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1
EvolutionEvolutionDiversity of LifeDiversity of Life
2
““Nothing in Nothing in biology biology
makes sense makes sense EXCEPT in the EXCEPT in the
light of light of evolution.” evolution.” Theodosius Theodosius DobzhanskyDobzhansky
Evolution
Charles Darwin in later yearsCharles Darwin in later years
3
History of History of Evolutionary Evolutionary
ThoughtThought
4
Early Ideas On Earth’s Early Ideas On Earth’s OrganismsOrganisms
AristotleAristotle believed believed species were species were fixed creationsfixed creations arranged by arranged by their their complexitycomplexity
Idea Idea lasted lasted 20002000 years years
5
Early Ideas On Earth’s Early Ideas On Earth’s OrganismsOrganisms
LinnaeusLinnaeus – 1 – 1stst to to group similar group similar organisms and organisms and assign them assign them LatinLatin names names
Two word name Two word name (Genus species)(Genus species)
Known as Known as Binomial Binomial nomenclaturenomenclature
6
:
Contributor’s to Darwin’s Contributor’s to Darwin’s thinking included:thinking included:
• Charles Lyell –Charles Lyell –uniformintarianism uniformintarianism (geologic processes still (geologic processes still changing Earth)changing Earth)
• Georges Cuvier – Georges Cuvier – species species extinction (Catastrophism)extinction (Catastrophism)
• Thomas Malthus – Thomas Malthus – struggle struggle for existence (resources)for existence (resources)
7
:
Contributor’s to Darwin’s Contributor’s to Darwin’s thinking included:thinking included:
• James Hutton - James Hutton - GradualismGradualism• Jean Baptiste Lamarck – Jean Baptiste Lamarck –
Inheritance of acquired Inheritance of acquired CharacteristicsCharacteristics andand Law of Law of Use and DisuseUse and Disuse
• Alfred Russel Wallace – Alfred Russel Wallace – organisms evolved from organisms evolved from common ancestorscommon ancestors
8
Evolutionary TimelineEvolutionary Timeline
9
CatastrophismCatastrophism
Idea proposed by Idea proposed by George George CuvierCuvier
Studied fossil in Studied fossil in sedimentary sedimentary rock stratarock strata of Paris of Paris
Found Found some species some species completely disappearedcompletely disappeared in in more recent layersmore recent layers
10
CatastrophismCatastrophism
Stated that Stated that species species disappear due disappear due to a to a catastrophic catastrophic event of the event of the earth’s crustearth’s crust (volcano, (volcano, earthquake…)earthquake…)
11
Hutton’s Theory of Hutton’s Theory of Geological ChangeGeological Change
James HuttonJames Hutton, 1795, Scottish , 1795, Scottish geologistgeologistStudied Studied invertebrate fossils in invertebrate fossils in Paris MuseumParis MuseumDescribed The Described The Geological Geological ForcesForces That Have Changed That Have Changed LifeLife on Earthon Earth Over Millions of Years Over Millions of Years (erosion, earthquakes, (erosion, earthquakes, volcanoes…)volcanoes…)
12
Hutton’s Theory of Hutton’s Theory of Geological ChangeGeological Change
Changes in Changes in Earth’s crust Earth’s crust due to due to slow slow continuous continuous processesprocesses
Idea Known as Idea Known as
GradualismGradualism
13
Charles LyellCharles Lyell Proposed theory of Proposed theory of
UniformintarianismUniformintarianism Geological Geological
processes at processes at uniform ratesuniform rates building & wearing building & wearing down Earth’s crustdown Earth’s crust
Proposed that the Proposed that the Earth was millions Earth was millions of yearsof years instead of instead of a few thousand a few thousand years oldyears old
14
Principles of GeologyPrinciples of Geology
Published by Published by LyellLyell Just Before Just Before The The BeagleBeagle Set Sail & read by Set Sail & read by DarwinDarwin
Explained Explained Geological Processes Geological Processes That Shaped The EarthThat Shaped The Earth
Helped Darwin Understand Helped Darwin Understand Sea Sea Shells In The Andes Mountains Shells In The Andes Mountains At 12,000+ FeetAt 12,000+ Feet– Expanded Earth’s AgeExpanded Earth’s Age
15
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Jean-Baptiste LamarckJean-Baptiste Lamarck, , 18091809
One Of First Scientists One Of First Scientists To Understand That To Understand That Change Occurs Over Change Occurs Over TimeTime
Stated that Changes Are Stated that Changes Are Adaptations To Adaptations To Environment Environment acquired in acquired in an organism’s lifetimean organism’s lifetime
Said acquired changes Said acquired changes were passed to offspringwere passed to offspring
16
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Idea called Idea called Law of Use Law of Use and Disuseand Disuse
If a body part If a body part were used, it were used, it got strongergot stronger
If body part If body part NOT used, it NOT used, it deteriorateddeteriorated
17
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Inheritance of Acquired Inheritance of Acquired CharacteristicsCharacteristics
Proposed That By Selective Use Proposed That By Selective Use Or Disuse Of Organs, Organisms Or Disuse Of Organs, Organisms Acquired Or Lost Certain Traits Acquired Or Lost Certain Traits During Their LifetimeDuring Their Lifetime
These These Traits Could Then Be Traits Could Then Be Passed On To Their OffspringPassed On To Their Offspring
Over Time This Led To Over Time This Led To New New SpeciesSpecies
18
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Use & Disuse - Use & Disuse - Organisms Could Organisms Could Change The Size Or Change The Size Or Shape Of Organs By Shape Of Organs By Using Them Or Not Using Them Or Not Using ThemUsing Them
Blacksmiths & Their Blacksmiths & Their SonsSons (muscular arms) (muscular arms)
Giraffe’s Necks Giraffe’s Necks LongerLonger from from stretching)stretching)
19
20
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Inheritance Of Acquired TraitsInheritance Of Acquired Traits– Traits Acquired During Ones Traits Acquired During Ones
Lifetime Would Be Passed To Lifetime Would Be Passed To OffspringOffspring
Clipped ears of dogs could be passed to offspring!
21
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Tendency Toward PerfectionTendency Toward Perfection Organisms Are Continually Organisms Are Continually
Changing and Acquiring Changing and Acquiring Features That Help Them Live Features That Help Them Live More Successfully In Their More Successfully In Their EnvironmentEnvironment
Example:Example: Bird Ancestors Bird Ancestors Desired To Fly So They Tried Desired To Fly So They Tried Until Wings DevelopedUntil Wings Developed
22
Lamarck’s MistakesLamarck’s Mistakes
Lamarck Did NOT Know how Lamarck Did NOT Know how traits were traits were inherited (Traits inherited (Traits are passed through genes)are passed through genes)
Genes Are NOT Changed By Genes Are NOT Changed By Activities In LifeActivities In Life
Change Through Change Through Mutation Mutation Occurs Before An Organism Occurs Before An Organism Is BornIs Born
He believed that species He believed that species disappear due to catastophic disappear due to catastophic
events (catastophism)events (catastophism)
23
Lyell
Lamark
Cuvier
Malth
us
Walla
ce
Hutton
18%
14%
23%
0%
5%
41%1.1. LyellLyell
2.2. LamarkLamark
3.3. CuvierCuvier
4.4. MalthusMalthus
5.5. WallaceWallace
6.6. HuttonHutton
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
The geologist who believed Earth was The geologist who believed Earth was much older than thought at the time, much older than thought at the time,
and it slowly changed over timeand it slowly changed over time
24
Lyell
Lamark
Cuvier
Malth
us
Walla
ce
Hutton
36%
11%
36%
11%
4%4%
1.1. LyellLyell
2.2. LamarkLamark
3.3. CuvierCuvier
4.4. MalthusMalthus
5.5. WallaceWallace
6.6. HuttonHutton
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
By studying fossils he came up By studying fossils he came up with the idea of gradualismwith the idea of gradualism
25
Lyell
Lamark
Cuvier
Malth
us
Walla
ce
Hutton
0%
23%
68%
0%5%5%
1.1. LyellLyell
2.2. LamarkLamark
3.3. CuvierCuvier
4.4. MalthusMalthus
5.5. WallaceWallace
6.6. HuttonHutton
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
He believed in “use and He believed in “use and disuse” which explained that disuse” which explained that
giraffes had long necks due to giraffes had long necks due to stretchingstretching
26
Lyell
Lamark
Cuvier
Malth
us
Walla
ce
Hutton
0%
89%
0%0%4%
7%
1.1. LyellLyell
2.2. LamarkLamark
3.3. CuvierCuvier
4.4. MalthusMalthus
5.5. WallaceWallace
6.6. HuttonHutton
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
27
Charles Darwin Charles Darwin the Naturalistthe Naturalist
28
Voyage of the BeagleVoyage of the Beagle
Charles DarwinCharles Darwin Born Feb. 12, 1809Born Feb. 12, 1809 Joined Crew of HMS Joined Crew of HMS
Beagle, 1831Beagle, 1831 NaturalistNaturalist 5 Year Voyage 5 Year Voyage
around worldaround world Avid Collector of Avid Collector of
Flora & FaunaFlora & Fauna Astounded By Astounded By
Variety of LifeVariety of Life
29A reconstruction of the HMS Beagle sailing off Patagonia.A reconstruction of the HMS Beagle sailing off Patagonia.
Darwin’s Voyage of Darwin’s Voyage of DiscoveryDiscovery
30
Darwin Left England in Darwin Left England in 18311831
Darwin returned 5 years later in 1836Darwin returned 5 years later in 1836
31
HMS Beagle’s VoyageHMS Beagle’s Voyage
32
The Galapagos The Galapagos IslandsIslands
Small Group of Islands 1000 Small Group of Islands 1000 km West of South Americakm West of South America
Very Different ClimatesVery Different Climates Animals On Islands UniqueAnimals On Islands Unique
»TortoisesTortoises»IguanasIguanas»FinchesFinches
33
The Galapagos The Galapagos IslandsIslands
Volcanic islandsVolcanic islands off off the coast of South the coast of South AmericaAmerica
Island species Island species varied from varied from mainland species & mainland species & from island-to-from island-to-island speciesisland species
Each island had Each island had long or short neck long or short neck tortoisestortoises
34
Marine Iguana
Lonesome George
Giant Tortoise
Frigate Bird
Blue-footed Boobie
38
The Flightless Cormorant
39
The Galapagos The Galapagos IslandsIslands
Finches on the islands Finches on the islands resembled a resembled a mainland finchmainland finch
More types of finches appeared on More types of finches appeared on the islandsthe islands where the available where the available food was different (seeds, nuts, food was different (seeds, nuts, berries, insects…)berries, insects…)
Finches had Finches had different types of different types of beaksbeaks adapted to their adapted to their type of food type of food gatheringgathering
40
41
Darwin’s Darwin’s Observations & Observations &
ConclusionsConclusionsThe Struggle for The Struggle for
ExistenceExistence
42
Voyage of the BeagleVoyage of the Beagle
During His Travels, Darwin During His Travels, Darwin Made Numerous Made Numerous Observations And Observations And Collected Evidence That Collected Evidence That Led Him To Propose A Led Him To Propose A Revolutionary HypothesisRevolutionary Hypothesis About The Way Life About The Way Life Changes Over TimeChanges Over Time
43
Darwin’s ObservationsDarwin’s Observations Patterns of Patterns of
Diversity were Diversity were shownshown
Unique Unique Adaptations in Adaptations in organismsorganisms
Species Not Evenly Species Not Evenly DistributedDistributed
» Australia, Australia, Kangaroos, but Kangaroos, but No RabbitsNo Rabbits
» S. America, S. America, LlamasLlamas
44
Darwin’s ObservationsDarwin’s Observations
Both Living Both Living Organisms & Organisms & Fossils collectedFossils collected
Fossils Fossils included:included:»TrilobitesTrilobites»Giant Ground Giant Ground Sloth of South Sloth of South AmericaAmerica
This species NO longer existed.This species NO longer existed. What had happened to them?What had happened to them?
45
Evidence for Evolution – The Fossil RecordEvidence for Evolution – The Fossil Record
46
DefinitioDefinitionn
• Evolution is the slow , gradual change in a population of organisms over time
47
Darwin’s ObservationsDarwin’s Observations
Left unchecked, the number of organisms of each species will increase exponentially, generation to generation
In nature, populations tend to remain stable in size
Environmental resources are limited
48
Darwin’s ConclusionDarwin’s Conclusion• Production of more
individuals than can be supported by the environment leads to a struggle for existence among individuals
• Only a fraction of offspring survive each generation
• Survival of the Fittest
49
Darwin’s ObservationsDarwin’s Observations• Individuals of a
population vary extensively in their characteristics with no two individuals being exactly alike.
• Much of this variation between individuals is inheritable.
50
Darwin’s ConclusionDarwin’s Conclusion
• Individuals who inherit characteristics most fit for their environment are likely to leave more offspring than less fit individuals
• Called Natural Selection
51
•The The unequal ability of individuals unequal ability of individuals to survive and reproduceto survive and reproduce leads to leads to a gradual change in a population, a gradual change in a population, with favorable characteristics with favorable characteristics accumulating over generations accumulating over generations (natural selection)(natural selection)•New species evolveNew species evolve
Darwin’Darwin’s s
Theory Theory of of
EvolutioEvolutionn
Darwin observed, in nature Darwin observed, in nature populations tend to ____ in populations tend to ____ in
size.size.
52
Gro
w
Shrin
k
Remain stable
Vary
0% 0%0%0%
20
1.1. GrowGrow
2.2. ShrinkShrink
3.3. Remain stableRemain stable
4.4. VaryVary
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
What limits population What limits population growth?growth?
53
Space
Food
Temperatu
re
All of t
he abo...
None of t
he ab...
0% 0% 0%0%0%
1.1. SpaceSpace
2.2. FoodFood
3.3. TemperatureTemperature
4.4. All of the aboveAll of the above
5.5. None of the None of the aboveabove
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
______ states that individuals who inherit ______ states that individuals who inherit characteristics most fit for their characteristics most fit for their
environment are likely to have more environment are likely to have more offspring.offspring.
54
0% 0%0%0%
1.1. Evolutionary Evolutionary theorytheory
2.2. Directional Directional selectionselection
3.3. Natural Natural selectionselection
4.4. Stabilizing Stabilizing selectionselection
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
What is the driving force What is the driving force behind evolution?behind evolution?
55
Time
Energy
The Sun
Natu
ral S
elect...
0% 0%0%0%
1.1. TimeTime
2.2. EnergyEnergy
3.3. The SunThe Sun
4.4. Natural Natural SelectionSelection
201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
56
Ideas That Shaped Ideas That Shaped Darwin’s ThinkingDarwin’s Thinking
Thomas MalthusThomas Malthus
57
Population GrowthPopulation Growth
Thomas MalthusThomas Malthus, 1798, 1798 EconomistEconomist Observed Observed Babies Being Born Babies Being Born
Faster Than People Were Faster Than People Were DyingDying
Population size Population size limited by limited by resourcesresources such as the Food such as the Food SupplySupply
58
The Struggle for The Struggle for ExistenceExistence
Malthus’ Influence:– High Birth Rates & Limited High Birth Rates & Limited
Resources Would Force Life & Resources Would Force Life & Death CompetitionDeath Competition
Each Species Struggles For:– FoodFood– Living SpaceLiving Space– MatesMates
59
Population GrowthPopulation Growth
MalthusMalthus Reasoned Reasoned That If The Human That If The Human Population Population Continued To Grow Continued To Grow UncheckedUnchecked, Sooner , Sooner or Later There Would or Later There Would Be Be Insufficient Living Insufficient Living Space & FoodSpace & Food For For EveryoneEveryone
Death Rate Will Death Rate Will Increase To Balance Increase To Balance Population sizePopulation size & & Food SupplyFood Supply
60
Population GrowthPopulation Growth Darwin Realized Darwin Realized
Malthus’s Principles Malthus’s Principles Were Visible In Were Visible In NatureNature
Plants & Animals Plants & Animals Produce Far More Produce Far More Offspring Than Can Offspring Than Can Be SupportedBe Supported– Most DieMost Die– If They Didn’t – Earth If They Didn’t – Earth
Would Be Overrun Would Be Overrun
61
Darwin’s Theory of Darwin’s Theory of EvolutionEvolution
Organisms Change Over Organisms Change Over TimeTime
62
Common Descent with Common Descent with ModificationModification
Darwin proposed Darwin proposed that organisms that organisms descended from descended from common ancestorscommon ancestors
Idea that Idea that organisms organisms change change with timewith time, , diverging from a diverging from a common formcommon form
Caused Caused evolution evolution of new speciesof new species
63.
Natural Selection Driving forceDriving force for for
evolutionevolution During the struggle During the struggle
for resources, for resources, strongest survive & strongest survive & reproducereproduce
Idea that at least Idea that at least some of the some of the differencesdifferences between between individuals, which individuals, which impact their survival impact their survival and fertility, are and fertility, are inheritableinheritable
64
Origin of SpeciesOrigin of Species
Darwin Presents His CaseDarwin Presents His Case
65
Publication of “On The Publication of “On The Origin of Species”Origin of Species”
Upon His Return To England, Upon His Return To England, Darwin Developed His Darwin Developed His Observations Into The Theory of Observations Into The Theory of EvolutionEvolution
But He But He Did Not Publish For Did Not Publish For 25 Years25 Years – –
Why?Why?
66
Publication of “On The Publication of “On The Origin of Species”Origin of Species”
Darwin Knew That His Theory Darwin Knew That His Theory Would Be Would Be Extremely Extremely ControversialControversial And Would Be And Would Be AttackedAttacked
His Theory His Theory Challenged Challenged Established Religious & Established Religious & Scientific BeliefsScientific Beliefs, Particularly , Particularly About The Creation Of ManAbout The Creation Of Man
67
Publication of “On The Publication of “On The Origin of Species”Origin of Species”
He Refused To Publish He Refused To Publish Until He Received An Essay Until He Received An Essay From From Alfred WallaceAlfred Wallace– Fellow NaturalistFellow Naturalist– Independently Developed Independently Developed
The Same TheoryThe Same Theory– After 25 Years, Someone After 25 Years, Someone
Else Had Come To The Else Had Come To The Same Conclusions From Same Conclusions From Their Observations Of Their Observations Of NatureNature
68
Wallace’s Wallace’s ContributionContribution
• Alfred Russel WallaceAlfred Russel Wallace Independently came Independently came to same Conclusion as to same Conclusion as Darwin that species Darwin that species changed over time changed over time because of their because of their struggle for existencestruggle for existence
• When Darwin read When Darwin read Wallace’s essay, Wallace’s essay, he he knew he had to knew he had to publish his findingspublish his findings
69
Publication of “On The Publication of “On The Origin of Species”Origin of Species”
Darwin Presented Wallace’s Darwin Presented Wallace’s Essay & Some Of His Work At A Essay & Some Of His Work At A Scientific Conference of the Scientific Conference of the Linnaean SocietyLinnaean Society in July of in July of 18581858
Then He Started On his book Then He Started On his book “Origin of Species”“Origin of Species”
It Took Darwin 18 Months To It Took Darwin 18 Months To Complete The BookComplete The Book
70
Natural Variation and Natural Variation and Artificial SelectionArtificial Selection
Abandoned The IdeaAbandoned The Idea That That Species Were Perfect & Species Were Perfect & UnchangingUnchanging
Observed Observed Significant Variation Significant Variation in All Speciesin All Species Observed Observed
Observed Observed Farmers Use VariationFarmers Use Variation To Improve Crops & Livestock To Improve Crops & Livestock
Called Called Selective BreedingSelective Breeding
71
Natural Variation and Natural Variation and Artificial SelectionArtificial Selection
Natural VariationNatural Variation– Differences Among Differences Among
Individuals Of A SpeciesIndividuals Of A Species Artificial SelectionArtificial Selection
– Selective Breeding To Selective Breeding To Enhance Desired Traits Enhance Desired Traits Among Stock or CropsAmong Stock or Crops
72
Natural Variation and Natural Variation and Artificial SelectionArtificial Selection
Key Concept:Key Concept:
In In Artificial SelectionArtificial Selection,, Nature Provided The Nature Provided The Variation Among Different Variation Among Different Organisms, And Humans Organisms, And Humans Selected Those Variations Selected Those Variations That They Found UsefulThat They Found Useful
73
74
Origin of SpeciesOrigin of Species
Concepts and ControversyConcepts and Controversy
75
Evolution By Natural Evolution By Natural Selection ConceptsSelection Concepts
The Struggle for ExistenceThe Struggle for Existence (compete for food, mates, space, (compete for food, mates, space, water, etc.)water, etc.)
Survival of the FittestSurvival of the Fittest (strongest (strongest able to survive and reproduce)able to survive and reproduce)
Descent with Modification Descent with Modification (new (new species arise from common species arise from common ancestor replacing less fit ancestor replacing less fit species)species)
76
Survival of the FittestSurvival of the Fittest
Fitness– Ability of an Individual To Ability of an Individual To
Survive & ReproduceSurvive & Reproduce Adaptation
– Inherited Characteristic Inherited Characteristic That Increases an That Increases an Organisms Chance for Organisms Chance for SurvivalSurvival
77
Survival of the FittestSurvival of the Fittest
Adaptations Can Be:–Physical
»Speed, Camouflage, Claws, Speed, Camouflage, Claws, Quills, etc.Quills, etc.
– BehavioralBehavioral»Solitary, Herds, Packs, Solitary, Herds, Packs, Activity, etc.Activity, etc.
78
Survival of the FittestSurvival of the Fittest
Fitness Is Central To The Is Central To The Process Of EvolutionProcess Of Evolution
Individuals With Low FitnessIndividuals With Low Fitness– DieDie– Produce Few OffspringProduce Few Offspring
Survival of the Fittest
AKA AKA Natural Selection
79
Survival of the FittestSurvival of the Fittest
Key ConceptOver Time, Natural Over Time, Natural Selection Results In Selection Results In Changes In The Inherited Changes In The Inherited Characteristics Of A Characteristics Of A Population. These Changes Population. These Changes Increase A Species Fitness Increase A Species Fitness In Its EnvironmentIn Its Environment
80
Natural SelectionNatural Selection
Cannot Be Seen DirectlyCannot Be Seen Directly It Can Only Be Observed As It Can Only Be Observed As
Changes In A Population Changes In A Population Over Many Successive Over Many Successive GenerationsGenerations– RadiationRadiation– Fossil RecordFossil Record
81
Descent With Descent With ModificationModification
Takes Place Over Takes Place Over Long Periods of Time of Time
Natural Selection Can Be Natural Selection Can Be Observed As Changes In As Changes In– Body StructuresBody Structures– Ecological NichesEcological Niches– HabitatsHabitats
82
Descent With Descent With ModificationModification
Species Species Today Look Different From Their From Their AncestorsAncestors
Each Living Species HasEach Living Species Has– DescendedDescended– With ChangesWith Changes– From Other SpeciesFrom Other Species– Over TimeOver Time
83
Descent With Descent With ModificationModification
84
Descent With Descent With ModificationModification
ImpliesImplies– All Living Organisms Are RelatedAll Living Organisms Are Related– Single Tree of LifeSingle Tree of Life
»DNA, Body Structures, Energy DNA, Body Structures, Energy SourcesSources
Common Descent– All Species, Living & Extinct, All Species, Living & Extinct,
Were Derived From Common Were Derived From Common AncestorsAncestors
85
.
Major Problem in Darwin’s Theory
• No mechanism to explain natural selection
• How could favorable variations be transmitted to later generations?
• With the rediscovery of Mendel’s work in the first half of the 20th century, the missing link in evolutionary theory was found
86
Opposition to EvolutionOpposition to Evolution
• The upheaval surrounding evolution began with Darwin’s publication of On the Origin of Species By Means of Natural Selection
• The debate continues nearly 150 years later
87
Theory of Evolution Theory of Evolution TodayToday
Supporting EvidenceSupporting Evidence
88
Homologous StructuresHomologous Structures
89
Evidence for Evolution - Comparative Embryology
Similarities In Embryonic Development
90Similarities in DNA Similarities in DNA
SequenceSequence
91
Evolution Evolution of of
pesticide pesticide resistancresistanc
e in e in response response
to to selectionselection
92
Evidence for Evolution – Evolution Observed
Evolution of drug-resistance in HIV
93
Evidence for Evolution – Evolution Observed
Selection against small guppies results in an increase in average size
94
Evolutionary Time Scales
Macroevolution: Long time Long time scale events scale events
that create and that create and destroy destroy species.species.
95
Microevolution:
Short time scale events
(generation-to-generation) that
change the genotypes and phenotypes of
populations
Evolutionary Time Scales
96
Evidence of EvolutionEvidence of EvolutionKey Concept
Darwin Argued That Living Things Darwin Argued That Living Things Have Been Evolving On Earth For Have Been Evolving On Earth For Millions of YearsMillions of Years. Evidence For This . Evidence For This Process Could Be Found In:Process Could Be Found In:
– The The Fossil RecordFossil Record– The The Geographical DistributionGeographical Distribution of of
Living SpeciesLiving Species– Homologous StructuresHomologous Structures of Living of Living
OrganismsOrganisms– Similarities In Similarities In Early DevelopmentEarly Development
97
Fossil RecordFossil Record
Earth is Earth is Billions of Years OldBillions of Years Old Fossils In Different Layers of Fossils In Different Layers of
Rock (sedimentary Rock Rock (sedimentary Rock Strata) Showed Evidence Of Strata) Showed Evidence Of Gradual Change Over TimeGradual Change Over Time
98
Geographic Distribution Geographic Distribution of Living Speciesof Living Species
Different Different Animals On Animals On Different Different Continents But Continents But Similar Similar Adaptations To Adaptations To Shared Shared EnvironmentsEnvironments
99
Homologous Body Homologous Body StructuresStructures
Scientists Noticed Animals With Scientists Noticed Animals With Backbones (Vertebrates) Had Backbones (Vertebrates) Had Similar Bone StructureSimilar Bone Structure
May May Differ In Form or FunctionDiffer In Form or Function Limb Bones Develop In Similar Limb Bones Develop In Similar
PatternsPatterns»Arms, Wings, Legs, FlippersArms, Wings, Legs, Flippers
100
Homologous Body Homologous Body StructuresStructures
Structures That Have Different Structures That Have Different Mature Forms But Develop From Mature Forms But Develop From The Same Embryonic TissuesThe Same Embryonic Tissues
Strong Evidence That Strong Evidence That All Four-All Four-Limbed Animals With Backbones Limbed Animals With Backbones Descended, With Modification, Descended, With Modification, From A From A Common AncestorCommon Ancestor
Help Scientist Group AnimalsHelp Scientist Group Animals
101
Homologous Body Homologous Body StructuresStructures
102
Homologous Body Homologous Body StructuresStructures
Not All Serve Important Not All Serve Important FunctionsFunctions– Vestigial OrgansVestigial Organs
» Appendix In ManAppendix In Man» Legs On SkinksLegs On Skinks
103
Similarities In Early Similarities In Early DevelopmentDevelopment
Embryonic Structures Of Embryonic Structures Of Different Species Show Different Species Show Significant SimilaritiesSignificant Similarities
EmbryoEmbryo – early stages of – early stages of vertebrate developmentvertebrate development
104
Human Fetus – 5 weeksHuman Fetus – 5 weeks
105
Chicken Turtle
Rat
106
ReviewReview
107
Darwin's TheoryDarwin's Theory
1.1. Individual Organisms In Individual Organisms In Nature Differ From One Nature Differ From One Another. Some Of This Another. Some Of This Variation Is InheritedVariation Is Inherited
2.2. Organisms In Nature Produce Organisms In Nature Produce More Offspring Than Can More Offspring Than Can Survive, And Many Of These Survive, And Many Of These Offspring Do No ReproduceOffspring Do No Reproduce
108
Darwin's TheoryDarwin's Theory
3.3. Because More Organisms Are Because More Organisms Are Produced Than Can Survive, Produced Than Can Survive, Members Of Each Species Members Of Each Species Must Compete For Limited Must Compete For Limited ResourcesResources
4.4. Because Each Organism Is Because Each Organism Is Unique, Each Has Different Unique, Each Has Different Advantages & Disadvantages Advantages & Disadvantages In The Struggle For ExistenceIn The Struggle For Existence
109
Darwin's TheoryDarwin's Theory
5.5. Individuals Best Suited To Their Individuals Best Suited To Their Environment Survive & Reproduce Environment Survive & Reproduce Successfully – Passing Their Traits Successfully – Passing Their Traits To Their Offspring.To Their Offspring.
6.6. Species Change Over Time. Over Species Change Over Time. Over Long Periods, Natural Selection Long Periods, Natural Selection Causes Changes That May Causes Changes That May Eventually Lead To New SpeciesEventually Lead To New Species
110
Darwin's TheoryDarwin's Theory
7.7. Species Alive Today Have Species Alive Today Have Descended With Modifications Descended With Modifications From Species That Lived In From Species That Lived In The PastThe Past
8.8. All Organisms On Earth Are All Organisms On Earth Are United Into A Single Tree Of United Into A Single Tree Of Life By Common DescentLife By Common Descent
Evolution SimulationEvolution Simulation
http://www2.edc.org/weblabs/NaturalSelection/NaturalSelectionMenu.html
111
Lamark’s explanation for the Lamark’s explanation for the modification of species modification of species
depended ondepended on
112
Inherit
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Convergent e
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The law of s
up...
Natu
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0% 0%0%0%
1.1. Inheritance of Inheritance of acquired acquired characteristicscharacteristics
2.2. Convergent Convergent evolutionevolution
3.3. The law of The law of superpositionsuperposition
4.4. Natural selectionNatural selection
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The idea that processes occurring now on The idea that processes occurring now on Earth are much the same as those that Earth are much the same as those that
occurred long ago is calledoccurred long ago is called
113
Unifo
rmita
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Relativism
Evolutionaria
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0% 0%0%0%
1.1. UniformitarianisUniformitarianismm
2.2. RelativismRelativism
3.3. EvolutionarianisEvolutionarianismm
4.4. Convergent Convergent evolutionevolution
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The observation that organisms The observation that organisms arise in locations where similar, arise in locations where similar,
extinct organisms lived is extinct organisms lived is calledcalled
114 Su
perpositi
on
Biogeography
Unifo
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rian...
evolution
0% 0%0%0%
1.1. SuperpositionSuperposition
2.2. BiogeographyBiogeography
3.3. UniformitarianisUniformitarianismm
4.4. evolutionevolution
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The similarities in the The similarities in the Galapagos finches impliedGalapagos finches implied
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Coevolution
Convergent e
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Adaptive ra
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Desce
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0% 0%0%0%
1.1. CoevolutionCoevolution
2.2. Convergent Convergent evolutionevolution
3.3. Adaptive Adaptive radiationradiation
4.4. Descent from Descent from different remote different remote ancestorsancestors
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21 22 23 24 25 26 27 28 29 30
Difference in reproductive Difference in reproductive success issuccess is
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An acquire
d tr...
Adaptive ra
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Coevolution
0% 0%0%0%
1.1. An acquired An acquired traittrait
2.2. Adaptive Adaptive radiationradiation
3.3. Natural Natural selectionselection
4.4. Coevolution Coevolution
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Great similarity between Great similarity between species impliesspecies implies
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Recent c
ommon ...
Remote co
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Succe
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Extincti
on
0% 0%0%0%
20
1.1. Recent common Recent common ancestryancestry
2.2. Remote Remote common common ancestryancestry
3.3. Successful Successful reproductionreproduction
4.4. Extinction Extinction 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
Features that were useful in Features that were useful in ancestors but are no longer ancestors but are no longer
useful are calleduseful are called
118
Analogous feat..
.
Homologo
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20
1.1. Analogous Analogous featuresfeatures
2.2. Homologous Homologous featuresfeatures
3.3. Unexpressed Unexpressed genesgenes
4.4. Vestigial Vestigial featuresfeatures
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
Similar features in different Similar features in different species that originated in a species that originated in a shared ancestor are calledshared ancestor are called
119
Vestigial
feat..
.
Analogous feat..
.
Homologo
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20
1.1. Vestigial featuresVestigial features
2.2. Analogous Analogous featuresfeatures
3.3. Homologous Homologous featuresfeatures
4.4. Unexpressed Unexpressed genesgenes
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
A humming bird and a humming moth have a A humming bird and a humming moth have a number of superficial features in common with number of superficial features in common with
each other. This is an example ofeach other. This is an example of
120
Dive
rgent e
vol...
Coevolution
Convergent e
vo...
Superp
osition
0% 0%0%0%
20
1.1. Divergent Divergent evolutionevolution
2.2. CoevolutionCoevolution
3.3. Convergent Convergent evolutionevolution
4.4. Superposition Superposition
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