Charles Darwin studied medicine at Edinburgh University but was repulsed by surgery without anesthesia. He then studied to become a clergyman at Cambridge University. After Cambridge, he was recommended for a surveying trip on the HMS Beagle where he worked as a naturalist for 5 years sailing around the world. His observations and evidence collected on this voyage, especially from the Galapagos Islands, led to his theory of evolution by natural selection, which challenged the prevailing views that species were fixed and unchanging and had been created only a few thousand years ago.
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Darwin and natural_selection
2. studied medicine atstudied medicine at
Edinburgh UniversityEdinburgh University
(1825-1827) where the(1825-1827) where the
sight of blood andsight of blood and
surgery withoutsurgery without
anesthetics repulsed himanesthetics repulsed him
studied medicine atstudied medicine at
Edinburgh UniversityEdinburgh University
(1825-1827) where the(1825-1827) where the
sight of blood andsight of blood and
surgery withoutsurgery without
anesthetics repulsed himanesthetics repulsed him
studied to become astudied to become a
clergyman at Cambridgeclergyman at Cambridge
University (1827-1831)University (1827-1831)
studied to become astudied to become a
clergyman at Cambridgeclergyman at Cambridge
University (1827-1831)University (1827-1831)
born in Shrewsbury,born in Shrewsbury,
England, in 1809England, in 1809
born in Shrewsbury,born in Shrewsbury,
England, in 1809England, in 1809
3. After Cambridge, Charles was recommendedAfter Cambridge, Charles was recommended
for a surveying trip on thefor a surveying trip on the HMS BeagleHMS Beagle..
After Cambridge, Charles was recommendedAfter Cambridge, Charles was recommended
for a surveying trip on thefor a surveying trip on the HMS BeagleHMS Beagle..
Darwin sailed around the world on theDarwin sailed around the world on the
BeagleBeagle for 5 years, working as a naturalist.for 5 years, working as a naturalist.
Darwin sailed around the world on theDarwin sailed around the world on the
BeagleBeagle for 5 years, working as a naturalist.for 5 years, working as a naturalist.
4. Darwin made manyDarwin made many
observations andobservations and
collected evidencecollected evidence
on his voyage thaton his voyage that
led to his theoryled to his theory
about the way lifeabout the way life
changes.changes.
Darwin made manyDarwin made many
observations andobservations and
collected evidencecollected evidence
on his voyage thaton his voyage that
led to his theoryled to his theory
about the way lifeabout the way life
changes.changes.
5. At the time Darwin madeAt the time Darwin made
his trip, the majority ofhis trip, the majority of
people believed the Earthpeople believed the Earth
and all of its forms of lifeand all of its forms of life
had been created only ahad been created only a
few thousand years infew thousand years in
the past.the past.
At the time Darwin madeAt the time Darwin made
his trip, the majority ofhis trip, the majority of
people believed the Earthpeople believed the Earth
and all of its forms of lifeand all of its forms of life
had been created only ahad been created only a
few thousand years infew thousand years in
the past.the past.
6. People also believed inPeople also believed in fixity of speciesfixity of species;; in otherin other
words, species never changedwords, species never changed..
People also believed inPeople also believed in fixity of speciesfixity of species;; in otherin other
words, species never changedwords, species never changed..
After carefulAfter careful
observation andobservation and
study of newstudy of new
scientificscientific
discoveries,discoveries,
Darwin began toDarwin began to
think otherwise.think otherwise.
After carefulAfter careful
observation andobservation and
study of newstudy of new
scientificscientific
discoveries,discoveries,
Darwin began toDarwin began to
think otherwise.think otherwise.
People also believed that the Earth had notPeople also believed that the Earth had not
changed during those few thousand yearschanged during those few thousand years..
People also believed that the Earth had notPeople also believed that the Earth had not
changed during those few thousand yearschanged during those few thousand years..
The first dinosaur to be described
scientifically was Megalosaurus
by William Buckland in 1824.
7. Darwin was influencedDarwin was influenced
by geologist Jamesby geologist James
Hutton’s writings thatHutton’s writings that
described geologicdescribed geologic
forces he thought hadforces he thought had
changed and were stillchanged and were still
changing the earth.changing the earth.
Darwin was influencedDarwin was influenced
by geologist Jamesby geologist James
Hutton’s writings thatHutton’s writings that
described geologicdescribed geologic
forces he thought hadforces he thought had
changed and were stillchanged and were still
changing the earth.changing the earth.
Hutton proposed thatHutton proposed that
the Earth had to bethe Earth had to be
much more than a fewmuch more than a few
thousand years old.thousand years old.
Hutton proposed thatHutton proposed that
the Earth had to bethe Earth had to be
much more than a fewmuch more than a few
thousand years old.thousand years old.
The Father of GeologyThe Father of GeologyThe Father of GeologyThe Father of Geology
8. Darwin was alsoDarwin was also
influenced byinfluenced by
geologist Charlesgeologist Charles
Lyell who wroteLyell who wrote
Principia GeologicaPrincipia Geologica..
Darwin was alsoDarwin was also
influenced byinfluenced by
geologist Charlesgeologist Charles
Lyell who wroteLyell who wrote
Principia GeologicaPrincipia Geologica..
Lyell’s book proposedLyell’s book proposed
that tremendousthat tremendous
geologic processesgeologic processes
had shaped the Earthhad shaped the Earth
such as seen insuch as seen in
volcanoes active involcanoes active in
the present.the present.
Lyell’s book proposedLyell’s book proposed
that tremendousthat tremendous
geologic processesgeologic processes
had shaped the Earthhad shaped the Earth
such as seen insuch as seen in
volcanoes active involcanoes active in
the present.the present.
9. On the voyage,On the voyage,
Darwin noticedDarwin noticed
that everywhere hethat everywhere he
went, the animalswent, the animals
and plants differedand plants differed
vastly.vastly.
On the voyage,On the voyage,
Darwin noticedDarwin noticed
that everywhere hethat everywhere he
went, the animalswent, the animals
and plants differedand plants differed
vastly.vastly.
Patterns in the speciesPatterns in the species
suggested that thesuggested that the
species had changedspecies had changed
over time and had givenover time and had given
rise to new and differentrise to new and different
species.species.
Patterns in the speciesPatterns in the species
suggested that thesuggested that the
species had changedspecies had changed
over time and had givenover time and had given
rise to new and differentrise to new and different
species.species.
10. The GalapagosThe Galapagos
Islands lie 500 milesIslands lie 500 miles
west of Ecuador inwest of Ecuador in
the Pacific Ocean,the Pacific Ocean,
directly on thedirectly on the
equator.equator.
The GalapagosThe Galapagos
Islands lie 500 milesIslands lie 500 miles
west of Ecuador inwest of Ecuador in
the Pacific Ocean,the Pacific Ocean,
directly on thedirectly on the
equator.equator.
Many of Darwin’sMany of Darwin’s
conclusions wereconclusions were
based onbased on
observations ofobservations of
wildlife in thewildlife in the
Galapagos Islands.Galapagos Islands.
Many of Darwin’sMany of Darwin’s
conclusions wereconclusions were
based onbased on
observations ofobservations of
wildlife in thewildlife in the
Galapagos Islands.Galapagos Islands.
“Galapagos” means turtle.
11. What it must have been
like to be Darwin…
Darwin noticed onDarwin noticed on
these islands,these islands,
there were severalthere were several
types of finches.types of finches.
Darwin noticed onDarwin noticed on
these islands,these islands,
there were severalthere were several
types of finches.types of finches.
12. In particular,In particular,
Darwin observedDarwin observed
something oddsomething odd
about theabout the
finches: they allfinches: they all
looked like alooked like a
bird he had seenbird he had seen
on the Southon the South
AmericanAmerican
continent.continent.
In particular,In particular,
Darwin observedDarwin observed
something oddsomething odd
about theabout the
finches: they allfinches: they all
looked like alooked like a
bird he had seenbird he had seen
on the Southon the South
AmericanAmerican
continent.continent.
13. Darwin wondered if the birds and otherDarwin wondered if the birds and other
animals had beenanimals had been createdcreated to match theirto match their
environment, why didn’t these birds look likeenvironment, why didn’t these birds look like
the birds of the African continent, since thethe birds of the African continent, since the
environments of both the Galapagos andenvironments of both the Galapagos and
Africa were similar.Africa were similar.
Darwin wondered if the birds and otherDarwin wondered if the birds and other
animals had beenanimals had been createdcreated to match theirto match their
environment, why didn’t these birds look likeenvironment, why didn’t these birds look like
the birds of the African continent, since thethe birds of the African continent, since the
environments of both the Galapagos andenvironments of both the Galapagos and
Africa were similar.Africa were similar.
14. Darwin guessed thatDarwin guessed that
some of the birdssome of the birds
from South Americafrom South America
migrated to themigrated to the
Galapagos.Galapagos.
Darwin guessed thatDarwin guessed that
some of the birdssome of the birds
from South Americafrom South America
migrated to themigrated to the
Galapagos.Galapagos.
Once on the islands,Once on the islands,
the birds must havethe birds must have
changed over thechanged over the
years.years.
Once on the islands,Once on the islands,
the birds must havethe birds must have
changed over thechanged over the
years.years.
15. This would explain the numerous species ofThis would explain the numerous species of
birds present.birds present.
This would explain the numerous species ofThis would explain the numerous species of
birds present.birds present.
woodpecker
finch
cactus finch
large ground
finch
16. Darwin called this…Darwin called this…
oror
(change in species over time)(change in species over time)
Darwin concluded:Darwin concluded:
Each species has descended, with changes,Each species has descended, with changes,
from other species over time.from other species over time.
Darwin concluded:Darwin concluded:
Each species has descended, with changes,Each species has descended, with changes,
from other species over time.from other species over time.
Descent With ModificationsDescent With ModificationsDescent With ModificationsDescent With Modifications
17. Malthus was a BritishMalthus was a British
social scientist whosocial scientist who
proposed theories onproposed theories on
factors controllingfactors controlling
population growth:population growth:
Malthus was a BritishMalthus was a British
social scientist whosocial scientist who
proposed theories onproposed theories on
factors controllingfactors controlling
population growth:population growth:
People have more children than arePeople have more children than are
able to survive.able to survive.
People have more children than arePeople have more children than are
able to survive.able to survive.
There are built-in population checks:There are built-in population checks:
disease, famine, and war.disease, famine, and war.
There are built-in population checks:There are built-in population checks:
disease, famine, and war.disease, famine, and war.
Darwin based his theoryDarwin based his theory
on his own observationson his own observations
and the writings ofand the writings of
Thomas Malthus.Thomas Malthus.
Darwin based his theoryDarwin based his theory
on his own observationson his own observations
and the writings ofand the writings of
Thomas Malthus.Thomas Malthus.
18. Darwin extended theseDarwin extended these
principles to biology, whichprinciples to biology, which
helped him form his theory of…helped him form his theory of…
Darwin extended theseDarwin extended these
principles to biology, whichprinciples to biology, which
helped him form his theory of…helped him form his theory of…
……or Survival of the Fittest.or Survival of the Fittest.……or Survival of the Fittest.or Survival of the Fittest.
19. Natural selection was theNatural selection was the
mechanism by whichmechanism by which
Darwin proposed thatDarwin proposed that
evolution took place.evolution took place.
Natural selection was theNatural selection was the
mechanism by whichmechanism by which
Darwin proposed thatDarwin proposed that
evolution took place.evolution took place.
Darwin published hisDarwin published his
theory in the booktheory in the book
Darwin published hisDarwin published his
theory in the booktheory in the book
21. 1. All species have genetic variation.1. All species have genetic variation.1. All species have genetic variation.1. All species have genetic variation.
Every species is different,Every species is different,
even within itself.even within itself.
Every species is different,Every species is different,
even within itself.even within itself.
Variation is caused byVariation is caused by
mutations and meiosis.mutations and meiosis.
Variation is caused byVariation is caused by
mutations and meiosis.mutations and meiosis.
22. 2.2. Organisms produce more offspring thanOrganisms produce more offspring than
can survivecan survive. Many that survive do not. Many that survive do not
produce offspring.produce offspring.
2.2. Organisms produce more offspring thanOrganisms produce more offspring than
can survivecan survive. Many that survive do not. Many that survive do not
produce offspring.produce offspring.
The female green sea turtle lays a clutch of aboutThe female green sea turtle lays a clutch of about
110 eggs. She may lay several clutches.110 eggs. She may lay several clutches.
The female green sea turtle lays a clutch of aboutThe female green sea turtle lays a clutch of about
110 eggs. She may lay several clutches.110 eggs. She may lay several clutches.
It is likely thatIt is likely that less than 1%less than 1%
of the hatchlings will everof the hatchlings will ever
reach sexual maturity.reach sexual maturity.
It is likely thatIt is likely that less than 1%less than 1%
of the hatchlings will everof the hatchlings will ever
reach sexual maturity.reach sexual maturity.
23. 3.3. Since more organisms are produced thanSince more organisms are produced than
can survive, there iscan survive, there is competitioncompetition (struggle for(struggle for
existence)existence)..
3.3. Since more organisms are produced thanSince more organisms are produced than
can survive, there iscan survive, there is competitioncompetition (struggle for(struggle for
existence)existence)..
Competition exists WITHIN and AMONG species.Competition exists WITHIN and AMONG species.Competition exists WITHIN and AMONG species.Competition exists WITHIN and AMONG species.
foodfoodfoodfood
Within and Among Species for
And Within a Species for
waterwaterwaterwater
matesmatesmatesmates
sheltersheltersheltershelter spacespacespacespace
24. The constant struggle for survival is affected by
short-term natural disasters. (drought, fires,
floods, snowstorms, hurricanes, and tornadoes)
The constant struggle for survival is affected by
short-term natural disasters. (drought, fires,
floods, snowstorms, hurricanes, and tornadoes)
The constant struggle for survival
is also affected by long-term
changes in the environment. (ice
ages, biome shifts, etc)
The constant struggle for survival
is also affected by long-term
changes in the environment. (ice
ages, biome shifts, etc)
25. 4.4. Survival of the fittestSurvival of the fittest Some organismsSome organisms
are more suited to their environment as aare more suited to their environment as a
result of variations in the species.result of variations in the species.
4.4. Survival of the fittestSurvival of the fittest Some organismsSome organisms
are more suited to their environment as aare more suited to their environment as a
result of variations in the species.result of variations in the species.
Fitness: the ability of an individual tothe ability of an individual to
survive and reproduce in its specificsurvive and reproduce in its specific
environment. Fitness is a result of adaptations.environment. Fitness is a result of adaptations.
Fitness: the ability of an individual tothe ability of an individual to
survive and reproduce in its specificsurvive and reproduce in its specific
environment. Fitness is a result of adaptations.environment. Fitness is a result of adaptations.
He who spreads the most genes wins!He who spreads the most genes wins!He who spreads the most genes wins!He who spreads the most genes wins!
1st
Individuals that are fit to their environmentIndividuals that are fit to their environment
survive and leave more offspring than thosesurvive and leave more offspring than those
who aren’t.who aren’t.
Individuals that are fit to their environmentIndividuals that are fit to their environment
survive and leave more offspring than thosesurvive and leave more offspring than those
who aren’t.who aren’t.
26. 5.5. Descent with modificationDescent with modification:: Living speciesLiving species
today are descended with modifications fromtoday are descended with modifications from
common ancestral species that lived in thecommon ancestral species that lived in the
past.past.
5.5. Descent with modificationDescent with modification:: Living speciesLiving species
today are descended with modifications fromtoday are descended with modifications from
common ancestral species that lived in thecommon ancestral species that lived in the
past.past.
Over time, genes for lessOver time, genes for less
favored characteristics will befavored characteristics will be
eliminated from the gene pool.eliminated from the gene pool.
Over time, genes for lessOver time, genes for less
favored characteristics will befavored characteristics will be
eliminated from the gene pool.eliminated from the gene pool.
Example: giraffes and theirExample: giraffes and their
increasingly longer necks.increasingly longer necks.
Example: giraffes and theirExample: giraffes and their
increasingly longer necks.increasingly longer necks.
Characteristics of fit individualsCharacteristics of fit individuals
increase in a population over time.increase in a population over time.
Characteristics of fit individualsCharacteristics of fit individuals
increase in a population over time.increase in a population over time.
27. Natural Selection: Survival of the FittestNatural Selection: Survival of the FittestNatural Selection: Survival of the FittestNatural Selection: Survival of the Fittest
the variation exists first.the variation exists first.the variation exists first.the variation exists first.
AnAn adaptationadaptation is any inherited characteristicis any inherited characteristic
(a genetic variation) that can increase an(a genetic variation) that can increase an
organism’s chance of survival.organism’s chance of survival.
AnAn adaptationadaptation is any inherited characteristicis any inherited characteristic
(a genetic variation) that can increase an(a genetic variation) that can increase an
organism’s chance of survival.organism’s chance of survival.
the environment changes.the environment changes.the environment changes.the environment changes.
a variation may give an advantagea variation may give an advantage
to survive environmental change.to survive environmental change.
a variation may give an advantagea variation may give an advantage
to survive environmental change.to survive environmental change.
An organism does not changeAn organism does not change
because of need or desire tobecause of need or desire to
survive. The organism eithersurvive. The organism either
already has the variation thatalready has the variation that
enables it to survive or it dies.enables it to survive or it dies.
An organism does not changeAn organism does not change
because of need or desire tobecause of need or desire to
survive. The organism eithersurvive. The organism either
already has the variation thatalready has the variation that
enables it to survive or it dies.enables it to survive or it dies.
28. As the environment changes, organisms mustAs the environment changes, organisms must
have variations that allow them to survivehave variations that allow them to survive
(adapt) to those changes or die(adapt) to those changes or die
As the environment changes, organisms mustAs the environment changes, organisms must
have variations that allow them to survivehave variations that allow them to survive
(adapt) to those changes or die(adapt) to those changes or die
If an entire population ofIf an entire population of
a species cannot adapt,a species cannot adapt,
that species becomesthat species becomes
extinct.extinct.
If an entire population ofIf an entire population of
a species cannot adapt,a species cannot adapt,
that species becomesthat species becomes
extinct.extinct.
29. There have been at least 5 MASS extinctionsThere have been at least 5 MASS extinctions
during Earth’s history where a huge % of theduring Earth’s history where a huge % of the
living species were destroyedliving species were destroyed
There have been at least 5 MASS extinctionsThere have been at least 5 MASS extinctions
during Earth’s history where a huge % of theduring Earth’s history where a huge % of the
living species were destroyedliving species were destroyed
At least one ofAt least one of
these has beenthese has been
attributed toattributed to
meteor impact andmeteor impact and
it’sit’s
consequences.consequences.
At least one ofAt least one of
these has beenthese has been
attributed toattributed to
meteor impact andmeteor impact and
it’sit’s
consequences.consequences.
30. It is estimated thatIt is estimated that 1/5 or more of the world’s1/5 or more of the world’s
speciesspecies will become extinctwill become extinct if the rainforestsif the rainforests
are destroyed.are destroyed.
It is estimated thatIt is estimated that 1/5 or more of the world’s1/5 or more of the world’s
speciesspecies will become extinctwill become extinct if the rainforestsif the rainforests
are destroyed.are destroyed.
Many scientistsMany scientists
say that thesay that the
earth isearth is
currentlycurrently
experiencing aexperiencing a
mass extinctionmass extinction
crisis.crisis.
Many scientistsMany scientists
say that thesay that the
earth isearth is
currentlycurrently
experiencing aexperiencing a
mass extinctionmass extinction
crisis.crisis.
31. • What do you think biodiversity is?
• ANSWER: the variation of life forms in an
ecosystem
• How do you think biodiversity would be
affected by mass extinction?
• ANSWER: biodiversity would decrease
significantly
Life Variation
32. If we are in a period of mass extinction . . .If we are in a period of mass extinction . . .
What animals will your grandchildren be ableWhat animals will your grandchildren be able
to see in the wild?to see in the wild?
If we are in a period of mass extinction . . .If we are in a period of mass extinction . . .
What animals will your grandchildren be ableWhat animals will your grandchildren be able
to see in the wild?to see in the wild?
Visit the World
Wildlife Fund website
for more information
on endangered
species.
Photos by MartinHarvey
World Wildlife
Fund International
33. Davis, Donald E. “Meteor Impact”. (Also public domain from NASA.)
No date. Online image with permission. Dinosaurs and Their
Extinction. June 10, 2004.
<http://www.donaldedavis.com/PARTS/DDDINOS.html>
Davis, Donald E. “Meteor Impact”. (Also public domain from NASA.)
No date. Online image with permission. Dinosaurs and Their
Extinction. June 10, 2004.
<http://www.donaldedavis.com/PARTS/DDDINOS.html>
“Snow Alaska”. No date. Online image. Public Domain. Mineral
Management Service. June 10, 2004. GeekPhilospher.com
<http://geekphilosopher.com/bkg/snowAlaskaIce.htm>
“Snow Alaska”. No date. Online image. Public Domain. Mineral
Management Service. June 10, 2004. GeekPhilospher.com
<http://geekphilosopher.com/bkg/snowAlaskaIce.htm>
“Clearcut in Cameroon Rainforest”. No date. Online image. June 11,
2004. Earth Crash Earth Spirit.
<http://www.eces.org/archive/gallery/forestsgfx/forests39.shtml>
“Clearcut in Cameroon Rainforest”. No date. Online image. June 11,
2004. Earth Crash Earth Spirit.
<http://www.eces.org/archive/gallery/forestsgfx/forests39.shtml>
Harvey, Martin. No date. Online image. World Wildlife Fund. June 11,
2004. <http://www.panda.org>
Harvey, Martin. No date. Online image. World Wildlife Fund. June 11,
2004. <http://www.panda.org>
“Allosaur”. No date. Online image. Public Domain. Dinosaur National
Monument. National Park Service. June 10, 2004.
http://www.nps.gov/dino/index.htm
“Allosaur”. No date. Online image. Public Domain. Dinosaur National
Monument. National Park Service. June 10, 2004.
http://www.nps.gov/dino/index.htm
Editor's Notes
Photo from original manuscript of William Buckland
Mineral Management Service photo courtesy of GeekPhilospher.com
http://geekphilosopher.com/bkg/snowAlaskaIce.htm
Photo – National Park Service – Dinosaur National Monument
For an article on mass extinctions and the % of loss, see
http://www.space.com/scienceastronomy/planetearth/extinction_sidebar_000907.html
Photo courtesy of Donald E. Davis, also in public domain from NASA.
Current mass extinction crisis will wipe out 24% of the world&apos;s mammals within 30 years (including tigers, rhinos, Asian elephants, cheetahs and mountain gorillas); 12% of birds and over 5,000 plants are also expected to become extinct by 2032 due to loss of habitat, the introduction of non-native species, and other human impacts. (UNEP – United Nations Environment Program)
Photos by Martin Harvey from the World Wildlife Fund – www.panda.org