The History of Evolutionary Thought -...

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The History of

Evolutionary

Thought

First the basics:

Our Dating System:

CE stands for

"Common Era"

AD Anno Domini

"In the Year of the

Lord"

BCE stands for

"Before the

Common Era“

BC “Before

Christ”

ca. Stands for

“Circa” literally

means "about"

1. So what year is it and

why is it this year?

2. When is Jesus’

birthday celebrated?

3. Why does the calendar

not start “at that

point” if AD means

AD?

Hint: It has to do with a

religious ritual.

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Dionysius Exiguus (“Dennis the

Short” but equally validly “Little” or

“Humble”)

Job: To fix the true date of Easter (525 CE)

Four problems with what he came up with.

1. The actual date of birth is wrong.

At best 4 years too late but could be as much as 6

years too late.

2. Wrong season.

Clearly occurs in the fall or spring.

3. Starts with year 1 and not year 0.

Europe had not yet imported zero.

4. The year of our lord starts 7 days after he is born.

According to his Jewish religion he should not be

circumcised until 7 days later.

Do we really base our

calendar on a

circumcision?

No, as fulfilling as that might

be, the calendar was set ca

700 years before Jesus' birth.

Janus is the Roman god of gates and

doorways or beginning and endings; is

depicted with two faces looking in opposite

directions.

Numa Pompilius, the

second king of Rome

ca 700 BC, added the

two months Januarius

"January" and

Februarius "February".

He made January the

start of the new year.

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So the start of the new year is in place.

What about the 25th of December?

Two events take place around the 25th

of December. First, at this point in

history, December 25th is the winter

solstices (longest night). Second, by

this point the (in the Mediterranean

area) winter planting is completed.

The end of planting = Party Time!

There are a whole bunch of parties that

last from Dec. 13th to Dec. 25th, each

celebrating a different God who has direct

influence over the harvest. "the best of

days" (this is the “holiday season”)

Saturnalia Celebration Dec. 17-23

celebrated Saturn, the God of agriculture

and harvest (among his other duties).

This is the big one.

Deus Sol Invictus

("the Unconquered Sun God")

The Sun party on the 25th of Dec.

As the Sun is the giver of life, its easy to

see why this date is important. Many rulers

seek to align themselves with this god, often

depicting images of themselves with light

radiating out from their heads. The

Christian religion will adopt this painting

style hundreds of years before they adopt

the 25th as Jesus’ birthday.

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It’s all a bit fishy

So Jesus' date of birth is put on the 25th

so he can be circumcised on the first

day of the new year.

James Ussher (1581-1656)

Anglican Archbishop.

Note: The period of time between Creation and

the Flood depends on the version of the Old

Testament used: Hebrew (1656 years), Samaritan

(1307 years), or the Ethiopic text (2262 years).

Ussher favored the Hebrew version.

Published a chronology that

purported to date Creation to the

night preceding October 23, 4004

BCE.

Young Earth?

(Back then next day started at night fall.)

All of this of course is just the

Christian dating system. Most

major religions have their own

dating system.

For simply practical reasons we needed a

fixed date to start counting from. It is no

surprise that the Europeans chose this

date.

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Now on to

Early Evolutionary Thought

Anaximander (ca. 611 - 546 BCE).

Wrote a long poem, On Nature,

which was based on his learning.

•The world had arisen from an

undifferentiated, indeterminate

substance, the apeiron.

•The Earth, which had coalesced

out of the apeiron, had been

covered in water at one stage.

•Then plants and animals arising

from mud.

•Humans were not present at the

earliest stages; they arose from

fish.

Was a disciple of Anaximander,

developed Anaximander's

theories further. He observed

fossil fishes and shells, and

concluded that the land where

they were found had been

underwater at some time. He

taught that the world formed from

the condensation of water and

"primordial mud;" he was the first

person known to have used

fossils as evidence for a theory of

the history of the Earth.

Xenophanes of Colophon (Died ca. 490 BCE)

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Empedocles of Acragas

(Greek 490 - 430 BCE)

Postulated that the universe

was composed of four basic

elements -- earth, air, fire

and water. These elements

were stirred by two

fundamental forces, which

Empedocles called Love

and Strife. ("Attraction" and

"repulsion".)

The constant interplay of these

elements, alternately attracting and

repelling each other, had formed the

universe. Claimed that the Earth had

given birth to living creatures, but

that the first creatures had been

disembodied organs. These organs finally joined into

whole organisms, through the force of Love, but

some of these organisms, being monstrous and unfit

for life, had died out.

Conceived "natural selection" as a past event,

not as an ongoing process.

Empedocles cont.

Socrates (Greek ca. 470 - 399 BCE)

The gods are

perfect. And thus

our past

understanding is

wrong as we find

faults with the Gods

and the world.

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Founder of the

Academy in Athens,

the first institution of

higher learning in

the western world.

Plato (Greek 427 - 348 BCE)

Continues the notion of perfect. Believes there

are perfect animals, plants humans and Gods on

another plain unknown to humans on earth.

Aristotle (Greek 384 - 322 BCE) Student

of Plato and teacher of Alexander the

Great.

He was not a scientist. He

was a natural philosopher. He

did not rely on experiments to

determine facts. He relied on

his mind and “logic” to

create/deduce the facts. But

even so, he basically single-

handedly founded the sciences

of Logic, Biology and

Psychology.

Great Chain of Being (the scala naturae)

a graded scale of perfection rising from

plants on up to man. (Why nothing more

primitive then plants?)

Aristotle cont

Soul of an organism:

1. Plants possessed a vegetative soul,

responsible for reproduction and growth;

2. Animals a vegetative and a sensitive soul,

responsible for mobility and sensation;

3. Humans a vegetative, a sensitive, and a

rational soul, capable of thought and

reflection.

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Aristotle (Greek 384 – 322 BC)

It is his view that will, in 500-800 years,

influence the church's understanding of

the world. Even today, churches hold to

his views.

God

Angels

[Pope -- for Catholics]

Kings/Queens

Archbishops

Dukes/Duchesses

Bishops

Marquises/Marchionesses

Earls/Countesses

Viscounts/Viscountesses

Barons/Baronesses

Abbots/Deacons

Knights/Local Officials

Ladies-in-Waiting

St. Thomas Aquinas (1225 – 1274 CE)

Priests/Monks

Squires

Pages

Messengers

Merchants/Shopkeepers

Tradesmen

Yeomen Farmers

Soldiers/Town Watch

Household Servants

Tennant Farmers

Shephards/Herders

Beggars

Actors

Thieves/Pirates

Gypsies

Animals

Birds

Worms

Plants

Rocks

The Great Chain

of Being

Didacus Valades’s

Rhetorica Christiana

(1579 CE)

http://www.home.duq.edu/%7Ebonin/thomasbibliography.html

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Writes a philosophical poem

De Rerum Natura ("On the

Nature of Things").

In this poem Lucretius

proposed, among other

things, an "evolutionary"

theory similar to that of

Empedocles.

Titus Lucretius Carus (Roman 99 - 55 BCE)

1.Natural selection led to the extinction of once-

living "monstrous" organisms.

2.Those organisms that survived either survived

because of their strength, speed, or cunning, or

because of their usefulness to people.

3.But did not believe in the production of new

species from previously existing ones. He

denied that land-dwelling animals could ever

have evolved from marine animals. Like

Empedocles, he taught that plants and animals

had been born from the Earth, and that the

formation of new species was finished.

Titus Lucretius Carus (Roman 99 - 55 BCE)

Apollo

The School of Athens 1510

http://www.nationmaster.com/encyclopedia/Image:Sanzio-01.jpg

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Minerva

Socrates

Plato and Aristotle

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Pythagoras

Anaximander

Michelangelo

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Euclid

Ptolemy

Begin the Dark ages

476 CE

With the fall of Rome

(467 CE) almost all

scientific thought is

suppressed in Europe. The “Dark Ages”

only happens in Europe. The rest of the

world moves on. Evolutionary thought

continues to develop in China, India, and

the Islamic States.

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The intellectual crossroads for the world

have shutdown. Non-western ideas will

remain cut off from Europe until the

Enlightenment.

Non-western ideas are not mentioned

much in the writings of Enlightenment

thinkers, but they were read and surely

influenced thinking.

Al-Jahizc (Arabic ca 781 - 868 CE)

Believed that the environment

forced animals to struggle to

survive. Very close to natural

selection!

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By the end of the 1600s the word evolution is

showing up in the English language. It stems

from the Latin word "evolutio", meaning "unroll

like a scroll.” It is used to indicate that there is a

sequence taking place. Particularly that the end

event is more or less set and “contained” in the

beginning.

This concept removed God from

direct action and opened the door

for further thoughts on evolution

without the need for a God.

It is at this point that we get loads

of different ideas that range from

“God did it all” to “God put the

laws in place such that the

system could continue to improve

and become more perfect”

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Over the last 1,000 years

almost all critical/learned

thought on evolution has been

halted.

At the start of the 1600’s things

begin to change. The

enlightenment will be in full

swing by the 1700’s. This

marks the renewal of free

thinking and of real science.

James Ussher (1581-1656) Anglican Archbishop.

Earth is young 6,000

Antony van Leeuwenhoek (Holland 1632

- 1723 CE)

He discovered bacteria,

free-living and parasitic

microscopic protists,

sperm cells, blood cells,

microscopic nematodes

and rotifers and more.

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Nicolas Steno (Danish 1638 -1686 CE)

Latinized Stenonis

Studied Anatomy and Geology.

In 1667 he studied the head of a

rare large shark and found that the

teeth matched “tongue stones.”

He is the first to demonstrate that

fossils are not just rocks, but that

they are/were real bones. This

allows for the earth to be much

older then previously thought. He

however does not make this claim.

Nicolas Steno cont

He is credited with three of the defining

principles of the science of stratigraphy:

The law of superposition

The principle of original horizontality

The principle of lateral continuity

That is, it’s not just “Rock.”

Sir Isaac Newton (English 1643 –1727 CE) Philosophiae Naturalis Principia Mathematica

(1687)

Even today he is one of the greatest scientists in

world history.

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Pierre-Louis Moreau de Maupertuis

(French 1698 –1759 CE)

He is not a biologist and does not

study biology per se. BUT he did

say some very interesting things

that nearly nailed natural

selection down.

Pierre-Louis Moreau de Maupertuis cont.

He wrote: "Chance" producing

"an innumerable multitude of

individuals" a small number of

which had "fitness" to satisfy

their needs, while "another

infinitely greater number...

perished... The species we see

today are but the smallest part

of what blind destiny has

produced..."

This can only be clearly seen with hindsight.

But still, Wow!

Carl Linnaeus, (Swedish 1707 - 1778)

Latinized as Carolus Linnaeus

He was a botanist, physician

and zoologist.

He is the “Farther of Taxonomy.”

Particularly the “Binomial

Nomenclature” system we still

use today.

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Carl Linnaeus cont.

He was primarily a botanist

Linneaus believed that he

was classifying God's

creation. That it was the

duty of a “religious naturalist”

to reveal God’s plan in the

same way a preacher does.

He set out to reveal the truth

about the “great chain of

being” so that all could see

God’s plan.

Carl Linnaeus cont.

To do this he believed that

taxonomy should be based

on “observable

characteristics.”

Keep in mind that The Great

Chain of Being had no

branches and thus, Linnaeus

would need to put all species

one link after the other.

Carl Linnaeus cont.

Obviously this is not possible so he

made 3 Great Chains: Plants, Animals

and Rocks.

Note: 52 years earlier Leeuwenhoek

discovered animacules and bacteria

with his microscope but they are left

out.

Also note that this is still basically the way all

organisms are approached in most high schools

and many colleges.

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Carl Linnaeus cont.

Linnaeus is setting out to

name every living thing on the

planet. His first complete list is

published in the Systema

Natvrae. The first edition

(1735) only had 11 pages.

Carl Linnaeus cont.

It became quickly apparent to

him that the old naming

system was not going to work.

And that many people had

different names for the same

object.

He introduce the major

classification system

(K,P,C,O,F,G and S) and the

binomial names. This system

was not completely in place

until the 10th edition (1758).

Carl Linnaeus cont.

• No evolution, but support of evolution

• What about hybridization in plants

• He also noted that “nature is a battle field”

and that death keeps all in balance.

• He never stops believing that it is all the

work of God and that a complete record of

all organisms would still show God’s plan.

Even so, he provided all the evidence needed to

see evolution and natural selection.

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James Hutton (Scott 1726 - 1797)

Geologist

First formulated uniformitarianism

He is considered the father of modern

geology.

His book was big and a

very hard read. Almost

lost and forgotten until

Lyell

Georges-Louis Leclerc, Comte de Buffon

(French 1707 – 1788)

Naturalist,

Mathematician and

Biologist

Wrote the Historie Naturelle,

a 44 volume encyclopedia!

Buffon cont.

Noted:

•Common ancestry between apes

and Man

•Environment acted directly on

organisms through "organic particles"

(very Lamarckian)

•Uniformitarianism!

•Earth 75,000 years old at least.

(calculated by the cooling of the earth)

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Thought that species must have both

"improved" and/or "degenerated" after

dispersing away from a center of creation.

Buffon

Erasmus Darwin (English 1731-1802)

He was one of the leading

intellectuals of eighteenth

century England.

He was a physician, a poet,

philosopher, botanist, and

naturalist.

Charles Darwin's grandfather

Jean-Baptiste Lamarck (1744-1829)

Note: Lamarck died in obscurity.

His ideas were not taken

seriously or considered much by

his contemporaries.

Coined the term “invertebrates”

Anticipated cell theory: “Nobody can have life if its

constituent parts are not cellular tissue or are not

formed by cellular tissue.”

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That acquired traits can be

inherited. Organisms are not

passively altered by their

environment. As environments

change animals use different

parts of their bodies and these

parts improve. This

“improvement” is passed on.

Disuse would result in

shrinkage and disappearance

of the organ.


This gradual change

in an organism would

drive evolution.

Spot on for the results

seen. What about

bacteria?


Even though Darwin tried

to refute the Lamarckian

mechanism of inheritance,

he later admitted that the

heritable effects of use

and disuse might be

important in evolution.

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Political economist. He is best

known for his famous views on

population growth.

Thomas Malthus (English 1766 –1834)

Wrote An Essay on the Principle of

Population. It makes the prediction that

all populations would expand to their

maximum food supply, leading to a

decrease in food per person.

Thomas Malthus (English 1766 –1834)

This is the concept of a carrying

capacity used in biology today. He

referred to food, but is can be applied

to any resource. Basically he says

that all populations expand until they

hit their carrying capacity. At that

point all individual must win at

competing for a resource or suffer

reduced fitness and/or death. It is

one of the corner stones of Natural

Selection.

Naturalist and zoologist. He

was key in establishing the

fields of comparative anatomy

and paleontology by comparing

living animals with fossils.

He was the world's leading

expert on the anatomy of

animals by far!

George Cuvier (French 1769 – 1832)

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George Cuvier cont.

Established extinction as fact using fossil evidence.

Cuvier is the ‘Newton’ of natural science and his

concepts holds great weight among the learned

(unlike Buffon who postulated the same).

George Cuvier cont.

His study of geology and paleontology lead him to

be a major proponent of catastrophism. Keep in

mind that the fossil record, at this point, is

extremely paltry.

But it was also his

goal to stop

evolution. He was

not the only or first

supporter of

catastrophism, but

he was the most

influential.

Sir Charles Lyell (Scott1797 – 1875)

Geologist, uniformitarianism.

Wrote Principles of Geology and

The Geological Evidence of the

Antiquity of Man.

He was an outstanding writer and a great

scientist. Rejected the notion that a divine

work was needed or should be used to

explain the world.

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Sir Charles Lyell (Scott1797 – 1875)

He basically nailed down Uniformitarianism as

a reality. (took time to be accepted.)

This is one of the books Darwin took with him

on the Beagle.

Jean Louis Rodolphe Agassiz (American 1807 -

1873)

Zoologist, glaciologist, and geologist,

One of America’s first great

scientists.

Founding member of the National

Academy of Science in the US

He was the first to scientifically propose

that the Earth had been subject to a

past ice age. This again made the earth

old. It also could explain some “flood

events” seen in the geologic process.

Agassiz cont

He is also the last major scientist of the time

to always reject evolution

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After the 1906 San

Francisco earthquake,

Stanford President David

Starr Jordan wrote,

"Somebody—Dr. Angell,

perhaps—remarked that

'Agassiz was great in the

abstract but not in the

concrete.'"

Sir Richard Owen (English 1804–1892)

Biologist, comparative anatomist and

palaeontologist.

First to note "homologies" in

comparative anatomy. He thought

they showed "archetypes" in the

Divine mind. All his work would end

up supporting Evolution. Though

Owen opposed any hint of

transmutation.

Charles Darwin (England 1809 –1882)

Wrote On the Origin of Species (1859)

established evolution by common descent.

Stated that it was

natural selection that

“drove" evolution.

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Robert McCormick was the surgeon

assigned to the ship and as normal

protocol has it, he is also the naturalist

providing no other is in that spot. He

remained one of the two naturalists on

the ship and the official one on record

for the navy until he was assigned to

another ship while the Beagle was in

port in Brazil.

Beagle 1831 to 1836 (5 years!)




During this trip Darwin reads Lyell’s

book. He is convinced of many

things, including the great age of the

earth, and that there is a “center” for

creation. A center for which all

species radiated out from. Lyell

does not believe in evolution.



Darwin is going to find the center of

creation. He suspects that he will be

able to determine this by observing all

the species he can during this trip.

He quickly see big holes in Lyell's

thinking about life and abandons the

idea of a center fairly quickly.

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Darwin's first sketch of

an evolutionary tree

from his First Notebook

on Transmutation of

Species (1837). This is

the year after he

returns. The ideas

surrounding natural

selection are in his

mind but not yet

formulated.


The big idea:

Just as farmers choose who breeds

and who does not (a process he called

Artificial Selection), forces in nature

result in differential survival of species.

Natural Selection:

1. All individuals tend to produce more

offspring then can survive.

A. Why would they do this?

B. What/who is killing them?

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Natural Selection:



2. Variation exists about every trait.

A. He is saying that no one is exactly

equal at all their traits.

Natural Selection:




3. Some of this variation is heritable.

A. He has no idea what genes are but comes

up with a hereditary unit he calls

gemmules. He understands that not all

traits are heritable. But some clearly

are. Good heritable traits can benefit

offspring.

Natural Selection:




3. Some of this variation is heritable.

4. Individuals with the more favorable

traits tend to acquire more

resources and thus tend to leave

behind more offspring.

A. That is, they are more fit.

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Natural Selection can be summed up as

“Survival of the fittest.”

Biological Fitness refers to the number of

copies of your genes that are produced.

This includes your offspring but also the

offspring of others. “inclusive fitness”

In 1858, Alfred Russel Wallace sent

Darwin an essay describing his own

version of natural selection for a review.

This forced Darwin to publish. Lyell

helped the two do this together in an

cordial manner.

His 1859 book On the Origin of

Species established evolution by

common descent as the only viable

description of evolution and that

natural selection is the mechanism

driving evolution.

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Is that it?

Any thing missing to the

concept of evolution and

natural selection?

The Modern Synthesis of

Genetics and Evolution

Remember that Darwin did not

know about genes

Gregor Mendel (Austrian 1822 - 1884)

“Father of modern genetics"

"Experiments on Plant

Hybridization" 1866

His work was rediscovered in 1900

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Major figures in the development of

the modern synthesis include:

R. A. Fisher

Theodosius Dobzhansky

J.B.S. Haldane

Sewall Wright

Julian Huxley

Ernst Mayr

Bernhard Rensch

George Gaylord Simpson

G. Ledyard Stebbins

The modern theory of the mechanism of

evolution differs from Darwin’s idea in three

important respects:

1. It recognizes several mechanisms of

evolution in addition to natural

selection. One of these, random

genetic drift, may be as important

as natural selection.



important respects:

2. It recognizes that characteristics are

inherited as discrete entities called

genes. Variation within a population

is due to the presence of multiple

alleles of a gene.

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important respects:

3. It postulates that speciation is (usually)

due to the gradual accumulation of

small genetic changes. This is

equivalent to saying that

macroevolution is simply a lot of

microevolution.

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