millenia).
- Platonic Dogma’s meshed with Bible:
Single, perfect, harmonious, unchanging
creation
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
1. Constantine the Great
2. Middle Ages
- Fall of Rome (476) to Fall of Constantinople (1453)
- Catholic Church as the Political Power
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
1. Constantine the Great
2. Middle Ages
- Fall of Rome (476) to Fall of Constantinople (1453)
- Catholic Church as Political Power
- The Persians (900-1000ce)
- Ibn a-lHaytham (Alhazen)
- al-Biruni
- Ibn Sena (Avicenna)
Aristotelian logic
and Empiricism!!
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
1. Constantine the Great
2. Middle Ages
- Fall of Rome (476) to Fall of Constantinople (1453)
- Catholic Church as Political Power
...yes..
- Thomas Aquinas (1225-1274):
..
- must be an unmoved mover
- must be an initial causality
- must be an initial being
- must be an ultimate good
- the ‘design/purpose’ of nature
implies a designer
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
1. Constantine the Great
2. Middle Ages
- Fall of Rome (476) to Fall of Constantinople (1453)
- Catholic Church as Political Power
...yes..
- Thomas Aquinas (1225-1274):
..
- must be an unmoved mover
- must be an initial causality
- must be an initial being
- must be an ultimate good
- the ‘design/purpose’ of nature
implies a designer
- translating the Persians
(with Grosseteste and Bacon)
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
D. The Renaissance (1400-1700)
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
D. The Renaissance (1400-1700)
1. Voyages of Discovery
- 1488 - Dias - Rounds Cape of Good Hope
- 1492 - Columbus - "New World"
2. Scientific Revolution
a. Astronomy and Physics
1. Nikoli Copernik (1473-1543)
2. Galileo Galilei (1564-1642)
3. Johannes Kepler (1571-1630)
4. Isaac Newton (1642-1727)
Heliocentric solar system
- confirmed by Galileo’s observations
Planets orbit in imperfect ellipses
The motion of planets and other
material objects could be explained
and predicted based on constant laws
of nature
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
D. The Renaissance (1400-1700)
1. Voyages of Discovery
2. Scientific Revolution
a. Astronomy and Physics
b. The Age of the Earth
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
D. The Renaissance (1400-1700)
1. Voyages of Discovery
2. Scientific Revolution
a. Astronomy and Physics
b. The Age of the Earth
1. James Ussher (1581-1656):
Bishop who Applied logical rigor to
the History of the Earth as revealed in
the Bible... counted the 'begats'...
- creation began at 9am on October 23, 4004 b.c.
2. Scientific Revolution
a. Astronomy and Physics
b. The Age of the Earth
1. James Ussher (1581-1656)
2. Nicolaus Steno (1638-1686)
- introduced concept of stratigraphy and superposition
- sedimentary rocks are layered in order deposited
- erosion is continuous and is the primary agent of
geology on earth.
2. Scientific Revolution
3. Conclusions of the Revolution
- Mechanics of Physical Universe were de-deified
- Constant, physical laws governed nature.
- God as creator (first cause) of universe and laws by
which it operates; requires less intervention.
2. Scientific Revolution
3. Conclusions of the Revolution
- Mechanics of Physical Universe were de-deified
- Constant, physical laws governed nature.
- God as creator (first cause) of universe and laws by
which it operates; requires less intervention.
4. Counter-intuitive Effects on Biology
a. constant laws implied stasis since creation
b. conflict:
- Deists = secondary laws enough
- Natural theologians = diversity and perfection of
life requires a God attending to every detail.
"there is special providence in the fall
of a sparrow..."
- Shakespeare (1564-1616) - Hamlet
2. Scientific Revolution
3. Conclusions of the Revolution
- Mechanics of Physical Universe were de-deified
- Constant, physical laws governed nature.
- God as creator (first cause) of universe and laws by
which it operates; requires less intervention.
4. Counter-intuitive Effects on Biology
5. Resolution and Problems
- Life was divine and not explicable by natural law
- Natural Theology re-emerged
- An impressive cataloguing of nature… Botanist John
Ray's book (1691) "The Wisdom of God Manifest in
the Works of Creation"
- How did all these species fit on the ark? Why aren’t
they mentioned in the Bible? How did they get to the
new world as flood water receded?
II. The History of Evolutionary Thought
A. Early Greeks
B. 2nd Greek School
C. The Impact of Christianity
D. The Renaissance (1400-1700)
E. The Enlightenment (1700’s)
E. The Enlightenment (1700’s)
1. Cultural Climate
- American, French Revolutions over Monarchy/Authority
- reason as a way to solve humanity’s problems
E. The Enlightenment (1700’s)
1. Cultural Climate
2. Natural Theology
a. Carl Linne (1707-1778) - "Linnaeus"
- the great cataloger
- latin binomen system
- group species based on reproductive structures
-created higher taxa order, class, phylum (nested)
- Systema Naturae: Creationis telluris est gloria Dei ex
opere Naturae per Hominem solum -- "The Earth's
creation is the glory of God, as seen from the works of
Nature by Man alone." 1758
E. The Enlightenment (1700’s)
1. Cultural Climate
2. Natural Theology
a. Carl Linne (1707-1778) - "Linnaeus"
b. Georges Louis Leclerc, Comte de Buffon (1707-1788)
- the foremost "biologist" of
the 18th century
- 1749 Histoire Naturelle
- emphasized life-history of
organisms not their
classification (if all are
independent creations,
what does ‘similarity’
represent, anyway?)
- Was aware of evolution as
a possibility, but…
"Not only the ass and the horse, but also man, the apes, the quadrupeds, and all the
animals might be regarded as constituting but a single family... If it were admitted
that the ass is of the family of the horse, and different from the horse only because
it has varied from the original form, one could equally well say that the ape is of
the family of man, that he is a degenerate man, that man and ape have a common
origin; that, in fact, all the families, among plants as well as animals, have come
from a single stock, and that all the animals are descended from a single animal,
from which have sprung in the course of time, as a result of progress or of
degeneration, all the other races of animals. For if it were once shown that we are
justified in establishing these families; if it were granted that among animals and
plants there has been (I do say several species) but even a single one, which has
been produced in the course of direct decent from another species; if, for example,
it were true that the ass is but a degeneration from the horse - then there would no
longer be any limit to the power of nature, and we should not be wrong in
supposing that, with sufficient time, she has been able from a single being to derive
all the other organized beings. But this is by no means a proper representation of
nature. We are assured by the authority of revelation that all animals have
participated equally in the grace of direct Creation and that the first pair of every
species issued forth fully formed from the hands of the Creator."
Georges Buffon - Histoire Naturelle (1766)
E. The Enlightenment (1700’s)
1. Cultural Climate
2. Natural Theology
a. Carl Linne (1707-1778) - "Linnaeus"
b. Georges Louis Leclerc, Comte de Buffon (17071788)
"it makes no difference which of the authors of the
second half of the 18th century one reads - their
discussions are, in the last analysis, merely
commentaries on Buffon’s work. Except for Darwin and
Aristotle, there has been no other student of organisms
who has had as far-reaching an influence." Ernst Mayr
- Growth of Biological Thought (1982)
E. The Enlightenment (1700’s)
1. Cultural Climate
2. Natural Theology
a. Carl Linne (1707-1778) - "Linnaeus"
b. Georges Louis Leclerc, Comte de Buffon (1707-1788)
c. William Paley (1743-1805)
Theologian who restated
Aquinas’s “proof of God”,
largely using the ‘argument of
design’ and the ‘watchmaker’
analogy in his book, Natural
Theology (1802).
2. Natural Theology
a. Carl Linne (1707-1778) - "Linnaeus"
b. Georges Louis Leclerc, Comte de Buffon (1707-1788)
c. William Paley (1743-1805)
d. James Hutton (1726-1797)
- Wrote "Theory of the Earth" in 1795; marks the
discovery of "deep time" in English science.
d. James Hutton (1726-1797)
- Wrote "Theory of the Earth" in 1795; marks the
discovery of "deep time" in English science.
- Based on two observations:
- 1. granite is an
igneous rock, it infuses
itself into other rocks
(shists) and can only do
that when molten.
d. James Hutton (1726-1797)
- Wrote "Theory of the Earth" in 1795; marks the
discovery of "deep time" in English science.
- Based on two observations:
2. the proper interpretation
of “unconformities” boundaries between cycles
of uplift and erosion
Siccar Point unconformity, observed by Hutton
Process:
1. Initial depositional cycle
Process:
2. uplift (time)
Process:
3. erosion (time)
Process:
4. second depositional cycle (time)
d. James Hutton (1726-1797)
- the crust is recycled - the earth has "no vestige of a
beginning - no prospect of an end"
d. James Hutton (1726-1797)
- the crust is recycled - the earth has "no vestige of a
beginning - no prospect of an end"
Hadrian’s Wall – 122 a.d.
White Cliffs of Dover
Hutton supported the contention that the natural processes of
erosion and deposition occur at constant rates over geologic
time… so it must take eons for sediments to accumulate to the
depth of the cliffs., and natural weathered rock outcrops must
be extremely old if rock walls 1500 years old show almost no
sign of weathering. = UNIFORMITARIANISM
E. The Enlightenment (1700’s)
1. Cultural Climate
2. Natural Theology
3. Conclusions of the Period
All were creationists, their discoveries had to be
reconciled with their Biblical worldview. But there were
conflicts and inconsistencies:
- fossils and extinct species vs. plenitude and universal
harmony/perfection
- age of earth - 4004 bc? - uh, not likely...
- The earth has changed...
- How can life remain adapted if earth changes?
...could life change, too?