Biology
The Men of Biology
ARISTOTLE
• Father of Biology
• Natural philosopher,
identified some of the
known living
characteristics such
as reproduction.
The Men of Biology
Galen
- Studied the functions
of the kidneys and
spinal cord using the
Barbary ape.
The Men of Biology
Andres Vesalius
- was the founder of
modern anatomy.
- Broke traditions by
performing his own
dissection using
cadavers.
The Men of Biology
William Harvey
- Correctly described
how the blood is
pumped around the
body by the heart
The Men of Biology
Marie Francois Bichat
French anatomist and
physiologist whose
systematic study of
human tissues helped
found the science of
histology.
The Men of Biology
Henri Dutrochet
- Was credited for the
formation of cell
biology
- Discovered cells in
plants and actual
process of osmosis
Antony van Leeuwenhoek
• Dutch scientist, 1600s
• Used interest in developing magnifying lens to invent
microscope
• First to describe appearance of bacteria, red blood cells,
yeast, other microorganisms
Robert Hooke
• English physician, inventor
• Used early microscope to describe appearance of plants at
microscopic level
• Credited with creating the term cell
The Men of Biology
Robert Hooke
- Coined the term “Cell”
- First to observe a
plant cell (cork cell)
Robert Hooke
Robert Hooke1665- found cork
tissue contained
little
compartments he
called “Cells”.
They looked like
little rooms in a
monastery.
Hooke first to use the term cell
• Hooke had discovered
plant cells -- more
precisely, what Hooke
saw were the cell walls in
cork tissue.
• In fact, it was Hooke who
coined the term "cells":
the boxlike cells of cork
reminded him of the cells
of a monastery.
Robert Hooke:
• Discovered the cell – cork tissue using a newly invented
microscope; called them cells because they reminded him of
the cells of a monastery
• Published his book Micrographia in 1665
• Created the compound microscope and illumination system
– Used it to observe such organisms as insects, sponges,
bryozoans, foraminifera, bird feathers, etc.
• Observed fossils under the microscope and noted the
similarities between petrified wood and real wood and
created the theory that fossils are forms of animals
• Published two years after his death, Hooke’s Discourse of
Earthquakes in which he explained that fossils found in
inland regions are a result of times when that land was
under water
Robert Hooke
• Robert Hooke (1635-1703) was an
experimental scientist, mathematician,
architect, and astronomer. Secretary of the
Royal Society from 1677 to 1682, …
• Hooke was considered the “England’s Da
Vinci” because of his wide range of interests.
• His work Micrographia of 1665 contained his
microscopical investigations, which included
the first identification of biological cells.
• In his drafts of Book II, Newton had referred to
him as the most illustrious Hooke—
”Cl[arissimus] Hookius.”
• Hooke became involved in a dispute with Isaac
Newton over the priority of the discovery of the
inverse square law of gravitation.
Micrographia
Cork Seen Through Microscope
Hooke:
Objects the Hooke
observed under the microscope
Hooke’s compound
microscope
“1 The truth is, the science of Nature has been already too long made only a work
of the brain and the fancy: It is now high time that it should return to the plainness
and soundness of observations on material and obvious things. “ - Hooke
Microscope - 1662
•
In 1662 Robert Hooke was named Curator of Experiments
of the newly formed Royal Society of London.
•
Hooke devised the compound microscope and illumination
system and used it in his demonstrations at the Royal
Society's meetings.
•
He displayed plant cells! in a slice of cork (below).
The Men of Biology
Anton van Leeuwenhoek
- Helped in the
improvement of the
microscope
- First to describe muscles,
blood flow in capillaries,
spermatozoa, bacteria
and protozoans
Microscope -1668
•
The father of microscopy, Anton van Leeuwenhoek
of Holland, started as an apprentice in a dry goods store
where magnifying glasses were used to count the threads
in cloth.
•
He was the first to see and describe bacteria, yeast plants,
the teeming life in a drop of water, and the circulation of
blood corpuscles in capillaries.
" I have thought it my duty to put down
my discovery on paper, so that all
ingenious people might be informed
thereof' .
Anton Van Leeuwenhoek – 1600’s
• Dutch merchant
used magnifying
glass to view cloth
• Developed first
usable microscope.
• First person to view
small organisms in
pond water.
Leeuwenhoek first to view bacteria
• Leeuwenhoek took
samples of pond water
and view them
through his
microscope.
• Spirochetes
• Algae
• Protists
Antony van Leeuwenhoek:
(1632-1723)
• Inspired to take up microscopy by Hooke’s Micrographia
• Made over 500 microscopes, but only ten have survived to this day
• Leeuwenhoek was very skillful at grinding lenses and was able to use this
skill to magnify objects over 200 times
• Hired an illustrator to create drawing of what he saw under his microscopes
• In 1673, Leeuwenhoek began to write letters to the Royal Society of
London in which he described his findings under the microscopes – he
would correspond with this organization for the next fifty years; his letters
were collected and printed in the Philosophical Transactions of the Royal
Society
• Observed lake water and discovered numerous types of algae and other
small organisms
• Observed plaque from human teeth – the first known observation of living
bacteria
• Leeuwenhoek observed animal and plant tissues, mineral crystals, and
fossils
Leeuwenhoek:
Daphnia, small organism that
Leeuwenhoek found in lake water
Example of Leeuwenhoek’s microscopes
•
“. . . my work, which I've done for a long time, was not pursued in order to gain the
praise I now enjoy, but chiefly from a craving after knowledge, which I notice
resides in me more than in most other men. And therewithal, whenever I found out
anything remarkable, I have thought it my duty to put down my discovery on paper,
so that all ingenious people might be informed thereof. “ - Leeuwenhoek
Maria Merian: 1647 – 1717AD
• Dutch
• Studied plants and
animals
• Wrote a book of
drawings of insects in
various stages of
development
• Went to Surinam in
South America to
study insects
• Fell ill with malaria
and her health was
never strong again
• Her book on Surinam
insects was published
in 1705AD
• First time European
scientists were able to
see South American
insects
The Men of Biology
Carolus Linnaeus
- Laid the foundations
for the modern
scheme of Taxonomy
- Introduced the use of
binomial
nomenclature (genus
+ species)
Carl Linnaeus
• Linnaeus was born in 1707,
the son of a Lutheran
clergyman, at Rashult in
Sweden.
• He began to study medicine at
the University of Lund in 1727,
transferring to the university of
Uppsala the following year.
• Linnaeus headed an
expedition to Lapland in 1732,
travelling 4,600 miles and
crossing the Scandinavian
Peninsula by foot to the Arctic
Ocean.
• On the journey he discovered
a hundred botanical species.
• In 1734, he mounted another
expedition to central Sweden.
• He finished his medical degree
at the University of Hardewijk
in Holland in 1735, then going
to the University of Leiden for
further studies.
• That year, he published
Systema Naturae, his
classification of plants based
on their sexual parts
Carl Linnaeus
• His method of binomial
nomenclature using genus and
species names was further
expounded when he published
Fundmenta Botanica and
Classes plantarum.
• This system used the flower
and the number and
arrangements of its sexual
organs of stamens and pistils
to group plants into twenty-four
classes which in turn are
divided into orders, genera and
species.
• In his publications, Linnaeus
provided a concise, usable
survey of all the world's plants
and animals as then known,
about 7,700 species of plants
and 4,400 species of animals.
• These works helped to
establish and standardize the
consistent binomial
nomenclature for species
which he introduced on a world
scale for plants in 1753, and
for animals in 1758, and which
is used today.
Carl Linnaeus
•
•
•
His Species Plantarum 10th edition,
volume 1(1758), have accordingly
been accepted by international
agreement as the official starting
points for botanical and zoological
nomenclature.
Scientific names published before
then have no validity unless
adopted by Linnaeus or by later
authors.
This confers a high scientific
importance on the specimens
used by Linnaeus for their
preparation, many of which are in
his personal collections now
treasured by the Linnean
Society.
• Twenty-three of Linnaeus'
students themselves
became professors and
this spread his methods
widely, as did his
extensive
correspondence with
leading naturalists all
over Europe.
•
•
In the mid-1700s, the Swedish
biologist, Carolus Linnaeus,
shortened the long descriptive
terms for each organism to a
binomial system, using only the
genus (group) and species
(individual kind) name.
For example, the two oaks
shown below belong to the
genus Quercus (always
italicized or underlined) for
oaks, and phellos or rubra
(always in lower case italics or
underlined), for the willow or
red oak
The Men of Biology
Charles Darwin
- Pioneered the
evolutionary theory
- Proponent of the
theory of natural
selection
Darwin’s achievements
• Transformed biological science
– Both style and content
– Still the cornerstone of biology
– Now the cutting edge of psychology
• Transformed attitudes of humanity to our
place in the universe
His books (not just on evolution)
•
•
•
•
Beagle voyage
Coral reefs
Volcanic islands
Geology of South
America
• Barnacles
• Species
• Man
•
•
•
•
Emotions
Climbing plants
Domestication
Cross and self
fertilisation
• Orchids
• Worms
• Autobiography
Contribution to style of science
• Pre-Darwin, science was done in homage
to God
• Was primarily descriptive
• Deduction and theorising was disparaged
as “speculation”
• Darwin used detailed observation to
explore much larger questions - helped
change scientific methods
Charles Darwin: 1809 – 1882
AD
• British
• From his
observations, he
• Studied medicine and
developed the theory
to be a priest for the
of evolution.
Anglican Church
• Famous Evidence:
• Spent most of his
the tortoises of the
time collecting beetles
Galapagos Islands in
and butterflies
the
Pacific
• Went on a scientific
expedition on the
Beagle voyage
Darwin’s Expedition - 1831
• Hired as Naturalist on H.M.S. Beagle
• Sailed on Five Year Scientific
Expedition
– Down East Coast of South America
– Up Pacific Coast to Galapagos Islands
– Made Stops on Mainland and Islands
– Observed Variety of Life and Habitats
Joining the Beagle Voyage
• Not paid for 5 years on Beagle.
• Actually, he had to pay!
• Was lucky to get on
– replaced someone who was
shot in a duel
– his father opposed him going
• Mainly asked because of his class, to keep
Captain Fitzroy company
• It was the making of him
http://evolution.berkeley.edu/evolibrary/home.php
http://evolution.berkeley.edu/evolibrary/home.php
www.darwinday.org/englishL/life/be
www.darwinday.org/englishL/life/beagle.ht
Used by permission of Darwin Day
Celebration (at DarwinDay.org), 2006
I have called this principle, by which
each slight variation, if useful, is preserved,
by the term Natural Selection.
—Charles Darwin from "The Origin of Species"
http://evolution.berkeley.edu/evol
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
Full-scale replica of the Beagle
sailing off the coast of South
America.
General plan of
the Beagle based
on a drawing by a
shipmate during
the voyage of the
Beagle. Darwin
wrote that, “I have
just room to turn
around and that is
all.”
Voyage of HMS Beagle –1831-1836
A five year, circumnavigation of the globe, with the
principal objective to map the coast line of South
America.
Galapogos, 1835
• Portrayed as a “Eureka” experience.
• Actually, was hugely homesick
• Did not recognise significance until back in
England, 1837.
– Worked out theory much later.
– First inkling of natural selection in 1838.
• Turtles & finches were key evidence
– On boat home, ate turtles, dumped shells
– Thought finches different species; didn’t even
label them properly
Darwin in Australia
• Only visited three places in Australia
– Sydney, Jan 1836
– Hobart, Feb 1836
– Albany, Mar 1836
“On the whole I do not like New South Wales. It is no doubt an
admirable place to accumulate pounds and shillings; but heaven
forbid that I should live where every man is sure be somewhere
between a petty rogue and a bloodthirsty villain.” (Darwin to
Henslow)
“I have called this principle, by which each slight variation, if useful, is
preserved, by the term Natural Selection.”
- CHARLES DARWIN
• Darwin was the British
naturalist who became famous
for his theories of evolution
and natural selection.
• Like several scientists before
him, Darwin believed all the life
on earth evolved (developed
gradually) over millions of
years from a few common
ancestors.
• From 1831 to 1836 Darwin
served as naturalist aboard the
H.M.S. Beagle on a British
science expedition around the
world.
•
• In South America Darwin
found fossils of extinct animals
that were similar to modern
species.
• On the Galapagos Islands in
the Pacific Ocean he noticed
many variations among plants
and animals of the same
general type as those in South
America.
• The expedition visited places
around the world, and Darwin
studied plants and animals
everywhere he went, collecting
specimens for further study.
The Darwinian Thesis
Fact 1. Organisms have enormous reproductive potential
(Malthus)
Exponential growth
Time
Numbers
Fact 2. Populations are at equilibrium (Observation)
Logistic Growth
Time
Fact 3. Resources are limited (0bservation).
If organisms have enormous reproductive potential, yet do not
realize that potential owing to the fact that resources are limited
then there must be ….
Inference 1. … a struggle for existence.
Fact 4. Individuals are unique; there is individual variation.
(Observation)
Variation in shell color and
banding pattern within a single
species of Caribbean snail.
Darwin was impressed with the
fact that no two individuals are
exactly alike.
In contrast to the Platonic idea
that the eternal idealized type
was what mattered, Darwin
made individual variation an
integral part of his theory of
evolutionary change.
Inference 2. If there is a struggle for existence and there is
individual variation, then some individuals, owing to their
unique set of traits, will be better equipped to prevail in the
struggle for existence. In other words,
NATURE SELECTION will occur.
Trait in
Offspring
Fact 5. Some individual variation can be transmitted from one
generation to the next (personal observation, experience with
animal breeding).
Trait in Parents
Offspring resemble
their parents, but
not precisely. Thus,
differences among
individuals in the
parental generation
tend to be reflected
in individuals of the
descendent
generation.
Inference 3. Natural selection, operating over the immensity
of
Geologic time, will produce evolutionary change, or DESCENT
WITH MODIFICATION, to use Darwin’s expression.
IN SUMMARY: According to the Darwinian
Thesis, evolution proceeds by means of
agents of natural selection, operating
on heritable variation within populations,
to bring about ancestor-descendant
change.
That substantial changes can be induced
in plants and animals by artificial
selection is obvious. Consider the many
very different breeds of dogs, all
descended from a single ancestral
species (the wolf).
But can we find examples of natural
selection operating in nature?
•
•
•
•
•
•
Upon his return to London
Darwin conducted thorough
research of his notes and
specimens.
Out of this study grew several
related theories:
one, evolution did occur;
two, evolutionary change was
gradual, requiring thousands to
millions of years;
three, the primary mechanism
for evolution was a process
called natural selection;
and four, the millions of species
alive today arose from a single
original life form through a
branching process called
“speciation.”
• Darwin's theory of
evolutionary selection holds
that variation within species
occurs randomly and that
the survival or extinction of
each organism is determined
by that organism's ability to
adapt to its environment.
• He set these theories forth in
his book called, On the
Origin of Species by Means
of Natural Selection, or the
Preservation of Favoured
Races in the Struggle for
Life (1859) or “The Origin of
Species” for short.
1836 – 1839
Back in London, Darwin became a well-known
scientist/ naturalist, more of a geologist
than a biologist.
However, he began several notebooks on
biology and evolution, having become
convinced that species were not immutable
but changed and evolved.
In 1838 he read Thomas Malthus’ essay on
population and conceived the importance of
natural selection in evolution.
In 1839 he married his first cousin. Emma
Wedgwood, and they had 10 children born
between 1841 and 1854.
Summary of Origin of Species
• Proposed Evolution Resulting from Natural
Selection:
– Organisms Produce Many Offspring
– Competition for Food, Territory, Mates, etc.
– Those With Best Traits Survive
– Organisms Change Over Many Generations
• Time Frame: Millions of Years
Darwin’s Support for His
Theory
• Characteristics of Organisms Coincide
With Habitats
• Changes Produced by Breeding of
Organisms
• Geologic Ages Suggested by Charles
Lyell
• Similarities of Various Organisms
Limitations of Darwin’s
Theory
• Apparent Limits to Variation
• No Mechanism For Sufficiently New
Characteristics
• Transitional Forms Would Require
Special Environments
• Oversimplified View of Living Cells
• The Origin of Life Unexplained
• Limitations of Fossil Record
Limitations of the Fossil
Record
• Sudden Appearance of Complex Life
• Lack of Clear Transitional Forms
• Gives More Evidence For Species
Disappearance
Limitations of the Fossil
Record
• Sudden Appearance of Complex Life
• Lack of Clear Transitional Forms
• Gives More Evidence For Species
Disappearance
• Explanation of Strata Insufficient
Scientists’ Initial Reactions
to Darwin’s Work
• A Compilation of Assertions and
Hypotheses
• Unsupported by Scientific Testing
• Contains Assumptions that Cannot Be
Supported
• Violates the Principles of Cause and
Effect
• Illogical Conclusions
So Why Was It Eventually
Accepted?
• It Passed Rigorous Scientific Testing?
– No, His Hypotheses Are Not Testable
• Were Transitional Fossils Found?
– No Clearly Substantiated Links Found Yet
• A Mechanism to Produce New Traits
Discovered?
– Mutations Result in Lost Genetic Information
The Acceptance of Darwin’s
Theory of Evolution
• Natural Selection of Genetic Variations
is Observable
– Limited to Genes Already Present
– New Traits Produced Only By Mutations
– Overwhelming Odds Against Good
Mutations
Ultimately, Acceptance
Depended On One Factor:
Willingness to Accept a Naturalistic
Explanation
Ultimately, Acceptance
Depended On One Factor:
Willingness to Accept a Naturalistic
Explanation
• Darwin's work had a tremendous
impact on religious thought.
• Many people strongly opposed
the idea of evolution because it
conflicted with their religious
convictions.
• Darwin avoided talking about
the theological and sociological
aspects of his work, but other
writers used his theories to
support their own theories about
society.
• Darwin was a reserved,
thorough, hard working scholar
who concerned himself with the
feelings and emotions not only
of his family, but friends and
peers as well.
• It has been supposed that
Darwin renounced evolution
on his deathbed. Shortly
after his death, temperance
campaigner and evangelist
Lady Elizabeth Hope claimed
she visited Darwin at his
deathbed, and witnessed the
renunciation.
• Her story was printed in a
Boston newspaper and
subsequently spread. Lady
Hope's story was refuted by
Darwin's daughter Henrietta
who stated, “I was present at
his deathbed ... He never
recanted any of his scientific
views, either then or earlier.”
Charles Darwin
• Many people felt
Darwin’s ideas
clashed with the
Bible’s story of
Genesis
• Debate 1860 in
Oxford: the Bishop of
Oxford made a
speech attacking
Darwin
• Thomas Huxley
defended Darwin’s
ideas
• Unfortunately, people
missed the important
point of Darwin’s work
that he said young
animals inherit their
features from their
parents but he did not
have the evidence for
it
Religious conflict
• Samuel Wilberforce vs T.H.Huxley
Religion did accommodate
Darwin to some extent
Years
“Was
later
it from
Wilberforce
your
“If the
“For
question
once reality
is whether
and his
I
n
fell
mother’s
off his horse,
side orlanded
your on would
brain
rather
camehave
into a
contact, and
his father’s
head andside
wasthat
killed.
you
miserable
the result
ape for
wasafatal.”
were descended from an grandfather or a man of
not literalist
ape?”  Many religious leadersmeans
and influence who
 Science served religion,
so these
its findings
were
uses
gifts
to taken as
revelations of God’s plan
introduce ridicule into a
grave scientific discussion, I
n
unhesitatingly affirm my
preference for the ape!”
Buried in Westminster
Abbey
 The Times: “The Abbey needed Darwin more than Darwin
needed the Abbey.”
Darwin’s Theory of Evolution
Challenged Christian Ideas
•  The value of human beings:
made in God’s image  just another
animal
•  The purpose of human beings:
part of God’s Plan  accidental
without purpose
•  The eternal future of human
beings: eternal soul  this life
only
Varied Responses to Darwin
• The Science vs
Religion Battle oversimplifies responses
to Darwin
• Many Christians
welcomed and
supported Darwin’s
ideas from the start
Varied Responses to Darwin
1. Some Christians abandoned their
faith
a. Industrialisation and
Urbanisation had done much
already to cut people’s links
with the churches
b. Some became Humanists; some
supported Social Darwinism
2. Some Christians rejected evolution
– interpreted Genesis literally;
USA Bible Belt; Monkey Trials
3. Many Christians welcomed and
supported evolution from the start,
reinterpreting their Christian
message
Some Used Evolution as a Basis
for Living: Social Darwinism
• Some used Darwin's theory of
evolution and survival of the
fittest to guide human society
• Competition weeds out the
weak
• Charity, benefits or aid
wrongly allow weak to survive
Criticism:
• Misapplied DESCRIPTIVE biological theories
• Became a PRESCRIPTIVE guide to how we should behave
The Men of Biology
Gregor Mendel
- Father of Genetics
- First to discover the
ability of organisms
(pea plants) to pass
traits from parents to
offspring.
Major events in the history of
Molecular Biology 1800 - 1870
•
•
1865 Gregor Mendel discover
the basic rules of heredity of
garden pea.
– An individual organism has
two alternative heredity
units for a given trait
(dominant trait v.s.
recessive trait)
1869 Johann Friedrich Miescher
discovered DNA and named it
nuclein.
Mendel: The Father of Genetics
Johann Miescher
Gregor Mendel
• Gregor Mendel (1822 - 1884)
– Augustinian monk who taught natural science to high school students
– Studied the theories of heredity based on his experiments with pea
plants during seven years-> basic laws of inheritance
– His work was so brilliant and unprecedented at the time it appeared
that it took thirty-four years for the rest of the scientific community to
catch up to it. He set the stage for the discovery of genes and DNA.
– Mendel was the first person to trace the characteristics of successive
generations of a living thing
– From his studies, Mendel derived certain basic laws of heredity:
• hereditary factors do not combine, but are passed intact
• each member of the parental generation transmits only half of its
hereditary factors to each offspring (with certain factors "dominant" over
others)
• different offspring of the same parents receive different sets of hereditary
factors.
Gregor Mendel: 1822 – 1884
AD
• Austrian
• Monk
• Mendel realized that
the parent plants
were passing on their
features to their
seedlings in the form
of chemical
messages in the
pollen---genes
• Mendel’s pea plants for two
genes for growing
• GS—grow short
• GT---grow tall
• But only one set of genes is
switched on
• By counting the different
types of pea plant in each
crop, Mendel found that
plants carried the genes to
Grow Short and Grow Tall
always grew tall.
Mendel
• The only plants that
• Mendel grew 28,000
grew short were those
pea plants.
with the gene Grow
• He studied their
Short and Grow
height, flower color,
Short.
and five other
• This was a dramatic
characteristics.
discovery because it
• From his work, we get
showed how genes
a new branch of
work and some genes
biology called
override each other.
genetics.
How Molecular Biology came about?
• Microscopic biology began
in 1665
• Robert
Hooke
• Robert Hooke (1635-1703)
discovered organisms are
made up of cells
• Matthias Schleiden (18041881) and Theodor
Schwann (1810-1882)
further expanded the study
of cells in 1830s
• Matthias
Schleiden
• Theodor
Schwann
The Men of Biology
James Watson and
Francis Crick
- Discovered the double
helix structure of the
DNA