ch. 15 the theory of evolution unit 4 :. evolution chapter 15 diversity of life
TRANSCRIPT
Ch. 15 The Theory of Ch. 15 The Theory of EvolutionEvolution
Unit 4Unit 4::
EvolutionChapter 15
Diversity of Life
““Nothing in Nothing in biology makes biology makes
sense EXCEPT in sense EXCEPT in the light of the light of evolution.” evolution.” Theodosius Theodosius DobzhanskyDobzhansky
Charles Darwin in later Charles Darwin in later yearsyears
History of History of
Evolutionary Evolutionary
ThoughtThought
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 complexity.complexity.
Idea Idea lasted lasted 20002000 years. years.
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 . .
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 for struggle for existence (resources).existence (resources).
Contributor’s to Darwin’s Contributor’s to Darwin’s thinking included:thinking included:
• James Hutton - James Hutton - GradualismGradualism• John Baptiste Lamarck – John Baptiste Lamarck –
Inheritance of acquired Inheritance of acquired CharacteristicsCharacteristics andand Law of Use Law of Use and Disuse.and Disuse.
• Alfred Russel Wallace – Alfred Russel Wallace – organisms evolved from common organisms evolved from common ancestors.ancestors.
CatastrophismCatastrophism
Idea proposed by Idea proposed by George CuvierGeorge CuvierStudied fossil in Studied fossil in sedimentary sedimentary
rock stratarock strata of Paris of ParisFound Found some species completely some species completely
disappeareddisappeared in more recent in more recent layerslayers
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…)
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 ForcesGeological Forces That Have Changed That Have Changed LifeLife on Earthon Earth Over Millions of Years (erosion, Over Millions of Years (erosion, earthquakes, volcanoes…)earthquakes, volcanoes…)
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
Charles LyellCharles Lyell
Proposed theory of Proposed theory of UniformintarianismUniformintarianism
Geological processes Geological processes at at uniform ratesuniform rates building & wearing building & wearing down Earth’s crustdown Earth’s crust
Proposed that the Proposed that the Earth was millions of Earth was millions of yearsyears instead of a instead of a few thousand years few thousand years oldold
Principles of GeologyPrinciples of Geology
Published by Published by LyellLyell Just Before The Just Before The BeagleBeagle Set Sail & read by Darwin Set Sail & read by Darwin
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 At Shells In The Andes Mountains At 12,000+ Feet12,000+ Feet
Expanded Earth’s AgeExpanded Earth’s Age
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 Stated that Changes Are Adaptations To Are Adaptations To Environment Environment acquired acquired in an organism’s in an organism’s lifetimelifetime
Said acquired changes Said acquired changes were passed to were passed to offspringoffspring
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Idea called Idea called Law Law of Use and of Use and DisuseDisuse
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
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Inheritance of Acquired Inheritance of Acquired CharacteristicsCharacteristics
Proposed That By Selective Use Or Proposed That By Selective Use Or Disuse Of Organs, Organisms 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
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 Shape Of Organs By Using Them Or By Using Them Or Not Using ThemNot Using Them
Blacksmiths & Blacksmiths & Their SonsTheir Sons (muscular arms)(muscular arms)
Giraffe’s Necks Giraffe’s Necks LongerLonger from from stretching)stretching)
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Inheritance Of Acquired TraitsInheritance Of Acquired TraitsTraits Acquired During Ones Lifetime Traits Acquired During Ones Lifetime
Would Be Passed To OffspringWould Be Passed To Offspring
Clipped ears of dogs could be passed to Clipped ears of dogs could be passed to offspring.offspring.
Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution
Tendency Toward PerfectionTendency Toward PerfectionOrganisms Are Continually Organisms Are Continually
Changing and Acquiring Features Changing and Acquiring Features That Help Them Live More That Help Them Live More Successfully In Their Successfully In Their EnvironmentEnvironment
Example:Example: Bird Ancestors Desired Bird Ancestors Desired To Fly So They Tried Until Wings To Fly So They Tried Until Wings DevelopedDeveloped
Lamarck’s MistakesLamarck’s Mistakes
Lamarck Did NOT Know how Lamarck Did NOT Know how traits were traits were inherited (Traits are inherited (Traits are passed through genes)passed through genes)
Genes Are NOT Changed By Genes Are NOT Changed By Activities In LifeActivities In Life
Change Through Change Through Mutation Occurs Mutation Occurs Before An Organism Is BornBefore An Organism Is Born
Charles Darwin the Charles Darwin the NaturalistNaturalist
Voyage of the BeagleVoyage of the Beagle
Charles DarwinCharles Darwin Born Feb. 12, 1809.Born Feb. 12, 1809. Joined Crew of HMS Joined Crew of HMS
Beagle, 1831.Beagle, 1831. NaturalistNaturalist 5 Year Voyage around 5 Year Voyage around
world.world. Avid Collector of Flora Avid Collector of Flora
& Fauna.& Fauna. Astounded By Variety Astounded By Variety
of Life.of Life.
Darwin’s Voyage of Darwin’s Voyage of DiscoveryDiscovery
A reconstruction of the HMS Beagle A reconstruction of the HMS Beagle sailing off Patagonia.sailing off Patagonia.
Darwin Left England in Darwin Left England in 18311831
Darwin returned 5 years later in Darwin returned 5 years later in 18361836
HMS Beagle’s VoyageHMS Beagle’s Voyage
The Galapagos IslandsThe Galapagos Islands
Small Group of Islands Small Group of Islands 1000 km West of South 1000 km West of South AmericaAmerica
Very Different ClimatesVery Different ClimatesAnimals On Islands Animals On Islands
UniqueUniqueTortoisesTortoisesIguanasIguanasFinchesFinches
The Galapagos IslandsThe Galapagos Islands
Volcanic islandsVolcanic islands off off the coast of South the coast of South AmericaAmerica
Island species varied Island species varied from mainland from mainland species & from species & from island-to-island island-to-island speciesspecies
Each island had long Each island had long or short neck or short neck tortoisestortoises
The Galapagos IslandsThe Galapagos Islands
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 food where the available food was different (seeds, nuts, berries, was different (seeds, nuts, berries, insects…)insects…)
Finches had Finches had different types of beaksdifferent types of beaks adapted to their adapted to their type of food type of food gatheringgathering
Darwin’s Observations & Darwin’s Observations & ConclusionsConclusions
The Struggle for The Struggle for ExistenceExistence
Voyage of the BeagleVoyage of the Beagle
During His Travels, Darwin Made During His Travels, Darwin Made Numerous Observations And Numerous Observations And Collected Evidence That Led Him Collected Evidence That Led Him To Propose A To Propose A Revolutionary Revolutionary HypothesisHypothesis About The Way Life About The Way Life Changes Over TimeChanges Over Time
Darwin’s ObservationsDarwin’s Observations
Patterns of Patterns of Diversity were Diversity were shownshown
Unique Adaptations Unique Adaptations in organismsin organisms
Species Not Evenly Species Not Evenly DistributedDistributed
Australia, Australia, Kangaroos, but No Kangaroos, but No RabbitsRabbits
S. America, S. America, LlamasLlamas
Darwin’s ObservationsDarwin’s Observations
Both Living Organisms & Both Living Organisms & Fossils collectedFossils collected
Fossils included:Fossils included:TrilobitesTrilobitesGiant Ground Sloth of Giant Ground Sloth of South AmericaSouth America
This species NO longer existed.This species NO longer existed. What had happened to them?What had happened to them?
Evidence for Evolution – Evidence for Evolution – The Fossil RecordThe Fossil Record
DefinitionDefinition
Evolution is the slow , gradual change in a population of organisms over time
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.
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.
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.
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.
Darwin’s Darwin’s Theory of Theory of EvolutionEvolution
• The The unequal ability of individuals to unequal ability of individuals to survive and reproducesurvive and reproduce leads to a gradual leads to a gradual change in a population, with favorable change in a population, with favorable characteristics accumulating over characteristics accumulating over generations generations (natural selection)(natural selection)
• New species evolveNew species evolve
Darwin’s Theory of Darwin’s Theory of EvolutionEvolution
Organisms Organisms Change Over Change Over
TimeTime
Common Descent with Common Descent with ModificationModification
Darwin proposed Darwin proposed that organisms that organisms descended from descended from common ancestors.common ancestors.
Idea that organisms Idea that organisms change with timechange with time, , diverging from a diverging from a common form.common form.
Caused Caused evolution of evolution of new speciesnew species . .
Natural Selection
Driving forceDriving force for for evolutionevolution
During the struggle for During the struggle for resources, resources, strongest strongest survive & reproducesurvive & reproduce
Idea that at least Idea that at least some some of the differencesof the differences between individuals, between individuals, which impact their which impact their survival and fertility, survival and fertility, are are inheritableinheritable
Origin of SpeciesOrigin of Species
Darwin Presents His CaseDarwin Presents His Case
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 Observations Darwin Developed His Observations Into The Theory of EvolutionInto The Theory of Evolution
But He But He Did Not Publish For 25 Did Not Publish For 25 YearsYears – –
Why?Why?
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 & Scientific Established Religious & Scientific BeliefsBeliefs, Particularly About The , Particularly About The Creation Of ManCreation Of Man
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 Until He Received An Essay From Essay From Alfred WallaceAlfred WallaceFellow NaturalistFellow NaturalistIndependently Independently
Developed The Same Developed The Same TheoryTheory
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
Wallace’s ContributionWallace’s Contribution
• Alfred Russel WallaceAlfred Russel Wallace Independently came Independently came to same Conclusion to same Conclusion as Darwin that as Darwin that species changed over species changed over time because of their time because of their struggle for struggle for existenceexistence
• 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
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
Natural Variation and Natural Variation and Artificial SelectionArtificial Selection
Abandoned The IdeaAbandoned The Idea That Species That Species Were Perfect & UnchangingWere Perfect & Unchanging
Observed Observed Significant Variation in Significant Variation in All SpeciesAll Species Observed Observed
Observed Observed Farmers Use VariationFarmers Use Variation To Improve Crops & Livestock To Improve Crops & Livestock
Called Called Selective BreedingSelective Breeding
Natural Variation and Natural Variation and Artificial SelectionArtificial Selection
Natural VariationNatural VariationDifferences Among Individuals Differences Among Individuals
Of A SpeciesOf A SpeciesArtificial SelectionArtificial Selection
Selective Breeding To Enhance Selective Breeding To Enhance Desired Traits Among Stock or Desired Traits Among Stock or CropsCrops
Natural Variation and Natural Variation and Artificial SelectionArtificial Selection
Key Concept:Key Concept:
In In Artificial SelectionArtificial Selection,, Nature Nature Provided The Variation Provided The Variation Among Different Among Different Organisms, And Humans Organisms, And Humans Selected Those Variations Selected Those Variations That They Found UsefulThat They Found Useful
Origin of SpeciesOrigin of Species
Concepts and Concepts and ControversyControversy
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)
Survival of the FittestSurvival of the Fittest
Fitness Ability of an Individual To Ability of an Individual To
Survive & ReproduceSurvive & Reproduce Adaptation
Inherited Characteristic That Inherited Characteristic That Increases an Organisms Increases an Organisms Chance for SurvivalChance for Survival
Survival of the FittestSurvival of the Fittest
Adaptations Can Be:Physical
Speed, Camouflage, Claws, Speed, Camouflage, Claws, Quills, etc.Quills, etc.
BehavioralBehavioralSolitary, Herds, Packs, Solitary, Herds, Packs, Activity, etc.Activity, etc.
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 FitnessDieDieProduce Few OffspringProduce Few Offspring
Survival of the Fittest
AKA AKA Natural Selection
Survival of the FittestSurvival of the Fittest
Key ConceptOver Time, Natural Selection Over Time, Natural Selection Results In Changes In The Results In Changes In The Inherited Characteristics Of Inherited Characteristics Of A Population. These A Population. These Changes Increase A Species Changes Increase A Species Fitness In Its EnvironmentFitness In Its Environment
Natural SelectionNatural Selection
Descent With ModificationDescent With Modification
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 InBody StructuresBody StructuresEcological NichesEcological NichesHabitatsHabitats
Descent With ModificationDescent With Modification
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 InBody StructuresBody StructuresEcological NichesEcological NichesHabitatsHabitats
Descent With ModificationDescent With Modification
Descent With ModificationDescent With Modification
ImpliesImpliesAll Living Organisms Are RelatedAll Living Organisms Are RelatedSingle Tree of LifeSingle Tree of Life
DNA, Body Structures, Energy DNA, Body Structures, Energy SourcesSources
Common DescentAll Species, Living & Extinct, All Species, Living & Extinct,
Were Derived From Common Were Derived From Common AncestorsAncestors
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
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
I. Work of Charles DarwinI. Work of Charles DarwinA. A. Charles DarwinCharles Darwin gave us the gave us the
Theory of Evolution.Theory of Evolution.B. Theory of Evolution from study on B. Theory of Evolution from study on
Galapagos IslandsGalapagos Islands1. Nature uses 1. Nature uses natural selectionnatural selection = only = only
the strong survive.the strong survive.2. The 2. The allelesalleles that increase survival rate that increase survival rate
become become dominant.dominant.3. 3. Artificial SelectionArtificial Selection = nature allows for = nature allows for
the weak to die before breeding, leading the weak to die before breeding, leading to the stronger mating cause specific to the stronger mating cause specific traits to show.traits to show.
II. Evidence Darwin says Proves II. Evidence Darwin says Proves EvolutionEvolution
A. Camouflage = insects that blend A. Camouflage = insects that blend in with environment escape in with environment escape predators; increase survival.predators; increase survival.
B. Mimicry = insects that look similar B. Mimicry = insects that look similar to other insects that birds will not to other insects that birds will not eat; these genes increase survival eat; these genes increase survival rate rate Ex: viceroy butterfly and Monarch Ex: viceroy butterfly and Monarch
butterfly. Monarch favorite food of birdsbutterfly. Monarch favorite food of birds
C. Embryo of fish, reptile, bird, C. Embryo of fish, reptile, bird, mammal look very much alike in mammal look very much alike in beginning all have gill slits and tailsbeginning all have gill slits and tails
D. Vestigial Structure = have an D. Vestigial Structure = have an organ but has no function for organ but has no function for organism.organism.Ex: appendix of manEx: appendix of man
E. Biochemistry = DNA of different E. Biochemistry = DNA of different species is very similar.species is very similar.
F. Homologous structures = bones of F. Homologous structures = bones of various animals have the same various animals have the same pattern and similar functions (see pg. pattern and similar functions (see pg. _____)_____)
(Homologous Structures)(Homologous Structures)
G. Analogous structures = structures G. Analogous structures = structures are similar in function but the are similar in function but the materials of the structures are materials of the structures are differentdifferentEx: bird’s wing to butterfly wingEx: bird’s wing to butterfly wing
H. Fossils show a change in a specific H. Fossils show a change in a specific animal’s structureanimal’s structure
I. Today we see evolution in bacteria I. Today we see evolution in bacteria – penicillin is not effective on new – penicillin is not effective on new strands of bacteria (evolution strands of bacteria (evolution happened)happened)
(Analogous Structures)(Analogous Structures)
Homologous vs AnalogousHomologous vs Analogous
II.II. Evidence of Evolution.Evidence of Evolution.(Biochemical)(Biochemical)
Comparing genetic informationComparing genetic information (the sequence of amino acids)(the sequence of amino acids)DNA Fingerprinting (gel DNA Fingerprinting (gel
electrophoresis)electrophoresis)
Ex. Ex. Hemoglobin Hemoglobin (red blood cell (red blood cell protein)protein)The amino acid sequence for this The amino acid sequence for this protein in humans is almost identical protein in humans is almost identical to the sequence in gorillas. Differ by to the sequence in gorillas. Differ by one amino acid. In frogs, it differs by one amino acid. In frogs, it differs by 67 amino acids. So, humans and 67 amino acids. So, humans and gorillas shared a common ancestor gorillas shared a common ancestor more recently than humans and more recently than humans and frogs.frogs.